Prognostic impact of short-term ambulatory blood pressure variability for microvascular and macrovascular outcomes in patients with type 2 diabetes: the Rio de Janeiro Type 2 Diabetes Cohort Study

OBJECTIVE: To evaluate the prognostic importance of short-term blood pressure variability (BPV) for the occurrence of macrovascular and microvascular complications in individuals with type 2 diabetes. METHODS: Six hundred and forty patients had 24-h ambulatory BP monitoring performed at baseline and were followed-up over a median of 11.2 years. Daytime, night-time and 24-h SBP and DBPV parameters (standard deviations and variation coefficients) were calculated. Multivariate Cox analysis, adjusted for risk factors and mean BPs, examined the associations between BPV and the occurrence of microvascular (retinopathy, microalbuminuria, renal function deterioration, peripheral neuropathy) and macrovascular complications [total cardiovascular events (CVEs), major adverse CVEs [MACEs]), and cardiovascular and all-cause mortalities. Improvements in risk discrimination were assessed by the C-statistic and Integrated Discrimination Improvement (IDI) index. RESULTS: During follow-up, 186 patients had a CVE (150 MACEs), and 237 patients died (107 from cardiovascular diseases); 155 newly developed or worsened diabetic retinopathy, 200 achieved the renal composite outcome (124 newly developed microalbuminuria and 102 deteriorated renal function), and 170 newly developed or worsened peripheral neuropathy. Daytime DBPV was the best predictor for all cardiovascular outcomes and mortality, with hazard ratios (for increments of 1SD) ranging from 1.27 (95% CI 1.09-1.48) for all-cause mortality to 1.55 (1.29-1.85) for MACEs, and it improved cardiovascular risk discrimination (with increases in C-statistic of up to 0.026, and IDIs of up to 22.8%). No BPV parameter predicted any microvascular outcome. CONCLUSION: Short-term BPV, particularly daytime DBPV, predicts future development of macrovascular complications and mortality and improves cardiovascular risk discrimination in patients with diabetes.