Cystatin-C and inflammatory markers in the ambulatory elderly

Pharmacokinetics/pharmacodynamics analysis and establishment of optimal dosing regimens using unbound cefmetazole concentration for patients infected with Extended-Spectrum β-lactamase producing Enterobacterales (ESBL-E)

STUDY OBJECTIVE

Establish methods for measuring cefmetazole (CMZ) concentrations conduct a pharmacokinetic/pharmacodynamic (PK/PD) analysis using unbound CMZ concentrations for extended-spectrum β-lactamase producing enterobacterales (ESBL-E) and investigate optimal dosing regimens for not undergoing hemodialysis (non-HD) and undergoing hemodialysis (HD) patients.

DESIGN

Prospective observational study.

PATIENTS

Included patients treated with CMZ who provided written informed consent and were admitted to the Tokyo Bay Urayasu Ichikawa Medical Center between August 2021 and July 2022.

MEASUREMENTS

Total and Unbound CMZ concentration was measured by high-performance liquid chromatography (HPLC) with solid-phase extraction and ultrafiltration.

SETTING

Determining the CMZ dosing regimen involved modified creatinine clearance (CLCR ) with measured body weight (BW) using the Cockcroft-Gault equation. For non-HD patients, blood samples were collected during at least three points. For patients undergoing HD, 1 g was administered via intravenous infusion, or rapid intravenous injection after HD, or 30 min before the end of HD. Blood samples were collected before HD (pre-HD), and 1 and 3 h after starting HD and post-HD. All blood samples were collected at steady-state. Patient information was collected from electronic medical records. An unbound PK model was constructed for the non-HD patients. A nomogram was constructed using Monte Carlo simulations with a 90% probability of target attainment at 70% free time above the minimum inhibitory concentration (MIC). For the HD patients, a nomogram was used to determine the optimal dosing regimen for each HD schedule.

MAIN RESULTS

CMZ measurement methods were established. A model analysis of unbound PK in 37 non-HD patients incorporated creatinine clearance (CLCR ) using the Cockcroft-Gault equation, albumin (ALB) for clearance and body weight (BW) for the volume of distribution. In Monte Carlo simulations, nomograms corresponding to the MIC (known and unknown) were generated for each covariate. Using the nomogram, non-HD patients with an ESBL-E MIC of 8 mg/L, a BW of 60 kg, an ALB of 25 g/L, and a CLCR of 60 mL/min required administration of 2 g every 6 h (1- and 3-h infusions). Unbound PK model parameters were calculated for 7 HD patients, and the optimal dosing regimens following PK/PD were determined for each HD schedule. In HD patients, the regimen after and during HD was established using a treatment that was effective up to an ESBL-E MIC of 4 mg/L.

CONCLUSIONS

The nomogram for CMZ regimens established by PK/PD analysis of measured CMZ concentrations enables optimal CMZ dosing for ESBL-E-infected patients.

Creatinine-cystatin C ratio and death with a functioning graft in kidney transplant recipients

Death with a functioning graft is important cause of graft loss after kidney transplantation. However, little is known about factors predicting death with a functioning graft among kidney transplant recipients. In this study, we evaluated the association between post-transplant creatinine-cystatin C ratio and death with a functioning graft in 1592 kidney transplant recipients. We divided the patients into tertiles based on sex-specific creatinine-cystatin C ratio. Among the 1592 recipients, 39.5% were female, and 86.1% underwent living-donor kidney transplantation. The cut-off value for the lowest creatinine-cystatin C ratio tertile was 0.86 in males and 0.73 in females. The lowest tertile had a significantly lower 5-year patient survival rate and was independently associated with death with a functioning graft (adjusted hazard ratio 2.574, 95% confidence interval 1.339-4.950, P < 0.001). Infection was the most common cause of death in the lowest tertile group, accounting for 62% of deaths. A low creatinine-cystatin C ratio was significantly associated with an increased risk of death with a functioning graft after kidney transplantation.

Association of serum cystatin C level with coronary atherosclerotic plaque burden: a comprehensive analysis of observational studies and genetic study

BACKGROUND AND AIMS

Epidemiological studies show that high circulating cystatin C is associated with risk of cardiovascular disease (CVD), independent of creatinine-based renal function measurements. However, the relationship between serum cystatin C level and coronary atherosclerotic plaque burden is limited. We aimed to evaluate the relationship between circulating cystatin C and coronary atherosclerotic plaque burden.

METHODS

This study was a cross-sectional study based on China community population. Measurements of plaque burden were based on the segment-involvement score (SIS) and segment stenosis score (SSS), which derived from the Coronary Artery Tree Model Depicting Coronary Artery Plaque Scores. Logistic regression model was used to demonstrate the association between cystatin C level and coronary artery plaque burden. Mendelian randomization (MR) analyses were conducted to assess the causal effect of cystatin C level on coronary atherosclerosis risk.

RESULTS

A total of 3,043 objects were included in the present study. The odds risks (OR) of severe plaque burden in the highest serum cystatin C levels (OR: 2.50; Cl:1.59-3.91; P < 0.001) and medium-level cystatin C levels (OR: 1.86; 95% Cl: 1.21-2.88; P = 0.005) were significantly higher after fulled adjusted confounders compared with the lowest levels of serum cystatin C by SSS. The MR analysis showed that genetic predicted cystatin C levels was associated with an increased risk of coronary atherosclerosis (OR, 1.004; 95% CI, 1.002-1.006, P < 0.001) .

CONCLUSION

Elevated serum cystatin C levels were associated with coronary atherosclerotic plaque burden. Cystatin C levels had a causal effect on an increased risk of coronary atherosclerosis at the genetic level. WHAT IS ALREADY KNOWN ON THIS TOPIC?: Coronary artery disease is currently the most common cardiovascular disease and the leading global cause of mortality. Previous studies reported that higher serum cystatin C levels were associated with an increased risk for future cardiovascular events, independent of the normal creatinine levels or estimated glomerular filtration rate (eGFR) values. The presence of high-risk coronary atherosclerotic plaque burden is associated with increased risk of cardiovascular events. However, the association between serum cystatin C and coronary atherosclerotic plaque burden is not very clear. WHAT THIS STUDY ADDS?: Our study demonstrated that the elevated serum cystatin C levels were associated with coronary atherosclerotic plaque burden. In addition, we found that serum cystatin C levels had a causal effect on an increased risk of coronary atherosclerosis at the genetic level. HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY?: Current research finds that serum cystatin C levels were associated with coronary atherosclerosis. The metabolic pathway of cystatin C could be a target for new therapies against CAD.

Characterization of peripheral blood inflammatory indicators and OCT imaging biological markers in diabetic retinopathy with or without nephropathy

Objective

To observe the distribution characteristics of peripheral blood inflammatory indexes and retinal macular area optical coherence tomography (OCT) imaging biomarkers in patients with diabetic retinopathy (DR) with or without diabetic nephropathy (DN), in order to seek clinical biomarkers that can predict the development of DR and DN.

Methods

A total of 169 inpatients with DR who visited the ophthalmology department of the Affiliated Hospital of Chengdu University of Traditional Chinese Medicine from October 2020 to June 2022 and had complete clinical data were collected, and the patients with DR were divided into two major groups, DR and DR/DN, according to whether they had DN, and then further divided into four subgroups, Non-proliferative DR(NPDR), proliferative DR(PDR), NPDR/DN and PDR/DN, according to the stage of DR. The distribution characteristics of peripheral blood inflammatory indexes [Neutrophil to lymphocyte ratio(NLR) and Platelet to neutrophil ratio(PLR)], renal function indexes [Cystatin-C(CYS-C), Creatinine(Crea), Uric acid(UA)and Urinary albumin to creatinine ratio(UACR)] and OCT imaging indexes [Hyperreflective foci(HRF), Disorgnization of retinal inner layers(DRIL), Outer retinal tubulations(ORTs), Central retinal thickness(CRT), Retinal nerve fiber layer(RNFL) and Ganglion cell layer(GCL)] were analyzed between the above subgroups.

Results

There was no difference between DR and DR/DN groups in terms of gender, family history of diabetes, duration of diabetes and Body mass index(BMI) (P>0.05), the mean age of the DR/DN group was significantly lower than that of the DR group (P<0.05), and the proportion of the DR/DN group with a history of hypertension was significantly higher than that of the DR group (P<0.05); there was no significant difference in hemoglobin A1C(HbA1c) between DR and DR/DN groups (P>0.05). (P>0.05), Hemoglobin(HGB) was significantly higher in the DR group than in the DR/DN group (P <0.05), NLR, PLR, Crea, UA and CYS-C were significantly higher in the DR/DN group than in the DR group (P<0.05); there was no significant difference in the comparison of HRF, DRIL, ORTs positive rate and CRT between the DR and DR/DN groups (P>0.05). RNFL and GCL thickness were significantly lower in the DR/DN group than in the DR group (P<0.05); history of hypertension (OR=2.759), NLR (OR=1.316), PLR (OR=1.009), Crea (OR=1.018), UA (OR=1.004), CYS-C (OR=3.742) were the independent (OR=0.951), age (OR=0.951), HGB (OR=0.976), RNFL (OR=0.909) and GCL (OR=0.945) were independent protective factors for DR/DN; RNFL (OR=0.899) and GCL (OR=0.935) were independent protective factors for NPDR/DN, RNFL (OR=0.852) and GCL (OR=0.928) were independent protective factors for PDR/DN. ROC curve analysis showed that the area under the curve (AUC) for CYS-C, PLR, Crea, UA and the combination of the four indicators to predict DR/DN were 0.717, 0.625, 0.647, 0.616 and 0.717, respectively.

Conclusions

(1) Low age combined with hypertension HGB, NLR, PLR, CYS-C, Crea and UA may be serum biological markers for predicting DN in DR; meanwhile, PLR, CYS-C, Crea, UA and the combination of the four indicators can be used for risk assessment and adjunctive diagnosis of DN in DR combined with hypertension. (2) The RNFL and GCL thickness in the temporal aspect of the central macular sulcus may be imaging biological markers for predicting DN in DR; meanwhile, GCL thickness may have important value for risk prediction and diagnosis of DN in combination with DR.

