Change in Proteinuria or Albuminuria as a Surrogate for Cardiovascular and Other Major Clinical Outcomes: A Systematic Review and Meta-analysis

Urinary Plasminogen as a Marker of Disease Progression in Human Glomerular Disease

RATIONALE & OBJECTIVE

Glomerular disorders have a highly variable clinical course, and biomarkers that reflect the molecular mechanisms underlying their progression are needed. Based on our previous work identifying plasminogen as a direct cause of podocyte injury, we designed this study to test the association between urine plasmin(ogen) (ie, plasmin and its precursor plasminogen) and end-stage kidney disease (ESKD).

STUDY DESIGN

Multicenter cohort study.

SETTING & PARTICIPANTS

1,010 patients enrolled in the CureGN Cohort with biopsy-proven glomerular disease (focal segmental glomerulosclerosis, membranous nephropathy, and immunoglobulin A nephropathy).

PREDICTORS

The main predictor was urine plasmin(ogen) at baseline. Levels were measured by an electrochemiluminescent immunoassay developed de novo. Traditional clinical and analytical characteristics were used for adjustment. The ratio of urine plasmin(ogen)/expected plasmin(ogen) was evaluated as a predictor in a separate model.

OUTCOME

Progression to ESKD.

ANALYTICAL APPROACH

Cox regression was used to examine the association between urinary plasmin(ogen) and time to ESKD. Urinary markers were log2 transformed to approximate normal distribution and normalized to urinary creatinine (Log2uPlasminogen/cr, Log2 urinary protein/cr [UPCR]). Expected plasmin(ogen) was calculated by multiple linear regression.

RESULTS

Adjusted Log2uPlasminogen/cr was significantly associated with ESKD (HR per doubling Log2 uPlasminogen/cr 1.31 [95% CI, 1.22-1.40], P<0.001). Comparison of the predictive performance of the models including Log2 uPlasminogen/cr, Log2 UPCR, or both markers showed the plasmin(ogen) model superiority. The ratio of measured/expected urine plasmin(ogen) was independently associated with ESKD: HR, 0.41 (95% CI, 0.22-0.77) if ratio<0.8 and HR 2.42 (95% CI, 1.54-3.78) if ratio>1.1 (compared with ratio between 0.8 and 1.1).

LIMITATIONS

Single plasmin(ogen) determination does not allow for the study of changes over time. The use of a cohort of mostly white patients and the restriction to patients with 3 glomerular disorders limits the external validity of our analysis.

CONCLUSIONS

Urinary plasmin(ogen) and the ratio of measured/expected plasmin(ogen) are independently associated with ESKD in a cohort of patients with glomerular disease. Taken together with our previous experimental findings, urinary plasmin(ogen) could be a useful biomarker in prognostic decision making and a target for the development of novel therapies in patients with proteinuria and glomerular disease.

PLAIN-LANGUAGE SUMMARY

Glomerular diseases are an important cause of morbidity and mortality in patients of all ages. Knowing the individual risk of progression to dialysis or transplantation would help to plan the follow-up and treatment of these patients. Our work studies the usefulness of urinary plasminogen as a marker of progression in this context, since previous studies indicate that plasminogen may be involved in the mechanisms responsible for the progression of these disorders. Our work in a sample of 1,010 patients with glomerular disease demonstrates that urinary plasminogen (as well as the ratio of measured to expected plasminogen) is associated with the risk of progression to end-stage kidney disease. Urine plasminogen exhibited good performance and, if further validated, could enable risk stratification for timely interventions in patients with proteinuria and glomerular disease.

Flexible evaluation of surrogate markers with Bayesian model averaging

When long-term follow up is required for a primary endpoint in a randomized clinical trial, a valid surrogate marker can help to estimate the treatment effect and accelerate the decision process. Several model-based methods have been developed to evaluate the proportion of the treatment effect that is explained by the treatment effect on the surrogate marker. More recently, a nonparametric approach has been proposed allowing for more flexibility by avoiding the restrictive parametric model assumptions required in the model-based methods. While the model-based approaches suffer from potential mis-specification of the models, the nonparametric method fails to give desirable estimates when the sample size is small, or when the range of the data does not follow certain conditions. In this paper, we propose a Bayesian model averaging approach to estimate the proportion of treatment effect explained by the surrogate marker. Our procedure offers a compromise between the model-based approach and the nonparametric approach by introducing model flexibility via averaging over several candidate models and maintains the strength of parametric models with respect to inference. We compare our approach with previous model-based methods and the nonparametric method. Simulation studies demonstrate the advantage of our method when surrogate supports are inconsistent and sample sizes are small. We illustrate our method using data from the Diabetes Prevention Program study to examine hemoglobin A1c as a surrogate marker for fasting glucose.

