We found that Blacks were five percentage points less likely to be adherent to CRCS than Whites. This gap is smaller in magnitude than most prior studies, which have documented Black/White differences in CRCS ranging from 6% to 18%,14,16,18,19,65–67
but is consistent with more recent results from national surveys and a prior VA study that used a nationally representative sample.68
In addition, this observed disparity was no longer present when we adjusted for demographic and health factors. It is also noteworthy that we found no racial difference in physician recommendations for CRCS (84% for Blacks, 85% for Whites) which, as we found, is a strong correlate of CRCS.
The high rates of CRCS adherence among Black and White veterans (72% and 77%, respectively) are considerably higher than national rates among Blacks and Whites during a similar period (48.6% and 56.8%).69
These high screening rates are likely to be due, in part, to various VHA efforts initiated over the past ten years to increase adherence to CRCS, including the implementation of clinical reminders as part of the electronic medical record and an incentivized audit-and-feedback system of performance measures.21–24
This study builds upon prior studies examining racial disparities in adherence to CRCS, only a few of which have examined the extent to which cognitive and environmental factors contribute to disparities.19,66
Counter to our hypotheses, race differences in adherence to CRCS were explained by race differences in demographic/health-related factors and social/medical environmental factors, but not by cognitive factors. Although more research is needed to fully understand this pattern of results, it is likely that race differences in utilization of the VA as a source of care is a contributing factor. For example, one potential explanation for the relatively low rates of screening among disadvantaged White veterans is that these individuals are more likely to live in rural areas than their Black counterparts and therefore may have more difficulty accessing VA care.70,71
Also, the dominant modes of CRC screening differ within and outside the VA. FOBT is the dominant mode of screening within the VA whereas screening by colonoscopy is more common outside the VA. We conducted additional analyses and found that, among those who were adherent to CRCS, Black veterans had significantly higher rates of FOBT (60% vs. 53%, p
0.025) and lower rates of colonoscopy compared with White veterans (47% vs. 57%, p
= 0.012). It may be the case that higher SES Black veterans, who are more likely than their lower SES Black counterparts to receive care outside the VA, are less likely to be offered a colonoscopy than whites receiving care outside the VA. Alternatively, higher SES blacks may be less likely than their white counterparts to find the option of colonoscopy acceptable (perhaps because it is an invasive procedure or because they are more likely to be unmarried and hence lack the necessary support required for the procedure).
There are several limitations to this study. Because the combined measure is based in part on self-report, and some over reporting of adherence does occur in this population,51
this measure may have led to some overestimation of adherence. However, our adherence estimates (from data collected in 2007) correspond closely to the 2007 adherence estimate of 78% derived from the VA national performance measurement system (based on medical records only).72
Additionally, the results of this study—particularly high rates of screening and the “reversal” of disparities that we found among disadvantaged patients—might not apply outside of the VA, which has made great strides at implementing CRCS system-wide.21
These results have several implications for research, policy, and practice. First, other healthcare systems can build on the VA’s success in promoting CRCS. Second, while the use of FOBT as the primary screening mode in VA has been successful, it is critical to ensure that positive FOBTs are appropriately followed up with diagnostic colonoscopy and to ensure that Black patients are as likely as white patients to receive appropriate follow-up. Two recent studies conducted in the VA, including one study based on a nationally representative cohort of VA patients,30,73
suggest that, although follow-up rates are similar for Black and White veterans, they are disappointingly low for both groups. Finally, there is a need for additional research to understand the “reverse” disparities we found among less advantaged, White veterans. If it is the case that living in a rural setting accounts for low rates of CRCS among disadvantaged White veterans, it will be critical to develop strategies to improve screening in this population.70,71
Additional research is also needed to understand why Black veterans are less likely to be screened by colonoscopy than their White counterparts.