Uric Acid Is an Independent Risk Factor for Decline in Kidney Function, Cardiovascular Events, and Mortality in Patients With Type 1 Diabetes

Abstract

OBJECTIVE Previous studies have provided inconclusive results on the role of uric acid (UA) in risk prediction. Here we aimed to improve the power and precision of the predictive value of UA for the risk of decline in kidney function, cardiovascular events (CVEs), and mortality in patients with type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS Plasma UA was measured in 670 patients with T1D and various degrees of albuminuria, ranging from normoalbuminuria to macroalbuminuria. Associations of UA with an estimated glomerular filtration rate (eGFR) decline of ≥30%, CVEs, and mortality were analyzed. The median follow-up time was 5.3 years [interquartile range (IQR) 2.7–6.2 years] for a decline in eGFR of ≥30%, 5.8 years (2.5–6.4 years) for progression in albuminuria status, 5.1 years (4.7–5.6 years) for CVE, and 6.2 years (5.8–6.7 years) for mortality. Both univariable and multivariable associations of UA with relevant outcomes and variables were reported. Hazard ratios (HRs) were calculated per doubling of the UA level. RESULTS A doubling in UA level was associated with a higher risk of decline in eGFR of ≥30% (n = 89) (HR 3.18 [IQR 1.71–5.93]; P < 0.001), CVE (n = 94) (HR 2.25 [IQR 1.20–4.21]; P = 0.011), and mortality (n = 58) (HR 2.58 [IQR 1.12–5.90]; P = 0.025) in adjusted analyses. Adding UA to the adjusted model including conventional risk factors improved the relative integrated discrimination index by 12.6% for a decline in eGFR of ≥30% (P < 0.001), 6.5% for CVE (P = 0.010), and 11.8% (P = 0.003) for mortality. A doubling in UA level was also associated with a steeper decline in eGFR (P < 0.0026) and a steeper increase in urine albumin-to-creatinine ratio (P < 0.0027) in adjusted analysis. CONCLUSIONS In individuals with T1D, a higher UA level is associated with a higher risk of decline in kidney function, CVE, and mortality, independently of other risk factors. Our results suggest that UA has a promising role in risk stratification among individuals with T1D.