Changes in proteinuria and the associated risks of ischemic heart disease, acute myocardial infarction, and angina pectoris in Korean population

OBJECTIVES

Proteinuria is widely used to predict cardiovascular risk. However, there is insufficient evidence to predict how changes in proteinuria may affect the incidence of cardiovascular disease.

METHODS

The study included 265,236 Korean adults who underwent health checkups in 2003-2004 and 2007-2008. They were categorized into 4 groups based on changes in proteinuria (negative: negative → negative; resolved: proteinuria ≥1+ → negative; incident: negative → proteinuria ≥1+; persistent: proteinuria ≥1+ → proteinuria ≥1+). We conducted 6 years of follow-up to identify the risks of developing ischemic heart disease (IHD), acute myocardial infarction (AMI), and angina pectoris according to changes in proteinuria. A multivariate Cox proportional-hazards model was used to calculate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for incident IHD, AMI, and angina pectoris.

RESULTS

The IHD risk (expressed as HR [95% CI]) was the highest for persistent proteinuria, followed in descending order by incident and resolved proteinuria, compared with negative proteinuria (negative: reference, resolved: 1.211 [95% CI, 1.104 to 1.329], incident: 1.288 [95% CI, 1.184 to 1.400], and persistent: 1.578 [95% CI, 1.324 to 1.881]). The same pattern was associated with AMI (negative: reference, resolved: 1.401 [95% CI, 1.048 to 1.872], incident: 1.606 [95% CI, 1.268 to 2.035], and persistent: 2.069 [95% CI, 1.281 to 3.342]) and angina pectoris (negative: reference, resolved: 1.184 [95% CI, 1.065 to 1.316], incident: 1.275 [95% CI, 1.160 to 1.401], and persistent: 1.554 [95% CI, 1.272 to 1.899]).

CONCLUSIONS

Experiencing proteinuria increased the risks of IHD, AMI, and angina pectoris even after proteinuria resolved.

Association between Proteinuria Status and Risk of Hypertension: A Nationwide Population-Based Cohort Study

Proteinuria is associated with cardiovascular disease. However, the relationship between changes in proteinuria status and hypertension remains unclear. This study aimed to explore the association between changes in proteinuria status and the risk of developing hypertension with the data from the Korean National Health Insurance Database. We included participants without prior hypertension history who underwent their first health examination in 2003-2004 and a second examination in 2005-2006. Based on their proteinuria status during these two examinations, participants were classified into four groups: the proteinuria-free, proteinuria-resolved, proteinuria-developed, and chronic proteinuria groups. The study outcome was the incidence of hypertension. The study included 935,723 participants followed for a median of 14.2 years (mean age: 40.96 ± 11.01, 62.5% male participants). During this period, 346,686 (37.1%) cases of hypertension were reported. The chronic proteinuria group had the highest hypertension risk, followed by the proteinuria-developed, proteinuria-resolved, and proteinuria-free groups (p < 0.001). Those who recovered from proteinuria had a lower risk of developing hypertension than those with chronic proteinuria (hazard ratio: 0.58; 95% confidence interval: 0.53-0.63, p < 0.001). In contrast, individuals who developed proteinuria had a higher risk of hypertension than proteinuria-free individuals (hazard ratio: 1.31; 95% confidence interval: 1.26-1.35, p < 0.001). Our findings suggest a significant association between proteinuria status changes and hypertension. Effective management of proteinuria may potentially decrease the risk of developing hypertension.

Association of proteinuria and risk of incident atrial fibrillation in the general population: A prospective study of Kailuan study participants

BACKGROUND

Proteinuria is a well-known cardiovascular risk factor, but whether it independently increases the risk for atrial fibrillation (AF) in Chinese population is unknown. To address this deficiency, herein, we investigated the association between proteinuria detected using urine dipstick test and the risk of AF.

METHODS

This was a prospective cohort study of Kailuan study participants who underwent the 2006-2007 and 2010-2011 health checkups and was free from AF. Participants were classified into four groups based on the level of proteinuria: [-, trace (±), 1+, ≥2+]. The outcome was incident AF as confirmed by 12-lead electrocardiography.

