Association between the serum zinc level and nutritional status represented by the geriatric nutritional Rrisk index

BACKGROUND

Although it is widely known that patients with chronic kidney disease (CKD) can develop zinc deficiency, in our previous analysis, the estimated glomerular filtration rate (eGFR) was not independently associated with the serum zinc level. Thus, a post hoc analysis was conducted to investigate the involvement of nutritional status.

METHODS

A total of 655 subjects not on dialysis (402 males; mean age, 57 ± 18 years) who underwent serum zinc level measurements at Jikei University Hospital between April 2018 and March 2019 were selected using the Standardized Structured Medical Information eXchange2 (SS-MIX2) system. In addition, anthropometric data and the Geriatric Nutritional Risk Index (GNRI) representing nutritional status were obtained, and the relationship between the serum zinc level and nutritional status was investigated by multiple regression analysis.

RESULTS

The serum albumin level and the GNRI were lower in the zinc-deficiency group, and both were positively associated with the serum zinc level (rho = 0.44, P < 0.01 and rho = 0.44, P < 0.01, respectively). On multiple regression analysis, the GNRI (t = 3.09, P < 0.01) and serum albumin level (t = 4.75, P < 0.01) were independently associated with the serum zinc level. Although a higher eGFR was associated with a higher serum zinc level, this association disappeared on multivariate analysis.

CONCLUSION

In this post hoc analysis, the GNRI, as well as the serum albumin level, were correlated with the serum zinc level, indicating that nutritional status is an important determinant of the zinc level. Further investigations are needed to clarify the effects of nutritional status and kidney function on zinc deficiency.

The relation between proteinuria and the severity of COVID-19

BACKGROUND

The association between proteinuria, which is also an indicator of chronic kidney disease (CKD), and coronavirus disease 2019 (COVID-19) severity is unclear.

METHODS

We selected 342 hospitalized patients with COVID-19 diagnosed via polymerase chain reaction testing between February 2020 and October 2022 and who had at least one urinalysis 14-365 days before admission.

RESULTS

Proteinuria before admission was associated neither with oxygen administration nor developing pneumonia in multivariate analysis (odds ratio [OR] 1.03; 95% confidence interval (CI) 0.44-2.40, p = 0.95 and OR 1.01; 95% CI 0.47-2.17, p = 0.98, respectively). Proteinuria on admission was associated both with oxygen administration and developing pneumonia in multivariate analysis (OR 3.29; 95% CI 1.37-7.88, p < 0.01 and OR 3.81; 95% CI 1.68-8.62, p < 0.01, respectively). The percentage of patients with proteinuria on admission was significantly higher than those before admission (37.4% vs. 17.8%; p < 0.01). In the subgroup analysis, proteinuria on admission among patients with eGFR ≥ 60 mL/min/1.73 m2 was associated with both oxygen administration and developing pneumonia (OR 4.86; 95% CI 1.22-19.38, p = 0.03, OR 3.65; 95% CI 1.06-12.58, p = 0.04, respectively). In contrast, proteinuria on admission among patients with eGFR < 60 mL/min/1.73 m2 was associated with developing pneumonia (OR 6.45; 95%CI 1.78-23.35, p = 0.01), not with oxygen administration (OR 3.28; 95% CI 0.92-11.72, p = 0.07).

CONCLUSIONS

Although underlying proteinuria before admission was not associated with COVID-19 severity, proteinuria on admission was associated with oxygen demand and developing pneumonia.

Role of cystatin C in the detection of sight-threatening diabetic retinopathy in Asian Indians with type 2 diabetes

AIM

To study the association between cystatin C and sight-threatening diabetic retinopathy (STDR) in Asian Indians with type 2 diabetes (T2DM).

METHODS

In a cross-sectional study carried out at two tertiary centres in India in 2022, individuals with T2DM underwent clinical and ophthalmic assessments and estimation of serum cystatin C. Grading of DR was done by retina specialists. STDR was defined by the presence of severe non-proliferative DR (NPDR), proliferative DR (PDR) and/or diabetic macular edema. Receiver operating characteristic (ROC) curves were used to identify cystatin C cut-off value for detecting STDR.

RESULTS

Among 420 individuals with T2DM (mean age 56 ± 9 years; mean duration of diabetes 14.5 ± 7.9 years), 121 (24.1 %) had No-DR, 119 (28.3 %) had No-STDR and 200 (49.6 %) had STDR. Mean cystatin C level was significantly higher in individuals with STDR compared to those with no-STDR and No-DR (1.34 vs 1.06 vs 0.93 mg/L, p < 0.001). Cystatin C cut-off value ≥1.11 mg/L had a C statistic of 0.944 (95 % CI: 0.909-0.968, p < 0.001), 96.8 % sensitivity and 78.2 % specificity for detection of STDR.

CONCLUSION

Elevated serum cystatin C was strongly associated with STDR and could possibly be used as a biomarker for screening for sight-threatening diabetic retinopathy.

Update of dialysis initiation timing in end stage kidney disease patients: is it a resolved question? A systematic literature review

BACKGROUND

The exact optimal timing of dialysis for ESKD patients remains unknown. This study systematically reviewed the available evidence with regard to the optimal initiation of maintenance dialysis in ESKD patients.

METHODS

An electronic search was performed in Embase, PubMed and the Cochrane Library in order to find studies investigating associations between variables reference to "start of dialysis" and outcomes. Quality assessment and bias assessment were performed by the Newcastle-Ottawa scale and the ROBINSI tool. Due to the heterogeneity of studies, a meta-analysis could not be performed.

RESULTS

Thirteen studies were included; four studies included only haemodialysis patients, three peritoneal dialysis, six both; study outcomes included mortality, cardiovascular events, technique failure, quality of life and others. Nine studies mainly focused on the optimal GFR of maintenance dialysis initiation; five studies showed none association between GFR and mortality or other adverse outcomes, two studies showed dialysis initiation at higher GFR levels were with poor prognosis, and 2 studies showed higher GFR levels with better prognosis. Three studies paid attention to comprehensive assessment of uremic signs and/or symptoms for optimal dialysis initiation; uremic burden based on 7 uremic indicators (hemoglobin, serum albumin, blood urea nitrogen, serum creatinine, potassium, phosphorus, and bicarbonate) were not associated with mortality; another equation (combination of sex, age, serum creatinine, blood urea nitrogen, serum albumin, haemoglobin, serum phosphorus, diabetes mellitus, and heart failure) based on fuzzy mathematics to assess the timing of haemodialysis initiation was accuracy to prognose 3-year survival; the third study found that volume overload or hypertension was associated with the highest risk for subsequent mortality. Two studies compared urgent or optimal start in dialysis, a study reported increased survival in optimal start patients, another reported no differences between Urgent-Start-PD and Early-Start-PD regarding 6-month outcomes.

LIMITATIONS

Heterogeneity among the studies was quite high, with differences in sample size, variable and group characteristics; no RCT studies were included, which weakened the strength of evidences.

CONCLUSIONS

The criteria for dialysis initiation were varied. Most studies proved that GFR at dialysis initiation was not associated with mortality, timing of dialysis initiation should not be based on GFR, assessments of volume load and patient's tolerance to volume overload are prospective approaches.

Monoclonal Gammopathy of Undetermined Significance in Patients With Transthyretin Amyloidosis (ATTR): Analysis Using the iStopMM Criteria

INTRODUCTION

To identify the prevalence of monoclonal gammopathy of undetermined significance (MGUS) in patients with transthyretin amyloid (ATTR). We used the iStopMM study revised reference ranges for serum free light-chain (sFLC) corrected for eGFR to identify ATTR patients with light-chain MGUS (LC-MGUS). Characteristics and frequencies of the ATTR cohort with underlying MGUS was compared to a cohort of MGUS patients without ATTR.

PATIENTS AND METHODS

A retrospective analysis of ATTR and MGUS patients evaluated at our center between January 2014 to December 2021. A total of 149, predominantly male (87.5%) ATTR patients with a median age of 82 were included. This cohort was compared to 228 MGUS patients.

RESULTS

Of the 149 ATTR patients, 27 (18.1%) had coexisting MGUS. Among ATTR patients with MGUS, 12/27 (44%) had LC-MGUS based on sFLC abnormalities assessed using the iStopMM reference ranges. Of the MGUS only cohort, 44/228 (19.3%) met criteria for LC-MGUS. Utilizing the iStopMM reference ranges, 6 ATTR patients did not meet criteria for abnormal sFLCs, uncovering a 20% false-positive rate.

CONCLUSION

We noted higher rates of MGUS, particularly LC-MGUS, among ATTR patients when compared to our MGUS only cohort. The high prevalence remained after utilizing the iStopMM sFLC corrected for eGFR reference ranges. Additionally, 6 ATTR patients with renal-dysfunction would have met MGUS criteria if not evaluated using the iStopMM revised measures. These findings emphasize careful interpretation of sFLC abnormalities and encourage providers to keep ATTR on the differential when work-up uncovers sFLC aberrations.

Association of the estimated glomerular filtration rate (eGFR) and/or proteinuria to predict the risk of initiation of dialysis in people with and without diabetes

Aims

To determine the associations between combined urinary protein (UP) and a reduced estimated glomerular filtration rate (eGFR) and the risk of starting dialysis with or without diabetes mellitus (DM).

Methods

A nationwide database with claims data on 335,778 people with and without DM aged 19-72 years in Japan was used to elucidate the impact of the severities of UP and eGFR on starting dialysis. Initiation of dialysis was determined from claims using ICD-10 codes and medical procedures. Using multivariate Cox modeling, we investigated the severities of UP and eGFR to predict the initiation of dialysis with and without DM.

Results

Both eGFR < 60 and UP(+) were independent predictors for starting dialysis with and without DM, and their values exhibited a synergistic risk of dialysis. eGFR < 60 presented a nearly twofold risk for starting dialysis compared to UP(+) regardless of DM. Risk of starting dialysis was increased with UP(+) and eGFR ≥ 60 accompanied by DM although this association was not observed without DM. Those who had UP(-) and eGFR < 60 had a high risk of starting dialysis regardless of DM. Compared with DM(-)UP(-)eGFR ≥ 60, HRs for starting dialysis for DM(+)UP(+)eGFR ≥ 60, DM(+)UP(-)eGFR < 60 and DM(+)UP(+)eGFR < 60 significantly increased 17.7 (10.6-29.7), 25.5 (13.8-47.1) and 358.1 (239.1-536.5) times, respectively.

Conclusions

eGFR < 60 and UP(+) together presented an extremely high risk of dialysis especially with DM. UP( +) increased the risk of starting dialysis regardless of the eGFR with DM. Both patient education and a treatment strategy by physicians might be helpful to avoid the progression of renal failure.

Body fluid regulation via chronic inhibition of sodium-glucose cotransporter-2 in patients with heart failure: a post hoc analysis of the CANDLE trial

BACKGROUND

In patients with chronic heart failure (CHF) and type 2 diabetes (T2D), sodium-glucose cotransporter-2 (SGLT2) inhibition improves cardiorenal outcomes, but details of the effects on distinct subsets of body fluid volume remain incomplete.

