State mandates and Sample characteristics
Of the 45 states included in the study, 22 states and DC had passed mandates requiring private insurance plans to cover the full range of colorectal cancer screening tests consistent with ACS guidelines on or before December 31, 2008 (Table ). The analytic sample consisted of 293,626 individuals aged 50-64 years who reported having health insurance coverage (Table ). Respondents were evenly distributed across years (2002 to 2008) and between the sexes (49% male vs. 51% female). Individuals were mostly in the age-groups of 50-54 (40.6%) and 55-59 years (32.8%), were primarily White, non-Hispanic (79.1%), had college or some college degrees (65.8%), and in higher- and middle-household income groups (≥$50,000: 50.8%, 25,000 to ≤50,000: 23.6%). The majority of respondents reported "better" or "good" health status (81.9%), and were married or members of unmarried couples (74.7%) (Table ). Across states, the percent of the population 50-64 years who were privately insured averaged over 2002-2008 was generally high and ranged from 69% in Arkansas to 88% in Minnesota (data not shown).
Descriptive characteristics of US Adults with Health Insurance, aged 50-64 years, surveyed in the period of 2002-2008
Impact of state CRC screening mandates on CRC screening utilization in the past year
In unadjusted analyses, having a state CRC screening mandate for at least 1 year was associated with a 0.4% point increase in the probability of flexible sigmoidoscopy or colonoscopy in the past year (OR: 1.03, 95% CI: 0.99, 1.08, p = 0.09) (Table ). Adjustment for state- and year-fixed effects, individual covariates, and state-level proportions of privately insured adults resulted in a stronger mandate effect compared to unadjusted analyses; the probability of CRC screening was 1.4% points higher among individuals residing in states with mandates than those without (17.5% vs. 16.1%, OR: 1.10, 95% CI: 1.02, 1.20, p = 0.02) (Table ). Additionally, we considered the possibility that state mandates require more than one year of implementation to be effective in changing CRC utilization patterns. CRC utilization rates did not differ significantly between respondents in states with laws in place for different time intervals.
Impact of Colorectal Cancer Screening coverage mandates on Endoscopy Screening a Use in Past Year among US Adults with Health Insurance aged 50-64 years, 2002-2008
The two-way interaction terms between state mandates and demographic- and socioeconomic- variables were not statistically significant; indicating that the effect of mandates did not differ significantly between subgroups of respondents based on their race/ethnicity, education, and household income levels (data not shown). However, linear contrasts of the adjusted probabilities indicated that the effect of mandates was significant and stronger in higher-educated respondents (16.7% vs. 18.3%, contrast: 1.6% points, p = 0.01) but not in lower-educated respondents (15% vs. 15.8%, contrast: 0.8%, p = 0.12). A three-way interaction variable between state mandates, a collapsed two-level version of the household income (low- and middle-income: < $50,000, and high income group: ≥$50,000), and education level (lower-education: less than high school or high school graduate, and higher-education: college graduate or some college graduate) was statistically significant (p < 0.005). Linear contrasts of the adjusted probabilities from the interaction term indicated that among low- and middle-income individuals, the effect of state mandates was positive and significant only among higher-educated individuals (14.4% vs. 17.9%, contrast: 3.5% points, p < 0.001) but not among lower-educated individuals (13.7% vs. 14.1%, contrast: 0.4% points, p = 0.5). Conversely, state mandates resulted in marginally higher CRC utilization rates among lower educated-high income individuals (15.3% vs. 18.0%, contrast: 2.7% points, p < 0.05), but not among high educated-high income individuals (17.9% vs. 19.1%, contrast: 1.2% points, p = 0.12).