Does Medicare Coverage Of
Colonoscopy Reduce Racial/
Ethnic Disparities In Cancer
Screening Among the Elderly?
Disparities between screening rates of non-Hispanic white and
Hispanic beneficiaries became significant after Medicare coverage
began.
by Ya-Chen Tina Shih, Lirong Zhao, and Linda S. Elting
ABSTRACT:Racial and ethnic disparities in colorectal cancer screening have been docu-mented extensively in the literature. In July 2001 Medicare began covering colonoscopy for average-risk beneficiaries. We examined the effect of Medicare reimbursement on the rate and disparity of colorectal cancer screening among the elderly in the United States. This policy alleviated the screening disparity between non-Hispanic whites and blacks, but the gap between Hispanics and non-Hispanic whites has widened. Overall, fewer than half of the elderly are screened, even though Medicare now covers colonoscopy. [Health Affairs
25, no. 4 (2006): 1153–1162; 10.1377/hlthaff.25.4.1153]
C
o l o r e c t a l c a n c e r i s t h e t h i r d most commonly diagnosedmalig-nancy and the second leading U.S. cause of cancer death.1The association
between colorectal cancer screening and reduced colorectal cancer mortal-ity is well established; hence, screening of average-risk populations is
recom-mended.2 Despite these recommendations, colorectal cancer screening in the
United States is used much less than that for breast or cervical cancer. A study us-ing data from the National Health Interview Survey (NHIS) reported 67 percent and 80 percent screening rates for mammography and Pap smears, respectively,
but a rate of less than 40 percent for colorectal cancer screening.3
Racial and ethnic disparities in colorectal cancer screening have been docu-mented extensively; most studies have found a lower rate of screening among
ra-cial/ethnic minorities.4Lack of health insurance and variations in coverage are two
of the most frequently cited reasons for the observed racial/ethnic disparities in
use of or access to health care.5Disparities in colorectal cancer screening have
per-Ya-Chen Tina Shih ([email protected]) is an associate professor in the Section of Health Services Research, Department of Biostatistics and Applied Mathematics, M.D. Anderson Cancer Center at the University of Texas in Houston. Lirong Zhao is a statistical analyst there, and Linda Elting is a professor.
sisted among Medicare beneficiaries.6One plausible explanation is that previous
studies reporting racial/ethnic disparities in colorectal cancer screening were based on data collected in the 1980s or 1990s, when Medicare coverage of colo-rectal cancer screening was limited to “high-risk” beneficiaries. The lack of insur-ance coverage for colonoscopy for those of average risk might have created access barriers for the lower-income elderly, and it likely led to the previously observed racial/ethnic disparities in screening among Medicare beneficiaries.
Medicare began paying for colonoscopy screening for average-risk beneficiaries
on 1 July 2001.7Medicare reimbursement for this screening procedure had been
limited to those at high risk, whereas fecal occult blood test and flexible
sigmoid-oscopy were covered for all elderly beneficiaries.8Medicare’s reimbursement for
colonoscopy reduces financial barriers to screening and should increase its use among the elderly. Two studies have documented an increase in the rate of endo-scopic colorectal cancer screening among Medicare beneficiaries and those ages 50–64.9One reported a significant (p<.01) increase in use of colonoscopy in a
ter-tiary institution within six months after the policy went into effect.10The other
observed an increase in the rate of screening from 4.6 percent before to 14.2 percent after the coverage change among average-risk patients in a large network of
gastro-intestinal physicians.11To our knowledge, no studies have examined the effect of this
Medicare policy on the rate of colorectal cancer screening in a nationally represen-tative sample of the U.S. elderly population or its impact on screening disparities among the elderly in various racial/ethnic groups. Our study is intended to fill that gap.
Study Data And Methods
nData source. For this study, we used the 2000 Cancer Control Module (CCM) and 2003 Cancer Screening Supplement (CSS) of the NHIS. The NHIS is a
nationally representative probabilistic annual health survey.12It has been the
pri-mary source of information on the health of civilian, noninstitutionalized U.S. households since 1957. A CCM was administered in the 2000 NHIS to examine can-cer-screening behavior and cancer risk factors such as diet, nutrition, physical activ-ity, and family history. The 2003 NHIS also fielded a CSS, but it covered only some of the questions asked in 2000. To examine whether Medicare coverage of colonos-copy changed the pattern of screening colonoscolonos-copy use among the elderly, we se-lected two years of NHIS data, 2000 and 2003, which contain information on the use of colonoscopy. The two years represent pre- and postcoverage periods. Our study was limited to respondents age sixty-five and older.