RESULTS

During a median of 11.90 years of follow-up, we documented 514 incident AF cases among 60,599 participants. Proteinuria was found in 6302 (10.40%) participants. Relative to participants without proteinuria at the baseline, those with proteinuria (≥2+) had an 83.9% higher risk (95% confidence interval [CI], 1.073-3.154, p = .0267) of developing AF, after adjusted for confounding variables. The result was consistent in the sensitivity analysis. Compared to consistently negative proteinuria, the risk of AF significantly increased in the aggravated proteinuria group (hazard ratio [HR] 1.552, 95% CI 1.140-2.114) and the persistent proteinuria group (HR 2.485, 95% CI 1.414-4.366). Among participants with resolved proteinuria (from positive to negative), the risk of incident AF was not significantly increased compared to those with persistently negative proteinuria (HR 1.300, 95% CI 0.743-2.276).

CONCLUSIONS

Proteinuria could be a modifiable risk factor for predicting AF development. Knowing the presence of proteinuria may improve risk stratification for decision-making about AF prevention.

Change in albuminuria as a surrogate endpoint for cardiovascular and renal outcomes in patients with diabetes

For the purpose of predicting clinical outcomes in patients with diabetes and chronic kidney disease, change in albuminuria is a good candidate to be a surrogate marker for future cardiovascular events and progression of kidney disease. Spot urine albumin/creatinine ratio is convenient and recognized as a viable alternative to 24-h albumin, with some limitations. Although there is sufficient evidence to validate its use in clinical trials as a surrogate endpoint for renal outcomes, this is not yet the case for cardiovascular outcomes. While change in albuminuria as a primary or secondary endpoint is trial-specific, its use should be encouraged, nonetheless.

Albuminuria and Heart Failure: JACC State-of-the-Art Review

Although chronic kidney disease is characterized by low glomerular filtration rate (GFR) or albuminuria, estimated GFR (eGFR) is more widely utilized as a marker of risk profile in cardiovascular diseases, including heart failure (HF). The presence and magnitude of albuminuria confers a strong prognostic association in forecasting risk of incident HF as well as its progression, irrespective of eGFR. Despite the high prevalence of albuminuria in HF, whether it adds incremental prognostic information in clinical practice and serves as an independent risk marker, and whether there are any therapeutic implications of assessing albuminuria in patients with HF is less well-established. In this narrative review, we assess the potential role of albuminuria in risk profiling for development and progression of HF, strengths and limitations of utilizing albuminuria as a risk marker, its ability to serve in HF risk prediction models, and the implications of adopting albuminuria as an effective parameter in cardiovascular trials and practice.

Clinical Trial Design Principles and Outcomes Definitions for Device-Based Therapies for Hypertension: A Consensus Document From the Hypertension Academic Research Consortium

The clinical implications of hypertension in addition to a high prevalence of both uncontrolled blood pressure and medication nonadherence promote interest in developing device-based approaches to hypertension treatment. The expansion of device-based therapies and ongoing clinical trials underscores the need for consistency in trial design, conduct, and definitions of clinical study elements to permit trial comparability and data poolability. Standardizing methods of blood pressure assessment, effectiveness measures beyond blood pressure alone, and safety outcomes are paramount. The Hypertension Academic Research Consortium (HARC) document represents an integration of evolving evidence and consensus opinion among leading experts in cardiovascular medicine and hypertension research with regulatory perspectives on clinical trial design and methodology. The HARC document integrates the collective information among device-based therapies for hypertension to better address existing challenges and identify unmet needs for technologies proposed to treat the world’s leading cause of death and disability. Consistent with the Academic Research Consortium charter, this document proposes pragmatic consensus clinical design principles and outcomes definitions for studies aimed at evaluating device-based hypertension therapies.

Association of proteinuria and hypertension with incident atrial fibrillation in an elderly population: nationwide data from a community-based elderly cohort

OBJECTIVE

The excess risk of atrial fibrillation in relation to the presence of proteinuria associated with hypertension has not been well elucidated. We aimed to determine the effect of hypertension and/or proteinuria on the incidence of atrial fibrillation. Second, we evaluated whether the associations with temporal changes in proteinuria status on the incidence of atrial fibrillation.

