The Impact of the Affordable Care Act on Colorectal Cancer Incidence and Mortality: the case of Kaiser Permanente of Northern California

BackgroundThe Patient Protection and Affordable Care Act (ACA) eliminated cost sharing for preventive services, including colorectal cancer (CRC) screening for individuals aged 50 to 75 with private health insurance. The present study is the first to examine the impact of the no-cost CRC screening due to the ACA on CRC incidence and mortality. MethodsWe modeled trends in CRC incidence and CRC-related mortality in an open cohort of 2,113,283 Kaiser Permanente Northern California (KPNC) members aged 50 years and older between 2003 and 2016 using an interrupted time series design. Individual-level data were analyzed at the month-level. Analyses were adjusted for age, race/ethnicity and sex. As a sensitivity analysis, we considered a controlled approach, with a comparison group of KPNC members covered by health plans with pre-ACA zero cost-sharing for CRC screening. ResultsA total of 178,582,512 person-months were used in the analysis of CRC incidence, of which 48% occurred in the period before the ACA was passed into law (1/1/2003-3/31/2010) and 52% after (4/1/2010-12/31/2016). In primary analyses, the model for CRC incidence indicated a drop in the trend coinciding with the passage of the ACA (change in level incidence rate ratio, IRR: 0.83, 95% CI: 0.77-0.90, p-value < 0.0001), followed by a decrease in trend (change in slope IRR: 0.97/year, 95% CI: 0.93-1.00, p-value = 0.05). Results for CRC-related mortality were similar. Our controlled results indicate that free screening due to the ACA was associated with greater improvements in CRC outcomes among members previously covered by health plans with out-of-pocket costs for screening, compared to health plans with zero cost sharing for screening before the ACA went into effect. ConclusionsWe found that free CRC screening due to the ACA was associated with a decrease in age-, race/ethnicity- and sex-adjusted CRC incidence and CRC-related mortality, after accounting for contemporaneous competing interventions. Furthermore, these findings were robust to the addition of a comparison group with zero cost sharing both pre- and post-ACA.