METHODS

This was a post hoc analysis of patients with CHF and T2D in the CANDLE trial (UMIN000017669), an investigator-initiated, multi-center, randomized open-label trial that compared the effect of canagliflozin (100 mg, n = 113) with glimepiride (starting dose: 0.5 mg, n = 120) on changes in N-terminal pro-brain natriuretic peptide. The estimated plasma volume (ePV, calculated with the Straus formula) and estimated extracellular volume (eEV, determined by the body surface area) were compared between treatment groups at weeks 4, 12, and 24.

RESULTS

Among 233 patients analyzed, 166 (71.2%) had an ejection fraction (EF) > 50%. Reductions in ePV and eEV were observed only in the canagliflozin group until week 12 (change from baseline at week 12, ePV; - 7.63%; 95% confidence interval [CI], - 10.71 to - 4.55%, p < 0.001, eEV; - 123.15 mL; 95% CI, - 190.38 to - 55.92 mL, p < 0.001). While ePV stopped falling after week 12, eEV continued to fall until week 24 ([change from baseline at week 24] - [change from baseline at week 12], ePV; 1.01%; 95%CI, - 2.30-4.32%, p = 0.549, eEV; - 125.15 mL; 95% CI, - 184.35 to - 65.95 mL, p < 0.001).

CONCLUSIONS

Maintenance of a modest reduction in ePV and continuous removal of eEV via chronic SGLT2 inhibition suggests that favorable body fluid regulation contributes to the cardiorenal benefits of SGLT2 inhibitors in patients with CHF, irrespective of EF.

TRIAL REGISTRATION

UMIN000017669.

Relationship between metformin use and lactic acidosis in advanced chronic kidney disease: The REMIND-TMU study

BACKGROUND

Evidence of metformin-associated lactic acidosis (MALA) in advanced chronic kidney disease (CKD) has been limited due to high mortality rate but rare incidence rate. The mechanism of increased MALA in advanced CKD is mainly based on the hypothesis of decreased drug elimination, which might also be confounded by increased comorbidities as CKD progresses. The goal of the study is to analyze the incidence and associated factors of lactic acidosis between metformin user and non-user with advanced CKD.

METHODS

This study used a three million population-based, propensity score-matched cohort from 2008 to 2016. The primary outcome was laboratory-defined lactic acidosis. Relationships between the probability of lactic acidosis and various estimated glomerular filtration rate (eGFR) values in advanced CKD patients were also presented in regression analysis.

RESULTS

Adults with type 2 diabetes whose eGFR was <30 mL/min/1.73 m² were enrolled in this study. After the process of propensity score matching, 7707 patients were divided into metformin and non-metformin groups. In linear regression model, metformin significantly increased the risk of lactic acidosis (p=0.0204) as the eGFR declined in advanced CKD over a mean follow up of over 600 days even after confounder adjustment with age, sex and comorbidities.

CONCLUSIONS

Metformin was associated with a significant increased risk of laboratory-defined lactic acidosis (p=0.0204) even after adjusting confounder such as age, sex and underlying comorbidities. This "REMIND" study reminds us that metformin-associated lactic acidosis is mainly caused by decreased drug renal elimination other than underlying comorbidities in advanced CKD patients.

Polygenic association of glomerular filtration rate decline in world trade center responders

BACKGROUND

The factors associated with estimated glomerular filtrate rate (eGFR) decline in low risk adults remain relatively unknown. We hypothesized that a polygenic risk score (PRS) will be associated with eGFR decline.

METHODS

We analyzed genetic data from 1,601 adult participants with European ancestry in the World Trade Center Health Program (baseline age 49.68 ± 8.79 years, 93% male, 23% hypertensive, 7% diabetic and 1% with cardiovascular disease) with ≥ three serial measures of serum creatinine. PRSs were calculated from an aggregation of single nucleotide polymorphisms (SNPs) from a recent, large-scale genome-wide association study (GWAS) of rapid eGFR decline. Generalized linear models were used to evaluate the association of PRS with renal outcomes: baseline eGFR and CKD stage, rate of change in eGFR, stable versus declining eGFR over a 3-5-year observation period. eGFR decline was defined in separate analyses as "clinical" (> -1.0 ml/min/1.73 m2/year) or "empirical" (lower most quartile of eGFR slopes).

RESULTS

The mean baseline eGFR was ~ 86 ml/min/1.73 m2. Subjects with decline in eGFR were more likely to be diabetic. PRS was significantly associated with lower baseline eGFR (B = -0.96, p = 0.002), higher CKD stage (OR = 1.17, p = 0.010), decline in eGFR (OR = 1.14, p = 0.036) relative to stable eGFR, and the lower quartile of eGFR slopes (OR = 1.21, p = 0.008), after adjusting for established risk factors for CKD.

CONCLUSION

Common genetic variants are associated with eGFR decline in middle-aged adults with relatively low comorbidity burdens.

The correlation study on chest CT features and kidney injury in severe COVID-19 pneumonia from a multicenter cohort study

BACKGROUND

Among confirmed severe COVID-19 patients, although the serum creatinine level is normal, they also have developed kidney injury. Early detection of kidney injury can guide doctors to choose drugs reasonably. Study found that COVID-19 have some special chest CT features. The study aimed to explore which chest CT features are more likely appear in severe COVID-19 and the relationship between related (special) chest CT features and kidney injury or clinical prognosis.

METHODS

In this retrospective study, 162 patients of severe COVID-19 from 13 medical centers in China were enrolled and divided into three groups according to the estimated glomerular filtration rate (eGFR) level: Group A (eGFR < 60 ml/min/1.73 m²), Group B (60 ml/min/1.73 m² ≤ eGFR < 90 ml/min/1.73 m²), and Group C (eGFR ≥ 90 ml/min/1.73 m²). The demographics, clinical features, auxiliary examination, and clinical prognosis were collected and compared. The chest CT features and eGFR were assessed using univariate and multivariate Cox regression. The influence of chest CT features on eGFR and clinical prognosis were calculated using the Cox proportional hazards regression model.

RESULTS

Demographic and clinical features showed significant differences in age, hypertension, and fatigue among the Group A, Group B, and Group C (all P < 0.05). Auxiliary examination results revealed that leukocyte count, platelet count, C-reactive protein, aspartate aminotransferase, creatine kinase, respiratory rate ≥ 30 breaths/min, and CT images rapid progression (>50%) within 24-48 h among the three groups were significantly different (all P < 0.05). Compared to Group C (all P < 0.017), Groups A and B were more likely to show crazy-paving pattern. Logistic regression analysis indicated that eGFR was an independent risk factor of the appearance of crazy-paving pattern. The eGFR and crazy-paving pattern have a mutually reinforcing relationship, and eGFR (HR = 0.549, 95% CI = 0.331-0.909, P = 0.020) and crazy-paving pattern (HR = 2.996, 95% CI = 1.010-8.714, P = 0.048) were independent risk factors of mortality. The mortality of severe COVID-19 with the appearance of crazy-paving pattern on chest CT was significantly higher than that of the patients without its appearance (all P < 0.05).

CONCLUSIONS

The crazy-paving pattern is more likely to appear in the chest CT of patients with severe COVID-19. In severe COVID-19, the appearance of the crazy-paving pattern on chest CT indicates the occurrence of kidney injury and proneness to death. The crazy-paving pattern can be used by doctors as an early warning indicator and a guidance of reasonable drug selection.

Changes in glomerular filtration rate and metabolomic differences in severely ill coronavirus disease survivors 3 months after discharge

To explore the recovery of renal function in severely ill coronavirus disease (COVID-19) survivors and determine the plasma metabolomic profile of patients with different renal outcomes 3 months after discharge, we included 89 severe COVID-19 survivors who had been discharged from Wuhan Union Hospital for 3 months. All patients had no underlying kidney disease before admission. At patient recruitment, renal function assessment, laboratory examination, chest computed tomography (CT) were performed. Liquid chromatography-mass spectrometry was used to detect metabolites in the plasma. We analyzed the longitudinally change in the estimated glomerular filtration rate (eGFR) based on serum creatinine and cystatin-c levels using the CKD-EPI equation and explored the metabolomic differences in patients with different eGFR change patterns from hospitalization to 3 months after discharge. Lung CT showed good recovery; however, the median eGFR significantly decreased at the 3-month follow-up. Among the 89 severely ill COVID-19 patients, 69 (77.5%) showed abnormal eGFR (<90 mL/min per 1.73 m²) at 3 months after discharge. Age (odds ratio [OR] = 1.26, 95% confidence interval [CI] = 1.08-1.47, p = 0.003), body mass index (OR = 1.97, 95% CI = 1.20-3.22, p = 0.007), and cystatin-c level (OR = 1.22, 95% CI = 1.07-1.39, p = 0.003) at discharge were independent risk factors for post-discharge abnormal eGFR. Plasma metabolomics at the 3-months follow-up revealed that β-pseudouridine, uridine, and 2-(dimethylamino) guanosine levels gradually increased with an abnormal degree of eGFR. Moreover, the kynurenine pathway in tryptophan metabolism, vitamin B6 metabolism, cysteine and methionine metabolism, and arginine biosynthesis were also perturbed in survivors with abnormal eGFR.

The effect of triglycerides to high-density lipoprotein cholesterol ratio on the reduction of renal function: findings from China health and retirement longitudinal study (CHARLS)

BACKGROUND

Previous studies show that abnormal lipoprotein metabolism can increase the prevalence of chronic kidney disease (CKD). This study prospectively investigated the association of triglycerides to high-density lipoprotein cholesterol (TG/HDL-C) ratio and renal dysfunction in the Chinese population.

METHODS

This longitudinal cohort research examined 7,316 participants (age range: 22-93) from the China Health and Retirement Longitudinal Study (CHARLS), including 6,560 individuals with estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m2 (normal renal function, NRF) group and 756 with eGFR < 60 mL/min/1.73 m2 (impaired renal function, IRF) group. In NRF group, reduction in renal function was defined as eGFR < 60 mL/min/1.73 m2 at exit visit and in IRF group, it was defined as decline in eGFR category, average eGFR decline > 5 mL/min/1.73 m2 per year or > 30 % decrease in eGFR from baseline.

RESULTS

The study results showed that TG/HDL-C ratio was positively associated with the risk of renal function decline in the NRF group (OR 1.30, 95 %CI 1.03-1.65, P = 0.03) and the IRF group (OR 1.90, 95 %CI 1.21-3.23, P = 0.02) when adjusting for age, gender, obesity, diabetes, hypertension, waist circumference, drinking, smoking, history of heart disease and stroke, low-density lipoprotein cholesterol and eGFR category. Analysis of the IRF group indicated that relative to the group of TG/HDL-C < 1.60, the group of TG/HDL-C ≥ 2.97 had an increased risk for the decline of eGFR category (OR 1.89, 95 %CI 1.12-3.21, P = 0.02) and > 30 % decline in eGFR (OR 2.56, 95 %CI 1.05-6.38, P = 0.04).

CONCLUSIONS

The high TG/HDL-C ratio was an independent risk factor for declining renal function in the Chinese population.

Endogenous estrogen exposure and chronic kidney disease; a 15-year prospective cohort study

BACKGROUND

Despite strong evidence demonstrating the role of estrogen as a protective factor for kidney function in women, limited data are available regarding the influence of endogenous estrogen exposure (EEE) on chronic kidney disease (CKD). The present study aimed to assess the incidence of CKD in women with various levels of EEE.

