Prediction modeling of postpartum blood pressure spikes and investigation of preventive management strategies

Abstract

Evaluate clinical predictors of blood pressure (BP) spikes 3-7 days postpartum (PP) and investigate clinical management strategies to prevent spikes and lower associated morbidity. A retrospective cohort study of PP women participating in remote BP monitoring. Postpartum BP spike was defined as BP ≥140/ 90 if on an antihypertensive and BP ≥150/100 if not on an antihypertensive. We created three at- risk patient clusters (low, medium, and high) to predict patient risk of PP BP spike on PP days 3-7. The variables most important in defining the clusters were BMI, tobacco use, gestational age at delivery, and chronic hypertension. The conditional average treatment effect (CATE) was estimated with causal forest for two management strategies: 1) PP length of stay < or ≥ 3 days and 2) discharge on antihypertensive medication based on predicted PP BP spike risk. A CATE value < 0 represents a positive effect in preventing PP BP spikes. The propensity score related estimate (Q) was estimated regarding the treatment option to discharge on meds based on different BP thresholds a) ≥ 130 and/or ≥ 80, b) ≥ 140 and/or ≥ 90 or c) ≥ 150 and/or ≥ 100. The smaller the Q-value, the greater the treatment effect in preventing BP spikes. Of 413 patients included, 267 (64.6%) had a PP BP spike. The CATE was < 0 for medium- or high-risk patients staying ≥3 days PP. The CATE was < 0 for medium-risk patients and antihypertensive use at discharge. The Q-value estimates for discharging on antihypertensives at different BP thresholds were: Qa = 135.80, Qb = 129.18, Qc = 82.11. We evaluated three strategies to prevent PP BP spikes and concluded; 1) medium and high-risk patients should be considered for a longer PP stay or consider participating in daily home monitoring if discharged earlier, 2) medium-risk patients should be prescribed antihypertensives at discharge, and 3) antihypertensive treatment should be prescribed if patients have BP ≥140/90 at discharge.View Large Image Figure ViewerDownload Hi-res image Download (PPT)