Trends in County-Level Rates of New-Onset Hypertensive Disorders of Pregnancy in US, 2007-2019

Given that new-onset hypertension in pregnancy is a leading risk factor for adverse maternal and neonatal outcomes, we sought to define geographic variation in county-level rates and trends of new-onset hypertensive disorders of pregnancy (HDP) in the US. Deidentified records of all live births to individuals aged 20-44 years in the US between 2007 to 2019 were obtained from the National Vital Statistics System. HDP was defined as hypertension newly diagnosed during pregnancy after 20 weeks of gestation and includes gestational hypertension and preeclampsia. Hierarchical Bayesian spatiotemporal models were used to estimate annual rates for new-onset HDP at the county-level. Next, log-linear regression models were used to quantify percent change in new-onset HDP rates between 2007-2019. Lastly, we applied the Lee-Carter method to generate projected rates through 2030. In 2007, the national age-standardized rate of HDP was 3.9 (95% confidence interval [CI]: 3.9-3.9) per 100 live births. Rates of HDP varied significantly among counties (Figure 1), with an absolute difference between the 90th percentile (6.9 per 100 live births) and the 10th percentile (2.8) counties of 4.1 (95% CI 4.0-4.3). By 2019, the age-standardized rate of HDP had increased to 7.9 (95% CI 7.9-8.0) with mean % change nationally of 102% (95% CI 84-122). Statistical increases in HDP rates occurred in 94.1% (95% CI 93.1-95.0) of counties with significant heterogeneity in the magnitude of increase; the greatest increases were observed in clusters of the Northeast, South, and West regions (Figure 2). By 2030, projected rates of HDP were estimated at 14.9 per 100 live births (12.8-17.5) with an increase in the absolute difference between the 90th-10th percentile counties to 21.7 (20.7-22.8). Age-standardized rates of HDP have increased substantially at the national level and in nearly all counties. However, substantial geographic differences in county-level HDP cross-sectional rates and temporal increases may lead to widening geographic inequities in HDP.View Large Image Figure ViewerDownload Hi-res image Download (PPT)