METHODS

In a prospective population-based study over a 15-year follow-up, a total of 3043 eligible women aged 30-70 years, participating in Tehran-Lipid and Glucose-Study were recruited and divided into two groups (EEE < 11 and EEE ≥ 11 years). EEE calculated based on age at menarche, age at menopause, number and duration of pregnancies, lactation, and duration of oral contraceptive use after excluding the progesterone dominant phase of the menstrual cycle. Cox's proportional hazards model was applied to estimate the hazard ratio of CKD between the study groups, after adjusting for confounders.

RESULTS

The total cumulative incidence rate of CKD was 50.1 per 1000 person years; 95% CI: 47.7-52.6); this was 53.9 (95%CI, 50.2-57.8) and 47.1 (95%CI, 44.0-50.4) per 1000 person years in women with EEE < 11 and EEE ≥ 11 years, respectively. The model adjusted for age, BMI, smoking, hypertension, and diabetes showed that the hazard ratio (HR) of incidence CKD in women with EEE < 11 compare to those with EEE ≥ 11 years in the subgroup of women aged< 45 years was 2.66(95% CI, 2.2, 3.2), whereas, in the subgroup aged ≥45 years, it was 1.22 (95% CI, 1.04, 1.4).

CONCLUSION

This study shows a higher HR of CKD incidence in women with low EEE levels in their later life. Screening of these women for CKD may be recommended.

Effect of tolvaptan in Japanese patients with autosomal dominant polycystic kidney disease: a post hoc analysis of TEMPO 3:4 and TEMPO Extension Japan

Background

Autosomal dominant polycystic kidney disease (ADPKD) is a progressive condition that eventually leads to end-stage renal disease. A phase 3 trial of tolvaptan (TEMPO 3:4; NCT00428948) and its open-label extension (TEMPO Extension Japan: TEMPO-EXTJ; NCT01280721) were conducted in patients with ADPKD. In this post hoc analysis, effects on renal function and the safety profile of tolvaptan were assessed over a long-term period that included the 3-year TEMPO 3:4 and the approximately 3-year TEMPO-EXTJ trials.

Methods

Patients from Japanese trial sites who completed TEMPO 3:4 were offered participation in TEMPO-EXTJ. Patients whose efficacy parameters were measured at year 2 in TEMPO-EXTJ for efficacy evaluation were included. The annual slope of the estimated glomerular filtration rate (eGFR) and growth in total kidney volume (TKV) were analyzed.

Results

In patients who received tolvaptan in TEMPO 3:4 and TEMPO-EXTJ, the annual slope of eGFR (mL/min/1.73 m²) was − 3.480 in TEMPO 3:4 and − 3.417 in TEMPO-EXTJ, with no apparent effect of an approximately 3.6-month off-treatment interval between the two trials. In patients who received a placebo in TEMPO 3:4 before initiating tolvaptan in TEMPO-EXTJ, the slope of eGFR was significantly less steep from TEMPO 3:4 (− 4.287) to TEMPO-EXTJ (− 3.364), a difference of 0.923 (P = 0.0441).

Conclusion

The TEMPO-EXTJ trial supports a sustained beneficial effect of tolvaptan on eGFR. In patients who received a placebo in TEMPO 3:4, initiation of tolvaptan in TEMPO-EXTJ was associated with a significant slowing of eGFR decline.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10157-021-02083-y.

Associations between air pollutant exposure and renal function: A prospective study of older adults without chronic kidney disease

We used real-world exposure scenarios to evaluate the effect of six ambient air pollutant (PM_2.5, PM₁₀, NO₂, SO₂, CO, and O₃) exposure on renal function among older adults without chronic kidney disease (CKD). We recruited 169 older adults without CKD in Beijing, China, for a longitudinal study from 2016 to 2018. The Modification of Diet in Renal Disease (MDRD) and the Chronic Kidney Disease Epidemiology Collaboration (EPI) equations were employed to derive the estimated glomerular filtration rate (eGFR). A linear mixed-effects model with random intercepts for participants was employed to determine the effects of air pollutants on renal function evaluated on the basis of eGFR and urinary albumin/creatinine ratio at different exposure windows (1-, 2-, 3-, 5-, 7-, 14-, 28-, 45-, and 60-days moving averages). An interquartile range (IQR) increase in NO₂ for was associated with significant decreases of in eGFR (MDRD equation) [percentage changes: -4.49 (95% confidence interval: -8.44, -0.37), -5.51 (-10.43, -0.33), -2.26 (-4.38, -0.08), -3.71 (-6.67, -0.65), -5.44 (-9.58, -1.11), -5.50 (-10.24, -0.51), -6.15 (-10.73, -1.33), and -6.34 (-11.17, -1.25) for 1-, 2-, 5-, 7-, 14-, 28-, 45-, and 60-days moving averages, respectively] and in eGFR (EPI equation) [percentage changes: -5.04 (-7.09, -2.94), -6.25 (-8.81, -3.62), -5.16 (-7.34, -2.92), -5.10 (-7.85, -2.28), -5.83 (-8.23, -3.36), -6.04 (-8.55, -3.47) for 1-, 2-, 14-, 28-, 45-, and 60-days moving averages, respectively]. In two-pollutant model, only the association of NO₂ exposure with eGFR remained robust after adjustment for any other pollutant. This association was stronger for individuals with hypertension for the EPI equation or BMI <25 kg/m² for the MDRD equation at lags 1 and 1-2. Our findings suggest that NO₂ exposure is associated with eGFR reduction among older adults without CKD for short (1-, 2-days) and medium (14-, 28-, 45-, 60-days) term exposure periods; thus, NO₂ exposure may contribute to renal impairment.

Prognostic value of estimated glomerular filtration rate and presence of proteinuria in type B aortic intramural hematoma

Background

Although aggressive medical treatment is recommended in patients with type B aortic intramural hematoma (IMH), a variety of aortic events can occur during the later period. For early identification of these patients, the present study was aimed at evaluating the prognostic validity of estimated glomerular filtration rate (eGFR) and the presence of proteinuria in type B aortic IMH.

Methods

Data of 61 patients with type B IMH in Peking University People's Hospital from January 2008 to December 2018 were retrospectively collected. The serum creatinine level and urine protein levels were measured at admission. And eGFR were calculated by the CKD-EPI equation. Adverse aortic-related events were defined as a composite of satisfaction of criteria for surgical conversion (with or without actual surgical intervention) and death from aortic rupture.

Results

Initial eGFR was significantly different between patients with adverse aortic-related events and those without (P=0.003). On multivariate analysis, eGFR <90 mL/min/1.73 m² (OR, 8.726; 95% CI: 1.711-46.144; P=0.009) and ULP (OR, 17.516; 95% CI: 3.322-92.258; P=0.001) were independent predictors of adverse aorta-related events. Furthermore, eGFR <90 mL/min/1.73 m² and proteinuria (+) (OR, 8.344; P=0.030) had significantly greater rates of aortic-related events. In addition, eGFR <90 mL/min/1.73 m² and proteinuria (+) had incremental prognostic value (C-statistic, 0.860, P=0.039) compared with ulcer-like projection (C-statistic, 0.815) alone.

Conclusions

Initial eGFR and presence of proteinuria were able to provide incremental prognostic information in addition to ulcer-like projection in patients with type B aortic IMH.

The change in kidney function was associated with carotid artery plaque in a community-based population: A cohort study

BACKGROUND AND AIMS

We performed the current study to evaluate the association between dynamic change in estimated glomerular filtration rate (eGFR) and the risk of carotid artery plaque (CAP) in a community-based population.

METHODS AND RESULTS

A total number of 37,093 Chinese adults (21,790 men and 15,303 women, aged 42.6 ± 11.6 years) free of chronic kidney diseases were enrolled. The change in eGFR was calculated based on two measurements in 2013 and 2014 (mean interval: 1.2 y). Participants were further classified into three groups based on the change in eGFR: fast-decrease (<-3.3%), stable (from -3.3% to 3.3%), and fast-increase (≥3.3%). CAP was annually assessed by ultrasound B model throughout the study (2013-2018). We have identified 1,624 new cases of CAP (16.0 per 1000 person-year) during follow up. Compared to participants with stable eGFR, participants in both fast-decrease and fast-increase groups were associated with 1.99 folds (HR = 1.99, 95% CI: 1.54, 2.57) and 3.15 folds (HR = 3.15, 95% CI: 2.38, 4.16) higher likelihood of developing CAP. The association between continuous change in eGFR and the risk of CAP demonstrate a "U" shape. Sensitivity analysis generated similar results with main analysis.

CONCLUSIONS

Both fast decrease and increase in eGFR were associated with the risk of developing CAP in Chinese adults.

Association of exposure to phthalates and environmental phenolics with markers of kidney function: Korean National Environmental Health Survey (KoNEHS) 2015-2017

Increasing number of consumer chemicals have been associated with chronic kidney disease (CKD) in human populations. However, many studies that investigated estimated glomerular filtration rate (eGRF) as an outcome reported inconsistent associations. In the present study, we employed a subset (n = 1292) of a nationally representative adult population participating in Korean National Environmental Health Survey (KoNEHS) 2015-2017, and assessed associations of major phthalates, bisphenol A (BPA), and parabens with both eGRF and albuminuria. In order to address a potential collider issue, a covariate-adjusted standardization method was applied, in addition to the conventional creatinine-correction, for adjusting urine dilution. Regardless of adjustment method, urinary DEHP metabolites showed significant positive associations with albumin to creatinine ratio (ACR). In addition, urinary metabolites of other heavy molecular weight phthalates such as MCOP and MCNP showed significant positive associations with ACR in the female population, but only following the covariate-adjusted standardization. For eGFR, conventional creatinine-correction resulted in positive associations with most of measured phthalate metabolites. However, with the covariate-adjusted standardization, most of positive associations with eGFR disappeared, and instead, significant negative associations were observed for MnBP, BPA, and EtP. Secondary analysis following stratification by CKD status, as well as principal component analysis (PCA), generally supported the observed associations. The present observations highlight the importance of urine dilution adjustment method for association studies on eGFR, and suggest potential effects of several consumer chemicals on adverse kidney function among humans.

A cross-sectional study on metabolic similarities and differences between inpatients with schizophrenia and those with mood disorders

BACKGROUND

One of the main causes of death in psychiatric patients is cardiovascular diseases which are closely related with lifestyle-related diseases. Psychiatric disorders include schizophrenia and mood disorders, whose symptoms and treatment medicines are different, suggesting that they might have different metabolic disorders. Thus, we studied the differences of lifestyle-related diseases between schizophrenia and mood disorders in Japan.

METHODS

This cross-sectional study was performed from 2015 to 2017. Study participants were 189 Japanese hospitalized patients (144 schizophrenia group, 45 mood disorders group) in the department of psychiatry at Kohnodai hospital. We examined physical disorders, metabolic status of glucose and lipid, estimated glomerular filtration rate (eGFR) and brain magnetic resonance imaging. We compared these data between schizophrenia and mood disorders groups using analysis of covariance or logistic regression analysis. In comparisons between inpatients with schizophrenia or mood disorders group and the standard, we quoted 'The National Health and Nutrition Survey in Japan 2015' by Ministry of Health, Labor and Welfare as the standard.

