Isolated office hypertension (IOH) has been associated with structural cardiac abnormalities; however, its relation to worse cardiovascular prognosis remains uncertain. Less is known regarding the consequences of uncontrolled IOH in treated hypertensives. The aim was to investigate whether uncontrolled IOH was independently associated with two subclinical markers of cardiovascular disease, aortic stiffness and left ventricular hypertrophy (LVH). Clinical laboratory and 24-h ambulatory blood pressure (BP) data were obtained in 523 hypertensive patients with type 2 diabetes. Controlled office-ambulatory hypertension was defined by office blood pressure <140/90 mm Hg and 24-h BP <130/80 mm Hg, whereas uncontrolled IOH by office blood pressure> or =140/90 mm Hg and 24-h BP <130/80 mm Hg. Arterial stiffness was assessed by carotid-femoral pulse wave velocity (PWV) and left ventricular mass index (LVMI) by echocardiography. Statistics included multivariate linear and logistic regressions. According to BP patterns, 152 patients (29.1%) had controlled office-ambulatory hypertension, and 172 (32.9%) had uncontrolled IOH. Patients with uncontrolled IOH had greater LVMI (62.0+/-21.9 vs. 52.9+/-17.0 g m(-2.7), P<0.001) and PWV (11.5+/-2.4 vs. 10.2+/-2.1 m s(-1), P<0.001) than those with controlled hypertension. On linear model, after adjustment for several potential confounders, patients with uncontrolled IOH persisted with higher PWV (P=0.003) and LVMI (P=0.015). On logistic regression, the presence of uncontrolled IOH was independently associated with 2.7-fold (95% CI: 1.3-5.5) and 2.1-fold (95% CI: 1.1-4.0) higher risks of having increased aortic stiffness and LVH, respectively. In conclusion, uncontrolled IOH is associated with increased aortic stiffness and LVH in hypertensive type 2 diabetic patients. This may be a link to augmented cardiovascular risk.