Plasma growth differentiation factor-15 independently predicts all-cause and cardiovascular mortality as well as deterioration of kidney function in type 1 diabetic patients with nephropathy

OBJECTIVE - Growth deferentiation factor-15 (GDF-15) is involved in inflammation and apoptosis. Expression is induced in the heart in response to ischemia and in atherosclerotic plaques. The aim of this study was to investigate GDF-15 levels in relation to all-cause mortality, cardiovascular mortality and morbidity, decline in glomerular filtration rate (GFR), and progression toward end-stage renal disease (ESRD). RESEARCH DESIGN AND METHODS - The study was a prospective observational follow-up study including 451 type 1 diabetic patients with diabetic nephropathy (274 men, aged 42.1 ± 0.5 years [means ± SD], diabetes duration 28.3 ± 8.9 years, GFR 76 ± 33 ml/min/1.73 m²) and a control group of 440 patients with longstanding type 1 diabetes and persistent normoalbuminuria (232 men, aged 45.4 ± 11.5 years, duration of diabetes 27.7 ± 10.1 years). The patients were followed for 8.1 (0.0-12.9) years (median [range]). RESULTS - Among normoalbuminuric patients, GDF-15 above the median predicted an adjusted (age, systolic blood pressure [sBP], and estimated GFR) increased risk of all-cause mortality (hazard ratio [HR] 3.6 [95% CI 1.3-10.3]; P = 0.014). Among patients with diabetic nephropathy, higher (fourth quartile) versus lower (first quartile) GDF-15 levels predict allcause mortality (covariate-adjusted [sex, age, smoking, blood pressure, A1C, cholesterol, GFR, N-terminal prohormone B-type natriuretic peptide, antihypertensive treatment, and previous cardiovascular events]; HR 4.86 [95% CI 1.37-17.30]) as well as fatal and nonfatal cardiovascular events (adjusted HR 5.59 [1.23-25.43] and 3.55 [1.08-11.64], respectively). In addition, higher GDF-15 levels predict faster decline in GFR (P < 0.001) but not development of ESRD. CONCLUSIONS - Higher levels of GDF-15 are a predictor of all-cause and cardiovascular mortality and morbidity in patients with diabetic nephropathy. Furthermore, higher levels of GDF-15 are associated with faster deterioration of kidney function.