This study found that use of CRC screening among the Medicare beneficiaries studied has continued to increase from 2000 to 2005. However, the rates of increase varied by race and ethnicity resulting in complex patterns of disparities over time. Compared to whites, blacks had a greater increase in use of CRC screening between 2000 and 2003, resulting in a smaller black–white difference in 2003 as has been reported in previous studies.12
However, the gap widened slightly in 2005: among blacks, there was no significant increase in use of CRC screening between 2003 and 2005, while rates among whites continued to increase. This apparent slow down in the use of CRC screening among blacks between 2003 and 2005 is of concern, and suggests that the increasing trends observed in some previous studies16
may not continue. The Hispanic–white difference remained unchanged in 2005.
Previous studies have found CRC screening disparities by race,6,22
SES, and healthcare access.8,14
This study shows that the black–white differences changed over time, and most of the racial differences were explained by socioeconomic inequalities and differences in healthcare access. In contrast to previous studies,3,6,10,12,16–18
these findings highlight the need for continued attention to blacks and Hispanics. There are no clear explanations for the observed pattern of change in use of CRC screening among blacks between 2000 and 2005. It is plausible that the initial sharp increase in use of CRC screening was due in part to the Medicare policy change, which may have been augmented by celebrity promotion (such as Katie Couric)30
and increasing recommendation by healthcare providers. “Wear-out”31
of effects of celebrity endorsements of screening colonoscopy may be a possible explanation for the slowdown in the rate of increase of CRC screening among blacks in the later study period. However, other factors including socioeconomic disadvantage may have contributed to the patterns observed.32,33
It is possible that these various factors differentially affected blacks compared to Hispanics, whose rates of screening were lower but increased steadily during the study period. Additional studies are needed to understand the underlying reasons for the observed differences and to determine if the trends continue.
This study also builds on previous reports.8,14
A study among Medicare beneficiaries in North and South Carolina found that racial differences were attenuated after adjusting for sociodemographic and healthcare access factors including health insurance.14
Data from the Behavioral Risk Factor Surveillance System, also showed persistent racial disparities in CRC screening from 2000 to 2006.6
Although similar findings were observed, this study provides a clearer picture of CRC screening disparities among Medicare beneficiaries than previous analyses.6,14,22
This study analyzed screening trends over time on a nationally representative sample and used more detailed data on healthcare access indicators.
This study found that black and Hispanic Medicare enrollees earned less and had lower educational levels and were less likely to have supplemental health insurance than whites. Therefore, they are more likely to benefit from Medicare’s expansion of CRC screening benefits. For each of the study years, black–white and Hispanic–white differences in screening were attenuated or disappeared after adjustment for health insurance coverage and having a usual place of medical care. This suggests that the combination of socioeconomic disadvantage and limited access to health care21
reduces the potential that expansion of coverage will close the racial gaps in use of CRC screening. As more physicians and patients choose colonoscopy over FOBT,34–37
the resulting higher cost of screening may pose a bigger barrier to screening for minority populations. Beneficiaries pay up to 25% of Medicare-allowed costs for colonoscopy,15
which was about $625 (in 2007 dollars) for the procedure alone, but was $812 if polypectomy was performed.38
Thus, cost-sharing policies that are not based on ability to pay may have only a limited impact on disparities.7,39
To eliminate disparities in CRC screening among Medicare enrollees, there is a potential benefit of a policy of targeted expansion of screening coverage to those most at risk, particularly those with less education and income. There is also a potential benefit of more aggressive promotion of stool-based screening tests which are effective in reducing incidence and mortality for CRC40,41
and are fully covered by Medicare.15
There was an encouraging 17% increase in the use of screening among those aged 65–80 years over the 6-year study period. It is likely that increasing awareness of screening due to promotion by celebrities30
and professional medical organizations,27
and increasing recommendation by healthcare providers42,43
augmented the impact of Medicare’s policy change. However, even if the current increasing trend is sustained, the U.S. public health goal of increasing the use of CRC screening to 70% by 2010 among eligible adults will not be achieved for this population for whom CRC screening is a covered benefit.
A limitation of this study is the inability to distinguish between use of sigmoidoscopy and colonoscopy. Therefore, the primary analyses used a definition of CRC screening that did not include colonoscopies done more than 5 years prior to the interview date. However, analyses using a more inclusive definition of CRC screening did not materially change these findings.
This study was based on self-report and study participants may not have accurately recalled the type of or indication for screening examination, resulting in misclassification of study participants with respect to the outcome studied. However, previous studies have confirmed the accuracy of self-reported CRC screening, particularly endoscopy.44
Any potential misclassifications likely affected the 3 racial ethnic groups equally in a nondifferential manner and may have attenuated the differences in use of screening.
Reducing cancer health disparities and deaths from CRC through increased use of screening is a U.S. public health priority.45
This study found that despite the expansion of benefits for CRC screening, which would be expected to disproportionally benefit racial and ethnic minorities, racial differences in screening persist due in part to differences in health insurance coverage, education and income. The study also found a possible reversal of the initial attenuation of black–white difference that occurred after Medicare implemented its CRC screening policy change in 2001. Given the benefits to be derived from increasing rates of screening among minority populations, greater attention needs to be paid to improving access to CRC screening if disparities are to be eliminated. This may be accomplished through targeted expansion of coverage for screening to people in lower socioeconomic groups who have the highest burden for CRC combined with community-based programs and effective interventions in physicians’ offices to consider all CRC screening. Attention should also be given to ongoing promotion of available Medicare benefits for screening.