Regional Variation in Antenatal Late Preterm Steroid Use following the ALPS Trial

Objective To assess regional variation in the use of late preterm steroids use after the publication of the Antenatal Late Preterm Steroids (ALPS) Trial and to understand factors associated with a region’s pace of adoption. Methods This was a repeated cross-sectional study using US natality data across hospital referral regions (HRRs) within the US from February 2015 to October 2017. Inclusion criteria included live-born, non-anomalous, singleton, late preterm (34-36 completed weeks of gestation) neonates born to individuals without pregestational diabetes. HRRs were categorized as either a “slower” or “faster” adopter of antenatal late preterm steroids based on the observed versus expected pace of antenatal steroid adoption in a 1-year period after the trial’s dissemination compared to a 1-year pre-dissemination period. Patient and regional factors hypothesized a priori to be associated with the uptake of late preterm steroids were compared between faster and slower adopters. Results There were 666,097 late preterm births in 282 HRRs during the study period. Of the included HRRs, 136 (48.2%) were considered faster adopters and 146 (51.8%) slower adopters. Faster adopters increased their steroid use by 12.1-percentage points (5.9% to 18.0%) compared to a 5.5-point increase (3.7% to 9.2%) among slower adopters (p<0.001). Most examined patient and regional factors were not associated with a region’s pace of adoption. The only factor associated with being a faster adopter was the regional prevalence of prior preterm birth (adjusted odds ratio 2.04, 95% confidence interval 1.48-2.82). Conclusion There was widespread geographic variation in the adoption of antenatal steroid administration for late preterm births that largely remained unexplained by population factors. Future research should focus on patient, provider, and system-level factors that may be influencing the adoption of late preterm steroids. Namely, this work can provide insights to barriers to timely or equitable access to new evidence-based practices and can guide future dissemination strategies with the goal of more uniform adoption.