Researchers say sleeping BP may be novel target for diabetes prevention.
According to new research, taking hypertension medication before bed rather than in the morning not only lowers nighttime blood pressure (BP) but protects against new-onset diabetes.
Lead researcher, Ramón Hermida, PhD, of the University of Vigo, Spain stated that sleeping BP — but not daytime or 48-hour ambulatory BP — was found to be a significant predictor of new-onset diabetes and may be a novel target for prevention.
Medications that block the renin-angiotensin-aldosterone system (RAAS), such as angiotensin receptor blockers (ARBs) and ACE inhibitors, had the strongest antidiabetic effect. “Activation of the renin-angiotensin-aldosterone system (RAAS) and consequent elevations of angiotensin II and aldosterone contributes to increased hepatic glucose release and decreased insulin sensitivity,” the investigators wrote. They added that the RAAS follows a circadian rhythm, becoming active during sleep.
Accordingly, in addition to BP-lowering, RAAS blockade might also serve as an effective strategy to control impaired glucose and insulin tolerance.
The prospective study included more than 2,000 hypertensive patients enrolled in the Ambulatory Blood Pressure Monitoring for Prediction of Cardiovascular Events (MAPEC) study. Their average age was 53, and they were roughly half men and half women. Participants were randomized to a bedtime group that took the entire daily dose of one or more of their hypertension medications before bed, and a daytime group that took all their hypertension medications upon waking.
Blood pressure was assessed annually in both groups by daytime clinic measurement and by 48-hour ambulatory blood pressure (ABP) monitoring. Blinded investigators assessed the development of new-onset diabetes. During a median follow-up of 5.9 years, 171 study participants developed diabetes. Incidence of new-onset diabetes was significantly lower in the bedtime group (4.8%) versus the daytime group (12%) (P<0.001).
After adjusting for factors, including fasting glucose, waist circumference, and chronic kidney disease, the investigators found the bedtime group was 57% less likely to develop diabetes (P<0.001).
All classes of hypertension drugs showed some protective effect against diabetes in the bedtime group, but the strongest effect was found for ARBs (P<0.001), ACE inhibitors (P=0.015), and beta blockers (P=0.021).
Several assessments of blood pressure were significantly lower in the bedtime group versus the daytime group, including the mean sleeping systolic BP (109.6 ±13.9 mmHg versus 114.4 ± 15.2 mmHg; P<0.001), the percentage of decline in sleeping systolic BP (12% versus 9%; P<0.001), and the percentage of those whose sleeping BP was controlled (72% versus 59%; P<0.001).
In a separately published analysis in the same journal, the investigators reported that mean sleeping systolic BP as measured by ambulatory monitoring was a significant and independent predictor of new-onset diabetes. For each 1-standard deviation elevation in mean sleeping systolic BP, the risk of diabetes increased by almost 30% (P<0.001).
The daytime BP measured in the clinic or by ambulatory monitoring did not predict new-onset diabetes.
The research team concluded that “lowering asleep BP, a novel therapeutic target requiring ABP evaluation, could be a significant method for reducing new-onset diabetes risk.”
In summary, ambulatory BP monitoring is needed not only for proper diagnosis of hypertension and quantification of cardiovascular risk, but also, within this context, for evaluation of the individual’s risk of developing diabetes, rendering ambulatory BP a cost-effective technique that should be recommended in all adults.
In conclusion, changing the time of ingestion of hypertension medications, a zero-cost intervention, has been shown to reduce cardiovascular morbidity and mortality and, be in keeping with the new findings.
This study reinforces the importance of taking hypertension medication at night, particularly drugs that have an anti-renin effect — ACE inhibitors, ARBs, and mineralocorticoid receptor antagonists.
It is a known fact that dosing at night is preferable for a lot of drugs, in particular drugs that modulate the RAAS. Hypertension specialists know this. But the average person in the field may not be aware of this.
- Sleeping BP — but not daytime or ambulatory BP — was found to be a significant predictor of new-onset diabetes and may be a novel target for diabetes prevention.
- The incidence of new-onset diabetes among hypertensive patients was significantly lower in those taking BP medications at bedtime versus on waking.
- This study reinforces the importance of taking hypertension medication at night.