Glomerular filtration rate by different measures and albuminuria are associated with risk of frailty: the Rugao Longitudinal Ageing Study

BACKGROUND AND AIM

A decreased estimated glomerular filtration rate (eGFR) is associated with frailty, but the association between kidney function and frailty using multidimensional assessments has not been entirely examined. We aimed to investigate whether albuminuria and the eGFR using different biomarkers were associated with frailty.

METHODS

A total of 1830 older adults were included. Kidney function was assessed by the eGFR (based on combined creatinine-cystatin C [eGFR_cr-cys]) and β₂-microglobulin [eGFR_B2M]) and urine albumin-creatinine ratio (UACR). Frailty was measured by the Fried phenotype (FP) and frailty index (FI). Logistic regression models were used to investigate cross-sectional and longitudinal associations of baseline kidney measures with prevalent and incident frailty.

RESULTS

At baseline, kidney function was associated with prevalent frailty. During the 2-year follow-up, a decreased eGFR (per 10 units) was associated with an increased risk of incident frailty using the FP (eGFR_cr-cys: OR 1.18, 95% CI 1.03-1.35; eGFR_B2M: OR 1.14, 95% CI 1.02-1.29, respectively) and FI (eGFR_B2M: OR 1.18, 95% CI 1.04-1.65). An increased logUACR was associated with a higher risk of incident frailty using the FP (OR 1.18, 95% CI 1.03-1.35). Additionally, individuals with chronic kidney disease (CKD) had a higher risk of incident frailty using the FP (eGFR_cr-cys: OR 2.13, 95% CI 1.28-3.47; eGFR_B2M: OR 1.58, 95% CI 1.10-2.29, respectively) and FI (eGFR_cr-cys: OR 1.97, 95% CI 1.15-3.32; eGFR_B2M: OR 1.51, 95% CI 1.03-2.24, respectively).

CONCLUSION

Kidney function decline and CKD were associated with an increased risk of prevalent and incident frailty in older adults. Physicians should pay more attention to monitoring frailty status in older adults with CKD, even in those with kidney function decline.

Associations of serum cystatin C and its change with new-onset cardiovascular disease in Chinese general population

BACKGROUND AND AIMS

The relation of serum cystatin C with new-onset cardiovascular disease (CVD) remains uncertain. We aimed to evaluate the prospective associations of serum cystatin C and its change with new-onset CVD in Chinese general population.

METHODS AND RESULTS

A total of 7064 participants free of CVD at baseline were enrolled from the China Health and Retirement Longitudinal Study. The change in serum cystatin C was calculated as cystatin C concentration at 2015 wave minus that at baseline (2011 wave). The primary outcome was new-onset CVD, defined as self-reported physician-diagnosed heart disease, stroke, or both during follow-up. The secondary outcomes were new-onset heart disease, and new-onset stroke. During a median follow-up duration of 7.0 years, a total of 1116 (15.8%) subjects developed new-onset CVD. Overall, after the adjustments for eGFR and other important covariates, there was a positive association between serum cystatin C and new-onset CVD (per SD mg/L increment; adjusted HR, 1.13; 95%CI: 1.08,1.18). When cystatin C was assessed as quintiles, the adjusted HRs for participants in the second, third, fourth and fifth quintiles were 1.15 (95%CI: 0.93, 1.41), 1.37 (95%CI: 1.11, 1.68), 1.47 (95%CI: 1.19, 1.81), and 2.03 (95%CI: 1.60, 2.56), respectively, compared with those in quintile 1 (P for trend<0.001). Furthermore, there was a positive association between the increase in cystatin C concentration and the subsequent new-onset CVD (per SD mg/L increment; adjusted HR, 1.14; 95%CI: 1.02,1.27).

CONCLUSION

Both serum cystatin C and its increase were positively associated with new-onset CVD among Chinese general population.

Mild to moderate decrease in eGFR and cognitive decline in older adults

BACKGROUND

Whether mild to moderately low estimated glomerular filtration rate (eGFR) is associated with cognitive decline in older adults is not clear. We evaluated changes in cognition in relation to baseline eGFR in older adults participating in the Alzheimer's Disease Neuroimaging Initiative (ADNI).

METHODS

This is a longitudinal secondary analysis of an established observational cohort. We used data from the ADNI, an National Institutes of Health-funded, multicenter longitudinal observational study that includes participants with and without cognitive impairment who were administered a comprehensive battery of neuropsychological tests every 6 months. We related the Chronic Kidney Disease Epidemiology Collaboration eGFR with previously validated cognition composite scores for memory (ADNI-Mem) and executive function (ADNI-EF) in multivariable linear regression analysis adjusted for age, sex, race and level of education.

RESULTS

A total of 1127 ADNI participants (mean age 74 ± 7 years, 57% men, 97% Caucasian, mean follow-up 6 ± 2.6 years) were included in the analysis. The mean baseline eGFR was 76 ± 19 mL/min/1.73 m2, with 6% with eGFR <45, 22% with eGFR 45-<60, 51% with eGFR 60-90 and 21% with eGFR >90 mL/min/1.73 m2 at baseline. Both ADNI-Mem and ADNI-EF scores declined over time. In the multivariable linear regression model, older age (β = -0.117, P = 0.01), female sex (β = 0.312, P < 0.001) and lower education (β = 0.079, P < 0.001) were associated with a decline in ADNI-Mem scores, whereas baseline eGFR (each 10 mL/min/1.73 m2 change) was not {β = -0.03 [confidence interval (CI) -0.06-0.001], P = 0.11}. Similarly, older age (β = -0.278, P < 0.001) and lower education (β = 0.099, P < 0.001) were associated with a decline in ADNI-EF scores, whereas baseline eGFR was not [β = 0.004 (95% CI -0.04-0.04), P = 0.84].

CONCLUSIONS

In this cohort from the ADNI study, there was no association between baseline eGFR and cognitive decline in older adults with mild to moderately low eGFR.

Association between circulating cystatin C and hyperuricemia: a cross-sectional study

INTRODUCTION/OBJECTIVES

Circulating cystatin C has reportedly been related to cardiovascular disease, diabetes, and metabolic syndrome, apart from its traditional role in estimating the glomerular filtration rate. However, whether circulating cystatin C is related to hyperuricemia remains unclear.

METHOD

We included 2406 men and 1273 women who attended their annual health checkups in this study. Anthropometric and biochemical parameters were measured. Hyperuricemia was diagnosed as fasting serum uric acid > 420 µmol/L in men and women.

RESULTS

A total of 695 (18.9%) participants were diagnosed with hyperuricemia. Hyperuricemic patients had significantly higher serum cystatin C levels than healthy controls (0.91 (0.83-1.02) versus 0.82 (0.72-0.92) mg/L, P < 0.001). Serum cystatin C levels were positively related to the prevalence of hyperuricemia, which was 5.18%, 14.76%, 22.66%, and 31.24% in participants with serum cystatin C levels in the first, second, third, and fourth quartiles, respectively (P < 0.001 for trend). In stepwise multivariate logistic regression analysis, participants with serum cystatin C in the fourth quartile had a more than twofold increased risk of hyperuricemia (OR 2.262, 95% CI 1.495-3.422; P < 0.001) compared with those with serum cystatin C in the first quartile. In subgroup analyses, the fourth quartile of cystatin C was related to increased risks of hyperuricemia in both non-obese and obese participants (OR 4.405, 95% CI 1.472-13.184, P = 0.008; OR 1.891, 95% CI 1.228-2.911, P = 0.004, respectively), in non-metabolic syndrome participants (OR 3.043, 95% CI 1.692-5.473; P < 0.001) but not in metabolic syndrome participants (OR 1.689, 95% CI 0.937-3.045; P = 0.081), and in non-non-alcoholic fatty liver disease (non-NAFLD) (OR 2.128, 95% CI 1.424-3.180; P < 0.001, respectively) and young and middle-aged participants (OR 2.235, 95% CI 1.492-3.348, P < 0.001) but not in NAFLD and elderly participants.

CONCLUSIONS

This study revealed a positive association of circulating cystatin C with hyperuricemia. Key Points • Serum cystatin C is associated with an increased risk of hyperuricemia. • Serum cystatin C is a useful biomarker in distinguishing patients at high risk of having hyperuricemia.

Utility of a Score for Predicting Glomerular Filtration Rate Overestimation in Patients with Cardiovascular and Renal Diseases and Their Risk Factors

Objective We recently reported a novel score for the detection of glomerular filtration rate (GFR) overestimation using a creatinine-based equation. We examined the utility of this score in patients with cardiovascular/renal diseases and diabetes mellitus. Methods We enrolled 1,425 patients (65±15 years old; 37% women) who were admitted to our hospital for the management of cardiovascular and renal diseases and their risk factors. Overestimation of the GFR (OE) was defined as a creatinine-based GFR (eGFRcre) ≥120% of the cystatin C-based estimated GFR. The OE score was calculated as the sum of the scores for the body weight, hemoglobin concentration, and blood urea nitrogen (BUN)/serum creatinine (Scr), totaling 1 point if the body weight was <63.0 kg in men or <42.0 kg in women, 1 point if the hemoglobin concentration was <12.4 g/dL in men or <11.0 g/dL in women, and 1 point if the BUN/Scr was >26.5. Results The proportion of patients with OE was 14.2%. The score predicted OE with a sensitivity of 70.8% and a specificity of 99.6%, and the sensitivity was increased in patients ≥75 years old (88.3%) and decreased in diabetics (58.6%). When patients were divided into subgroups by the total score, the frequencies of OE were 8% (59/754), 14% (72/502), 38% (58/151), and 72% (13/18) in patients with scores of 0, 1, 2, and 3, respectively. Conclusion The OE score is useful for detecting elderly cases of cardiovascular and renal diseases in which eGFRcre overestimates the GFR, although its utility is limited in diabetics.

