Oral combined lisinopril and hydrochlorothiazide superior to nifedipine for BP control in postpartum hypertension

The researchers noted that diuretics and angiotensin-converting enzyme inhibitors are underutilized for postpartum hypertension due to their teratogenicity during pregnancy. Michal Fishel Bartal, the University of Texas Health Science Center at Houston, Houston, TX, and colleagues aimed to evaluate whether combined oral hydrochlorothiazide and lisinopril therapy produced superior short-term BP control versus nifedipine among postpartum individuals with hypertension requiring pharmacologic treatment.

For this purpose, the researchers performed a pilot randomized controlled trial from 2021 to 2022, including patients with chronic hypertension or hypertensive disorders of pregnancy with two systolic BP measurements ≥150 mm Hg and diastolic BP measurements ≥100 mm Hg within 72 hours after delivery.

Participants were randomized to receive either combined lisinopril and hydrochlorothiazide therapy or nifedipine therapy after participants' stratification by diagnosis (hypertensive disorders of pregnancy versus chronic hypertension).

Stage 2 hypertension (systolic BP of ≥140 mm Hg and diastolic BP ≥90 mm Hg) was determined using a home blood pressure monitor on days 7 to 10 following delivery or at readmission to the hospital for BP control (primary outcome). The secondary results were severe maternal morbidity, hospital length of stay, need for IV (intravenous) medications after randomization, adverse events, medication compliance, and blood pressure at the first clinic visit.

Given the limited available data on combined lisinopril and hydrochlorothiazide therapy use in postpartum care, a pilot trial comprising 70 individuals was planned. A preplanned Bayesian analysis was conducted to estimate the probability of harm or benefit with a neutral informative prior. In an intention-to-treat study, relative risks were calculated.

The study led to the following findings:

· Of 111 eligible individuals, 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 12.8% of participants.

· The primary outcome occurred in 27% of participants in the hydrochlorothiazide and lisinopril group and 43% in the nifedipine group.

· 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.

"Our findings suggest a high probability that combined lisinopril and hydrochlorothiazide therapy produces superior short-term BP control versus nifedipine," the researchers wrote. "These findings need to be confirmed in a larger trial."

Reference:

Fishel Bartal M, Blackwell SC, Pedroza C, Lawal D, Amro F, Samuel J, Chauhan SP, Sibai BM. Oral combined hydrochlorothiazide and lisinopril vs nifedipine for postpartum hypertension: a comparative-effectiveness pilot randomized controlled trial. Am J Obstet Gynecol. 2023 Feb 12:S0002-9378(23)00023-6. doi: 10.1016/j.ajog.2023.01.015. Epub ahead of print. PMID: 36787814.