ADHERENCE TO ORAL ANTIHYPERTENSIVE THERAPY AND ADHERENCE-SUPPORTING CARE PATHWAYS AMONG POSTPARTUM OUTPATIENTS WITH HYPERTENSIVE DISORDERS OF PREGNANCY: A COMPREHENSIVE SYSTEMATIC REVIEW AND META-ANALYSIS OF RANDOMIZED CONTROLLED TRIALS AND PRIMARY STUDIES

Abstract

Introduction: Hypertensive disorders of pregnancy (HDP) frequently persist or worsen after hospital discharge, and more than half of hypertension-related maternal deaths occur postpartum. The effectiveness of outpatient antihypertensive therapy depends on initiation, implementation and persistence of medication-taking, and on adherence to blood pressure (BP) surveillance and follow-up, yet these behaviours have not been synthesised together for postpartum outpatients. This review aimed to quantify adherence to postpartum oral antihypertensive therapy and to adherence-supporting care, to evaluate structured pathways (remote BP monitoring, self-management with titration, coaching, pharmacist counselling) and discharge agent choice, and to map determinants of non-adherence.^1–3

Methods: The study strictly adhered to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 guidelines. Randomized controlled trials (RCTs), cohort (prospective and retrospective), case–control, cross-sectional and other observational studies of postpartum outpatients with HDP were eligible; systematic reviews and meta-analyses were excluded from data synthesis but used in the Discussion. Risk of bias was assessed with RoB 2, ROBINS-I and the Newcastle–Ottawa Scale. DerSimonian–Laird random-effects models pooled logit-transformed proportions, risk ratios (RR), odds ratios (OR) and mean differences (MD); heterogeneity (I², τ², prediction intervals), subgroup, leave-one-out and small-study analyses (funnel plots, Egger test) were performed, and certainty was graded with GRADE.^4,5

Results: 25 studies (3 RCTs, 22 observational; ≈1.07 million participants; 2022–2026; USA, UK, Denmark, Switzerland, China, Tanzania and Nigeria) met inclusion criteria, spanning 12 outcome domains. Primary adherence (first fill within 7 days) was 73.4% (95% CI 70.5–76.0), whereas only 42.2% (41.8–42.6) of 63,312 women persisted without discontinuation. Pooled adherence to postpartum BP surveillance/follow-up was 77.5% (95% CI 67.1–85.3; I² = 95.1%; 95% PI 32.8–96.0). Structured pathways increased follow-up/BP ascertainment adherence (RR 1.57, 95% CI 1.49–1.66; I² = 0%) and BP control (RR 1.44, 1.33–1.56), reduced hypertension-related readmission/emergency visits (RR 0.69, 0.49–0.99), and lowered systolic (MD -5.52 mmHg, -7.04 to -4.00) and diastolic BP (MD -4.51 mmHg, -6.37 to -2.66). Discharge on labetalol versus once-daily extended-release nifedipine was associated with higher readmission (adjusted OR 1.95, 1.22–3.14). Younger age, Black or Hispanic/Asian ethnicity, public insurance, lower education and multiparity predicted lower adherence or engagement. No small-study effect was detected (Egger p = 0.30).^3,6–9

Discussion: Postpartum antihypertensive care displays a steep adherence cascade: most women initiate therapy, but more than half discontinue early, and attendance at BP surveillance is variable. Structured, clinician-supported pathways consistently improve engagement and BP outcomes, and simpler once-daily regimens appear safer. Certainty of evidence ranged from moderate (BP reduction, follow-up adherence) to very low (medication-taking prevalence), with a critical scarcity of direct medication-adherence measurement and of data from Southeast Asia, including Indonesia.^10–12

Conclusion: Adherence to postpartum antihypertensive therapy among outpatients is suboptimal and decays over time. Discharge bundles combining once-daily regimens, education, home BP self-monitoring with clinician titration, and navigated transition to primary care are recommended, together with validated adherence metrics and context-specific trials in low- and middle-income countries.^2,13