Reversed Circadian Blood Pressure Rhythm Independently Predicts Endstage Renal Failure in Non–Insulin-Dependent Diabetes Mellitus Subjects

Abstract

To investigate the significance of reversed circadian blood pressure (BP) rhythm as a predictor for diabetic endstage renal failure, introduction of hemodialysis (HD) was determined as an end point in 325 non–insulin-dependent diabetes mellitus (NIDDM) subjects, in whom 24-h BPs had been monitored during their first admissions between 1988 and 1996. Circadian BP rhythm was analyzed by the COSINOR method, as previously reported. After exclusion of 68 dropout subjects, 257 were recruited for further analyses, in which 194 had normal circadian BP rhythms (N), and the remaining 63 had reversed rhythms (R). During this follow-up period, the numbers of HD-introduced subjects in N and R were 6 and 16, respectively, showing a higher prevalence in the latter ( p < 0.001, χ 2 test). Follow-up periods were significantly shorter in HD-introduced diabetic subjects of N and R than those in HD-free subjects of each group. In baseline characteristics, there were no differences in age, gender, or serum creatinine between HD-free and HD-introduced subjects of N or R. With regard to microvascular complications, the degree of retinopathy and nephropathy in N and R tended to be more pronounced in HD-introduced subjects than in HD-free subjects. Further, mean levels of circadian mean BP rhythms in HD-introduced subjects of N or R were similarly high, compared with those in HD-free subjects of each group, irrespective of circadian BP pattern. Unadjusted HD-free times were estimated by the Kaplan–Meier method, with a significant difference noted between N and R ( p < 0.001; log-rank test). The Cox proportional-hazards model adjusted for circadian BP pattern, age, gender, hlood pressure level, glycemic control, duration of diabetes, serum total protein, and serum creatinine demonstrated that circadian BP pattern, age, gender (female), blood pressure level (hypertension), and serum creatinine exhibited significant high relative risks. Thus, our data suggest that reversed circadian BP rhythm is an independent predictor of endstage renal failure in NIDDM subjects.