Nonadherence to treatment protocol for severe hypertension in pregnancy

Hypertensive disorders of pregnancy are one of the leading causes of maternal mortality and severe morbidity. The American College of Obstetricians and Gynecologists recommends treatment of persistent severe hypertension because this has been shown to improve overall outcomes. Treatment remains inconsistent and may be influenced by patient-level sociodemographic and clinical characteristics.

This study aimed to identify which factors are associated with nonadherence to an institutional protocol for the treatment of severe hypertension in pregnancy.

Retrospective cohort study of patients who had persistent severe hypertension (≥2 systolic blood pressures ≥160 mm Hg and/or diastolic blood pressures >110 mm Hg between 15 and 60 minutes apart) during their delivery hospitalization in 3 hospitals within an integrated health system from February 1, 2018 to March 1, 2020. Adherence to an institutional protocol was defined as receiving antihypertensive medication within 1 hour of a second severe blood pressure measurement. Demographic information, medical comorbidities, and delivery hospitalization characteristics were compared between women who received treatment based on institutional protocol and those who did not. Patient zone improvement plan codes were linked to neighborhood-level data from the US Census Bureau's American Community Survey to extract socioeconomic characteristics. A multivariable logistic regression was performed to evaluate factors associated with delayed treatment while adjusting for potential confounders.

Of the 996 patients included, 449 (45%) received treatment within 60 minutes and 547 (55%) did not. Having an elevated, nonsevere range blood pressure (adjusted odds ratio, 0.55; 95% confidence interval, 0.38-0.79) or a severe range blood pressure (adjusted odds ratio, 0.25; 95% confidence interval, 0.16-0.38) on admission, persistent severe hypertension ≥1 hour before or after delivery (adjusted odds ratio, 0.27; 95% confidence interval, 0.27-0.45), and chronic hypertension (adjusted odds ratio, 0.58; 95% confidence interval, 0.37-0.93) were associated with timely treatment. Hospital site (adjusted odds ratio, 1.97; 95% confidence interval, 1.18-3.28) and increasing gestational age (adjusted odds ratio, 1.14; 95% confidence interval, 1.07-1.21) were associated with nonadherence to treatment protocol. A subanalysis evaluating treatment in 344 (35%) patients who had a nonelevated blood pressure on admission showed that White race, persistent severe hypertension within 1 hour of delivery, increasing gestational age, body mass index, twin gestation, preferred language other than English or Spanish, and a higher neighborhood unemployment rate were associated with nonadherence to treatment protocol.

Several factors were associated with nonadherence to an institutional protocol for treatment of persistent severe hypertension. Provider bias may impact whether treatment is executed or not. Awareness of these risk factors may improve timely administration of antihypertensive medication in pregnant and postpartum patients.