nKey variables. The key variables for the study were the use of endoscopic colorectal cancer screening (the outcome of interest), and Medicare beneficiaries’
swered “yes,” we considered him or her to have been screened. Race/ethnicity was classified into four categories: Hispanic, non-Hispanic white, non-Hispanic black, and non-Hispanic other races; included in the “other races” were American Indi-ans/Alaska Natives, Asians, Native Hawaiians and other Pacific Islanders.
nOther explanatory variables.We included age and sex in addition to race/ ethnicity. Age was categorized into three groups: 65–74, 75–84, and 85+, since
stud-ies have shown a nonlinear relationship between age and screening.13We described
geographic characteristics by census region and location in a metropolitan statisti-cal area (MSA). Because of confidentiality concerns, the MSA variable is no longer available in the 2003 NHIS. Education attainment was categorized into four groups; we dichotomized marital status as married or not married and place of birth as
U.S.-born or foreign-U.S.-born. Income was classified in four income levels and unknown.14
Barriers to access included the lack of a usual source of care or lack of supplemental insurance (private insurance or Medicaid). Health status was measured as self-perceived health and self-reported cancer history (yes or no). All explanatory vari-ables are listed in Exhibit 1.
nStatistical analysis. We first compared the differences in colorectal cancer screening rates between the 2000 and 2003 samples for the four defined
racial/eth-nic groups, using Wald chi-square statistics.15We then used multivariate logistic
re-gression to examine the differences in the likelihood of screening across racial/eth-nic groups, while controlling for other factors that have been found to be associated with this screening in the literature, such as socioeconomic status or access barriers. We employed appropriate weighting procedures in Stata 8.0 and defined statistical significance asp<.05.
Study Results
nDescriptive statistics.Exhibit 1 compares the characteristics of the 2000 and 2003 NHIS populations. On average, a significantly higher proportion of the elderly in 2003 were in the oldest age group (eighty-five years and older), and a lower pro-portion were at the lowest education level (less than high school) or in the poor/ near-poor income group. No differences were found in the distribution of other pop-ulation characteristics.
nRacial/ethnic groups. In 2003, the rate of endoscopic colorectal cancer screening was significantly higher than in 2000 (p<.001) (Exhibit 1). Across the four racial/ethnic groups, we found a significant increase in the rate of screening from
2000 to 2003 for non-Hispanic whites (p<.01) and non-Hispanic blacks (p=.022)
(Exhibit 2). Differences between 2000 and 2003 were not statistically significant among Hispanics or non-Hispanic other races. In both years, the Hispanic elderly had the lowest rate of endoscopic colorectal cancer screening among the elderly studied.
nComparisons of the odds of screening in multivariate logistic models. Af-ter other confounders were controlled for, in 2000, non-Hispanic blacks were less
EXHIBIT 1
Descriptive Statistics, Study Population For The Assessment Of Screening Colonoscopy For Colorectal Cancer Among The U.S. Elderly, 2000 And 2003
2000 (N = 6,180) 2003 (N = 5,759)
Number Percent Number Percent pvalue
Had colorectal cancer screening 2,533 42.84 2,657 48.04 <.001
Race/ethnicity Hispanic Non-Hispanic white Non-Hispanic black Non-Hispanic other 573 4,807 696 104 5.85 83.85 8.17 2.13 537 4,466 627 129 5.89 83.41 8.21 2.49 .7493 Age (years) 65–74 75–85 85+ 3,241 2,305 634 54.62 36.53 8.85 2,902 2,146 711 52.83 36.37 10.80 .0038 Sex Male Female 2,324 3,856 42.54 57.46 2,143 3,616 42.33 57.67 .8530 Census region Northeast Midwest South West 1,253 1,443 2,224 1,260 21.15 24.29 35.71 18.85 1,173 1,307 2,149 1,130 21.86 23.88 36.61 17.66 .3639 Foreign-born Yes No 687 5,493 10.7 89.93 627 5,132 9.74 90.26 .6551
Highest education attained Less than high school High school diploma Some college
College degree and above
2,113 1,981 1,163 828 31.57 34.02 19.18 15.23 1,730 1,860 1,161 897 27.66 34.54 20.94 16.86 .0007 Marital status Married Not married 2,518 3,662 55.62 44.38 2,334 3,425 55.58 44.42 .9689 Income Poor/near-poor Low income Middle income Upper income Unknown 2,071 771 474 792 2,072 28.03 13.44 8.13 15.53 34.87 1,665 797 427 798 2,072 24.09 14.69 8.27 16.39 36.57 .0013
Private supplemental insurance Yes No 4,474 1,706 70.65 29.35 4,129 1,630 69.87 30.13 .5266 Medicaid Yes No 591 5,589 7.18 92.82 566 5,193 7.51 92.50 .5414
Usual source of care Yes No 5,900 280 95.69 4.31 5,538 221 96.36 3.64 .0988
likely to have had endoscopic colorectal cancer screening compared with non-His-panic whites; the odds of screening increased in 2003, and the previously observed disparities between these two groups were no longer significant in 2003 (Exhibit 3). In contrast, the odds of screening declined for Hispanics between the two study years, and the differences between Hispanics and non-Hispanic whites became
sig-nificant in 2003 (p=.048). No statistically significant differences were found
be-tween non-Hispanic whites and non-Hispanic others in either year.
