Factors Associated with Appropriate Treatment of Acute-Onset Severe Obstetric Hypertension

Abstract Background The American College of Obstetricians and Gynecologists (ACOG) recommends pregnant patients receive expeditious treatment with first-line antihypertensive agents within one hour of confirmed severe hypertension to reduce the risk of 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. Objective We aimed to identify factors associated with receiving guideline-concordant treatment for obstetric hypertensive emergency. Study Design We present a case-control study of all pregnant and postpartum patients who had persistent severe hypertension (≥2 systolic blood pressures (BP) ≥160 mmHg and/or diastolic BP ≥110 mmHg within 1 hour of each other) during their delivery hospitalization at a tertiary hospital from 10/01/2013 to 8/31/2020. Data were extracted from hospital electronic medical records using standard definitions and billing and diagnosis codes. We defined receipt of recommended treatment as administration of a first-line antihypertensive agent (intravenous labetalol, intravenous hydralazine, or oral immediate-release nifedipine) within 60 minutes of the first or second severe-range BP during their delivery hospitalization. Delayed treatment was defined as administration of a first-line agent >60 minutes after the second elevated BP. Patients were considered untreated if a first-line agent was never administered. Maternal sociodemographic, clinical and pregnancy factors, and time and day of week of the hypertensive emergency were compared among patients who received 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. Results Of 39,918 deliveries, 1,987 (5.0%) were complicated by severe persistent obstetric hypertension. Of these patients, 532 (26.8%) received recommended treatment, 356 (17.9%) received delayed treatment, and 1,099 (55.3%) did not receive any first-line antihypertensive therapy. Multinomial regression models comparing these three groups indicate patients receiving recommended treatment were more likely to be Black (aOR 1.85, 95% CI 1.36-2.51), Hispanic (aOR 1.77, 95% CI 1.28-2.52), or pregnant and Conclusions Approximately half of obstetric patients with at least two documented severely elevated blood pressures did not receive recommended antihypertensive treatment. Of those who did receive treatment, about 40% had delayed treatment. Black and Hispanic race and preterm gestation were associated with increased likelihood of receiving recommended treatment, compared with White race and term pregnancies. Patients whose severe obstetric hypertension 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 obstetric hypertension or other pregnancy complications were less likely to be treated. However, treatment improved significantly over time with implementation of targeted quality measures and specific institutional policies based on ACOG’s latest sHTN management guidelines.