The characteristics of new semi-quantitative method for diagnosing proteinuria by using random urine samples

Plasma NGAL levels in stable kidney transplant recipients and the risk of allograft loss

BACKGROUND

The objective of this study was to investigate the utility of neutrophil gelatinase-associated lipocalin (NGAL) and calprotectin (CPT) to predict long-term graft survival in stable kidney transplant recipients (KTR).

METHODS

A total of 709 stable outpatient KTR were enrolled >2 months post-transplant. The utility of plasma and urinary NGAL (pNGAL, uNGAL) and plasma and urinary CPT at enrollment to predict death-censored graft loss was evaluated during a 58-month follow-up.

RESULTS

Among biomarkers, pNGAL showed the best predictive ability for graft loss and was the only biomarker with an area under the curve (AUC) > 0.7 for graft loss within 5 years. Patients with graft loss within 5 years (n = 49) had a median pNGAL of 304 [interquartile range (IQR) 235-358] versus 182 (IQR 128-246) ng/mL with surviving grafts (P < .001). Time-dependent receiver operating characteristic analyses at 58 months indicated an AUC for pNGAL of 0.795, serum creatinine-based Chronic Kidney Disease Epidemiology Collaboration estimated glomerular filtration rate (eGFR) had an AUC of 0.866. pNGAL added to a model based on conventional risk factors for graft loss with death as competing risk (age, transplant age, presence of donor-specific antibodies, presence of proteinuria, history of delayed graft function) had a strong independent association with graft loss {subdistribution hazard ratio (sHR) for binary log-transformed pNGAL [log2(pNGAL)] 3.4, 95% confidence interval (CI) 2.24-5.15, P < .0001}. This association was substantially attenuated when eGFR was added to the model [sHR for log2(pNGAL) 1.63, 95% CI 0.92-2.88, P = .095]. Category-free net reclassification improvement of a risk model including log2(pNGAL) in addition to conventional risk factors and eGFR was 54.3% (95% CI 9.2%-99.3%) but C-statistic did not improve significantly.

CONCLUSIONS

pNGAL was an independent predictor of renal allograft loss in stable KTR from one transplant center but did not show consistent added value when compared with baseline predictors including the conventional marker eGFR. Future studies in larger cohorts are warranted.

Association between cumulative uric acid to high-density lipoprotein cholesterol ratio and the incidence and progression of chronic kidney disease

Objective

The ratio of uric acid to high-density lipoprotein cholesterol (UHR) was related to the risk of chronic kidney disease (CKD), we aimed to investigate the association of cumulative UHR (cumUHR) with incidence and progression of CKD.

Methods

Our study included a total of 49,913 participants (mean age 52.57 years, 77% males) from the Kailuan Study conducted between 2006 and 2018. Participants who completed three consecutive physical examinations were included. Cumulative UHR (cumUHR) was computed as the summed average UHR between two consecutive physical examinations, multiplied by the time between the two examinations. Participants were then categorized into four groups based on cumUHR quartiles. Subsequently, participants were further divided into a CKD group and a non-CKD group. The associations between cumUHR and CKD and it's progression were assessed by Cox proportional hazards regression models. The cumulative incidence of endpoint events was compared between the cumUHR groups using the log-rank test. The C-index, net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were calculated to assess the predictive performance of cumUHR.

Results

After a mean follow-up of 8.0 ± 1.7 years, there were 4843 cases of new-onset CKD, 2504 of low eGFR, and 2617 of proteinuria in the non-CKD group. Within the CKD group, there were 1952 cases of decline in eGFR category, 1465 of >30% decline in eGFR, and 2100 of increased proteinuria. In the non-CKD group, the adjusted hazard ratios (HRs) and confidence intervals (CIs) in the fourth quartile were 1.484 (1.362-1.617), 1.643 (1.457-1.852), and 1.324 (1.179-1.486) for new-onset CKD, low eGFR, and proteinuria, respectively. In the CKD group, the adjusted HRs in the fourth quartile were 1.337 (1.164-1.534), 1.428 (1.216-1.677), and 1.446 (1.267-1.651) for decline in eGFR category, >30% decline in eGFR, and increase in proteinuria, respectively. In addition, we separately added a single UHR measurement and cumUHR to the CKD base prediction model and the CKD progression base prediction model, and found that the models added cumUHR had the highest predictive value.

Conclusion

High cumUHR exposure was an independent risk factor for the incidence and progression of CKD, and it was a better predictor than a single UHR measurement.

Association between the High-Sensitivity C-Reactive Protein/Albumin Ratio and New-Onset Chronic Kidney Disease in Chinese Individuals

INTRODUCTION

Inflammation is associated with development of chronic kidney disease (CKD). However, the association of the high-sensitivity C-reactive protein (hs-CRP)/albumin ratio (CAR) on the risk of CKD in the general population is unknown. This study explored the relationship between the CAR and CKD and the ability of this ratio to predict CKD in the general population.

METHODS

A total of 47,472 participants in the Kailuan study who met the inclusion criteria in 2010 were selected and grouped using the quartile method. A Cox proportional hazard regression model was used to evaluate the association of the CAR on the risk of CKD. The C-index, net reclassification index (NRI), and overall identification index (IDI) were calculated to evaluate the ability of the CAR to predict CKD.

RESULTS

During a follow-up of 378,383 person-years, CKD events occurred in 6,249 study participants (13.16%). The Cox proportional hazard regression model showed that the hazard ratio (95% confidence interval) for CKD events was 1.18 (1.10-1.28) in the Q3 group and 1.42 (1.32-1.53) in the Q4 group when compared with the Q1 group. Compared with the single index, the C-index, NRI, and IDI values were significantly improved when the CAR was added for prediction of risk of CKD.

