All-cause and cardiovascular disease mortality in underweight patients with diabetic nephropathy: BioBank Japan cohort.

We aimed to determine mortality risk in underweight patients with diabetic nephropathy for microalbuminuria or macroalbuminuria. We analyzed mortality and death-cause data from BioBank Japan, with baseline years 2003-2007. We analyzed mortality rates from all causes and ischemic heart disease, according to body mass index (<18.5, 18.5-21.9, 22-24.9 and ≥25 kg/m2 ). The mean (standard deviation) of patient age, body mass index, and glycated hemoglobin at enrollment was 61.6 years (11.7 years), 25.0 kg/m2 (4.4 kg/m2 ) and 7.7% (1.5%), respectively. Hazard ratios of all-cause and ischemic heart disease mortality were highest (1.79 [P = 0.0001] and 2.95 [P = 0.027], respectively) in patients with body mass index <18.5 kg/m2 , as compared with body mass index 22-24.9 kg/m2 . All-cause mortality risk for body mass index <18.5 kg/m2 was similar to that for current smokers (hazard ratio 1.70, P < 0.0001). Underweight could be a predictor of mortality risk in patients with diabetic nephropathy for microalbuminuria or macroalbuminuria.