(813) Trends in Hypertensive Disorders in the United States Post Aspirin Recommendation Guidelines: A Nationwide Study

Objective: To determine if there were changes in the rates of hypertensive disorders of pregnancy (HDP) in the United States after the publication of aspirin recommendation guidelines by the United States Preventive Services Task Force (USPSTF) and the American College of Obstetricians and Gynecologists (ACOG).

Study Design: A population-based retrospective cohort study was performed using the US Natality database. The pre-aspirin recommendation guidelines (pre-ASA) group were births from 2010-2014. The post-aspirin recommendation guidelines (post-ASA) group - including both the USPSTF and ACOG guidelines - were births from 2016-2021. Births that occurred in 2015 were excluded. Outcomes were rates of HDP. Univariable and multivariable analyses were performed. A logistic regression was used to project the HDP rate over time based on the pre-ASA group rate and was compared, per year, using Wald confidence intervals.

Results: There were 12,127,659 births in the pre-ASA group and 17,665,217 births in the post-ASA group. After adjusting for baseline clinical differences, the post-ASA group had a higher rate of overall HDP than the pre-ASA group (7.7% vs 4.9%; aOR 1.58 [1.57-1.59]). However, the post-ASA group had a lower rate of preterm birth complicated with HDP prior to 37 weeks (21.6% vs 23.7%; aOR 0.90 [0.89-0.91]) and prior to 34 weeks (6.0% vs 7.5%; aOR 0.79 [0.78-0.81]) than the pre-ASA group. The observed HDP rate post-ASA implementation was higher than projected for overall HDP and preterm birth with HDP < 37 weeks, but not different for the preterm birth with HDP < 34 weeks. Both preterm periods showed a downtrending pattern.

Conclusion: While HDP remains on the rise overall, the rates are downtrending among preterm births. This observed trend, however, remains either higher or no different compared to the projected trend post-ASA implementation guidelines. While aspirin may provide some efficacy for HDP prophylaxis, it is worthwhile to continue focusing on public health efforts to address known modifiable risk factors for preeclampsia such as obesity, chronic hypertension, and diabetes.