Masked nocturnal hypertension-a novel marker of risk in type 2 diabetes

This study was designed to evaluate the prevalence of masked nocturnal hypertension (MNHT) and its impact on arterial stiffness and central blood pressure in patients with type 2 diabetes. Middle-aged patients (n = 414) with type 2 diabetes underwent clinic and ambulatory BP measurements and applanation tonometry. MNHT (clinic BP < 130/80 mmHg and night-time BP a parts per thousand yenaEuro parts per thousand 120/70 mmHg) was found in 7.2% of patients (n = 30). Compared with patients with both clinical and nocturnal normotension (n = 70), patients with MNHT had higher aortic pulse wave velocity (PWV) (10.2 +/- 1.8 m/s vs 9.4 +/- 1.7 m/s; p = 0.03) and higher central BP (117.6 +/- 13.9/74.0 +/- 9.1 mmHg vs 110.4 +/- 16.4/69.7 +/- 9.6 mmHg, p = 0.04). In patients with clinical normotension, night-time systolic BP correlated significantly with PWV. Thirty per cent of patients with clinical normotension had nocturnal hypertension. This was accompanied by increased arterial stiffness and higher central BP. We conclude that in clinically normotensive patients with type 2 diabetes, ambulatory BP measurement may help clinicians to identify patients with increased cardiovascular risk.