Chronic kidney disease measures for cardiovascular risk prediction

Chronic kidney disease (CKD) affects 15-20% of adults globally and causes various complications, one of the most important being cardiovascular disease (CVD). CKD has been associated with many CVD subtypes, especially severe ones like heart failure, independent of potential confounders such as diabetes and hypertension. There is no consensus in major clinical guidelines as to how to incorporate the two key measures of CKD (glomerular filtration rate and albuminuria) for CVD risk prediction. This is a critical missed opportunity to appropriately refine predicted risk and personalize prevention therapies according to CKD status, particularly since these measures are often already evaluated in clinical care. In this review, we provide an overview of CKD definition and staging, the subtypes of CVD most associated with CKD, major pathophysiological mechanisms, and the current state of CKD as a predictor of CVD in major clinical guidelines. We will introduce the novel concept of a "CKD Add-on", which allows the incorporation of CKD measures in existing risk prediction models, and the implications of taking into account CKD in the management of CVD risk.

Association between cystatin C and diabetic retinopathy among type 2 diabetic patients in China: a Meta-analysis

AIM

To explore the correlation between cystatin C (Cys-C) and diabetic retinopathy (DR) in those patients with type 2 diabetes mellitus (DM) in China.

METHODS

Articles were collected from China National Knowledge Infrastructure (CNKI), Wanfang, VIP, PubMed, EMBASE, Cochrane Library, Clinical Trials.gov, and Google Scholar. Quality and risk of bias within included studies was assessed using the Newcastle-Ottawa scale (NOS). Heterogeneity was determined by using Cochran's Q-test and Higgins I ² statistics. Mean differences (MDs) and 95% confidence intervals (CIs) of Cys-C within the diabetes without retinopathy (DWR) and DR, DWR and non-proliferative diabetic retinopathy (NPDR), NPDR and proliferative diabetic retinopathy (PDR) were collected by using random-effects model because of high heterogeneity. Meta-analysis was conducted based on 23 articles of 2331 DR including NPDR and PDR patients and 2023 DWR patients through Review Manager 5.3. Subgroup analyses were also performed according to DM duration, body mass index (BMI), total cholesterol (TC), total triglycerides (TG), low-density lipoprotein C (LDL-C), and high-density lipoprotein C (HDL-C), sample origins and methods. Publication bias was assessed by the funnel plot.

RESULTS

Cys-C level in DR patients was increased compared with that of DWR (total MD: 0.69, 95%CI: 0.41 to 0.97, Z=4.79, P<0.01). Besides, the synthesized results of the studies showed the similar findings in the DWR vs NPDR group (total MD: 0.29, 95%CI 0.20 to 0.39, Z=6.02, P<0.01) and the NPDR vs PDR group (total MD: 0.63, 95%CI 0.43 to 0.82, Z=6.33, P<0.01). Heterogeneity of most of the subgroup analyses was still obvious (I ²≥50%, P<0.1). Forest plots of different subgroups indicated that there was a slight increase of Cys-C during the period between DWR and DR, DWR and NPDR, NPDR and PDR. Funnel plot showed that there was no significant publication bias.

CONCLUSION

The elevated Cys-C is closely related with DR and probably plays a critical role in its progression.

Cystatin C predicts the risk of incident cerebrovascular disease in the elderly: A meta-analysis on survival date studies

BACKGROUND

Stroke is the third leading cause of global year of life lost in all-age and second-ranked cause of disability adjusted life years in middle-aged and elder population. Therefore, it is critical to study the relationship between vascular-related risk factors and cerebrovascular diseases. Several cross-sectional studies have shown that Cystatin C (Cys C) is an independent risk factor for cerebrovascular diseases and levels of Cys C are significantly higher in stroke patients than in healthy individuals. In this meta-analysis, we introduce a Cox proportional hazards model to evaluate the causality between Cys C and the risk of cerebrovascular accident in the elderly.

METHODS

We searched PubMed, EMBASE, the Web of Science, and the Cochrane Library from 1985 to 2019 for studies on the relationship between serum Cys C and incidence stroke with Cox proportional hazards models. We conducted a subgroup analysis of the selected studies to determine a connection between atherosclerosis and stroke. Finally, 7 research studies, including 26,768 patients without a history of cerebrovascular, were studied.

RESULTS

After comparing the maximum and minimum Cys C levels, the hazard ratio for all types of stroke, including ischemic and hemorrhagic stroke, was 1.18 (95% confidence interval 1.04-1.31) with moderate heterogeneity (I2 = 43.0%; P = .119) in a fixed-effect model after pooled adjustment for other potential risk factors. In the subgroup analysis, the hazard ratio and 95% confidence interval for Cys C stratified by atherosclerosis was 1.85 (0.97-2.72). As shown in Egger linear regression test, there was no distinct publication bias (P = .153).

CONCLUSION

Increased serum Cys C is significantly associated with future stroke events in the elderly, especially in patients with carotid atherosclerosis. Thus, serum levels of Cys C could serve as a predicted biomarker for stroke attack.

Is trimethoprim/sulfamethoxazole-associated increase in serum creatinine a pseudo-elevation or true nephrotoxicity?

INTRODUCTION

The aim of this study was to determine the rates of trimethoprim/sulfamethoxazole (TMP/SMX)-associated pseudo-elevation and true nephrotoxicity by comparison of creatinine-estimated and cystatin C-estimated GFRs (glomerular filtration rates) before and after TMP/SMX administrations.

METHODS

Patients in whom serum creatinine and cystatin C were simultaneously measured are the cohort of this study. A decreasing of creatinine-estimated GFR posterior to TMP/SMX by ≥ 20% and a decreasing of cystatine C-estimated GFR posterior to TMP/SMX by ≥ 20% were defined as true nephrotoxicity. A decreasing of creatinine-estimated GFR posterior to TMP/SMX by ≥ 20% and a decreasing of cystatine C-estimated GFR posterior to TMP/SMX by < 20% were defined as pseudo-elevation.

RESULTS

A total of 66 patients were enrolled. Within the 19 patients in whom serum creatinine and cystatin C were measured simultaneously both before and after TMP/SMX administrations, 10 patients (52.6%) had nephrotoxicity. Fewer random error and systematic bias between creatinine- and cystatine C-estimated GFR were observed after TMP/SMX than before TMP/SMX by Bland-Altman analysis.

CONCLUSIONS

Using cystatin C, we reveled TMP/SMX-associated nephrotoxicity is not uncommon. We should equally pay attention to TMP/SMX-associated nephrotoxicity and pseudo-elevation. In spite of pseudo-elevation, creatinine-estimated GFR after receiving TMP/SMX is ironically reliable as surrogate maker for renal clearance.

Cross-Sectional and Longitudinal Performance of Creatinine- and Cystatin C-Based Estimating Equations Relative to Exogenously Measured Glomerular Filtration Rate in HIV-Positive and HIV-Negative Persons

BACKGROUND

Reliable estimates of glomerular filtration rate (GFR) are important in the clinical management of HIV-positive patients. Data on the performance of widely used estimating equations (eGFR) relative to exogenously measured GFR are sparse in this population.

METHODS

We evaluated cross-sectional and longitudinal accuracy and bias of eGFR, based on creatinine and cystatin C, relative to disappearance of infused iohexol from plasma (iGFR) in a cohort of participants followed annually for up to 7 years.

RESULTS

A total of 222 HIV-positive and 139 HIV-negative participants contributed 1240 visits with valid iGFR and eGFR measures. Estimated GFR based on both creatinine and cystatin C performed the best. Estimated GFR based on creatinine alone overestimated iGFR by 9 mL·min·1.73 m on average and was significantly less accurate in HIV-positive than HIV-negative individuals. The performance of equations based on either creatinine alone or cystatin C alone were significantly affected by participant factors (eg, non-suppressed HIV RNA, nadir CD4 count, hepatitis C virus coinfection). The average iGFR slope was -4% per year in HIV-positive participants. In both HIV-positive and HIV-negative participants, eGFR slope measures were generally unbiased but inaccurate, with only 60%-74% of observations falling within ±5% points of iGFR slope.

CONCLUSIONS

Both creatinine and cystatin C have limitations as GFR indices in HIV-positive individuals. Estimated GFR based on both creatinine and cystatin C performed best in our study and may be preferred in HIV-positive persons with kidney disease or comorbidities that place them at high risk for kidney disease.

Cystatin C as a potential biomarker to evaluate migraine

BACKGROUND

Migraine is a multifactorial neurovascular syndrome and closely associated to inflammation. Cystatin C (Cys C) is a neuroendocrine polypeptide which also plays a role in inflammation. Objective: To investigate the levels of Cys C in migraine patients without aura.

METHODS

A total of 80 participants were included in the study; 40 patients and 40 healthy controls. Serum Cys C levels were investigated by using enzyme-linked immunosorbent assay (ELISA). Statistical analysis were performed using Statistical Package for the Social Sciences (SPSS) version 22.0 (SPSS Inc, IL, USA).

RESULTS

Serum Cys C levels were found as 73.88 ng/mL in the patient group and 24.92 ng/mL in the healthy control group, being significantly higher among patients (p=0.000). Serum Cys C levels were significacntly different across age subgroups among patients (p=0.049), but not among controls. However, visual analog scale (VAS) (p=0.707), disease duration time (p=0.725) and body mass index (p=0.136) were not significantly different between the two groups.

CONCLUSION

Our findings demonstrate that high serum Cys C levels are independently associated to migraine without aura. To the best of our knowledge, this is the first study to determine the serum levels of Cys C in patients with migraine. Thus, serum Cys C may be a potential biomarker of migraine.

Overestimation of glomerular filtration rate by creatinine-based equation in heart failure patients is predicted by a novel scoring system

AIMS

Creatinine-based estimated glomerular filtration rate (eGFRcre) has been shown to overestimate the glomerular filtration rate (GFR) when it is compared with cystatin C-based estimated GFR (eGFRcys) in older people. We investigated clinical determinants of GFR overestimation by eGFRcre and developed a score for prediction of GFR overestimation (OE) in heart failure patients.

METHODS

We retrospectively examined 244 Japanese heart failure patients (aged 72.2 ± 13.1 years; 48% women) who had no known extrarenal factors that affect serum cystatin C concentration. eGFR OE by eGFRcre was defined as eGFRcre being ≥120% of cystatin C-based eGFR.