RESULTS

eGFR and prevalence of smoking were significantly lower in patients with mood disorder group than those with schizophrenia group by adjustment for age. In comparisons between patients with schizophrenia group or mood disorders group and each standard, the ratio of silent brain infarction (SBI) and cerebral infarction were significantly high in both groups. Schizophrenia group showed significantly higher prevalence of diabetes, low high-density lipoprotein (HDL) cholesterolemia, metabolic syndrome and smoking than the standard. Mood disorders group had significantly high prevalence of low HDL-cholesterolemia compared with the standard. Fasting blood glucose and HbA1c were significantly higher in schizophrenia group and female mood disorders group than the standard. Female mood disorders group had significantly decreased eGFR with increased ratio of eGFR < 60 ml/min than the standard.

CONCLUSIONS

Participants of both groups had increased ratio of SBI and cerebral infarction, accompanied with glucose and lipid disorders. Compared with schizophrenia group, mood disorders group showed significantly low eGFR and prevalence of smoking.

Association of renal function and depressive symptoms: Evidence from the China health and retirement longitudinal study

AIM

We examined the association between kidney function and risks of depression in a nationally representative sample of community-dwelling older adults.

METHODS

Participants were a subset selected from the China Health and Retirement Longitudinal Study. Estimated glomerular filtration rate (eGFR) was calculated using chronic kidney disease epidemiology collaboration equations. Incident depression was defined by a score of 10 or higher on the 10-item Center for Epidemiologic Studies Depression Scale, use of antidepressant medications, or both, at the 2015 follow-up visit. Multiple linear regression analyses were used to examine the baseline eGFR and CESD-10 score during follow up. The associations between level of renal function at baseline and incident depression were assessed using multivariate logistic regression analysis.

RESULTS

Over a four-year follow-up period, 22.8% (N = 773) of the participants reported incident depression. After multivariate analysis, baseline eGFRcr and eGFRcr-cys were significantly associated with higher depression score during follow up. Coefficients and 95%CI for eGFRcr and eGFRcr-cys were - 0.041(-0.066 to -0.016) and - 0.028(-0.051 to -0.005), respectively. Using eGFRcr-cys, the crude odds ratio (OR) for incident depression in the 4th quartile group was 1.60 (95%CI 1.23-2.06) than that in the 1st quartile group, (p for trend <0.001). Fully adjustment for confounding factors did not attenuate but strengthened the association (OR 2.46, 95%CI 1.61-3.76).

CONCLUSIONS

Among community-dwelling older adults over most of the range in renal function, eGFR was significantly, independently, and associated with incident depression.

The Difference Between Cystatin C- and Creatinine-Based Estimated GFR and Associations With Frailty and Adverse Outcomes: A Cohort Analysis of the Systolic Blood Pressure Intervention Trial (SPRINT)

RATIONALE & OBJECTIVE

In prior research and in practice, the difference between estimated glomerular filtration rate (eGFR) calculated from cystatin C level and eGFR calculated from creatinine level has not been assessed for clinical significance and relevance. We evaluated whether these differences contain important information about frailty.

STUDY DESIGN

A cohort analysis of the Systolic Blood Pressure Intervention Trial (SPRINT).

SETTING & PARTICIPANTS

9,092 hypertensive SPRINT participants who had baseline measurements of serum creatinine, cystatin C, and frailty.

EXPOSURE

eGFRs calculated using CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equations (eGFR_cys and eGFR_cr), and eGFR_Diff, calculated as eGFR_cys-eGFR_cr.

OUTCOMES

A validated 35-item frailty index that included questionnaire data for general and physical health, limitations of activities, pain, depression, sleep, energy level, self-care, and smoking status, as well as medical history, cognitive assessment, and laboratory data. We defined frailty as frailty index score>0.21 (range, 0-1). The incidence of injurious falls, hospitalizations, cardiovascular events, and mortality was also recorded.

ANALYTICAL APPROACH

We used logistic regression to model the cross-sectional association of baseline eGFR_Diff with frailty among all SPRINT participants. Adjusted proportional hazards regression was used to evaluate the association of eGFR_Diff with adverse outcomes and mortality.

RESULTS

Mean age was 68±9 (SD) years, mean eGFR_cys and eGFR_cr were 73±23 and 72±20mL/min/1.73m², and mean eGFR_Diff was 0.5±15mL/min/1.73m². In adjusted models, each 1-SD higher eGFR_Diff was associated with 24% lower odds of prevalent frailty (OR, 0.76; 95% CI, 0.71-0.81), as well as with lower incidence rate of injurious falls (HR, 0.84; 95% CI, 0.77-0.92), hospitalization (HR, 0.91; 95% CI, 0.88-0.95), cardiovascular events (HR, 0.89; 95% CI, 0.81-0.97), and all-cause mortality (HR, 0.71; 95% CI, 0.63-0.82); P<0.01.

LIMITATIONS

Gold-standard measure of kidney function and assessment of muscle mass were not available.

CONCLUSIONS

The difference between eGFR_cys and eGFR_cr is associated with frailty and health status. Positive eGFR_Diff is strongly associated with lower risks for longitudinal adverse outcomes and mortality, even after adjusting for chronic kidney disease stage and baseline frailty.

Bazedoxifene improves renal function and increases renal phosphate excretion in patients with postmenopausal osteoporosis

INTRODUCTION

Because aging is a predictor of renal insufficiency in the general population, renal function is a concern in postmenopausal patients undergoing treatment for osteoporosis. Although high serum phosphate concentration is a predictor of renal insufficiency, the effect of selective estrogen receptor modulator (SERM) on renal function and phosphate homeostasis remains to be established.

MATERIALS AND METHODS

We administered 20 mg/day bazedoxifene to 48 postmenopausal osteoporotic women who had been taking alfacalcidol for ≥ 6 months, and assessed lumbar spine bone mineral density (LS-BMD), renal function (by calculating estimated glomerular filtration rate using serum cystatin-C levels [eGFRcys] [range 38.0-98.2 mL/min/1.73 m²]), and phosphate homeostasis.

RESULTS

LS-BMD was significantly higher 6 months after the initiation of bazedoxifene administration. eGFRcys had increased by 3 months after initiation and was stable until 12 months. Serum phosphate gradually decreased after initiation, reaching statistical significance at 6 months. The changes in serum phosphate were also significant when the maximum tubular reabsorption rate of phosphate was normalized to glomerular filtration rate (TmP/GFR), indicating that bazedoxifene treatment reduces serum phosphate by increasing the urinary excretion of phosphate. The change in eGFRcys after the initiation of bazedoxifene was significantly negatively correlated with the change in serum phosphate, suggesting that a reduction in serum phosphate improves renal function.

CONCLUSION

Bazedoxifene improves renal function, possibly by increasing renal phosphate excretion, in postmenopausal osteoporotic women without severe renal insufficiency.

Kidney function and cognitive impairment among older hospitalized patients: a comparison of four glomerular filtration rate equations

BACKGROUND

The relationship between the estimated glomerular filtration rate (eGFR) and cognitive impairment may change as a function of the equation used. We aimed at investigating the association between four different eGFR equations and cognitive impairment among older hospitalized patients.

METHODS

Our series consisted of 795 older patients consecutively admitted to 7 geriatric and internal medicine acute care wards. The eGFR was calculated by Chronic Kidney Disease Epidemiologic Collaboration (CKD-EPI), Cockcroft-Gault (CG), Berlin Initiative Study (BIS) and Full Age Spectrum (FAS) equations. Study outcomes were total Mini Mental State Examination (MMSE) < 24 and sub-scores related to orientation to time, orientation to space, registration, calculation, three words recall, language and constructional praxis. Statistical analysis was carried out by logistic or Poisson regressions when appropriate. The accuracy of eGFR equations in identifying cognitive outcomes was investigated by calculating the area (AUC) under the receiver operating characteristic (ROC) curve for each equation.

RESULTS

After adjusting for potential confounders, eGFR < 30 was significantly associated with MMSE < 24 only with CKD-EPI equation (OR 2.03, 95% CI 1.04-3.96). eGFR < 30 was significantly associated with constructional apraxia with all study equations (CKD-EPI: OR 3.62, 95% CI 1.73-7.56; BIS: OR 2.86, 95% CI 1.31-6.26; FAS: OR 2.83, 95% CI 1.44-5.56; CG: OR 2.08, 95% CI 1.09-3.99). The accuracy of eGFR < 30 in identifying patients with defective constructional praxis was poor with all (BIS: AUC 0.54, 95% CI 0.52-0.55; CKD-EPI: AUC 0.55, 95% CI 0.53-0.57; CG: AUC 0.58, 95% CI 0.55-0.61; FAS: AUC 0.56, 95% CI 0.54-0.58).

CONCLUSIONS

Constructional apraxia may characterize the cognitive profile of older patients with severe CKD. The accuracy in identifying patients with constructional apraxia is only fair, and studies including other biomarkers of kidney function are needed.

Growth hormone deficiency with late-onset hypothalamic hypoadrenocorticism associated with respiratory and renal dysfunction: a case report

BACKGROUND

The prevalence of childhood-onset growth hormone (GH) deficiency (GHD) is estimated to be approximately 1 in 5000 or more, with the cause unknown in most cases (idiopathic isolated GHD). However, additional disorders of secretion of other pituitary hormones reportedly develop over time, with a frequency of 2-94% (median, 16%). Furthermore, median times to development of other anterior pituitary hormone deficiencies have been reported to be 6.4-9.4 years. On the other hand, adult patients affected by childhood-onset GHD reportedly develop impaired ventilation function due to reduced lung volumes and respiratory pressures, probably due to reductions in respiratory muscle strength. In addition, GH is known to play a role in stimulating the glomerular filtration rate (GFR), and the estimated GFR (eGFR) is decreased in patients with GHD.

CASE PRESENTATION

This case involved a 65-year-old woman. Her short stature had been identified at around 3 years of age, but no effective treatments had been provided. The patient was mostly amenorrheic, and hair loss became apparent in her late 30s. She developed hyperuricemia, dyslipidemia, and hypertension at 45 years of age. In addition, the patient was diagnosed with hypothyroidism at 50 years of age. At 58 years of age, endocrinological examination showed impaired secretion of thyroid-stimulating hormone, luteinizing hormone/follicle-stimulating hormone, and growth hormone, and magnetic resonance imaging showed an empty sella turcica. However, secretion ability of adrenocorticotropic hormone was retained. At 63 years of age, respiratory function tests confirmed a markedly restricted ventilation disorder (vital capacity, 0.54 L; percentage predicted vital capacity, 26.9%). Renal function had also decreased (eGFR, 25.0 mL/min/1.73 m²). Furthermore, she was diagnosed with hypothalamic secondary hypoadrenocorticism. The patient developed CO₂ narcosis at 65 years of age, and noninvasive positive pressure ventilation was started.

CONCLUSIONS

The rare case of a 65-year-old woman with childhood-onset GHD with panhypopituitarism, including late-onset secondary hypoadrenocorticism in her 60s, associated with severely impaired respiratory function and renal dysfunction, was reported. In GHD patients with risk factors for progression from isolated GHD to combined pituitary hormone deficiency, such as empty sella turcica, lifelong endocrinological monitoring may be important.

Efficacy of corticosteroids in immunoglobulin A nephropathy with less than 25% crescents

BACKGROUND

Crescent formation in immunoglobulin A nephropathy (IgAN) has been demonstrated to be a risk factor for worse outcomes. For IgAN patients with 0-25% crescentic glomeruli (C1), whether corticosteroids (CS) can improve the prognosis remains unclear. We tried to investigate the need for using CS in IgAN patients with C1 in different proteinuria levels.

