Cardiovascular prognosis of sustained and white-coat hypertension in patients with type 2 diabetes mellitus

Objective Cardiovascular prognosis in diabetic white-coat hypertension (WCH) has not yet been described. We designed this study to investigate the impact of WCH on cardiovascular events in patients with type 2 diabetes, compared with those having type 2 diabetes along with sustained hypertension (SH), and with nondiabetic hypertensive individuals. Methods We performed ambulatory blood pressure (BP) monitoring in 1207 consecutive hypertensive patients at baseline, and they were followed up for 49 +/- 22 months. The mean age was 70.7 +/- 9.8 years; 262 had type 2 diabetes; and 945 did not. They were classified as having SH with diabetes (n = 210); diabetic WCH (n = 52); SH alone (n = 719); or WCH alone (n = 226), using awake BP of 135/85 mmHg as the cutoff value. Cox regression models were used to calculate hazard ratios (HR) and 95% confidence intervals of the risk for cardiovascular events, after controlling for age, sex, body mass index, current smoking, serum creatinine, and clinical systolic BP. Results During the follow-up period, 97 cardiovascular events occurred. The incidence of cardiovascular events in the diabetic SH group was significantly higher than in the diabetic WCH, nondiabetic SH, and nondiabetic WCH (P<0.05; log-rank test) groups. In Cox regression analysis, the diabetic SH group had significantly higher risk of cardiovascular events compared with the diabetic WCH group (HR: 8.2; 95% confidence intervals: 1.09-61.8; P = 0.04). Although nonsignificant, the HRs in the SH and WCH groups, relative to diabetic WCH, exceeded 3.0. Conclusions The cardiovascular prognosis for diabetic WCH was better than that for diabetic SH during 4 years of follow-up.