RESULTS

The proportion of heart failure patients with OE was 14.3%. Patients with OE were older, had lower body weight and total skeletal muscle mass than those in patients without OE. Laboratory examinations showed that hemoglobin concentration was lower, and the ratio of blood urea nitrogen-to-creatinine was higher in patients with OE than in patients without OE. In multivariate regression analysis, body weight (<63.0 kg in men and <42.0 kg in women), hemoglobin level (<12.4 g/dL in men and <11.0 g/dL in women) and ratio of blood urea nitrogen-to-creatinine (>26.5) in addition to skeletal muscle mass were independently associated with OE. A score calculated by using cut-off levels of body weight, hemoglobin concentration and ratio of blood urea nitrogen-to-creatinine predicted OE with a sensitivity of 97.1% and a specificity of 98.1%.

CONCLUSION

Overestimation of GFR by eGFRcre is predictable by a novel scoring system, which might be useful for the detection of patients who require cystatin C-based eGFR measurement for accurate assessment of renal function. Geriatr Gerontol Int 2020; 20: 752-758.

The Value of a Cystatin C-based Estimated Glomerular Filtration Rate for Cardiovascular Assessment in a General Japanese Population: Results From the Iwate Tohoku Medical Megabank Project

BACKGROUND

Epidemiological studies have shown that high circulating cystatin C is associated with a risk of cardiovascular disease (CVD) independent of creatinine-based renal function measurements. The present study investigated the comparison between the cystatin C-based estimated glomerular filtration rate (GFRcys) and creatinine-based GFR (GFRcr) to determine whether these measurements are associated with CV biomarkers and elevated CVD risk in a general Japanese population.

METHODS

The Iwate Tohoku Medical Megabank Organization pooled individual participant data from a general population-based cohort study in Iwate prefecture (n = 29,375). Chronic kidney disease (CKD) was estimated using the GFRcys, GFRcr and the urine albumin-to-creatinine ratio (UACR).

RESULTS

The prevalence of CKD in the participants was found to be higher based on the GFRcr than the GFRcys. Multiple variable analyses after adjusting for baseline characteristics showed that high-sensitivity cardiac troponin T (hs-cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP) were associated with the GFRcys. The area under the receiver operating characteristic (AUROC) curve for identifying individuals with a high Suita score was higher for the GFRcys (AUROC = 0.68) than it was for the GFRcr (AUROC = 0.64, P < 0.001). The GFRcys provided reclassification improvement for the CVD risk prediction model by the GFRcr (net reclassification improvement = 0.341; integrated discrimination improvement = 0.018, respectively, P < 0.001).

CONCLUSIONS

The GFRcys is more closely associated with CV biomarkers, including hs-cTnT and NT-proBNP levels, and a high Suita score than the GFRcr, and it provides additional value in the assessment of CVD risk using GFRcr.

Serum cystatin C levels are decreased in type 1 diabetes mellitus patients with diabetic ketoacidosis

BACKGROUND

Cystatin C is a marker of renal function and risk factor for cardiovascular disease. Patients with acute myocardial infarction showed a significant decrease in cystatin C levels. It is unknown whether reduced serum cystatin C levels are connected to acute events or represent a negative acute phase response. The current study aimed to assess the association between cystatin C and the existence of diabetic ketoacidosis (DKA), an acute event in individuals with type 1 diabetes mellitus (T1DM).

METHODS

Cystatin C was measured in the control group (N.=322) and in T1DM patients with (N.=161) and without DKA (N.=146). Data were compared according to diabetes and ketoacidosis status. Correlation analysis was used to identify factors associated with cystatin C levels. A multiple stepwise regression analysis was used to determine which of the parameters that were significantly correlated with cystatin C in univariate analysis were independently related to cystatin C. Then, we assessed the independent association between cystatin C and the occurrence of DKA in T1DM patients.

RESULTS

Serum cystatin C levels were lower in patients with DKA than in patients without DKA. After adjustment for age, sex, fasting plasma glucose and creatinine, cystatin C was positively correlated with the duration of diabetes, systolic blood pressure (SBP), total cholesterol, triglycerides, uric acid and low-density lipoprotein cholesterol (P=0.004, P=0.022, P=0.013, P=0.035, P=0.006, P=0.012, respectively) and negatively correlated with hemoglobin (P<0.001). The duration of diabetes (P<0.001), total cholesterol (P=0.002), hemoglobin (P<0.001), SBP (P=0.011) and serum creatinine (P<0.001) were independently associated with cystatin C. Furthermore, we found that cystatin C was independently associated with the occurrence of DKA in T1DM patients (OR=0.004, 95% CI: 0.000-0.079, P<0.001).

CONCLUSIONS

Cystatin C was decreased in T1DM patients with DKA and was found to be an independent predictor of the occurrence of DKA in T1DM patients. The reduction in cystatin C levels might be significantly connected with acute events.

Plasma Cystatin C Associates With HIV-Associated Neurocognitive Disorder but Is a Poor Diagnostic Marker in Antiretroviral Therapy-Treated Individuals

OBJECTIVE

To examine associations between plasma cystatin C and neurocognitive impairment (NCI) and its performance as a diagnostic marker before and during initial antiretroviral therapy (ART).

METHODS

Multivariable logistic regression and generalized estimating equations examined associations with NCI, determined by neuropsychological measurements, in participants of a 48-week randomized clinical trial of initial ART. Receiver operator characteristic curves examined diagnostic models of NCI.

RESULTS

Cystatin C was associated with NCI before ART [odds ratio (OR) 3.4 (95% CI: 1.2 to 9.4) for each 2-fold increase in baseline levels] and during 48 weeks of ART, in models that excluded baseline measurements [OR 3.0 (1.2 to 7.8) for each 2-fold increase in time-updated levels]. The strength of association increased with more severe impairment using HIV-associated neurocognitive disorder criteria [OR 2.2 (0.8 to 6.0) with asymptomatic NCI and OR 4.0 (1.5 to 11.0) with mild neurocognitive disorder or HIV-associated dementia vs. no impairment, for each 2-fold increase in time-updated levels] or by global development score [OR 2.6 (1.1 to 6.3) with mild impairment and OR 4.6 (1.1 to 18.9) with moderate or severe impairment vs. no impairment]. Cystatin C performed poorly as a diagnostic marker for NCI, however, with an area under the receiver operator characteristic curve of 0.58 at baseline and 0.54 at week 48.

CONCLUSIONS

Higher plasma cystatin C levels were significantly associated with NCI, but these levels did not seem to be useful as a diagnostic marker for this condition.

Serum Cystatin C and Arterial Stiffness in Middle-Aged and Elderly Adults without Chronic Kidney Disease: A Population-Based Study

BACKGROUND Cystatin C is a protease inhibitor that is increased in the serum of patients with chronic kidney disease (CKD) and is associated with an increased risk of developing cardiovascular disease (CVD). This study aimed to evaluate the association between serum levels of cystatin C and arterial stiffness, associated with dyslipidemia, obesity, and increased pulse pressure, in middle-aged and elderly individuals without CKD in a population in China. MATERIAL AND METHODS A cross-sectional population-based study included 1,138 patients aged ≥40 years without CKD, defined as an estimated glomerular filtration rate measured by serum creatinine (eGFRSCr) ≥60 ml/min/1.73 m². Study participants provided clinical details, including height and weight, and blood samples for serum measurements of cystatin C and lipid profiles and completed a clinical questionnaire. Pulse pressure was calculated as the mean systolic pressure (SBP) minus the diastolic pressure (DBP). Data underwent multivariate logistic regression analysis. RESULTS An increase in serum levels of cystatin C was associated with an increased risk of arterial stiffness. Each standard deviation in the increase of cystatin C resulted in a 22% increased risk of dyslipidemia, a 27% increased risk of obesity, and a 24% increased risk of increased pulse pressure, after adjusting for confounders. These associations were further confirmed in a sensitivity analysis by excluding participants with hypertension, diabetes, and patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). CONCLUSIONS In middle-aged and elderly individuals without CKD, arterial stiffness determined by obesity, dyslipidemia and increased pulse pressure, was significantly associated with increased serum levels of cystatin C.

Serum Cystatin C, a Sensitive Marker of Renal Function and Cardiovascular Disease, Decreases After Smoking Cessation

Background: Smoking exerts detrimental effects during the progression of atherosclerotic vascular disease. Serum cystatin C is useful in the evaluation of early renal dysfunction and serves as a cardiovascular prognostic marker. This study measured changes in serum cystatin C after smoking cessation (SC). Methods and Results: In this study, patients who visited the SC clinic for the first time and succeeded in SC for 1 year were enrolled. In the entire cohort of 86 patients, body mass index (BMI, P<0.001) and waist circumference (WC, P<0.001) increased significantly at 3 months after SC compared with baseline. These values were further increased significantly (BMI, P<0.001; WC, P<0.001) from 3 months to 1 year after SC. Serum cystatin C decreased significantly at 3 months (P=0.045) after SC, and remained unchanged (P=0.482) from 3 months to 1 year after SC. Percent change from baseline to 3 months after SC in serum cystatin C was correlated with the percent change in serum monocyte chemoattractant protein 1 (P=0.047). Conclusions: Serum cystatin C, a marker of chronic kidney disease, was significantly reduced at 3 months after SC.

Association of serum albumin levels with kidney function decline and incident chronic kidney disease in elders

Background

Previous studies in HIV-infected individuals have demonstrated serum albumin to be strongly associated with kidney function decline, independent of urine albumin and inflammatory markers. Lower serum albumin concentrations may be an under-appreciated risk factor for kidney function decline in elders.

Methods

We performed a cohort analysis in the Health Aging and Body Composition Study, a cohort of well-functioning, bi-racial, community-dwelling elders between the age of 70 and 79 years. We examined the associations of serum albumin concentration with longitudinal kidney function decline by estimated glomerular filtration rate (eGFR). Outcomes included linear eGFR decline, rapid kidney function decline defined as >30% decrease in eGFR, defined as a final eGFR <60 mL/min/1.73 m2 in those with an eGFR >60 mL/min/1.73 m2 at baseline. Cystatin C-based eGFR was calculated at baseline, Year 3 and Year 10.

