Oral combined hydrochlorothiazide and lisinopril vs nifedipine for postpartum hypertension: a comparative-effectiveness pilot randomized controlled trial.

BACKGROUND

Angiotensin-converting enzyme inhibitors and diuretics may be underutilized for postpartum hypertension because of their teratogenicity during pregnancy.

OBJECTIVE

We evaluated whether combined oral hydrochlorothiazide and lisinopril therapy produced superior short-term blood pressure control when compared with nifedipine among postpartum individuals with hypertension requiring pharmacologic treatment.

STUDY

DESIGN

We performed a pilot randomized controlled trial (October 2021 to June 2022) that included individuals with chronic hypertension or hypertensive disorders of pregnancy with 2 systolic blood pressure measurements ≥150 mm Hg and/or diastolic blood pressure measurements ≥100 mm Hg within 72 hours after delivery. Participants were randomized to receive either combined hydrochlorothiazide and lisinopril therapy or nifedipine therapy after stratifying the participants by diagnosis (chronic hypertension vs hypertensive disorders of pregnancy). The primary outcome was stage 2 hypertension (systolic blood pressure ≥140 mm Hg and/or diastolic blood pressure ≥90 mm Hg) determined using a home blood pressure monitor on days 7 to 10 after delivery or at readmission to the hospital for blood pressure control. The secondary outcomes included severe maternal morbidity (any of the following: intensive care unit admission; hemolysis, elevated liver enzymes, low platelet count syndrome; eclampsia; stroke; cardiomyopathy; or maternal death), need for intravenous medications after randomization, hospital length of stay, blood pressure during first clinic visit, medication compliance, and adverse events. A pilot trial with 70 individuals was planned given the limited available data on combined hydrochlorothiazide and lisinopril therapy use in postpartum care. We calculated relative risks and 95% credible intervals in an intention-to-treat analysis. Finally, we conducted a preplanned Bayesian analysis to estimate the probability of benefit or harm with a neutral informative prior.

RESULTS

Of 111 eligible individuals, 70 (63%) agreed and were randomized (31 in the hydrochlorothiazide and lisinopril group and 36 in the nifedipine group; 3 withdrew consent after randomization), and the characteristics were similar at baseline between the groups. The primary outcome was unavailable for 9 (12.8%) participants. The primary outcome occurred in 27% of participants in the hydrochlorothiazide and lisinopril group and in 43% of the participants in the nifedipine group (posterior adjusted relative risk, 0.74; 95% credible interval, 0.40-1.31). Bayesian analysis indicated an 85% posterior probability of a reduction in the primary outcome with combined hydrochlorothiazide and lisinopril therapy relative to nifedipine treatment. No differences were noted in the secondary outcomes or adverse medication events.

CONCLUSION

The results of the pilot trial suggest a high probability that combined hydrochlorothiazide and lisinopril therapy produces superior short-term BP control when compared with nifedipine. These findings should be confirmed in a larger trial.