Impact of timing of antihypertensive treatment on mortality: an observational study from the Spanish Ambulatory Blood Pressure Monitoring Registry

Whether bedtime versus morning administration of antihypertensive therapy is beneficial on outcomes is controversial. We evaluated the risk of total and cardiovascular mortality in a very large observational cohort of treated hypertensive patients, according to the timing of their usual treatment administration (morning versus evening).Vital status and cause of death were obtained from death certificates of 28 406 treated hypertensive patients (mean age 62 years, 53% male individuals), enrolled in the Spanish Ambulatory Blood Pressure Monitoring (ABPM) Registry between 2004 and 2014. Among the 28 406 patients, most (86%) received their medication exclusively in the morning; whilst 13% were treated exclusively in the evening or at bedtime. Follow-up was for a median of 9.7 years and 4345 deaths occurred, of which 1478 were cardiovascular deaths.Using Cox-models adjusted for clinical confounders and 24-h SBP, and compared with patients treated in the morning (reference group), all-cause mortality [hazard ratio 1.01; 95% CI 0.93-1.09) and cardiovascular mortality (hazard ratio 1.04; 95% CI 0.91-1.19) was not significantly different in those receiving evening medication dosing. The results were consistent in all the subgroups of patients analysed.In this very large observational study, morning versus bedtime dosing of antihypertensive medication made no difference to the subsequent risk of all-cause or cardiovascular mortality. These findings are in accordance with results from a recent randomized controlled trial and do not support the hypothesis of a specific beneficial effect of night-time antihypertensive treatment dosing on risk of all-cause or cardiovascular death.