METHODS

A total of 120 eligible IgAN patients with C1 from two academic medical centers were retrospectively studied, and 57 (47.5%) received CS. Patients were grouped according to with or without CS. The outcomes were the rate of estimated glomerular filtration rate (eGFR) decline (ml/min per 1.73 m²/year) and a composite outcome (50% decrease in eGFR, end stage renal disease (ESRD) or death due to kidney disease). The progression of adverse outcome among them were analyzed in Kaplan-Meier curve. The independent significance of CS on renal outcome or eGFR decline rate were analyzed by multivariable Cox regression or linear regression.

RESULTS

Unadjusted Kaplan-Meier showed that the outcome of treated patients was better than that of the untreated patients. Multiple Cox regression and linear regression analysis found that CS independently protected the renal outcome and decreased the eGFR decline rate. In the subgroup analysis, multivariate linear regression showed that CS decreased the eGFR decline rate both in proteinuria ≥ 1 g/day and < 1 g/day.

CONCLUSIONS

CS protected the renal outcome and slowed the eGFR decline rate of IgAN patients with C1, it also decreased the eGFR decline rate even in those with initial proteinuria < 1 g/day.

"Acute kidney dysfunction with no rejection" is associated with poor renal outcomes at 2 years post kidney transplantation

Background

“Acute kidney dysfunction with no rejection” (ADNR) corresponds to acute kidney injury without histological evidence of acute rejection (AR) in kidney transplant recipients (KTR). The prognosis of ADNR is unknown.

Methods

From 2007 to 2015, we categorized KTR with for-cause kidney biopsy within the first 12 months post kidney transplantation (KTx) into ADNR (n = 93) and biopsy-proven AR (n = 22). Controls (C, n = 135) included KTR with no ADNR or AR within the first 24 months post-KTx. A piecewise linear regression with a single fixed-knot at 12 months served to establish intercepts and slopes of MDRD-eGFR variations from 12 to 24 months. The percentage of KTR with ≥30% reduction of eGFR from 12 to 24 months was calculated as a surrogate marker of future graft loss.

Results

The median time for for-cause biopsy was 22 [10–70] and 13 [7–43] days for ADNR and AR, respectively. At 12 months, eGFR was significantly higher in C (57.6 ± 14.9 mL/min/1.73m²) vs. ADNR (43.5 ± 15.4 mL/min/1.73m², p < 0.0001) and vs. AR (46.5 ± 15.2 mL/min/1.73m², p < 0.0065). The proportion of KTR with ≥30% reduction in eGFR from 12 to 24 months reached 16.3% in C vs. 29.9% in ADNR (p = 0.02) and vs. 15% in AR (not significant).

Conclusions

ADNR is associated with poor outcomes within 2 years post-KTx.

Creatinine- and cystatin C-based estimated glomerular filtration rate slopes for the prediction of kidney outcome: a comparative retrospective study

BACKGROUND

Many studies have evaluated the usefulness of creatinine- (eGFRcr) and cystatin C-based estimated glomerular filtration rate (eGFRcys) at specific time points in predicting renal outcome. This study compared the performance of both eGFR changing slopes in identifying patients at high risk of end-stage renal disease (ESRD).

METHODS

From 2012 to 2017, patients with more than three simultaneous measurements of serum creatinine and cystatin C for 1 year were identified. Rapid progression was defined as eGFR slope < - 5 mL/min/1.73 m²/year. The primary outcome was progression to ESRD.

RESULTS

Overall, 1323 patients were included. The baseline eGFRcr and eGFRcys were 39 (27-48) and 38 (27-50) mL/min/1.73 m², respectively. Over 2.9 years (range, 2.0-3.8 years) of follow-up, 134 subjects (10%) progressed to ESRD. Both the eGFRcr and eGFRcys slopes were associated with a higher risk of ESRD, independently of baseline eGFR (hazard ratio [HR] = 0.986 [0.982-0.991] and HR = 0.988 [0.983-0.993], respectively; all p <  0.001). The creatinine- and cystatin C-based rapid progressions were associated with increased risk of ESRD (HR = 2.22 [1.57-3.13], HR = 2.03 [1.44-2.86], respectively; all p <  0.001). In the subgroup analyses, the rapid progression group, defined on the basis of creatinine levels (n = 503), showed no association between the eGFRcys slope and ESRD risk (p = 0.31), whereas the eGFRcr slope contributed to further discriminating higher ESRD risk in the subjects with rapid progression based on eGFRcys slopes (n = 463; p = 0.003).

CONCLUSIONS

Both eGFR slopes were associated with future ESRD risk. The eGFRcr slope was comparable with the eGFRcys slope in predicting kidney outcome.

Association between reduced renal function and cardiovascular mortality in patients hospitalized with infection: A multi-center cohort study

BACKGROUND

Infection is one of the main reasons for hospitalization worldwide, and is associated with an increased risk of cardiovascular mortality. It is unclear whether this association is modified by the presence of reduced renal function. The aim of this study was to analyze the relationship between estimated glomerular filtration rate (eGFR) and cardiovascular mortality in patients hospitalized with infection.

METHODS

This cohort study included all adult, incident patients who were hospitalized at one of four hospitals in China between 2012 and 2015, had a discharge diagnosis of infection, and had a serum creatinine measurement at admission. Patients receiving renal replacement therapy were excluded. Hospital data were linked to death registry data. All-cause and cardiovascular mortality were evaluated according to admission eGFR [≥60 (reference), 30-59 and < 30 mL/min/1.73m²] using multivariable Cox regression and competing risk analyses.

RESULTS

During a median follow-up period of 2.39 years, 40,524 patients were hospitalized with infection (mean age 61 years, 54.3% female 18.4% diabetic). Of these, 4781 died. Lower admission eGFR was associated with progressively increased risks of cardiovascular mortality (≥60 mL/min/1.73m² reference; 30-59 mL/min/1.73m² subdistribution hazard ratio [SHR] 2.15, 95% CI 1.85-2.50, P< .01; <30 mL/min/1.73m² SHR 3.19, 95% CI 2.68-3.80, P < .01). The proportion of deaths due to cardiovascular disease increased as the eGFR decreased, predominantly due to ischemic heart disease.

CONCLUSIONS

Patients hospitalized with infections and reduced renal function have significantly increased risks of cardiovascular mortality. Heart status should be carefully monitored following infections, especially for those with reduced renal function.

Estimated glomerular filtration rate and functional status among older people: A systematic review

BACKGROUND

The association between chronic kidney disease (CKD) and functional status may change as a function of the equation used to estimate glomerular filtration rate (eGFR). We reviewed the predictive value of different eGFR equations in regard to frailty and disability outcomes.

METHODS

We searched Pubmed from inception to March 2018 for studies investigating the association between eGFR and self-reported and/or objective measures of frailty or disability. Cross-sectional and longitudinal studies were separately analysed.

RESULTS

We included 16 studies, one of which reporting both cross-sectional and longitudinal data. Three out of 7 cross-sectional studies compared different eGFR equations in regard to their association with functional status: two studies showed that cystatin C-based, but not creatinine-based eGFR may be associated with hand-grip strength or frailty; another study showed that two different creatinine-based eGFR equations may be similarly associated with disability. Four out of 10 longitudinal studies provided comparative data: two studies reported similar association with disability for different creatinine-based eGFR equations; one study showed that creatinine-based eGFR was not associated with frailty, but a not significant trend for association was observed with cystatin C-based eGFR; one study showed that cystatin C-based but not creatinine-based eGFR may predict incident mobility disability, while both methods may predict gait speed decline. High heterogeneity was observed in regard to confounders included in reviewed studies. None of them included the most recently published equations.

CONCLUSION

Available data do not support the superiority of one of the eGFR equations in terms of measuring or predicting functional decline.

Using All Longitudinal Data to Define Time to Specified Percentages of Estimated GFR Decline: A Simulation Study

RATIONALE & OBJECTIVE

The standard method to calculate time to the event of a specified percentage decline in estimated glomerular filtration rate (eGFR) uses 2 eGFR assessments, 1 at baseline and 1 at the event time. However, event times may be inaccurate due to eGFR variability and restriction of events to study visit times. We propose a novel method for calculating time to a specified percentage decline in eGFR that uses all available longitudinal eGFR assessments.

STUDY DESIGN

Simulation study and comparison of methods in 2 observational cohorts.

SETTINGS & PARTICIPANTS

Simulation data and study participants in the Nephrotic Syndrome Study Network (NEPTUNE) and Clinical Phenotyping and Resource Biobank Core (C-PROBE).

EXPOSURE

Analytical method for calculating time to a specified percentage decline in eGFR: standard 2-point method versus a regression method incorporating all available longitudinally assessed eGFR assessments.

OUTCOME

Time to percentage decline in eGFR.

ANALYTIC APPROACH

A 2-point method used only the baseline eGFR and first eGFR below the decline threshold. The comparison method used ordinary linear regression incorporating all longitudinal eGFR assessments to define the baseline measure and 40% decline threshold. Time to a 40% decline in eGFR was defined as the time when the regression line crossed the decline threshold. The 2 outcome calculation methods were compared using simulations to assess the accuracy of estimated event times and power to detect event time differences between groups. Comparison of event times calculated using each method was also implemented using data from NEPTUNE and C-PROBE.

RESULTS

The regression method incorporating all eGFR assessments was more accurate than the 2-point method in estimating event times in simulation analyses, particularly when eGFR variability was high, there was a greater correlation among successive eGFR values, or there were more missing data. This method was also more powerful in detecting differences between groups. Using NEPTUNE and C-PROBE data, the standard method estimated a more rapid rate of events, some likely representing transient reductions in kidney function, and was less likely to give accurate estimates in the presence of nonlinear eGFR trajectories.

LIMITATIONS

Computations required for our proposed method currently limit its use to research rather than clinical applications.

CONCLUSIONS

A regression method using all longitudinal eGFR values to estimate time to a percentage decline in eGFR increases accuracy and power over traditional methods, representing a potential improvement in the ability to discover treatment or biomarker effects on kidney disease progression.

Age- and height-adjusted total kidney volume growth rate in autosomal dominant polycystic kidney diseases

Background

The Mayo Clinic Image Classification (MIC) was proposed as a renal prognosis prediction model for autosomal dominant polycystic kidney disease (ADPKD). MIC is based on the assumption of exponential constant increase in height-adjusted total kidney volume (HtTKV). HtTKV growth rate is calculated by one-time measurement of HtTKV and age. We named it as an age-adjusted HtTKV growth rate (AHTKV-α). AHTKV-α was compared with HtTKV slope measured by at least two HtTKV values.

Methods

Comparison of repeatability between AHTKV-α and HtTKV slope, correlation of subgroups divided according to baseline AHTKV-α and HtTKV slope with disease manifestations, estimated glomerular filtration rate (eGFR) slope, and renal survival were analyzed in 296 patients with ADPKD. PKD genotype influences were compared between AHTKV-α and HtTKV slope in 88 patients with characterized PKD mutations.

Results

Absolute differences between baseline and follow-up measures were significantly larger for the HtTKV slope than for AHTKV-α (P < 0.0001). From baseline AHTKV-α-based subgroups A–E according to MIC, disease manifestations occurred earlier and future eGFR slopes became steeper (P < 0.0001). Multivariate hazard ratios of renal survival differed significantly among baseline AHTKV-α-based subgroups. Inter-subgroup differences in these predictors were less evident during baseline HtTKV slope-based classification. AHTKV-α values, but not HtTKV slopes, were significantly higher for PKD1 mutation carriers than for PKD2 mutation carriers (P < 0.0001).

