The prognostic importance of tight clinic blood pressure (BP) control is controversial in diabetic patients. The objective was to investigate the prognostic impact of clinic and ambulatory BPs for cardiovascular morbidity and mortality in type 2 diabetes.
In a prospective cohort study, 565 type 2 diabetic patients had clinical, laboratory and ambulatory BP monitoring (ABPM) data obtained at baseline and during follow-up. The primary endpoints were a composite of fatal and nonfatal cardiovascular events and all-cause mortality. Multivariable Cox survival and splines regression analyses assessed associations between each BP component [SBP, DBP and pulse pressure (PP)] and the endpoints.
After a median follow-up of 5.75 years, 88 total cardiovascular events and 70 all-cause deaths occurred. After adjustments for cardiovascular risk factors, clinic SBP and DBPs were predictive of the composite endpoint but not of all-cause mortality, whereas all ambulatory BP components were predictors of both endpoints. Ambulatory systolic and PPs were the strongest predictors and achieved ambulatory BPs during follow-up improved risk prediction in relation to baseline values. When categorized at clinically relevant cut-off values, risk began only at clinic BPs at least 140/90 mmHg, whereas for ambulatory BPs it began at lower values (≥120/75 mmHg for the 24-h period).
ABPM provides more valuable information regarding cardiovascular risk stratification than office BPs and should be performed, if possible, in every high-risk type 2 diabetic patient. Achieved 24-h ambulatory BPs less than 120/75 mmHg are associated with significant cardiovascular protection and, if confirmed by other studies, may be considered as BP treatment targets.