Associations between the rate of endoscopic colorectal cancer screening and other covariates were similar to those reported in the literature. However, we found that some associations appeared to have grown stronger over time, while others had become weaker. Most noticeably, sex differences in screening were
EXHIBIT 1
Descriptive Statistics, Study Population For The Assessment Of Screening
Colonoscopy For Colorectal Cancer Among The U.S. Elderly, 2000 And 2003 (cont.)
2000 (N = 6,180) 2003 (N = 5,759)
Number Percent Number Percent pvalue
Self-perceived health status Excellent Very good Good Fair Poor 783 1,590 2,167 1,186 444 12.80 26.15 35.37 18.65 7.02 728 1,532 1,987 1,074 428 12.90 27.02 34.19 18.59 7.29 .7044
SOURCE:Authors’ analysis of data from the National Health Interview Survey, 2000 and 2003.
NOTE:After survey weights were applied, 6,180 and 5,759 individuals represented 32,693,838 and 34,256,340 U.S. elderly in 2000 and 2003, respectively.
EXHIBIT 2
Rate Of Colorectal Cancer Screening Among U.S. Elderly, By Race/Ethnicity, 2000 And 2003
SOURCE:Authors’ analysis of data from the National Health Interview Survey, 2000 and 2003.
NOTE:Findings were statistically significant only for non-Hispanic whites ( < .001) and non-Hispanic blacks ( = .022).p p 40 30 20 10 0 Percent
Hispanic Non-Hispanic white Non-Hispanic black Non-Hispanic other
2000 2003
more apparent over time. Moreover, elderly in the low-income group in 2000 were not more likely to have been screened than those in the poor/near-poor income
EXHIBIT 3
Multivariate Logistic Models For Factors Associated With Colorectal Cancer Screening
2000 2003
Odds ratio 95% CI Odds ratio 95% CI
Race/ethnicity (reference group: non-Hispanic white) Hispanic Non-Hispanic black Non-Hispanic other Foreign-born 0.806 0.788 0.666 0.650 (0.622, 1.045) (0.630, 0.984) (0.425, 1.044) (0.521, 0.812) 0.768 0.909 0.636 0.855 (0.592, 0.997) (0.731, 1.131) (0.395, 1.024) (0.669, 1.092)
Age (years) (reference group: age 65–74) 75–84 85+ 1.042 0.716 (0.904, 1.201) (0.576, 0.889) 1.043 0.748 (0.902, 1.206) (0.597, 0.936) Male Married 1.104 1.316 (0.966, 1.261) (1.160, 1.493) 1.267 1.176 (1.115, 1.440) (1.034, 1.338)
Education attainment (reference group: less than high school)
High school diploma Some college College and above
1.318 1.544 2.113 (1.135, 1.530) (1.299, 1.835) (1.724, 2.589) 1.282 1.810 2.216 (1.084, 1.517) (1.490, 2.199) (1.790, 2.744)
Income status (reference group: poor/ near-poor) Low income Middle income Upper income Unknown 0.905 1.246 1.296 0.895 (0.741, 1.105) (0.967, 1.606) (1.044, 1.609) (0.769, 1.042) 1.479 1.564 1.503 0.926 (1.217, 1.798) (1.189, 2.056) (1.204, 1.876) (0.787, 1.090)
Census region (reference group: northeast) Midwest
South West
Metropolitan statistical area
0.968 0.930 1.236 1.108 (0.809, 1.158) (0.785, 1.103) (1.030, 1.482) (0.952, 1.289) 0.896 0.880 0.965 –a (0.732, 1.097) (0.726, 1.066) (0.782, 1.191) –a
Secondary insurance (reference group: none) Non-Medicaid Medicaid 1.300 0.805 (1.138, 1.486) (0.629, 1.032) 1.288 1.056 (1.107, 1.498) (0.815, 1.369)
Self-perceived health status (reference group: excellent) Very good Good Fair Poor 1.070 1.091 1.295 1.516 (0.866, 1.322) (0.892, 1.335) (1.043, 1.608) (1.142, 2.013) 1.134 1.152 1.135 0.990 (0.926, 1.389) (0.939, 1.413) (0.899, 1.432) (0.720, 1.361) History of cancer Usual source of care
1.358 2.908 (0.842, 2.190) (1.998, 4.234) 1.627 4.681 (1.021, 2.591) (3.092, 7.085)
SOURCE:Authors’ analysis of data from the National Health Interview Survey, 2000 and 2003.
NOTES:CI is confidence interval. aNot available
U.S.- and foreign-born groups and across geographic areas were no longer
signifi-cant in 2003 (p=.207). All other covariates showed a similar trend over time.
Discussion
The expansion of Medicare reimbursement of colonoscopy to the average-risk population on 1 July 2001 was intended to reduce the economic access barrier to colorectal cancer screening, including that associated with race/ethnicity. We conclude that although the above goal has been achieved overall, all sectors of the population have not benefited equally; there is still room for improvement. We found that even after Medicare began covering colonoscopy, more than half of el-derly respondents reported never having this screening procedure. The disparities in screening rates between non-Hispanic whites and non-Hispanic blacks have been reduced: They were no longer statistically significant after Medicare began covering colonoscopy. However, the disparities between the non-Hispanic whites and Hispanics became significant after Medicare coverage began.
A number of factors might have contributed to a lower rate of endoscopic colorectal cancer screening among elderly Hispanics and a slower rate of catching up after Medicare coverage became available. First, a disproportionately higher percentage of Hispanics were in the poor/near-poor income group; Hispanics ac-counted for less than 6 percent of the U.S. elderly population, but approximately 10 percent of the elderly in this income group were Hispanic. Also, a large percent-age of Hispanics were foreign-born. Additionally, Hispanic beneficiaries were less likely than others to have a usual source of care or private supplemental insurance. All of these factors might have contributed to the lower rate of screening observed in both years. After controlling for these and other factors, we found no significant association between Hispanic ethnicity and endoscopic colorectal cancer screen-ing in 2000 but strong evidence of disparities in screenscreen-ing among Hispanics in 2003. This suggests that factors uniquely associated with a lower rate of screening among Hispanic Medicare beneficiaries make this population more vulnerable even after economic barriers to screening have been removed. These might include a lack of awareness of the availability of Medicare coverage or cultural factors.
There are certainly cultural differences between Hispanics and blacks that could lead to the observed findings. These include barriers to seeking health care such as language and health literacy, a nihilistic view of a cancer diagnosis (as a death sentence), preference for not knowing about the disease before it becomes
symptomatic, and many others.16However, in most studies, the most consistent
predictor of cancer screening use is a recommendation from the health care
pro-vider.17 The second most consistent predictor is the patient’s perception of risk.
Both of these factors are strongly influenced by the prevalence of the disease in the population of interest. Therefore, it is important to note that both the incidence (39.0 per 100,000) and the mortality (14.2 per 100,000) associated with colorectal cancer among U.S. Hispanics are much lower than those observed among
non-Hispanic whites (53.6 and 20.1 per 100,000, respectively) and blacks (62.4 and 27.9
per 100,000, respectively).18Given the high incidence and mortality of colorectal
cancer among blacks, it is perhaps not surprising that their physicians would be more likely to recommend screening and that these patients would more likely comply, compared with Hispanics. This is a possible explanation, although not a justification, for the low rates of colorectal cancer screening among Hispanics. However, this observation points to the importance of tailoring interventions to specific populations. Specifically, among Hispanics and their physicians, aware-ness of risk could be an important target for intervention.
Although the coverage of colonoscopy was intended to reduce the economic burden of colorectal cancer screening for Medicare beneficiaries, such benefits are subject to the Part B deductible and a 20 percent copayment. The estimated cost of a colonoscopy, based on Medicare-allowable payments in 2000, was $695.95
without a biopsy and $1,003.76 with a biopsy.19 Therefore, beneficiaries paid a
$139.20 copayment or more, depending on whether a biopsy was performed, plus an annual deductible of $110 (in 2005) for Part B services. This out-of-pocket amount could be prohibitive for poor and near-poor beneficiaries. Some dually eli-gible beneficiaries avoid the out-of-pocket expenses through Medicaid coverage; however, as of 2004, screening colonoscopy was not covered by Medicaid in
thirty-two states.20 The lack of Medicaid coverage in many states probably
ex-plains the lack of association between Medicaid supplemental insurance and screening while private supplemental insurance was positively associated with screening. The increasing odds of screening found among beneficiaries in the low-income group, compared with those in the poor/near-poor group, suggest that the coverage of colonoscopy might have been effective in increasing the rate of screen-ing among people in the former group but has remained ineffective for those in the latter.