CONCLUSIONS

A higher CAR was an independent risk factor for CKD. The ability of the CAR to predict CKD was better than that of hs-CRP or albumin. The CAR provides an important reference index for predicting the risk of CKD.

The Cumulative Exposure to High-Sensitivity C-Reactive Protein Predicts the Risk of Chronic Kidney Diseases

BACKGROUND AND OBJECTIVES

This study was to characterize the association of cumulative exposure to increased high-sensitivity C-reactive protein (hs-CRP) with chronic kidney diseases (CKD).

METHODS

We included 35,194 participants with hs-CRP measured at three examinations in 2006, 2008, 2010. Participants were classified into nonexposed group (hs-CRP <3.0 mg/L in all 3 examinations), 1-exposed group (hs-CRP ≥3.0 mg/L in 1 of the 3 examinations), 2-exposed group (hs-CRP ≥3.0 mg/L in 2 of the 3 examinations), and 3-exposed group (hs-CRP ≥3.0 mg/L in 3 examinations). Cox proportional hazards models were used to assess the association of cumulative hs-CRP with incident CKD. CKD includes an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 or urinary protein positive.

RESULTS

The study showed the risk of CKD as the number of years of exposure to hs-CRP increases. Participants in 3-exposed group had significantly increased CKD risk with hazard ratio (HR) (95% confidence interval, CI) of 1.70 (1.49-1.93), in comparison with 1.47 (1.34-1.62) for participants in the 2-exposed group, and 1.08 (1.00-1.16) for those in the 1-exposed group (p < 0.01); meanwhile, the similar and significant associations were also observed for eGFR <60 mL/min/1.73 m2, proteinuria positive, in participants of the 3-exposed group in comparison with the nonexposed group, with respective HRs (95% CI) of 1.27 (1.01-1.58) and 2.27 (1.87-2.76).

CONCLUSIONS

Cumulative exposure to hs-CRP was associated with a subsequent increased risk of CKD and was of great value to risk prediction.

Sleep and CKD in Chinese Adults: A Cross-Sectional Study

BACKGROUND AND OBJECTIVES

To assess the association between self-reported sleep duration and quality and odds of having CKD in Chinese adults on the basis of a community study.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this cross-sectional study, we included 11,040 Chinese adults who participated in an ongoing prospective study, the Kailuan cohort. Survey questionnaire items addressed insomnia, daytime sleepiness, snoring, and sleep duration during their 2012 interview. Overall sleep quality was evaluated by summarizing these four sleep parameters. Fasting blood samples and single random midstream morning urine samples were collected in 2012 and analyzed for serum creatinine and proteinuria. CKD was defined by eGFR<60 ml/min per 1.73 m2 or proteinuria >300 mg/dl. We also examined those at high or very high risk of having CKD, on the basis of the Kidney Disease Improving Global Outcomes recommendations. The association between sleep quality and CKD was assessed using logistic regression model.

RESULTS

Worse overall sleep quality was associated with higher likelihood of being high or very high risk for CKD (multiadjusted odds ratio, 2.69; 95% confidence interval, 1.30 to 5.59 comparing two extreme categories; P trend <0.01), but not overall CKD (multiadjusted odds ratio, 1.58; 95% confidence interval, 0.89 to 2.80 comparing two extreme categories; P trend =0.46), after adjusting for potential confounders. Specifically, individuals with worse sleep quality were more likely to have proteinuria (multiadjusted odds ratio, 1.95; 95% confidence interval, 1.03 to 3.67 comparing two extreme categories; P trend =0.02), rather than lower eGFR level (multiadjusted mean eGFR levels were 96.4 and 93.6 ml/min per 1.73 m2 in the two extreme sleep categories, respectively; P trend =0.13). However, there was no statistically significant association between individual sleep parameters and CKD status.

CONCLUSIONS

Worse overall sleep quality was associated with higher odds of being high or very high risk for CKD and proteinuria in Chinese adults.

Microalbuminuria in subjects with hypertension attending specialist blood pressure clinics

Albuminuria is associated with increased risk of cardiovascular disease and target organ damage in patients with diabetes mellitus. In nondiabetic hypertensive patients, the threshold at which microalbuminuria (MAU) increases risk is unclear and there is evidence that cardiovascular risk may be increased in individuals with MAU levels lower than the usual recommended screening thresholds. We compared two definitions of MAU (on the basis of three early morning urine samples) in a cohort of hypertensive patients attending two specialist clinics in Scotland: conventional (MAU(C)) albumin-to-creatinine ratio (ACR) >2.5-25 mg mmol(-1) in males or >3.5-25 mg mmol(-1) in females; and low-grade (MAU(L)) ACR 1.2-2.5 in males or 1.7-3.5 mg mmol(-1) in females. Of the 1059 subjects screened, 786 (74%) were nondiabetic, with estimated glomerular filtration rate ⩾30 ml min(-1) per 1.73 m(2) and without gross proteinuria (low-risk subset). The average age was 58±15 years, body mass index 30±6 kg m(-2) and 46% were males. The prevalence of MAU(C) was 11% and 9.5% in the overall and low-risk subset, respectively, whereas MAU(L) prevalence was 11.1% and 10% respectively. The prevalence of cardiovascular disease was higher (24%) with albuminuria (both MAU(C) and MAU(L)) compared with 14% among those without albuminuria. The use of MAU(L) doubled the number of hypertensive subjects with increased cardiovascular risk who can be targeted for more rigorous risk reduction strategies. Consideration should be given to reducing the current threshold for MAU.