According to two Spanish studies in Diabetologia, elevated nighttime blood pressure may promote development of adult onset diabetes, and taking medication to control blood pressure at bedtime, might actually help reduce that risk.

In the first study, 2700 adults who were not diagnosed with diabetes, periodically underwent 48-hour ambulatory BP monitoring. Over 6 years’ median follow-up, 7% developed diabetes. Risk for diabetes was greater with higher levels of sleep-time systolic BP and with smaller BP declines during sleep. Systolic BP during sleep was the second most significant predictor of diabetes, behind fasting glucose.

In the same study group, patients with high BP, were randomized to take at least one of their BP medications before bed or to take all of their BP medications in the morning. Compared with the morning group, the nighttime group had better ambulatory BP control (particularly during night sleep) and was at significantly reduced risk for developing diabetes (12% vs. 5%). When taken at bedtime, angiotensin-receptor blockers, angiotensin-converting-enzyme inhibitors, and beta-blockers showed greater benefit.