METHODS AND RESULTS

A total of 85 434 participants with hypertension and 125 912 participants without hypertension with age at least 60 years from the Korea National Health Insurance Service-Senior cohort were included. Amongst controls (participants without proteinuria and hypertension), hypertension only, proteinuria only, and hypertension with proteinuria groups, the adjusted incidences of atrial fibrillation were 0.51, 0.69. 0.78 and 0.99 per 100 person-years, respectively after inverse probability of treatment weighting. Compared with controls, the weighted risks of atrial fibrillation in the hypertension only, proteinuria only and hypertension with proteinuria groups were increased by 37% (hazard ratio 1.37, 95% confidence interval, CI 1.30-1.44, P = 0.001), 55% (hazard ratio 1.55, 95% CI 1.28-1.88, P < 0.001), and 98% (hazard ratio 1.98, 95% CI 1.62-2.43, P < 0.001), respectively. Populations who had proteinuria in the first examination had an increased risk of atrial fibrillation even in the group whereby the proteinuria was resolved on the second examination (hazard ratio 1.36, 95% CI 1.12-2.31, P < 0.001). The presence of proteinuria in first and second analysis had the highest risk of incident atrial fibrillation (hazard ratio 1.61, 95% CI 1.12-2.31).

CONCLUSION

In conclusion, hypertension and/or proteinuria were associated with increased risk of atrial fibrillation, with the greatest risks when both are present. Proteinuria could be a useful factor for predicting atrial fibrillation development.

Proteinuria-Lowering Effects of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors in Chronic Kidney Disease Patients: A Real-World Multicentric Study

Control of dyslipidemia in chronic kidney disease (CKD) is not always guaranteed with statins and/or ezetimibe. Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) have opened up a new era in lipid control, but their effect on renal function and proteinuria in real life have not yet been evaluated. The aim of the present study was to analyze the evolution of renal function and proteinuria in a cohort of CKD patients treated with PCSK9i. This retrospective multicentric cohort study included CKD patients treated with PCSK9i. Baseline epidemiological data, comorbidities and laboratory findings (including estimated glomerular filtration rate [eGFR], proteinuria and lipid profile) were collected. The evolution of renal function, proteinuria and lipid profile was analyzed during the 1-year follow-up. The cohort included 76 patients (68% male, mean age 66 ± 10 years). The mean baseline creatinine was 1.55 ± 0.77 mg/dL, and the mean eGFR was 52 ± 22 mL/min/1.73 m². Reductions in LDL-cholesterol, total cholesterol and triglycerides during the first month were 51 ± 25%, 32 ± 25% and 11 ± 40%, respectively, levels that remained stable throughout the first year (p < 0.001 for LDL-cholesterol and total cholesterol trends and p = 0.002 for triglyceride trend). During follow-up, proteinuria improved from 57 (9–481) to 30 (7–520) mg/g (p = 0.021). In addition, eGFR remained stable, and no adverse events were reported. In our cohort, dyslipidemia treatment with PCSK9i was associated with decreased proteinuria in CKD patients, an effect that might be due to reduced lipid nephrotoxicity. Clinical trials are needed to further investigate whether this impact on proteinuria can significantly slow CKD progression in the long term.

Albuminuria, proteinuria, and dipsticks: novel relationships and utility in risk prediction

PURPOSE OF REVIEW

Albuminuria is associated with progression of kidney disease and is the accepted gold standard for screening, staging, and prognostication of chronic kidney disease. This review focuses on current literature that has explored applications of albuminuria as a surrogate outcome, variable used in kidney failure risk prediction for novel populations, and variable that may be predicted by other proteinuria measures.

RECENT FINDINGS

Change in albuminuria shows promise as a surrogate outcome for kidney failure, which may have major implications for trial design and conduct. The kidney failure risk equation (KFRE) has been validated extensively to date and has now been applied to pediatric patients with kidney disease, advanced age, different causes of kidney disease, various countries, and those with prior kidney transplants. As albumin-to-creatinine ratios (ACRs) are not always available to clinicians and researchers, two recent studies have independently developed equations to estimate ACR from other proteinuria measures.

SUMMARY

The utility of albuminuria and the KFRE continues to grow in novel populations. With the ability to convert more widely available (and inexpensive) proteinuria measures to ACR estimates, the prospect of incorporating kidney failure risk prediction into routine care within economically challenged healthcare jurisdictions may finally be realized.

Effect of linagliptin versus placebo on cardiovascular and kidney outcomes in nephrotic-range proteinuria and type 2 diabetes: the CARMELINA randomized controlled trial

BACKGROUND

Nephrotic-range proteinuria (NRP) is associated with rapid kidney function loss and increased cardiovascular (CV) disease risk. We assessed the effects of linagliptin (LINA) on CV and kidney outcomes in people with Type 2 diabetes (T2D) with or without NRP.

