Thresholds of ambulatory blood pressure associated with chronic complications in type 2 diabetes

Diagnostic cut-off values for ambulatory blood pressure monitoring (ABPM) in diabetic patients are not established. The aim was to investigate associations between office and ambulatory blood pressures (BPs) and diabetic chronic complications and to establish optimal threshold ambulatory BP values regarding the likehood of having microvascular complications in type 2 diabetes.

In a cross-sectional design, clinical, laboratory, and 24-h ABPM data were obtained in 550 type 2 diabetic patients. Multivariate logistic regression assessed the associations between office and ambulatory BPs and diabetic micro and macrovascular complications. Optimal threshold values for ambulatory BPs (daytime, night-time, and 24 h) were established by examining the best combination of systolic (SBP) and diastolic BP (DBP) that maximized the odds ratios (ORs) of having each microvascular complication.

After multivariate adjustment for all potential confounders, ambulatory SBPs were more strongly associated with diabetic complications than office BPs, except for retinopathy and nephropathy, in which both were equivalent. In general, night-time BPs were stronger correlates than daytime BPs. The optimal threshold ambulatory BP values were 125/75 mm Hg for daytime, 110/65 mm Hg for night-time, and 120/75 mm Hg for the 24-h period, with odds ranging from 1.7- to 2.3-fold of having each microvascular complication.

Except for retinopathy and advanced nephropathy, ambulatory BPs are better correlates of chronic complications than office BPs in type 2 diabetes. The association of microvascular complications with lower ambulatory BP levels than those reported as normal for nondiabetic patients may indicate that lower cut-off values for ambulatory BPs might be considered in type 2 diabetic patients.