Results

Mean age was 74 years, and mean eGFR was 73 mL/min/1.73 m2 at baseline. The mean rate of eGFR change was 1.81 mL/min/1.73 m2 per year. After multivariate adjustment, lower serum albumin concentrations were strongly and independently associated with kidney function decline (-0.11 mL/min/1.73 m2 per year for each standard deviation decrease serum albumin; -0.01 to - 0.20) with no attenuation after adjustment for urine albumin and inflammatory markers (-0.12, -0.03 to - 0.22). When divided into quartiles, serum albumin levels ≤3.80 g/dL were associated with increased odds of rapid kidney function decline (odds ratio 1.59; 1.12-2.26) and increased risk of incident chronic kidney disease (incident rate ratio 1.29; 1.03-1.62) relative to levels >4.21g/dL. Urine albumin to creatinine ratio (ACR) was also significantly and independently associated with kidney function decline (-0.08 mL/min/1.73 m2 per year for urine ACR >30 mg/g; -0.82 to - 0.13).

Conclusions

Lower serum albumin levels are strongly and independently associated with kidney function decline in elders, independent of clinical risk factors, urine albumin and measured inflammatory markers.

Adverse outcomes after non urological surgeries in patients with chronic kidney disease: a propensity-score-matched study

Objective

To evaluate the complications, mortality, and medical expenditures after nonurological surgical procedures in patients with chronic kidney disease (CKD).

Methods

Using claims data of Taiwan’s National Health Insurance, we conducted a matched cohort study of 35,643 patients with CKD who underwent nonurological surgeries in 2008–2013. By using a propensity-score matching procedure, 35,643 non-CKD patients were selected for comparison. Logistic regression was used to calculate the odds ratios (ORs) and the 95% confidence intervals (CIs) of postoperative complications and in-hospital mortality associated with CKD.

Results

The results showed that patients with CKD had higher risks of postoperative septicemia (OR: 1.78, 95% CI: 1.68–1.89), pneumonia (OR: 1.60, 95% CI: 1.48–1.73), stroke (OR: 1.34, 95% CI: 1.24–1.44), and in-hospital mortality (OR: 2.17, 95% CI: 1.90–2.47) compared with non-CKD patients. Longer hospital stays and higher medical expenditures after nonurological surgical procedures were noted in CKD patients. The association between CKD and postoperative adverse events was significant in both sexes, all of the age groups, and the other subgroups. Histories of myocardial infarction, epilepsy, and ages greater than 70 years were factors that were significantly associated with postoperative adverse events.

Conclusion

Compared with non-CKD patients, surgical patients with CKD exhibited more adverse events, with risks of in-hospital mortality that were approximately 2-fold higher after nonurinary surgery. These findings suggest an urgent need to revise the protocols for postoperative care in this population.

Serum cystatin C levels relate to no-reflow phenomenon in percutaneous coronary interventions in ST-segment elevation myocardial infarction

Background/Aim

No-reflow is a serious and frequent event during primary percutaneous coronary intervention (PPCI) for acute ST segment elevation myocardial infarction (STEMI). The aim of this study was to identify possible predictors for no-reflow.

Patients and methods

We investigated 218 patients with acute anterior STEMI who underwent PPCI from December 2016 to December 2018. No-reflow was defined as a coronary TIMI flow grade of ≤ 2. TIMI flow grade 3 was defined as normal reflow.

Results

In our study, the no-reflow phenomenon was observed in 39 patients (18%) during angiography. The patients of no-reflow group were found to be more older, diabetics, longer pain-to-balloon time, lower blood pressure, higher platelet counts and higher levels of D-Dimer and Cystatin C (Cys-C). In multivariate logistic regression analysis, only diabetes (OR = 0.371, 95% CI: 0.157–0.872, P = 0.023), longer pain-to-balloon time (OR = 1.147, 95% CI: 1.015–1.297, P = 0.028) and higher Cys-C level (OR = 10.07, 95% CI: 2.340–43.377, P = 0.002) were predictors for no-reflow.

Conclusion

Cys-C might be a useful predictor for the no-reflow phenomenon after PPCI in STEMI patients. It might help to screen STEMI patients with high risk of no-reflow on admission.

Differences in Kidney Function Estimates Based on Creatinine and/or Cystatin C in Non-Traumatic Amputation Patients and Their Impact on Drug Prescribing

Accurate kidney function estimates are necessary when prescribing renally-eliminated medications. Our objectives were to investigate how amputation affects estimated glomerular filtration rate (eGFR) and to determine if dosing recommendations differ among different eGFR equations. In a cohort study of non-traumatic amputation patients, eGFR based on creatinine and/or cystatin C were measured before and after amputation. Prescribed, renally-eliminated medications were compared with dosing guidelines in Renbase^®. Data from 38 patients with a median age of 75 years were analyzed. The median (range) eGFR was 65 (15⁻103), 38 (13⁻79), and 48 (13⁻86) mL/min/1.73 m² before amputation and 80 (22⁻107), 51 (13⁻95), and 62 (16⁻100) mL/min/1.73 m² after amputation for eGFR_Creatinine, eGFR_CystatinC, and eGFR_Combined, respectively (p < 0.01). From before to after amputation, eGFR increased on average by 8.5, 6.1, and 7.4 mL/min/1.73 m² for eGFR_Creatinine, eGFR_CystatinC, and eGFR_Combined (all p < 0.01), respectively. At least one renally-eliminated medication was prescribed at a higher dose than recommended in 37.8% of patients using eGFR_CystatinC, 17.6% using eGFR_Combined and 10.8% using eGFR_Creatinine. In conclusion, amputation affects eGFR regardless of the eGFR equations. The differences among equations would impact prescribing of renally-eliminated medications, particularly when switching from creatinine to cystatin C.

Predictive value of long-term changes of growth differentiation factor-15 over a 27-year-period for heart failure and death due to coronary heart disease

BACKGROUND

Growth differentiation factor-15 (GDF-15), Cystatin C and C-reactive protein (CRP) have been discussed as biomarkers for prediction of cardiac diseases. The aim of this study was to investigate the predictive value of single and repeated measurements of GDF-15 compared to Cystatin C and CRP for incidence of heart failure (HF) and death due to coronary heart disease (CHD) in the general population.

METHODS AND RESULTS

Levels of GDF-15, CRP and Cystatin C were determined in three repeated measurements collected 5 years apart in the DAN-MONICA (Danish-Multinational MONitoring of trends and determinants in Cardiovascular disease) cohort (participants at baseline n = 3785). Cox regression models adjusted for cardiovascular risk factors revealed significantly increased hazard ratios (HR) for GDF-15 for incident HF 1.36 (HR per interquartile range (IQR) increase, 95% confidence interval (CI): 1.16; 1.59) and for death from CHD 1.51 (HR per IQR increase, 95% CI: 1.31, 1.75) (both with p<0.001). Joint modeling of time-to-event and longitudinal GDF-15 over a median 27-year follow-up period showed that the marker evolution was positively associated with death of CHD (HR per IQR increase 3.02 95% CI: (2.26, 4.04), p < 0.001) and HF (HR per IQR increase 2.12 95% CI: (1.54, 2.92), p<0.001). However using Cox models with follow-up time starting at the time of the third examination, serial measurement of GDF-15, modeled as changes between the measurements, did not improve prediction over that of the most recent measurement.

CONCLUSIONS

GDF-15 is a promising biomarker for prediction of HF and death due to CHD in the general population, which may provide prognostic information to already established clinical biomarkers. Repeated measurements of GDF-15 displayed only a slight improvement in the prediction of these endpoints compared to a single measurement.

Inverse Relationship between Adherence to the Mediterranean Diet and Serum Cystatin C Levels

OBJECTIVE

The aim of the present study was to examine serum cystatin C levels in association with the Mediterranean diet in a healthy Greek population.

METHODS

Cystatin C together with basic clinical chemistry tests was measured in a total of 490 adults (46±16 years, 40% of males), who underwent an annual health check. Demographic, anthropometric and lifestyle characteristics were recorded, while adherence to the Mediterranean diet was evaluated through the MedDietScore (0-55).

RESULTS

The mean level of serum cystatin C was 0.84 mg/L, while men had increased serum cystatin C levels compared to women (0.86 mg/L vs. 0.83 mg/L, respectively, 0.017). After adjusting for age, gender, body mass index, smoking status, hypertension, diabetes, hypercholesterolemia, estimated glomerular filtration rate (eGFR), albumin and ferritin levels, each unit increase in MedDietScore led to 0.002 mg/dL drop off in cystatin C serum levels.

CONCLUSIONS

We have demonstrated an inverse relationship between the MedDietScore and serum cystatin C levels. Our finding that increases in MedDietScore are associated with decreases in serum cystatin C levels could imply that adherence to the Mediterranean diet may reduce the cardiovascular risk, as assessed by cystatin C, a prognostic marker of the cardiometabolic risk. This notion could have a great impact on public health.

Association between high cystatin C levels and carotid atherosclerosis

AIM

To investigate the association between carotid atherosclerosis and cystatin C (CysC) and to determine the optimal CysC cut-off value.

METHODS

One hundred twenty-eight subjects were included in this study. Atherosclerosis was defined as a maximum carotid plaque thickness (MCPT) of greater than 2 mm. A receiver operating characteristic curve analysis was used to determine the diagnostic value of serum CysC for atherosclerosis. The subjects were divided into two groups according to the CysC cut-off value. We screened for diabetes, hypertension, dyslipidemia, smoking status, alcohol consumption, and exercise behavior. The association between atherosclerosis and CysC levels was assessed using multivariate analysis.

RESULTS

The subjects were then divided into two groups according to the CysC cut-off value (0.73 mg/L). The median age of the high CysC group was 72 years (85% males), whereas that of the low CysC group was 61 years (63% males). The CysC levels were significantly correlated with Cr and estimated glomerular filtration rate (eGFR) values. Body-mass index, visceral fat area, hypertension, diabetes mellitus, and MCPT were significantly higher in the high CysC group than in the low CysC group. Furthermore, the eGFR was significantly lower in the high CysC group. Regarding lifestyle habits, only the exercise level was lower in the high CysC group than in the low CysC group. Multivariate analysis, adjusted for age and sex, revealed that high CysC levels were significantly associated with an MCPT of ≥ 2 mm (odds ratio: 2.92; 95%CI: 1.13-7.99).

CONCLUSION

Higher CysC levels were associated with an MCPT of ≥ 2 mm. The CysC cut-off value of 0.73 mg/L appears to aid in the diagnosis of atherosclerosis.

