Impact of White-coat Hypertension on Microvascular Complications in Type 2 Diabetes Mellitus

Abstract

Objective: To determine the impact of white-coat hypertension (WCH) on microvascular complications in type 2 diabetes mellitus (DM).

Research Design and Methods: A cross-sectional study was conducted in normotensive and WCH subjects selected from a cohort of 319 type 2 DM patients. Normotension was defined by office blood pressure (BP) <140/90 mmHg and daytime BP in ambulatory BP monitoring (ABPM) <135/85 mmHg. WCH was defined as office BP ≥140/90 mmHg and daytime BP on ABPM <135/85 mmHg. Subjects were evaluated for diabetic nephropathy (DN; 24 h urinary albumin excretion rate) and diabetic retinopathy (DR; classified according to the Global Diabetic Retinopathy Group)

Results: Forty-six type 2 DM patients had WCH (14.4%; age 56.6; 45.3% men) and 117, normotension (36.6%; age 55.8; 37.5% men). These groups did not differ in clinical and main laboratory characteristics. Systolic ABPM (24-h: 124.7±6.7 vs. 121.0±8.5 mmHg, P=0.01 and daytime: 126.6±7.2 vs. 123.2±8.2 mmHg, P=0.01) and BP loads were higher in WCH subjects than in the normotensive ones. WCH was associated with an increased risk for macroalbuminuria (OR 4.9, 95%CI 1.3-18.7, P=0.01). On multivariate analysis models, WCH was associated with macroalbuminuria (OR 2.0 95%CI 1.3-3.2, P=0.02) and increased the risk for both non-proliferative and proliferative DR (OR 2.7, 95%CI 1.2-6.6, P=0.02 for any degree of DR) after adjustments for confounding factors.

Conclusions: Type 2 DM patients with WCH have an increased risk for DR and DN. Therefore, WCH should not be considered a harmless condition and treatment should be considered.