Cystatin C, Albuminuria, and Mortality Among Older Adults With Diabetes

Abstract

OBJECTIVEAlbuminuria and impaired glomerular filtration rate (GFR) are each associated with poor health outcomes among individuals with diabetes. Joint associations of albuminuria and impaired GFR with mortality have not been comprehensively evaluated in this population.RESEARCH DESIGN AND METHODSThis is a cohort study among Cardiovascular Health Study participants with diabetes, mean age 78 years. GFR was estimated using serum cystatin C and serum creatinine. Albumin-to-creatinine ratio (ACR) was measured in single-voided urine samples.RESULTSOf 691 participants, 378 died over 10 years of follow-up. Cystatin C–estimated GFR <60 ml/min per 1.73 m2, creatinine-based estimated GFR <60 ml/min per 1.73 m2, and urine ACR ≥30 mg/g were each associated with increased mortality risk with hazard ratios of 1.73 (95% CI 1.37–2.18), 1.54 (1.21–1.97), and 1.73 (1.39–2.17), respectively, adjusting for age, sex, race, diabetes duration, hypoglycemic medications, hypertension, BMI, smoking, cholesterol, lipid-lowering medications, prevalent cardiovascular disease (CVD), and prevalent heart failure. Cystatin C–estimated GFR and urine ACR were additive in terms of mortality risk. Cystatin C–estimated GFR predicted mortality more strongly than creatinine-based estimated GFR.CONCLUSIONSAlbuminuria and impaired GFR were independent, additive risk factors for mortality among older adults with diabetes. These findings support current recommendations to regularly assess both albuminuria and GFR in the clinical care of patients with diabetes; a focus on interventions to prevent or treat CVD in the presence of albuminuria, impaired GFR, or both; and further consideration of cystatin C use in clinical care.

Age-Specific Association of Reduced Estimated Glomerular Filtration Rate and Albuminuria with All-Cause Mortality

“…Higher levels of albuminuria have been reported to be associated with increased mortality in prior studies of older adults with diabetes mellitus and in the general population (11,20). O'Hare and colleagues reported ACR levels Ն30 mg/g to be associated with increased mortality, regardless of age, among U.S. veterans with diabetes mellitus (11).…”

Cystatin C, creatinine, estimated glomerular filtration, and long-term mortality in stroke patients

“…24,25 It was shown that serum cystatin C is superior for prediction of mortality and cardiovascular events among elderly and among elderly diabetic patients compared to serum creatinine or estimated GFR based on creatinine. 26,27 In the past years, also equations based on both creatinine and cystatin C were developed, widely accepted is the CKD-EPI creatinine/cystatin equation. 28 It was also shown that serum cystatin C is a strong predictor of death in patients suffering from stroke, but there are no data about predicting long-term mortality in these patients comparing serum cystatin C and estimated GFR based on creatinine or creatinine and cystatin C. 29 The aim of our study was to compare the associations of serum creatinine, estimated GFR (CKD-EPI creatinine and CKD-EPI creatinine/cystatin equations), serum cystatin C and long-term mortality risk in patients suffering from ischemic stroke.…”

Prognostic value of serum cystatin C levels in cirrhotic patients with normal serum creatinine

“…CysC is supported by additional studies to be a good early predictor of acute kidney injury [15]. It has already been reported that CysC is linked to the mortality rate of patients with heart failure, regardless of objective renal function [16], and that it yields a higher rate of accuracy than serum Cr in predicting the mortality rate of diabetic patients [17].…”