Background: The 2009 US Preventive Services Task Force breast cancer screening update recommended against routine screening mammography for women aged 40-49; confusion and release of conflicting guidelines followed. We examined the impact of the USPSTF update on population-level screening mammography rates in women ages 40-49.
Methods and findings: We conducted a retrospective, interrupted time-series analysis using a nationally representative, privately-insured population from 1/1/2006-12/31/2011. Women ages 40-64 enrolled for ≥ 1 month were included. The primary outcome was receipt of screening mammography, identified using administrative claims-based algorithms. Time-series regression models were estimated to determine the effect of the guideline change on screening mammography rates. 5.5 million women ages 40-64 were included. A 1.8 per 1,000 women (p = 0.003) decrease in monthly screening mammography rates for 40-49 year-old women was observed two months following the guideline change; no initial effect was seen for 50-64 year-old women. However, two years following the guideline change, a slight increase in screening mammography rates above expected was observed in both age groups.
Conclusions: We detected a modest initial drop in screening mammography rates in women ages 40-49 immediately after the 2009 USPSTF guideline followed by an increase in screening rates. Unfavorable public reactions and release of conflicting statements may have tempered the initial impact. Renewal of the screening debate may have brought mammography to the forefront of women's minds, contributing to the observed increase in mammography rates two years after the guideline change. This pattern is unlikely to reflect informed choice and underscores the need for improved translation of evidence-based care and guidelines into practice.