Objectives We sought to validate, or refute, the common belief that bedtime diuretics are poorly tolerated due to nocturia.Design Prespecified prospective cohort analysis embedded within the randomised BedMed trial, in which hypertensive participants are randomised to morning versus bedtime antihypertensive administration.Setting 352 community family practices across 4 Canadian provinces between March 2017 and September 2020.Participants 552 hypertensive patients (65.6 years old, 57.4% female) already established on a single once-daily morning antihypertensive and randomised to switch that antihypertensive to bedtime. Of these, 203 used diuretics (27.1% thiazide alone, 70.0% thiazide/non-diuretic combinations) and 349 used non-diuretics.Intervention Switching the established antihypertensive from morning to bedtime, and comparing the experience of diuretic and non-diuretic users.Primary and secondary outcome measures Primary outcome: Adherence to bedtime allocation time at 6 months (defined as the willingness to continue with bedtime use, not an assessment of missed doses). Secondary 6-month outcomes: (1) nocturia considered to be a major burden and (2) increase in overnight urinations/week. All outcomes were self-reported and additionally collected at 6 weeks.Results At 6 months: Adherence to bedtime allocation time was lower in diuretic users than non-diuretic users (77.3% vs 89.8%; difference 12.6%; 95% CI 5.8% to 19.8%; p<0.0001; NNH 8.0), and more diuretic users considered nocturia a major burden (15.6% vs 1.3%; difference 14.2%; 95% CI 8.9% to 20.6%; p<0.0001; NNH 7.0). Compared with baseline, diuretic users experienced 1.0 more overnight urinations/week (95% CI 0.0 to 1.75; p=0.01). Results did not differ between sexes.Conclusions Switching diuretics to bedtime did promote nocturia, but only 15.6% found nocturia a major burden. At 6 months, 77.3% of diuretic users were adherent to bedtime dosing. Bedtime diuretic use is viable for many hypertensive patients, should it ever become clinically indicated.Trial registration number NCT02990663.