METHODS

Cardiovascular and renal microvascular outcome study with LINA randomized participants with T2D and CV disease and/or kidney disease to LINA 5 mg or placebo (PBO). The primary endpoint [time to first occurrence of 3-point major adverse cardiac events (3P-MACE)], and kidney outcomes, were evaluated by NRP status [urinary albumin:creatinine ratio (UACR) ≥2200 mg/g] at baseline (BL) in participants treated with one or more dose of study medication.

RESULTS

NRP was present in 646/6979 [9.3% (LINA/PBO n = 317/n = 329); median UACR 3486 (Q1: 2746/Q3: 4941) mg/g] participants, who compared with no-NRP were younger (62.3/66.1 years) and had lower estimated glomerular filtration rate (eGFR) (39.9/56.1 mL/min/1.73 m2). Over a median of 2.2 years, 3P-MACE occurred with a 2.0-fold higher rate in NRP versus no-NRP (PBO group), with a neutral LINA effect, regardless of NRP. The composite of time to renal death, end-stage kidney disease (ESKD) or decrease of ≥40 or ≥50% in eGFR, occurred with 12.3- and 13.6-fold higher rate with NRP (PBO group); evidence of heterogeneity of effects with LINA was observed for the former [NRP yes/no: hazard ratio 0.80 (0.63-1.01)/1.25 (1.02-1.54); P-interaction 0.005], but not the latter [0.83 (0.64-1.09)/1.17 (0.91-1.51), P-interaction 0.07]. No heterogeneity was observed for renal death or ESKD [0.88 (0.64-1.21)/0.94 (0.67-1.31), P-interaction 0.79]. Glycated haemoglobin A1c (HbA1c) was significantly reduced regardless of NRP, without increasing hypoglycaemia risk. Regression to normoalbuminuria [1.20 (1.07-1.34)] and reduction of UACR ≥50% [1.15 (1.07-1.25)] from BL, occurred more frequently with LINA, regardless of NRP status (P-interactions >0.05).

CONCLUSIONS

Individuals with T2D and NRP have a high disease burden. LINA reduces their albuminuria burden and HbA1c, without affecting CV or kidney risk.

Prevalence of chronic kidney disease and risk factors in North-Central Nigeria: a population-based survey

Background

Chronic kidney disease (CKD) is a growing challenge in low- and middle-income countries, particularly in sub-Saharan Africa. There is insufficient population-based data on CKD in Nigeria that is required to estimate its true burden, and to design prevention and management strategies. The study aims to determine the prevalence of CKD and its risk factors in Nigeria.

Methods

We studied 8 urban communities in Kwara State, North-Central zone of Nigeria. Blood pressure, fasting blood sugar, urinalysis, weight, height, waist circumference and hip circumference were obtained. Albuminuria and kidney length were measured by ultrasound while estimated glomerular filtration rate (eGFR) was derived from serum creatinine, using chronic disease epidemiology collaboration (CKD-EPI) equation. Associations of risk factors with CKD were determined by multivariate logistic regression and expressed as adjusted odds ratio (aOR) with corresponding 95% confidence intervals.

Results

One thousand three hundred and fifty-three adults ≥18 years (44% males) with mean age of 44.3 ± 14.4 years, were screened. Mean kidney lengths were: right, 93.5 ± 7.0 cm and left, 93.4 ± 7.5 cm. The age-adjusted prevalence of hypertension was 24%; diabetes 4%; obesity 8.7%; albuminuria of > 30 mg/L 7%; and dipstick proteinuria 13%. The age-adjusted prevalence of CKD by estimated GFR < 60 ml/min/1.73m² and/or Proteinuria was 12%. Diabetes (aOR 6.41, 95%CI = 3.50–11.73, P = 0.001), obesity (aOR 1.50, 95%CI = 1.10–2.05, P = 0.011), proteinuria (aOR 2.07, 95%CI = 1.05–4.08, P = 0.035); female sex (aOR 1.67, 95%CI = 1.47–1.89, P = 0.001); and age (aOR 1.89, 95%CI = 1.13–3.17, P = 0.015) were the identified predictors of CKD.

Conclusions

CKD and its risk factors are prevalent among middle-aged urban populations in North-Central Nigeria. It is common among women, fueled by diabetes, ageing, obesity, and albuminuria. These data add to existing regional studies of burden of CKD that may serve as template for a national prevention framework for CKD in Nigeria. One of the limitations of the study is that the participants were voluntary community dwellers and as such not representative for the community. The sample may thus have been subjected to selection bias possibly resulting in overestimation of CKD risk factors.