Non‐dipping circadian blood pressure and renal impairment are associated with increased mortality in diabetes mellitus

Summary Aims To assess the relevance of circadian blood pressure variation to future morbidity and mortality in patients with diabetes mellitus. Methods A retrospective descriptive 4 year follow‐up study of data collected after ambulatory blood pressure monitoring in a clinic setting. Results Seventy‐five patients (46 male; 29 female) of whom 41% had Type 1 diabetes and 59% Type 2 were followed up for a median of 42 months (11–56). The median creatinine for the whole group at baseline was 101 (56–501) μmol/l. The median circadian blood pressures for the total study population were 147 (110–194)/87 (66–109) mmHg during daytime and 132 (86–190)/77 (50–122) mmHg during night‐time. Half of the patients exhibited a fall in night‐time pressures to 10% lower than daytime pressures (dippers). Dippers were younger, 47 (32–75) years, than non‐dippers, 57 (35–79) years, P = 0.03. Over time, dippers had a lower mortality than non‐dippers, with 8% deaths in the cohort of dippers, 26% deaths in the cohort of non‐dippers, P = 0.04. Cox regression analysis revealed significant contributions from age, duration of diabetes and baseline renal function to subsequent mortality in non‐dippers. Analysing