title: Non-dipping circadian blood pressure and renal impairment are associated with increased mortality in diabetes mellitus.
abstract: OBJECTIVE
  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) micromol/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 current degree of renal impairment and original dipper status together revealed that, of those patients whose creatinine remained normal, 7% of patients whose blood pressure dipped had subsequently died and 10% of non-dipping patients had died; of those patients whose creatinine unequivocally rose, 10% of dipping patients had died and 42% of non-dipping patients had died, P = 0.03
  
  
  CONCLUSIONS
  Loss of circadian variation in blood pressure is associated with an increased mortality rate, regardless of diabetes type. The combination of non-dipping and subsequent renal impairment leads to the highest mortality rate. The study suggests a role for ambulatory blood pressure monitoring in day-to-day clinical practice to select patients with nephropathy who are at greatest risk, in an effort to alter outcome.
authors.affiliation: Department of Diabetes and Endocrinology, Nottingham City Hospital NHS Trust, UK. nsturroc@ncht.org.uk
authors.forename: N D
authors.initials: ND
authors.lastname: Sturrock
authors.forename: E
authors.initials: E
authors.lastname: George
authors.forename: N
authors.initials: N
authors.lastname: Pound
authors.forename: J
authors.initials: J
authors.lastname: Stevenson
authors.forename: G M
authors.initials: GM
authors.lastname: Peck
authors.forename: H
authors.initials: H
authors.lastname: Sowter
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D002318:Cardiovascular Diseases / Q000209:etiology / Q000503:physiopathology; D002940:Circadian Rhythm; D003922:Diabetes Mellitus, Type 1 / Q000401:mortality* / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000401:mortality* / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000209:etiology / Q000503:physiopathology; D003928:Diabetic Nephropathies / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors