Mandated Coverage of Preventive Care and Reduction in Disparities: Evidence From Colorectal Cancer Screening

摘要

Objectives. We identified correlates of racial/ethnic disparities in colorectal cancer screening and changes in disparities under state-mandated insurance coverage. Methods. Using Behavioral Risk Factor Surveillance System data, we estimated a Fairlie decomposition in the insured population aged 50 to 64 years and a regression-adjusted difference-in-difference-in-difference model of changes in screening attributable to mandates. Results. Under mandated coverage, blood stool test (BST) rates increased among Black, Asian, and Native American men, but rates among Whites also increased, so disparities did not change. Endoscopic screening rates increased by 10 percentage points for Hispanic men and 3 percentage points for non-Hispanic men. BST rates fell among Hispanic relative to non-Hispanic men. We found no changes for women. However, endoscopic screening rates improved among lower income individuals across all races and ethnicities. Conclusions. Mandates were associated with a reduction in endoscopic screening disparities only for Hispanic men but may indirectly reduce racial/ethnic disparities by increasing rates among lower income individuals. Findings imply that systematic differences in insurance coverage, or health plan fragmentation, likely existed without mandates. These findings underscore the need to research disparities within insured populations. Colorectal cancer (CRC) incidence and mortality rates have declined substantially for the overall population since the late 1990s as the result of a confluence of significant advances in screening, a consensus in screening recommendations for individuals aged 50 to 75 years from the medical community, and evidence of cost-effectiveness of screening. 1–5 Estimates have indicated that increases in screening explain approximately half of the observed decrease in incidence and in mortality. 6 Yet disparities in CRC screening, incidence, treatment, and mortality persist, even within insured populations. 7,8 The translation of advances in CRC screening procedures and adoption of uniform guidelines into practice occurs in the context of health services delivery settings, including the private health insurance system. Systematic fragmentation in health plan coverage of CRC screening may contribute to systematic disparities. We focused on disparities in screening by race and ethnicity among the insured population, examined the role of socioeconomic status (SES) and community-level factors in explaining these disparities, and estimated changes in these disparities associated with state-mandated insurance coverage of CRC screening procedures. In doing so, we provided an indirect analysis of the potential role of health plan fragmentation. Health plan fragmentation occurs when differences in the amounts and quality of health care consumed arise because of systematic differences in plan benefits and cost sharing. 9 Available data have suggested substantial fragmentation existed in coverage of CRC screening in the privately insured population before most state mandates. 10 For example, in a national sample of 180 plans, only 57% covered colonoscopy for average-risk individuals in 1999. 11 Between 1999 and 2011, 34 states and the District of Columbia enacted CRC screening mandates. In theory, mandated coverage should lead to more uniform coverage of screening procedures and reduce fragmentation. If fragmentation is correlated with race and ethnicity, then mandates may also reduce racial and ethnic disparities in screening. Several previous studies have examined the determinants of CRC screening disparities, and the majority of nationally representative studies have suggested that individual SES is a key determinant. 12–19 Indeed, several found that disparities were substantially reduced or even eliminated after adding measures of SES and access to care to regression models. 12–15 Yet, the data used in these studies did not indicate whether individuals’ insurance plans covered CRC screening. If the probability that an individual’s insurance plan covers CRC screening is correlated with observed measures of individual SES, then the apparent relationship between individual SES and screening may be due in part to underlying health plan fragmentation. Although there is no nationally representative data set that contains information about individuals’ insurance coverage for CRC screening, expansions in insurance coverage introduced through Medicare or state insurance mandates provide natural experiments in which it is possible to study underlying health plan fragmentation indirectly. If these expansions in coverage are associated with reductions in disparities, either directly or indirectly through a shift in screening patterns across the SES distribution, then this would suggest that health plan fragmentation may contribute to observed disparities. Only 1 previous study examined possible changes in screening disparities after state-mandated coverage and found no statisticall