Association Between Serum β2 -Microglobulin Levels and Prevalent and Incident Physical Frailty in Community-Dwelling Older Women

OBJECTIVES

To investigate whether higher serum β₂ -microglobulin (B2M) levels, a kidney function marker, are associated with prevalent and incident frailty in community-dwelling older women.

DESIGN

Cross-sectional and longitudinal analyses of a prospective cohort.

SETTING

Population-based cohort study in Tokyo, Japan.

PARTICIPANTS

Community-dwelling women aged 75 and older with adequate data for assessing frailty status (N = 1,191) and a subset of participants without baseline frailty but with repeated frailty assessment at 2 and 4 years of follow-up.

MEASUREMENTS

The primary predictor was B2M level. Outcomes were prevalent and incident frailty during the 4-year follow-up period. Frailty was defined as presence of three of the five Fried criteria: weight loss, exhaustion, weakness, slowness, and low physical activity. Adjusted odds ratios for the main confounders were obtained using logistic regression. Discrete-time Cox proportional hazards models were used to determine the risk of developing frailty.

RESULTS

The study included 241 (20.2%) women with prevalent frailty at baseline and 139 (21.1%) with incident frailty during the 4-year follow-up. On multivariate analysis adjusted for multiple potential confounders, the odds of prevalent frailty were 2.5 times as great with B2M levels of 1.9 to 2.1 mg/L as with levels less than 1.6 mg/L and 2.0 times as great with B2M levels of 2.2 mg/L or more. In the unadjusted model, B2M levels of 1.9 to 2.1 mg/L were associated with a greater incidence of frailty than B2M levels of less than 1.6 mg/L (hazard ratio = 1.72, 95% confidence interval = 1.04-2.86). In the multivariate analysis adjusted for potential confounders, no significant association was noted between the highest B2M quartile and incident frailty.

CONCLUSION

Higher B2M levels were independently associated with greater frailty at baseline in older adults but only slightly associated with greater risk of incident frailty over 4 years of follow-up.

Relationship between cystatin C and metabolic syndrome among Chinese premenopausal and postmenopausal women without recognized chronic kidney disease

OBJECTIVE

Although studies have shown that elevated cystatin C (Cys-C) levels are associated with the risk of metabolic syndrome (MetS) in the general population, few studies have examined the relationship between serum Cys-C levels and MetS, stratified by menopause status, among women in China. Therefore, we conducted this study to assess the relationship between Cys-C levels and MetS in Chinese premenopausal and postmenopausal women.

METHODS

We performed a cross-sectional analysis of the baseline data of 1,428 Chinese community-dwelling women who participated in the annual health checkup. MetS was defined by the updated National Cholesterol Education Program/Adult Treatment Panel III criteria. Binary logistic regression analysis was performed to estimate the association between Cys-C levels and MetS. One-way analysis of variance, followed by posttest for linear trends, was performed to evaluate the relationships between Cys-C levels and the number of MetS components. Ordinal regression analysis was used to determine whether menopause status and MetS components contribute to elevated levels of Cys-C.

RESULTS

The mean level of Cys-C was significantly higher in women with MetS than in those without MetS among both premenopausal and postmenopausal women, showing a progressive increase (P for trend < 0.001) in parallel with the progressive increment in the number of MetS components in all women. Higher Cys-C levels were found to be associated with the presence of MetS after adjusting for age, body mass index, and estimated glomerular filtration rate in all women. The higher odds ratio changed little, even after further adjustment for serum blood nitrogen, total cholesterol, low-density lipoprotein cholesterol, drinking status, and smoking status. Elevated Cys-C level was significantly associated with postmenopause status (P = 0.007), increased waist circumference (P = 0.006), and elevated blood pressure (P = 0.025).

CONCLUSIONS

Higher serum Cys-C levels are positively and independently associated with the presence of MetS in Chinese premenopausal and postmenopausal women. Elevated Cys-C levels are significantly associated with postmenopause status.

The Association of Serum Cystatin C with Glycosylated Hemoglobin in Korean Adults

BACKGROUND

Cystatin C has been known to be associated not only with early renal impairment but also with the incidence of diabetic conditions (prediabetes plus diabetes). However, it is not clear whether cystatin C levels are associated with the prevalence of diabetic conditions in Asian populations. We evaluated this association using glycosylated hemoglobin (HbA1c) levels as the definition of diabetes in Korean adults.

METHODS

We analyzed data from 1,559 Korean adults (937 men and 622 women) with available serum cystatin C and HbA1c values.

RESULTS

The serum cystatin C levels in subjects with prediabetes and diabetes were significantly increased (0.91±0.14 mg/L in prediabetes and 0.91±0.17 mg/L in diabetes vs. 0.88±0.13 mg/L in patients with normal glucose levels, P=0.001). At increasing cystatin C levels, the prevalence of subjects with prediabetes (30.2% vs. 14.6%, P<0.001) and those with diabetes (10.6% vs. 8.0%, P<0.001) significantly increased in the group with the highest cystatin C levels. The group with the highest cystatin C levels had a significantly increased odds ratio (OR) for the presence of diabetic conditions compared to the group with the lowest values in total subjects (OR, 2.35; 95% confidence interval [CI], 1.54 to 3.58; P<0.001) and in women (OR, 4.13; 95% CI, 1.97 to 8.65; P<0.001), though there was no significant increase after adjusting for multiple variables.

CONCLUSIONS

Higher levels of serum cystatin C are associated with an increased prevalence of diabetic conditions in Korean adults. Our findings may extend the positive association of cystatin C with diabetes incidence to an Asian population.

Association between Serum Cystatin C and Diabetic Foot Ulceration in Patients with Type 2 Diabetes: A Cross-Sectional Study

Serum cystatin C (CysC) has been identified as a possible potential biomarker in a variety of diabetic complications, including diabetic peripheral neuropathy and peripheral artery disease. We aimed to examine the association between CysC and diabetic foot ulceration (DFU) in patients with type 2 diabetes (T2D). 411 patients with T2D were enrolled in this cross-sectional study at a university hospital. Clinical manifestations and biochemical parameters were compared between DFU group and non-DFU group. The association between serum CysC and DFU was explored by binary logistic regression analysis. The cut point of CysC for DFU was also evaluated by receiver operating characteristic (ROC) curve. The prevalence of coronary artery disease, diabetic nephropathy (DN), and DFU dramatically increased with CysC (P < 0.01) in CysC quartiles. Multivariate logistic regression analysis indicated that the significant risk factors for DFU were serum CysC, coronary artery disease, hypertension, insulin use, the differences between supine and sitting TcPO₂, and hypertension. ROC curve analysis revealed that the cut point of CysC for DFU was 0.735 mg/L. Serum CysC levels correlated with DFU and severity of tissue loss. Our study results indicated that serum CysC was associated with a high prevalence of DFU in Chinese T2D subjects.

Which biomarkers are predictive specifically for cardiovascular or for non-cardiovascular mortality in men? Evidence from the Caerphilly Prospective Study (CaPS)

OBJECTIVE

To examine a panel of 28 biomarkers for prediction of cardiovascular disease (CVD) and non-CVD mortality in a population-based cohort of men.

METHODS

Starting in 1979, middle-aged men in Caerphilly underwent detailed medical examination. Subsequently 2171 men were re-examined during 1989-1993, and fasting blood samples obtained from 1911 men (88%). Fibrinogen, viscosity and white cell count (WCC), routine biochemistry tests and lipids were analysed using fresh samples. Stored aliquots were later analysed for novel biomarkers. Statistical analysis of CVD and non-CVD mortality follow-up used competing risk Cox regression models with biomarkers in thirds tested at the 1% significance level after covariate adjustment.

RESULTS

During an average of 15.4 years follow-up, troponin (subhazard ratio per third 1.71, 95% CI 1.46-1.99) and B-natriuretic peptide (BNP) (subhazard ratio per third 1.54, 95% CI 1.34-1.78) showed strong trends with CVD death but not with non-CVD death. WCC and fibrinogen showed similar weaker findings. Plasma viscosity, growth differentiation factor 15 (GDF-15) and interleukin-6 (IL-6) were associated positively with both CVD death and non-CVD death while total cholesterol was associated positively with CVD death but negatively with non-CVD death. C-reactive protein (C-RP), alkaline phosphatase, gamma-glutamyltransferase (GGT), retinol binding protein 4 (RBP-4) and vitamin B6 were significantly associated only with non-CVD death, the last two negatively. Troponin, BNP and IL-6 showed evidence of diminishing associations with CVD mortality through follow-up.

CONCLUSION

Biomarkers for cardiac necrosis were strong, specific predictors of CVD mortality while many inflammatory markers were equally predictive of non-CVD mortality.

Relationship of Changes in Cystatin-C With Serum Creatinine and Estimated Glomerular Filtration Rate in Kidney Transplantation

BACKGROUND

Serum creatinine (S-Cr) is the most commonly used marker for the assessment of renal function in kidney transplantation (KTx). Cystatin-C (Cys-C) has been proposed as an alternative marker of renal function for the estimated glomerular filtration rate (eGFR), which seems to be more accurate than S-Cr. The aim of this study was to investigate the relationship between changes in S-Cr, Cys-C, and eGFR measurements in KT patients during the early post-transplantation (post-Tx) period.

METHODS

Fifty consecutive patients, aged 15 to 70 years, were subjected to KT. Blood samples were collected at stable time-points on pre-Tx and post-Tx days 2, 6, and 14 and in the third month. Cys-C and S-Cr levels were measured, and GFR was estimated at all time-points using the Cockcroft-Gault and Le Bricon equations.

RESULTS

S-Cr and Cys-C levels decreased significantly post-Tx in all time-point determinations compared with pre-Tx levels. Both markers showed a parallel decrease, reaching normal levels in the third month. Estimated GFR post-Tx by S-Cr and Cys-C exhibited a parallel progressive increase without significant difference between the calculations. Correlation between S-Cr and Cys-C in all time-point determinations was positive and of high significance using Pearson's correlation (r = 0.969, P < .01; r = 0.951, P < .01; r = 0.969, P < .01; r = 0.701, P < .01). Also, the correlation between the eGFR by Cys-C and S-Cr was positive and of high significance in all post-Tx calculations (r = 0.896, P < .01; r = 0.935, P < .01; r = 0.929, P < .01; r = 0.861, P < .01). Ten recipients had acute rejection and were treated successfully with antirejection therapy. Their S-Cr, cys-C, and eGFR results were analyzed separately and showed a significant difference from no-rejection patients, with Cys-C being more sensitive to earlier eGFR changes.