Conclusion

MIC is a good renal prediction model applicable to Japanese patients also. AHTKV-α can be a more sensitive and reliable indicator in TKV growth rate than HtTKV slope.

Electronic supplementary material

The online version of this article (10.1007/s10157-018-1617-8) contains supplementary material, which is available to authorized users.

Optimal equation for estimation of glomerular filtration rate in autosomal dominant polycystic kidney disease: influence of tolvaptan

BACKGROUND

The reliability of various equations for estimating the GFR in ADPKD patients and the influence of tolvaptan on the resulting estimates have not been examined when GFR is calculated on the basis of inulin clearance.

METHODS

We obtained baseline and on-tolvaptan measured GFRs (mGFRs), calculated on the basis of inulin clearance, in 114 ADPKD, and these mGFRs were compared with eGFRs calculated according to four basic equations: the MDRD, CKD-EPI, and JSN-CKDI equations and the Cockcroft-Gault formula, as well as the influence of tolvaptan and of inclusion of cystatin C on accuracy of the results. Accuracy of each of the seven total equations was evaluated on the basis of the percentage of eGFR values within mGFR ± 30% (P₃₀).

RESULTS

mGFRs were distributed throughout CKD stages 1-5. Regardless of the CKD stage, P₃₀s of the MDRD, CKD-EPI, and JSN-CKDI equations did not differ significantly between baseline values and on-tolvaptan values. In CKD 1-2 patients, P₃₀ of the CKD-EPI equation was 100.0%, whether or not the patient was on-tolvaptan. In CKD 3-5 patients, P₃₀s of the MDRD, CKD-EPI, and JSN-CKDI equations were similar. For all four equations, regression coefficients and intercepts did not differ significantly between baseline and on-tolvaptan values, but accuracy of the Cockcroft-Gault formula was inferior to that of the other three equations. Incorporation of serum cystatin C reduced accuracy.

CONCLUSIONS

The CKD-EPI equation is most reliable, regardless of the severity of CKD. Tolvaptain intake has minimal influence and cystatin C incorporation does not improve accuracy.

Reduced estimated glomerular filtration rate is associated with depressive symptoms in elder Chinese: A population-based cross-sectional study

Depression has been associated with chronic kidney disease (CKD). However, few studies have examined whether such association exist in average older individuals with mild to moderate reduced kidney function. This study investigated the association between reduced estimated glomerular filtration rate (eGFR) and depressive symptoms in Chinese older population. Data was obtained from the Rugao Longevity and Ageing Study conducted in Jiangsu, China. Cockcroft-Gault (CG) equation was used to calculate eGFR. Depressive symptoms were defined by using Chinese version of 15-item Geriatric Depression Scale (GDS-15). The prevalence of depressive symptoms was 9.9% among 1749 elderly participants aged 70-84 years. Many elderly had a mild to moderate reduced renal function (84.3%, 57.1% in stage2 CKD and 27.2% in stage3 CKD, respectively). The overall GDS-15 score showed an upward trend with decreasing of eGFR (p < 0.05). Furthermore, a moderate decline of eGFR (in stage3 CKD) was significantly associated with increased risk of depressive symptoms even after adjusting for confounders (OR = 1.71, 95%CI 1.05-2.77, P = 0.03). Elder had no depressive symptoms if their eGFR was normal or mildly reduced. Our results suggest that a moderate decrease of eGFR (stage3 CKD) was independently associated with depressive symptoms in general Chinese elderly.

Validity of a Risk Prediction Equation for CKD After 10 Years of Follow-up in a Japanese Population: The Ibaraki Prefectural Health Study

BACKGROUND

Chronic kidney disease (CKD) is an important health problem for which risk equations have been developed for Western populations. This study aimed to develop and validate a risk prediction equation for CKD in a Japanese population.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

The study included 135,007 participants who completed an annual health checkup in 1993 to 1996 in the Ibaraki Prefecture in Japan. Participants were initially free of CKD (defined as stage 3, 4, or 5 CKD or proteinuria [2+ or 3+] by dipstick). Follow-up information was available from health checkups 10 years after the initial evaluation. We used data from 40,963 women and 17,892 men in the northern region of the prefecture for the development of risk prediction equations and 53,042 women and 23,110 men in the southern region for external validation.

PREDICTORS

Age, estimated glomerular filtration rate (eGFR), body mass index, proteinuria, hematuria, hypertension, diabetes mellitus, smoking, and drinking.

OUTCOME

Occurrence of CKD (defined as eGFR<60mL/min/1.73m² and/or proteinuria [2+ or 3+] by dipstick).

ANALYTICAL APPROACH

Logistic regression analysis to estimate risk for CKD stratified by sex.

RESULTS

During follow-up, 7,500 cases of CKD developed in the northern region and 8,964, in the southern region. Older age, proteinuria (1+), higher systolic blood pressure, medication for hypertension, and current smoking were associated with increased risk for CKD in both sexes, whereas higher eGFR and daily alcohol intake were associated with lower risk. C statistics of risk estimation equations for CKD at 10 years were >0.8 for both the development and external validation populations, and discrimination of the risk estimation was fairly good in women and men.

LIMITATIONS

Fluctuations in variables were not evaluated because the study used annual health checkups. This study excluded a large number of people for whom a 10-year health checkup was not available.

CONCLUSIONS

Estimations of risk for CKD after 10 years of follow-up in a general Japanese population can be achieved with a high level of validity.

Monitoring the estimated glomerular filtration rate (eGFR) in patients with small-cell lung cancer during chemotherapy: equations based on serum creatinine or cystatin C?

BACKGROUND

This study compared the differences between the estimated glomerular filtration rate (eGFR) calculated by several equations based on serum creatinine (Scr) and cystatin C (CysC) concentrations for monitoring renal function in patients with small-cell lung cancer (SCLC) during chemotherapy.

METHODS

Seventy-one patients with SCLC were retrospectively analyzed. The eGFR before and after each chemotherapy cycle was calculated by the following equations: the chronic kidney disease epidemiology collaboration (CKD-EPI) equation, the modification of diet in renal disease (MDRD) equation, the Cockcroft-Gault (CG) equation, and five CysC-based equations. The patients were compared among the different eGFR groups.

RESULTS

The mean decreases in eGFR_CKD-EPI (-2.25 ± 9.89 ml/min/1.73 m²) between each treatment cycle were more significant than the decreases in eGFR_CG (-0.46 ± 10.17 ml/min/1.73 m²), eGFR_MDRD (-0.48 ± 9.79 ml/min/1.73 m²), and five calculated eGFR_CysC (p < 0.05). Single-/multiparameter analyses showed that patients with a higher body mass index (BMI >23) and receiving more treatment cycles (>3) were at increased risk for developing renal impairment with an eGFR less than 60 ml/min/1.73 m² during chemotherapy.

CONCLUSIONS

The eGFR calculated by the CKD-EPI equation changed more significantly between each chemotherapy cycle than did the eGFR from the other equations based on Scr or CysC in patients with SCLC. Oncologists should pay more attention to the renal function of specific patient groups during treatment.

Kidney Function, Proteinuria, and Cancer Incidence: The Korean Heart Study

BACKGROUND

Reported associations of estimated glomerular filtration rate (eGFR) with cancer risk are inconsistent, and data for the proteinuria-cancer relationship are sparse. We sought to quantify the associations of cancer incidence with eGFR and with proteinuria in a large population-based cohort.

STUDY DESIGN

A prospective cohort study.

SETTING & PARTICIPANTS

242,583 adults (30-74 years old) without a diagnosis of cancer at baseline in the Korean Heart Study, based on health checkups in 1996 to 2004 with follow-up until 2012.

PREDICTORS

Creatinine-based eGFR (≥90, 60-89, 45-59, and <45mL/min/1.73m²) and dipstick proteinuria (undetectable/trace, 1+, 2+, and ≥3+).

OUTCOMES

Overall and site-specific cancer incidence based on ICD-10 codes.

RESULTS

15,165 cases of cancer were detected. The relationship between eGFR and incidence of any cancer was J shaped, with the lowest risk at 45 to 59mL/min/1.73m². There was 44% higher risk for any cancer among those with eGFRs<45mL/min/1.73m² compared with those with eGFRs≥90mL/min/1.73m² (HR, 1.44; 95% CI, 1.11-1.87). High proteinuria was also associated with cancer risk, showing a dose-response relationship (HRs of 1.24 [95% CI, 1.13-1.35], 1.38 [95% CI, 1.17-1.63], and 1.66 [95% CI, 1.30-2.12] for 1+, 2+, and ≥3+ vs undetectable/trace). Examining site-specific cancer, eGFR<45 (vs ≥45) mL/min/1.73m² was significantly associated with kidney and ureteral cancer, multiple myeloma, and leukemia, whereas proteinuria ≥ 1+ (vs undetectable/trace) was related to a broader set of cancers (ie, stomach, rectal, liver, lung, ovarian, kidney, bladder, and multiple myeloma). After excluding study participants with follow-up less than 3 years, the associations remained consistent for kidney cancer and myeloma with eGFR and for rectal, liver, lung, and ovarian cancer with proteinuria.

LIMITATIONS

Relatively small number of participants with severely reduced eGFR or 70 years or older.

CONCLUSIONS

Kidney measures, particularly proteinuria, were associated with increased incidence of cancer. Future studies are needed to better understand the pathophysiologic mechanisms underlying these associations.

Determinants of glomerular filtration rate following bariatric surgery in individuals with severe, otherwise uncomplicated, obesity: an observational, prospective study

AIMS

Obesity-induced nephropathy is an established clinical entity arising from a "maladaptive" response to lipid accumulation at the nephron level. Bariatric surgery positively affects renal function, reducing or increasing glomerular filtration rate (GFR) in subjects with hyperfiltration and renal impairment, respectively. The effect of this surgery in patients with normal estimated GFR (eGFR) is less clear.

METHODS

A complete clinical and biochemical assessment of 135 severely obese, otherwise healthy subjects, was obtained before Roux-en-Y gastric bypass (RYGB). All subjects underwent an OGTT with plasma glucose and insulin determinations. Follow-up data were recorded at 6, 12, 24 and 48 months after intervention.

RESULTS

Baseline eGFR was 98.2 ± 13.6 ml/min/1.73 m²; hyperfiltration (>120 ml/min/1.73 m²) was present in 7% of the cohort. No eGFR variation over the follow-up emerged, except at the last visit (-3.6 ± 1.4 ml/min/1.73 m² at month 48, p = 0.01 vs baseline). In the univariate analysis, the renal performance at 48 months was inversely related to baseline eGFR (r = -0.17, p = 0.04) and plasma triglycerides (r = -0.04, p = 0.05). Fasting and OGTT-derived variables did not impact eGFR. By multiple regression analysis, eGFR time course was independently predicted only by baseline eGFR (p = 0.03). Interestingly, patients having a baseline eGFR >100 ml/min/1.73 m² (median value) showed, after 48 months, an average loss of -8.3 ± 2.2 ml/min/1.73 m², while those with eGFR <100 exhibited a slight increase (+1.8 ± 2.3 ml/min/1.73 m², p < 0.01).

