Factors associated with appropriate treatment of acute-onset severe obstetrical hypertension

Abstract

The American College of Obstetricians and Gynecologists recommends that pregnant patients receive expeditious treatment with first-line antihypertensive agents within 1 hour of confirmed severe hypertension to reduce the risk for maternal stroke. However, it is unknown how often this guideline is followed and what factors influence a patient's likelihood of receiving guideline-concordant care. We aimed to identify factors associated with receiving guideline-concordant treatment for an obstetrical hypertensive emergency. We present a case-control study of all pregnant and postpartum patients who had persistent severe hypertension (≥2 systolic blood pressures ≥160 mm Hg or diastolic blood pressure ≥110 mm Hg, or both within 1 hour of each other) during their delivery hospitalization at a tertiary hospital from October 1, 2013, to August 31, 2020. Data were extracted from the hospital electronic medical records using standard definitions and billing and diagnosis codes. We defined receipt of the recommended treatment as administration of a first-line antihypertensive agent (intravenous labetalol, intravenous hydralazine, or immediate-release oral nifedipine) within 60 minutes of the first or second severe-range blood pressure measurement during their delivery hospitalization. Delayed treatment was defined as the administration of a first-line agent >60 minutes after the second elevated blood pressure measurement. Patients were considered untreated if a first-line agent was never administered. Maternal sociodemographic, clinical and pregnancy factors, and time and day of the week of the hypertensive emergency were compared among patients who received the recommended treatment, those who received delayed treatment, and those who were untreated. Bivariate analyses were performed, and multinomial and multivariable logistic regression models were used to adjust for potential confounders. Of the 39,918 deliveries in the cohort, 1987 (5.0%) were complicated by severe, persistent obstetrical hypertension. Of these patients, 532 (26.8%) received the recommended treatment, 356 (17.9%) received delayed treatment, and 1099 (55.3%) did not receive any first-line antihypertensive therapy. The multinomial regression models that were used to compare these 3 groups indicated that patients who received the recommended treatment were more likely to be Black (adjusted odds ratio, 1.85; 95% confidence interval, 1.36-2.51), Hispanic (adjusted odds ratio, 1.77; 95% confidence interval, 1.28-2.52), or pregnant and at <37 weeks of gestation (adjusted odds ratio, 6.65; 95% confidence interval, 5.08-8.72). Treatment was less likely if the severe obstetrical hypertension emergency occurred overnight (7:00 PM to 6:59 AM) (adjusted odds ratio, 0.79; 95% confidence interval, 0.64-0.97) or during the postpartum period (adjusted odds ratio, 0.66; 95% confidence interval, 0.51-0.86). Approximately half of obstetrical patients with at least 2 documented severely elevated blood pressure measurements did not receive the recommended antihypertensive treatment. Of those who did receive treatment, about 40% had delayed treatment. Black and Hispanic race and preterm gestation were associated with an increased likelihood of receiving the recommended treatment when compared with White race and term pregnancies. Patients whose severe obstetrical hypertension emergency occurred overnight and those who were postpartum were less likely to receive any first-line antihypertensive treatment. Overall, patients without sociodemographic and clinical risk factors for severe obstetrical hypertension or other pregnancy complications were less likely to be treated. However, treatment improved significantly over time with the implementation of targeted quality measures and specific institutional policies based on the American College of Obstetricians and Gynecologists' latest severe obstetrical hypertension management guidelines.