CONCLUSION

Cystatin-C is an alternative and accurate marker of renal function in KT patients showing similar diagnostic characteristics to S-Cr. However, Cys-C appears superior to S-Cr in reflecting early GFR temporary changes, which is critical for the early detection of acute rejection.

Increased cystatin C levels as a risk factor of cardiovascular events in patients with preserved estimated glomerular filtration rate after elective percutaneous coronary intervention with drug-eluting stents

Chronic kidney disease (CKD) is an important risk factor for coronary artery disease (CAD) and cardiovascular events. Cystatin C (CysC) has been proposed as a sensitive marker for CKD. However, the predictive value of CysC for cardiovascular events in CAD patients with preserved estimated glomerular filtration rate (eGFR) is unclear. We enrolled 277 consecutive patients undergoing elective percutaneous coronary intervention with sirolimus-eluting stents (SES). Patients with an eGFR ≤60 ml/min/1.73 m(2) were excluded. Serum CysC levels were measured immediately before SES implantation. Major adverse cardiac and cerebrovascular events (MACCE) were defined as cardiovascular death, acute coronary syndrome, stroke, and hospitalization because of congestive heart failure. After a median follow-up of 63 months, 29 patients had MACCE. The subjects were divided into 2 groups based on median serum CysC levels and eGFR (0.637 mg/L and 72.43 ml/min/1.73 m(2), respectively). Kaplan-Meier curves showed that the high CysC group had a significantly higher occurrence of MACCE than the low CysC group (p = 0.006), although a low level of eGFR was not significantly associated with an increased risk for occurrence of MACCE. Multivariate analysis revealed that serum CysC levels were an independent predictor of MACCE [hazards ratio: 1.30 per 0.1 mg/L (1.01-1.63), p = 0.038]. These data suggested that serum CysC level is an independent predictor of MACCE, even in patients with preserved eGFR after elective SES implantation.

Association of genetic variants with coronary artery disease and ischemic stroke in a longitudinal population-based genetic epidemiological study

Our previous studies identified nine genes and chromosomal region 3q28 as susceptibility loci for myocardial infarction, ischemic stroke or chronic kidney disease by genome-wide or candidate gene association studies. As coronary artery disease (CAD) and ischemic stroke may share genetic architecture, certain genetic variants may confer susceptibility to the two diseases. The present study examined the association of 13 polymorphisms at these 10 loci with the prevalence of CAD or ischemic stroke in community-dwelling individuals, with the aim of identifying genetic variants that confer susceptibility to the two conditions. Study subjects (170 with CAD, 117 with ischemic stroke and 5,718 controls) were recruited to the Inabe Health and Longevity Study, a longitudinal genetic epidemiological study of atherosclerotic, cardiovascular and metabolic diseases. The subjects were recruited from individuals who visited for an annual health checkup and they were followed up each year (mean follow-up period, 5 years). Longitudinal analysis with a generalized estimating equation, and with adjustment for age, gender, body mass index, smoking status, the prevalence of hypertension, diabetes mellitus and dyslipidemia and the serum concentration of creatinine, revealed that rs2074380 (G→A) and rs2074381 (A→G) of the α-kinase 1 (ALPK1) gene and rs8089 (T→G) of the thrombospondin 2 (THBS2) gene were significantly (P<2×10^-16) associated with the prevalence of CAD, with the AA genotype of rs2074380 and GG genotypes of rs2074381 and rs8089 being protective against this condition. Similar analysis revealed that rs9846911 (A→G) at chromosome 3q28, rs2074381 of ALPK1, rs8089 of THBS2 and rs6046 (G→A) of the coagulation factor VII gene were significantly (P<2×10^-16) associated with the prevalence of ischemic stroke, with the GG genotypes of rs9846911, rs2074381 and rs8089 and the AA genotype of rs6046 being protective against this condition. ALPK1 and THBS2 may thus be susceptibility loci for CAD and ischemic stroke.

Comparison of cystatin C and creatinine to determine the incidence of composite adverse outcomes in HIV-infected individuals

BACKGROUND

Cystatin C is an overall biomarker of pathophysiologic abnormalities that accompany chronic kidney disease (CKD). The utility of cystatin C is not fully understood in an HIV-infected population.

METHODS

This prospective study investigated 661 HIV-infected individuals for 4 years to determine the incidence of adverse outcomes, including all-cause mortality, cardiovascular disease, and renal dysfunction. The risk of developing the outcomes was discriminated with a 4 color-coded classification in a 3 × 6 contingency table, that combined 3 grades of dipstick proteinuria with 6 grades of estimated glomerular filtration rate (eGFR) calculated using either serum creatinine (eGFRcr) or cystatin C (eGFRcy): green, low risk; yellow, moderately increased risk; orange, high risk; and red, very high risk. The cumulative incidence of the outcomes was assessed by the Kaplan-Meier method, and the association between color-coded risk and the time to outcome was evaluated using multivariate proportional hazards analysis.

RESULTS

Compared with eGFRcr, the use of eGFRcy reduced the prevalence of risk ≥ orange by 0.8%. The adverse outcomes were significantly more likely to occur to the patients with baseline risk category ≥orange than those with ≤ yellow, independent of risk categories based on eGFRcr or eGFRcy. However, in multivariate analysis, risk category ≥orange with eGFRcy-based classification was significantly associated with adverse outcomes, but not the one with eGFRcr.

CONCLUSIONS

Replacing creatinine by cystatin C in the CKD color-coded risk classification may be appropriate to discriminate HIV-infected patients at increased risk of a poor prognosis.

Kidney function decline in metformin versus sulfonylurea initiators: assessment of time-dependent contribution of weight, blood pressure, and glycemic control

BACKGROUND AND OBJECTIVE

We recently reported that kidney function declined faster among initiators of sulfonylureas compared to metformin; however, sulfonylurea use compared to metformin use was also associated with increases in body mass index (BMI) and systolic blood pressure (SBP). We sought to determine if differences between sulfonylureas and metformin on kidney function decline were mediated by differential effects on BMI, SBP, or glucose control.

METHODS

We identified 13,238 veterans who initiated sulfonylurea or metformin treatment (2000–2007) with a baseline estimated glomerular filtration rate (eGFR) >60 mL/minute, and followed them until a study event occurred, non-persistence on treatment, loss of follow-up, or end of the study. The composite outcome was a sustained decline from baseline eGFR of ≥25%, end-stage renal disease, or death. We estimated the association of cumulative measurements of potential mediators including BMI, SBP, and glycated hemoglobin on the study outcome. We determined if controlling for these time-varying covariates accounted for the differences in outcome between sulfonylurea and metformin initiators.

RESULTS

Compared to sulfonylurea use, metformin use was associated with a lower risk for renal function decline or death [adjusted hazard ratio (aHR) 0.82, 95% confidence interval 0.70, 0.97]. This protective association remained significant [aHR 0.83 (0.70–0.98)] when accounting for the cumulative time-varying measurements of the three mediators of interest.

CONCLUSION

Metformin initiation was associated with a lower risk of kidney function decline or death compared to sulfonylureas, which which appeared to be independent of changes in BMI, SBP, and glycated hemoglobin over time.

Patients with chronic kidney disease/diabetes mellitus: the high-risk profile in acute coronary syndrome

Chronic kidney disease (CKD) and diabetes mellitus (DM) are highly prevalent, morbid diseases that are very common among patients presenting with acute coronary syndromes (ACS). Despite significant reductions in cardiovascular morbidity and mortality over the last half century, residual vascular risk remains disproportionately high in these populations. In large part, this is attributable to pre-existing vascular morbidity and substantial enrichment of traditional risk factors among those with either CKD or DM. Other factors, such as less aggressive therapeutic intervention and a unique atherothrombotic phenotype, are also contributory. The introduction of novel antiplatelet and antithrombotic agents over the last several years provides fresh opportunities to improve the adverse prognosis among patients with CKD or DM and concomitant ACS.

Clinical utility of serum cystatin C in predicting coronary artery disease in patients without chronic kidney disease

BACKGROUND

Cystatin C has been proposed as a novel marker of renal function and predictor of cardiovascular risk. The aim of this study was to investigate the role of cystatin C level as a predictor of cardiovascular events in patients with coronary artery disease (CAD).

METHODS

Three hundred and five coronary artery patients were included in this study. Serum cystatin C levels, high-sensitive C-reactive protein (hs-CRP), and oxidative stress were measured. Estimated glomerular filtration rate (eGFR) and the CAD severity score were calculated.

RESULTS

Cystatin C was correlated with the CAD severity score (r = 0.631, P < 0.0001) and was significantly elevated in the CAD severity score >50. Every 0.1 mg/l increase in cystatin C, 2 mg/l increase in hs-CRP, 0.2 mmol/l decrease in high-density lipoprotein cholesterol, 13.7 ml/min decrease in eGFR, and 1.51 μmol/l increase in homocysteine caused a 34, 12, 5, and 22% increase in the risk of having CAD, respectively.

CONCLUSION

Cystatin C could be a useful laboratory biochemical marker in predicting the severity of CAD. Cystatin C is associated with biochemical atherosclerosis markers such as CRP and homocysteine.

Fibroblast growth factor-23 and the long-term risk of hospital-associated AKI among community-dwelling older individuals

BACKGROUND AND OBJECTIVES

AKI occurs frequently in older persons. Elevated circulating fibroblast growth factor-23 (FGF-23), a known marker of impaired mineral metabolism, may also reflect tubular dysfunction and risk of AKI. This study evaluated FGF-23 as well as traditional markers of kidney disease, namely urine albumin-to-creatinine ratio (UACR) and creatinine-cystatin C estimated GFR (eGFRCrCyC), as risk factors for AKI in elderly individuals.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Plasma FGF-23, UACR, and eGFRCrCyC were measured in 3241 community-dwelling elderly individuals in the Cardiovascular Health Study. Hospitalization for AKI was defined by International Classification of Diseases, Ninth Revision, Clinical Modification codes. Associations of each biomarker with AKI were evaluated using Cox proportional hazards models adjusted for demographics, cardiovascular risk factors, and biomarkers of kidney function.