CONCLUSIONS

Long-term data confirm the safety of RYGB on renal function. Interestingly, a subtle hyperfiltration, i.e., occurring in high-normal range of eGFR, is attenuated by surgical procedure. Lastly, high serum triglycerides may track an unfavorable renal outcome.

Association of estimated glomerular filtration rate and urine albumin-to-creatinine ratio with incidence of cardiovascular diseases and mortality in chinese patients with type 2 diabetes mellitus - a population-based retrospective cohort study

BACKGROUND

Estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR) are renal markers associated with risks of cardiovascular diseases (CVD) and all-cause mortality in diabetic patients. This study aims to quantify such risks in Chinese diabetic patients based on eGFR and UACR.

METHODS

This was a territory-wide retrospective cohort study on primary care diabetic patients with documented eGFR and UACR but without baseline CVD in 2008/2009. They were followed up till 2013 on CVD events and mortality. Associations between eGFR/UACR and incidence of CVD/mortality were evaluated by multivariable Cox proportional models adjusted with socio-demographic and clinical characteristics.

RESULTS

The data of 66,311 patients who had valid baseline eGFR and UACR values were analysed. The risks of CVD events and mortality increased exponentially with the decrease in eGFR, with a hazard ratio (HR) increasing from 1.63 to 4.55 for CVD, and from 1.70 to 9.49 for mortality, associated with Stage 3 to 5 CKD, compared to Stage 1 CKD. UACR showed a positive linear association with CVD events and mortality. Microalbuminuria was associated with a HR of 1.58 and 2.08 for CVD and mortality in male (1.48 and 1.79 for female), respectively, compared to no microalbuminuria. Male patients with UACR 1-1.4 mg/mmol and eGFR ≥90 ml/min/1.73 m2 (60-89 ml/min/1.73 m2) had a HR of 1.25 (1.43) for CVD. Female patients with UACR 2.5-3.4 mg/ml and eGFR ≥90 ml/min/1.73 m2 (60-89 ml/min/1.73 m2) had a HR of 1.45 (1.65) for CVD.

CONCLUSIONS

Risks of CVD events and mortality increased exponentially with eGFR drop, while UACR showed positive predictive linear relationships, and the risks started even in high-normal albuminuria. UACR-based HR was further modified according to eGFR level, with risk progressed with CKD stage. Combining eGFR and UACR level was more accurate in predicting risk of CVD/mortality. The findings call for more aggressive screening and intervention of microalbuminuria in diabetic patients.

Estimated GFR Before and After Bariatric Surgery in CKD

BACKGROUND

Several reviews have recently detailed the beneficial effects of weight loss surgery for kidney function. However, these studies have a number of limitations, including small sample size, few done in chronic kidney disease (CKD) stages 3 and 4, and many not including the main bariatric surgery procedures used in the United States today.

STUDY DESIGN

This was an observational retrospective cohort study comparing propensity score-matched bariatric surgery patients and nonsurgery control patients who were referred for, but did not have, surgery. Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy were also compared using propensity matching.

SETTING & PARTICIPANTS

Patients (714 surgery patients; 714 controls) were from a large integrated health care system, a mean of 58±8 (SD) years old, and mostly women (77%) and non-Hispanic whites (56%) and had diabetes mellitus (66%) and/or hypertension (91%).

PREDICTOR

Predictors at the time of surgery or referral to surgery were age, sex, race/ethnicity, weight, and presence of diabetes and/or hypertension.

OUTCOMES

The primary outcome for this study was change in estimated glomerular filtration rate (eGFR) from serum creatinine level over a median 3-year follow-up period.

MEASUREMENTS

Serum creatinine was used to calculate eGFR using the CKD-EPI (CKD Epidemiology Collaboration) creatinine equation.

RESULTS

Surgery patients had 9.84 (95% CI, 8.05-11.62) mL/min/1.73m² greater eGFRs than controls at a median 3 years' follow-up and RYGB patients had 6.60 (95% CI, 3.42-9.78) mL/min/1.73m² greater eGFRs than sleeve gastrectomy patients during the same period.

LIMITATIONS

This study is limited by its nonrandomized observational study design, estimation of GFR, and large changes in muscle mass, which may affect serum creatinine level independent of changes in kidney function.

CONCLUSIONS

Bariatric surgery, especially the RYGB procedure, results in significant improvements for up to 3 years in eGFRs for patients with CKD stages 3 and 4.

Availability of information on renal function in Dutch community pharmacies

Background Early detection and monitoring of impaired renal function may prevent drug related problems. Objective To assess the availability of information on patient's renal function in Dutch community pharmacies, for patients using medication that might need monitoring in case of renal impairment. Methods Per pharmacy, 25 patients aged ≥65 years using at least one drug that requires monitoring, were randomly selected from the pharmacy information system. For these patients, information on renal function [estimated glomerular filtration rate (eGFR)], was obtained from the pharmacy information system. When absent, this information was obtained from the general practitioner (GP). Results Data were collected for 1632 patients. For 1201 patients (74 %) eGFR values were not directly available in the pharmacy, for another 194 patients (12 %) the eGFR value was not up-to-date. For 1082 patients information could be obtained from the GP, resulting in 942 additional recent eGFR values. Finally, recent information on renal function was available for 72 % (n = 1179) of selected patients. Conclusion In patients using drugs that require renal monitoring, information on renal function is often unknown in the pharmacy. For the majority of patients this information can be retrieved from the GP.

Estimated GFR, Albuminuria, and Cognitive Performance: The Maastricht Study

BACKGROUND

Reduced estimated glomerular filtration rate (eGFR) and albuminuria have been associated with worse cognitive performance. However, few studies have examined whether these associations are confined to older individuals or may be extended to the middle-aged population.

STUDY DESIGN

Cross-sectional analyses of a prospective population-based cohort study.

SETTING & PARTICIPANTS

2,987 individuals aged 40 to 75 years from the general population (The Maastricht Study).

PREDICTOR

eGFR and urinary albumin excretion (UAE).

OUTCOMES

Memory function, information processing speed, and executive function.

MEASUREMENTS

Analyses were adjusted for demographic variables (age, sex, and educational level), lifestyle factors (smoking behavior and alcohol consumption), depression, and cardiovascular disease risk factors (glucose metabolism status, waist circumference, total to high-density lipoprotein cholesterol ratio, triglyceride level, use of lipid-modifying medication, systolic blood pressure, use of antihypertensive medication, and prevalent cardiovascular disease).

RESULTS

UAE was <15mg/24 h in 2,439 (81.7%) participants, 15 to <30 mg/24 h in 309 (10.3%), and ≥30mg/24 h in 239 (8.0%). In the entire study population, UAE≥30mg/24 h was associated with lower information processing speed as compared to UAE<15mg/24 h (β [SD difference] = -0.148; 95% CI, -0.263 to -0.033) after full adjustment, whereas continuous albuminuria was not. However, significant interaction terms (P for interaction < 0.05) suggested that albuminuria was most strongly and extensively associated with cognitive performance in older individuals. Mean (±SD) eGFR, estimated by the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine-cystatin C equation (eGFR_cr-cys), was 88.4±14.6 mL/min/1.73m². eGFR_cr-cys was not associated with any of the domains of cognitive performance after full adjustment. However, significant interaction terms (P for interaction < 0.05) suggested that eGFR_cr-cys was associated with cognitive performance in older individuals.

LIMITATIONS

Cross-sectional design, which limited causal inferences.

CONCLUSIONS

In the entire study population, albuminuria was independently associated with lower information processing speed, whereas eGFR_cr-cys was not associated with cognitive performance. However, both were more strongly and extensively associated with cognitive performance in older individuals.

Urinary polycyclic aromatic hydrocarbons and measures of oxidative stress, inflammation and renal function in adolescents: NHANES 2003-2008

OBJECTIVE

Recent evidence has suggested that polycyclic aromatic hydrocarbons (PAHs) may contribute to cardiometabolic and kidney dysfunction by increasing oxidative stress, but little is known about impacts in childhood.

STUDY DESIGN

We performed cross-sectional analyses of 660 adolescents aged 12-19 years in the 2003-2008 National Health and Nutrition Examination Survey (NHANES), using levels of 10 monohydroxylated urinary PAH metabolites as our exposure. Our primary outcomes of interest were biomarkers of oxidative stress and renal function, including estimated glomerular filtration rate (eGFR), urinary albumin to creatinine ratio (ACR), insulin resistance, and serum uric acid, gamma glutamyl transferase (GGT) and C-reactive protein (CRP).

RESULTS

We observed statistically significant associations between PAH metabolites and levels of serum GGT, CRP, uric acid and eGFR. Each 100% increase in 2-hydroxyphenanthrene was related to a 3.36% increase in uric acid (95% CI: 0.338-6.372; p=0.032), a 3.86% increase in GGT (95% CI: 1.361-6.362; p=0.005) and a 16.78% increase in CRP (95% CI: 1.848-31.689; p=0.029). Each 100% increase in 4-hydroxyphenanthrene was associated with a 6.18% increase in GGT (95% CI: 4.064-8.301; p<0.001) and a 13.66% increase in CRP (95% CI: 2.764-24.564; p=0.017). Each 100% increase in 9-hydroxyfluorene was associated with a 2.58% increase in GGT (95% CI: 0.389-4776; p=0.024). Each 100% increase in 3-hydroxyphenanthrene was associated with a 2.66% decrease in eGFR (95% CI: -4.979 to -0.331; p=0.028).

CONCLUSIONS

Urinary PAH metabolites were associated with serum uric acid, GGT and CRP, suggesting possible impacts on cardiometabolic and kidney function in adolescents. Prospective work is needed to investigate the potential long-term health consequences of these findings.

Predicting outcomes in acute coronary syndrome using biochemical markers

OBJECTIVES

To assess risk prediction in patients with acute coronary syndrome (ACS) during the hospital stay, at 6 weeks and at 6 months period using high sensitivity C-reactive protein (hs-CRP), serum creatinine, cardiac troponin I, creatine kinase total, and MB levels.

METHODS

It was a prospective observational study. The primary outcome was taken as all-cause mortality. Patients with ACS were enrolled and followed up at 6 weeks and 6 months duration from the index event. Mortality and cause of death were recorded. The hs-CRP was estimated on admission, at 6 weeks, and at 6 months. The estimated glomerular filtration rate (eGFR) was calculated using the abbreviated modification of diet in renal disease (MDRD) formula at admission, at 6 weeks, and 6 months.

RESULTS

There were a total of 108 cases of ACS in the duration of 6 months who completed the follow-up. The hs-CRP level of >5mg/dl was highly significant for predicting mortality during hospital stay and at 6 weeks (p<0.001). There was 11% of in-hospital mortality (p<0.001). At 6 months, the overall mortality was 28% (p<0.001). There was a statistical significance with low eGFR (median eGFR 45ml/min/1.73m(2)) levels during the admission.

CONCLUSION

hs-CRP levels above 5mg/dl and the eGFR levels ≤30ml/min/1.73m(2) were significant in predicting mortality of the patients with ACS. This may provide simple assessment tools for predicting outcome in ACS in resource-poor settings if validated further.

A Meta-analysis of the Association of Estimated GFR, Albuminuria, Age, Race, and Sex With Acute Kidney Injury

BACKGROUND

Acute kidney injury (AKI) is a serious global public health problem. We aimed to quantify the risk of AKI associated with estimated glomerular filtration rate (eGFR), albuminuria (albumin-creatinine ratio [ACR]), age, sex, and race (African American and white).

