Colorectal cancer screening in the elderly population: disparities by dual Medicare-Medicaid enrollment status.

Colorectal cancer (CRC), a highly prevalent condition and a leading cancer-related cause of death in the elderly (Jemal et al. 2005), is potentially curable when detected early (Smith, Cokkinides, and Eyre 2005). In addition, when surgery for CRC is of an emergency and/or palliative nature, it is associated with a substantially elevated risk of mortality (McArdle and Hole 2004), especially in the frail elderly (Koperna, Kisser, and Schulz 1997). Consequently, the benefits of screening may not necessarily be limited to those who are healthy, but are likely to extend to older individuals, and to those with compromised health as well (Clark et al. 2004). The U.S. Preventive Services Task Force (USPSTF) recommends fecal occult blood test (FOBT) to be performed on an annual basis, and flexible sigmoidoscopy (FLEX) and colonoscopy at 10-year intervals (The U.S. Preventive Services Task Force 2005). It further recommends initiating CRC screening at 50 years of age in men and women at average risk for CRC, and earlier in individuals at higher risk for the disease, although there is no consensus on the age at which CRC screening should be discontinued. Despite the higher yield of CRC screening in older individuals, its benefits may be considered limited because of competing causes of death. Given the changing demographics, however, and the increasingly greater representation of healthier individuals in the older age groups, there may be less of a tendency to set an age limit beyond which CRC screening is no longer recommended. Also, because of the greater morbidity and mortality in patients presenting with emergency CRC resection, generally resulting from screening failure, the recommendation and practice of CRC screening in the context of age and the presence of comorbid conditions are likely to be reconsidered. Dually eligible Medicare–Medicaid beneficiaries (hereafter referred to as “duals”) represent the oldest, poorest, and frailest of the elderly population (The Henry J. Kaiser Family Foundation 2004; Murray and Shatto 1998). For example, whereas 73 percent of duals have annual incomes of $10,000 or less, only 12 percent of nonduals may be identified with such income levels. Similarly, duals are considerably more likely than nonduals to rate their health as poor or fair (52 versus 26 percent, respectively), to present significant limitations in activities of daily living (over 30 versus 11 percent), or to reside in nursing homes (19 versus 3 percent; The Henry J. Kaiser Family Foundation 2005). On the other hand, the above statistics imply that nearly 50 percent rate their health as good, very good, or excellent; two thirds report no limitations in their activities of daily living; and 80 percent are community-dwelling—suggesting that a sizable proportion of duals may in fact benefit from preventive care. Also, while most duals have low incomes, enrollment in Medicaid is likely to give them considerable leverage to access health services that they could not afford otherwise. The above descriptions attest to the complexity of issues in studying the health care needs of duals as a subgroup of Medicare beneficiaries at large, and illustrate the diversity in this population, especially relative to their health and functional status. In comparing the use of cancer screening between duals and nonduals, several factors need to be accounted for in formulating research hypotheses. First, considering differentials in health status between duals and nonduals, we can posit that because of competing priorities in addressing the complex health care needs in a sizable proportion of duals, management of acute and/or chronic ailments—rather than prevention—becomes the focus of care—hence the lower likelihood of undergoing cancer screening tests. Second, from the perspective of income, we postulate, based on previous studies, that lower income—and potentially lower educational attainment—is associated with underuse of preventive services (Katz and Hofer 1994; Katz, Zemencuk, and Hofer 2000), even if enrollment in Medicaid is conducive to greater access to health care. We therefore hypothesize that duals would experience a significantly lower rate of cancer screening than their nondual counterparts. The present study examines the use of CRC screening services among Medicare beneficiaries by dual Medicare–Medicaid enrollment status, an attribute largely understudied in the disparities literature. More specifically, we compare receipt of CRC screening by duals and nonduals 65 years of age or older, after adjusting for individual-level characteristics. Given the previously documented associations between county-level socioeconomic and health systems attributes with the use of CRC screening (Koroukian et al. 2005), relevant contextual variables are also accounted for in the analysis.