RESULTS

The mean participant age was 78 years; 60% of participants were women and 16% were African American. The median (interquartile range) values of biomarkers were as follows: FGF-23, 70 RU/ml (53, 99); UACR, 8.88 mg/g (4.71, 20.47); and eGFRCrCyC, 71 ml/min per 1.73 m(2) (59, 83). Hospitalized AKI occurred in 119 participants over 10.0 years of median follow-up. In fully adjusted analyses, compared with the lowest quartiles, the highest quartiles of FGF-23 (≥100 RU/ml) and UACR (≥20.9 mg/g) were associated with AKI (FGF-23: hazard ratio [HR], 1.99; 95% confidence interval [95% CI], 1.04 to 3.80; and UACR: HR, 3.35; 95% CI, 1.83 to 6.13). Compared with the highest quartile, the lowest quartile of eGFRCrCyC (<57 ml/min per 1.73 m(2)) was associated with AKI with an HR of 2.15 (95% CI, 1.21 to 3.82).

CONCLUSIONS

FGF-23 adjusted for albuminuria, cardiovascular disease risk factors, and baseline eGFR is independently associated with a higher risk of AKI hospitalizations in community-dwelling elderly individuals. Further studies to understand the nature of this association are warranted.

Definitions of and contributions to cardiovascular disease in systemic lupus erythematosus

Patients with systemic lupus erythematosus (SLE) have a significantly increased risk of cardiovascular disease (CVD). Increased prevalence of atherosclerosis may explain part of this enhanced risk, but SLE related CVD can also result from other mechanisms. Vascular events may be the result of several pathophysiologic mechanisms; some can be caused by atherosclerosis, others may be primarily thrombotic, and some may be due to ongoing inflammation. The traditional risk factors are of importance for the development of CVD in lupus. However, lupus-related factors, such as endothelial dysfunction and inflammation, renal impairment and disease activity, lupus phenotype, autoantibodies and genetic predisposition are equally or even more important. Risk factors may also contribute separately or in combination to increase the risk of atherosclerosis and clinical CVD in SLE. Studies investigating risk factors for CVD in SLE vary with respect to definition of outcome, it is, e.g. common that the terms atherosclerosis and clinical CVD are used interchangeably. Varying definitions and outcomes may thus explain divergent results of different studies and make comparisons difficult. This review summarizes some of the current knowledge regarding risk factors and mechanisms for atherosclerosis and clinical CVD in SLE. Aspects on the importance of CVD definitions and outcomes are briefly discussed.

Association of genetic variants of the α-kinase 1 gene with myocardial infarction in community-dwelling individuals

We previously demonstrated that rs2074380 (G→A, Gly870Ser) and rs2074381 (A→G, Asn916Asp) of the α-kinase 1 gene (ALPK1) were significantly associated with chronic kidney disease (CKD) in individuals with diabetes mellitus. As CKD is a significant risk factor for coronary heart disease, we hypothesized that rs2074380 and rs2074381 of ALPK1 may contribute to the genetic susceptibility to myocardial infarction (MI) through affecting the susceptibility to CKD. The aim of the present study was to investigate a possible association of rs2074380 and rs2074381 with MI in community-dwelling individuals. The study subjects comprised 5,771 community-dwelling individuals (41 subjects with MI and 5,730 controls) who were recruited to a population-based cohort study in Inabe, Japan. The comparison of allele frequencies and genotype distributions using the Chi-square test revealed that rs2074380 and rs2074381 were significantly associated with MI (P<0.05). The multivariable logistic regression analysis with adjustment for covariates demonstrated that rs2074380 (P=0.0354, dominant model) and rs2074381 (P=0.0438, dominant model) were significantly associated with MI, with the minor A and G alleles, respectively, being protective against this condition. A haplotype analysis of these polymorphisms indicated that the frequency of the major haplotype, G (rs2074380)-A (rs2074381), was significantly higher (permutation P=0.012), whereas that of the minor haplotype A-G was significantly lower (P=0.020), in subjects with MI compared to that observed among controls. Therefore, ALPK1 may be a susceptible locus for MI.

High levels of cystatin C predict the metabolic syndrome: the prospective Malmö Diet and Cancer Study

OBJECTIVE

Cystatin C is a novel marker of cardiovascular disease (CVD); however, the underlying mechanisms remain unclear. Here, we prospectively investigated whether plasma levels of cystatin C predict new-onset metabolic syndrome (MetS) as well as long-term progression and incidence of the different components of the MetS.

METHODS

Cystatin C was measured in 1502 individuals included in the Malmö Diet and Cancer cardiovascular cohort (mean age 56 years, 59% women) who were free from the MetS at baseline and subsequently underwent a follow-up examination after a median of 16 years. MetS was defined according to the NCEP-ATP-III guidelines. Logistic regression was used to adjust for covariates.

MAIN OUTCOME MEASURES

Metabolic syndrome and long-term progression as well as incidence of the different components of the MetS.

RESULTS

During follow-up, 428 subjects developed new-onset MetS. In age- and sex-adjusted analysis, compared with the lowest quartile of cystatin C, the odds ratios (95% confidence interval) for incident MetS in subjects with cystatin C levels in quartiles 2, 3 and 4 were 1.00 (0.71-1.40), 1.48 (1.06-2.07) and 1.91 (1.37-2.68), respectively (Ptrend  < 0.001); this linear association remained significant even after full multivariate adjustment (Ptrend  = 0.041). Interestingly, in this fully adjusted model, long-term progression of abdominal obesity was the only component of the MetS significantly associated with increasing quartiles of baseline cystatin C levels (Ptrend  = 0.008).

CONCLUSION

These findings suggest that cystatin C may adversely affect metabolic factors, particularly abdominal obesity, thus contributing to development of the MetS. Our results may help to explain the link between cystatin C and development of CVD.

Association between serum cystatin C, monocytes and other inflammatory markers

BACKGROUND

Cystatin C is a marker of renal function that appears to be associated with inflammation. The aim of the present study was to investigate whether there is any relationship between cystatin C, total and differential leukocyte count and other inflammatory markers.

METHODS

Cystatin C, creatinine, high sensitivity C-reactive protein (hs-CRP), haptoglobin, ferritin, serum albumin, glucose, total cholesterol, HDL and triglycerides together with total and differential leukocyte count were determined in 490 adults (46 ± 16 years, 40% men) who underwent a typical health examination. Glomerular filtration rate was estimated by the simplified Modification of Diet in Renal Disease formula. Anthropometric and lifestyle characteristics were also recorded.

RESULTS

After adjustment for demographic risk factors, comorbid health conditions and renal function, a positive and independent relationship of serum cystatin C levels with peripheral monocyte blood count (regression coefficient ± SE: 12 ± 3.38, P < 0.001) and white blood count (0.616 ± 0.278, P= 0.027) was evident. In this multiple linear regression analysis, other inflammatory markers (i.e. hs-CRP, haptoglobin, ferritin, albumin) did not seem to affect cystatin C blood levels.

CONCLUSION

The results of this study demonstrated that monocytes, which play an important role in chronic inflammation and atherosclerosis, were independently related with cystatin C concentrations. This finding may provide a plausible link for the usefulness of cystatin C in predicting increased cardiovascular risk.

Serum cystatin C and prediabetes in non-obese US adults

Diabetes mellitus is the leading cause of end stage renal disease. Cystatin C, a marker of early renal impairment has been shown to be associated with diabetes. However, it is not clear if cystatin C is associated with prediabetes, an early stage in the hyperglycemic continuum where prevention efforts have been shown to be effective in delaying or preventing the onset of diabetes. We examined 2,033 participants from the National Health and Nutrition Examination Survey 1999-2002, aged ≥ 20 years (female 47.2 %) who were free of diabetes mellitus, chronic kidney disease and with body mass index <30 kg/m(2). Prediabetes (n = 541) was defined as a 2-h glucose concentration of 140-199 mg/dL, or a fasting glucose concentration of 110-125 mg/dL, or an A1C value of 5.7-6.4 %. Cystatin C levels were categorized into gender-specific quartiles for analysis. Elevated levels of serum cystatin C were associated with prediabetes after adjusting for potential confounders including serum total cholesterol, systolic blood pressure, body mass index and C-reactive protein. Compared to those with cystatin C in the lowest quartile, the multivariable odds ratio (95 % confidence interval) of prediabetes among those in the highest quartile was 2.08 (1.09-3.97), p for trend = 0.02. Although, this association was stronger among women and non-Hispanic whites, there was no significant interaction by sex (p = 0.1) or by race-ethnicity (p = 0.6). Our findings suggest that elevated levels of serum cystatin C are associated with prediabetes in a nationally representative sample of non-obese US adults.

The prognostic value of cystatin C compared with trauma scores in multiple blunt trauma: a prospective cohort study

BACKGROUND

Many scoring systems have been developed to predict the prognosis of the traumatized patients in Emergency Departments, and the necessary calculations make complex scoring systems difficult to use as a part of the initial trauma patient assessment, and they also have limited accuracy.

STUDY OBJECTIVE

This study compares the accuracy of cystatin C with trauma scoring systems in predicting the mortality of trauma patients.

METHODS

Serum cystatin C levels were measured upon arrival in consecutive adult multiple blunt trauma patients during a 12-month period. Correlation analysis was used to assess the relationship between Injury Severity Score (ISS), Revised Trauma Score (RTS), Glasgow Coma Scale (GCS) Score, and cystatin C. Trauma scores and cystatin C were used in Cox regression models to predict trauma patients' risk of death.

RESULTS

During the study period, 153 patients were enrolled and 18 died. There were negative correlations between cystatin C levels and the GCS (r = -0.666, p < 0.001) as well as the RTS (r = -0.229, p = 0.004). A moderate correlation was found between the ISS and the cystatin C level (r = 0.492, p < 0.001). In Cox regression models, every increase in units of cystatin C levels and ISS (the cut-off levels were 0.93 mg/L and ≥ 16, respectively) results in a 4.22- and 1.068-fold increase in mortality, respectively.

CONCLUSION

Cystatin C may represent an important severity-of-illness indicator, easily available to clinicians during the initial assessment of trauma victims on admission.