STUDY DESIGN

Collaborative meta-analysis.

SETTING & POPULATION

8 general-population cohorts (1,285,049 participants) and 5 chronic kidney disease (CKD) cohorts (79,519 participants).

SELECTION CRITERIA FOR STUDIES

Available eGFR, ACR, and 50 or more AKI events.

PREDICTORS

Age, sex, race, eGFR, urine ACR, and interactions.

OUTCOME

Hospitalized with or for AKI, using Cox proportional hazards models to estimate HRs of AKI and random-effects meta-analysis to pool results.

RESULTS

16,480 (1.3%) general-population cohort participants had AKI over a mean follow-up of 4 years; 2,087 (2.6%) CKD participants had AKI over a mean follow-up of 1 year. Lower eGFR and higher ACR were strongly associated with AKI. Compared with eGFR of 80mL/min/1.73m(2), the adjusted HR of AKI at eGFR of 45mL/min/1.73m(2) was 3.35 (95% CI, 2.75-4.07). Compared with ACR of 5mg/g, the risk of AKI at ACR of 300mg/g was 2.73 (95% CI, 2.18-3.43). Older age was associated with higher risk of AKI, but this effect was attenuated with lower eGFR or higher ACR. Male sex was associated with higher risk of AKI, with a slight attenuation in lower eGFR but not in higher ACR. African Americans had higher AKI risk at higher levels of eGFR and most levels of ACR.

LIMITATIONS

Only 2 general-population cohorts could contribute to analyses by race; AKI identified by diagnostic code.

CONCLUSIONS

Reduced eGFR and increased ACR are consistent strong risk factors for AKI, whereas associations of AKI with age, sex, and race may be weaker in more advanced stages of CKD.

A Meta-analysis of the Association of Estimated GFR, Albuminuria, Diabetes Mellitus, and Hypertension With Acute Kidney Injury

BACKGROUND

Diabetes mellitus and hypertension are risk factors for acute kidney injury (AKI). Whether estimated glomerular filtration rate (eGFR) and urine albumin-creatinine ratio (ACR) remain risk factors for AKI in the presence and absence of these conditions is uncertain.

STUDY DESIGN

Meta-analysis of cohort studies.

SETTING & POPULATION

8 general-population (1,285,045 participants) and 5 chronic kidney disease (CKD; 79,519 participants) cohorts.

SELECTION CRITERIA FOR STUDIES

Cohorts participating in the CKD Prognosis Consortium.

PREDICTORS

Diabetes and hypertension status, eGFR by the 2009 CKD Epidemiology Collaboration creatinine equation, urine ACR, and interactions.

OUTCOME

Hospitalization with AKI, using Cox proportional hazards models to estimate HRs of AKI and random-effects meta-analysis to pool results.

RESULTS

During a mean follow-up of 4 years, there were 16,480 episodes of AKI in the general-population and 2,087 episodes in the CKD cohorts. Low eGFRs and high ACRs were associated with higher risks of AKI in individuals with or without diabetes and with or without hypertension. When compared to a common reference of eGFR of 80mL/min/1.73m(2) in nondiabetic patients, HRs for AKI were generally higher in diabetic patients at any level of eGFR. The same was true for diabetic patients at all levels of ACR compared with nondiabetic patients. The risk gradient for AKI with lower eGFRs was greater in those without diabetes than with diabetes, but similar with higher ACRs in those without versus with diabetes. Those with hypertension had a higher risk of AKI at eGFRs>60mL/min/1.73m(2) than those without hypertension. However, risk gradients for AKI with both lower eGFRs and higher ACRs were greater for those without than with hypertension.

LIMITATIONS

AKI identified by diagnostic code.

CONCLUSIONS

Lower eGFRs and higher ACRs are associated with higher risks of AKI among individuals with or without either diabetes or hypertension.

Enhanced creatinine and estimated glomerular filtration rate reporting to facilitate detection of acute kidney injury

OBJECTIVES

While acute kidney injury (AKI) can be diagnosed based on specified increases in a patient's plasma creatinine level, standard creatinine reporting methods typically only flag creatinine results as abnormal when outside the reference range and often fail to identify rising creatinine values indicative of AKI. Here, we evaluate the impact of this limitation in standard creatinine reporting and develop and implement an enhanced creatinine reporting algorithm.

METHODS

We evaluated 59,712 plasma creatinine results collected over approximately 3 months, using computational simulations and statistical analyses.

RESULTS

Our analyses demonstrated that 29% of creatinine results substantially increased over the patient's baseline and concerning for AKI remained within the normal reference range. These concerning results would not be flagged as abnormal using standard reporting. Likewise, we found that simple delta checks are also insensitive at AKI detection. To improve creatinine reporting, we developed and implemented an algorithm within our laboratory information system to alert clinicians to rising creatinine results, which we describe in this report.

CONCLUSION

While both creatinine reference limits and simple delta checks are insensitive for AKI identification, a simple algorithm can be implemented within a common laboratory information system to enhance AKI identification.

Subclinical carotid atherosclerosis and triglycerides predict the incidence of chronic kidney disease in the Japanese general population: results from the Kyushu and Okinawa Population Study (KOPS)

OBJECTIVE

To examine whether or not subclinical atherosclerosis independently predicts the incidence of chronic kidney disease (CKD) in the Japanese general population.

METHODS

This study is part of the Kyushu and Okinawa Population Study (KOPS), a survey of vascular events associated with lifestyle-related diseases. Participants who attended both baseline (2004-2007) and follow-up (2009-2012) examinations were eligible. The common carotid intima-media thickness (IMT) was assessed for each participant at baseline. The end point was the incidence of CKD, defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m(2) during the follow-up of participants without CKD at baseline.

RESULTS

During the five-year follow-up, 224 of the 1824 participants (12.3%) who developed CKD had higher carotid IMT (0.74 ± 0.22 vs. 0.65 ± 0.14 mm, P < 0.001), higher triglycerides (1.6 ± 0.8 vs. 1.3 ± 0.7 mmol/L, P < 0.001), and lower high density lipoprotein cholesterol (1.5 ± 0.4 vs. 1.6 ± 0.4 mmol/L, P < 0.001) at baseline than those who did not. In logistic regression analysis adjusted for significant covariates, eGFR (Odds ratio [OR] 0.83, 95% confidence interval (CI) 0.80-0.85, P < 0.001), carotid IMT (0.10 mm increase: OR 1.17, 95% CI 1.04-1.33, P = 0.010), and triglycerides (OR 1.35, 95% CI 1.06-1.73, P = 0.015) at baseline were independent predictors for the development of CKD.

CONCLUSIONS

Higher carotid IMT and hypertriglyceridemia were independently associated with the development of CKD in the population studied.

KDOQI US commentary on the 2012 KDIGO clinical practice guideline for the evaluation and management of CKD

The National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) guideline for evaluation, classification, and stratification of chronic kidney disease (CKD) was published in 2002. The KDOQI guideline was well accepted by the medical and public health communities, but concerns and criticisms arose as new evidence became available since the publication of the original guidelines. KDIGO (Kidney Disease: Improving Global Outcomes) recently published an updated guideline to clarify the definition and classification of CKD and to update recommendations for the evaluation and management of individuals with CKD based on new evidence published since 2002. The primary recommendations were to retain the current definition of CKD based on decreased glomerular filtration rate or markers of kidney damage for 3 months or more and to include the cause of kidney disease and level of albuminuria, as well as level of glomerular filtration rate, for CKD classification. NKF-KDOQI convened a work group to write a commentary on the KDIGO guideline in order to assist US practitioners in interpreting the KDIGO guideline and determining its applicability within their own practices. Overall, the commentary work group agreed with most of the recommendations contained in the KDIGO guidelines, particularly the recommendations regarding the definition and classification of CKD. However, there were some concerns about incorporating the cause of disease into CKD classification, in addition to certain recommendations for evaluation and management.

GFR estimation: from physiology to public health

Estimating glomerular filtration rate (GFR) is essential for clinical practice, research, and public health. Appropriate interpretation of estimated GFR (eGFR) requires understanding the principles of physiology, laboratory medicine, epidemiology, and biostatistics used in the development and validation of GFR estimating equations. Equations developed in diverse populations are less biased at higher GFRs than equations developed in chronic kidney disease (CKD) populations and are more appropriate for general use. Equations that include multiple endogenous filtration markers are more precise than equations including a single filtration marker. The CKD-EPI (CKD Epidemiology Collaboration) equations are the most accurate GFR estimating equations that have been evaluated in large diverse populations and are applicable for general clinical use. The 2009 CKD-EPI creatinine equation is more accurate in estimating GFR and prognosis than the 2006 MDRD (Modification of Diet in Renal Disease) Study equation and provides lower estimates of prevalence of decreased eGFR. It is useful as a "first test" for decreased eGFR and should replace the MDRD Study equation for routine reporting of serum creatinine-based eGFR by clinical laboratories. The 2012 CKD-EPI cystatin C equation is as accurate as the 2009 CKD-EPI creatinine equation in estimating GFR, does not require specification of race, and may be more accurate in patients with decreased muscle mass. The 2012 CKD-EPI creatinine-cystatin C equation is more accurate than the 2009 CKD-EPI creatinine and 2012 CKD-EPI cystatin C equations and is useful as a confirmatory test for decreased eGFR as determined by serum creatinine-based eGFR. Further improvement in GFR estimating equations will require development in more broadly representative populations, including diverse racial and ethnic groups, use of multiple filtration markers, and evaluation using statistical techniques to compare eGFR to "true GFR."

Timing of peritoneal dialysis initiation and mortality: analysis of the Canadian Organ Replacement Registry

BACKGROUND

Several observational studies of hemodialysis patients show an association between early dialysis therapy initiation and increased mortality. Few studies have examined this association among peritoneal dialysis patients.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

A cohort of 8,047 incident peritoneal dialysis patients who started dialysis therapy in 2001-2009 and were treated in Canada.

PREDICTOR

Estimated glomerular filtration rate (eGFR) at dialysis therapy initiation. Defined early, mid, and late starts as eGFR>10.5, 7.5-10.5, and <7.5mL/min/1.73m(2), respectively.

OUTCOMES

Time to death.

MEASUREMENTS

Proportional piecewise exponential survival models to compare mortality (overall and early) for the 3 predictor groups.

RESULTS

Between 2001 and 2009, the proportion of patients starting peritoneal dialysis therapy as early starts increased from 29% (95% CI, 26%-32%) to 44% (95% CI, 41%-47%). Compared with the late-start group, the overall mortality rate was not higher for the early- (adjusted HR, 1.08; 95% CI, 0.96-1.23) or mid-start (adjusted HR, 0.96; 95% CI, 0.86-1.09) groups. However, when examined yearly, patients in the early-start group were significantly more likely to die within the first year of dialysis therapy compared with those in the late-start group (adjusted HR, 1.38; 95% CI, 1.10-1.73), but not in subsequent years.

LIMITATIONS

Bias and residual confounding may have influenced the observed relationship between predictor and outcome.

CONCLUSIONS

Patients are initiating peritoneal dialysis therapy at increasingly higher eGFRs. Contrary to most observational studies assessing hemodialysis, the early initiation of peritoneal dialysis therapy, at eGFR>10.5mL/min/1.73m(2), is not associated with increased mortality.