nStudy limitations.We examined the impact of the expansion of Medicare cov-erage of colonoscopy on the rate of screening by comparing the rate before and after the coverage policy took effect. Because other time-varying factors such as an in-creasing awareness of the importance of colorectal cancer screening or a change in diet and physical activity might have also contributed to a higher rate of screening in 2003, our findings are best interpreted as variations in the odds of screening when the economic barrier of screening was reduced. It is difficult to quantify the extent to which these variations were attributable to the Medicare policy.
“Among Hispanics and their physicians, awareness of risk could be
an important target for intervention.”
the observed disparity in colorectal cancer screening between the Hispanic and non-Hispanic white elderly could have been attributable to a lack of Medicare in-surance among Hispanics. We could not address this issue because the low unin-surance rate (less than 5 percent) in the elderly population left us with an ex-tremely small number of observations for the uninsured subgroup in each racial/ethnic group. Future studies should consider combining several years of NHIS data to explore this issue.
We defined colorectal cancer screening as ever having had an endoscopic exam-ination. The NHIS also asked those who had received an examination the main reason for their most recent examination, in an attempt to differentiate examina-tions performed for screening from those for diagnosis or confirmation. Our analy-sis did not make such distinctions for two reasons. First, recent receipt of a confir-matory or diagnostic test does not necessarily imply that no earlier screening examination was done. Second, we believe that the elderly who have never had any examination pose the greatest public health concern. However, if we redefined our outcome of interest as endoscopic examinations for screening purposes only, we would have to combine two very heterogeneous groups, those never screened and those with an examination for nonscreening purposes, as the “no screening” group. Future studies are recommended to further explore this topic using more advanced multivariate methods such as ordered logit models.
nPolicy implications. On 15 September 2004 the Centers for Medicare and Medicaid Services elicited participation from health care providers and organiza-tions in the Cancer Prevention and Treatment Demonstration for Ethnic and Racial Minorities. African American, Hispanic, Asian American, Pacific Islander, and American Indian Medicare beneficiaries are eligible for recruitment. One of the pur-poses of this project is to “eliminate disparities in the rate of preventive cancer
screening measures.”22Our study makes a timely observation to inform this
demon-stration: It identifies Hispanic beneficiaries as those most urgently in need of in-creased colorectal cancer screening. Further, we have shown that demonstrations focusing on Hispanics should explore whether the rate of screening can be improved by waiving the Medicare copayment and deductible for colonoscopy.
The authors gratefully acknowledge editors ofHealth Affairsand two anonymous reviewers for their valuable comments on an earlier draft.
NOTES
1. American Cancer Society,Colorectal Cancer Facts and Figures—Special Edition 2005(Atlanta: ACS, 2005). 2. M. Pignone et al., “Screening for Colorectal Cancer in Adults at Average Risk: A Summary of the Evidence
for the U.S. Preventive Services Task Force,”Annals of Internal Medicine137, no. 2 (2002): 132–141.
3. N. Breen et al., “Progress in Cancer Screening over a Decade: Results of Cancer Screening from the 1987, 1992, and 1998 National Health Interview Surveys,”Journal of the National Cancer Institute93, no. 22 (2001): 1704–1713.
4. L.F. McMahon Jr. et al., “Racial and Gender Variation in Use of Diagnostic Colonic Procedures in the Michigan Medicare Population,”Medical Care37, no. 7 (1999): 712–717; L.C. Seeff et al., “Patterns and
Predic-tors of Colorectal Cancer Test Use in the Adult U.S. Population,”Cancer100, no. 10 (2004): 2093–2103; Y.C. Shih, L.S. Elting, and B. Levin, “Disparities in Colorectal Screening between US-Born and Foreign-Born Populations: Evidence from the 2000 National Health Interview Survey,”Journal of Cancer Education (forth-coming).
5. S.H. Zuvekas and G.S. Taliaferro, “Pathways to Access: Health Insurance, the Health Care Delivery System, and Racial/Ethnic Disparities, 1996–1999,”Health Affairs22, no. 2 (2003): 139–153; and M. Lillie-Blanton and C. Hoffman, “The Role of Health Insurance Coverage in Reducing Racial/Ethnic Disparities in Health Care,”Health Affairs24, no. 2 (2005): 398–408.
6. See McMahon et al., “Racial and Gender Variation”; C.W. Ko, W. Kreuter, and L.M. Baldwin, “Effect of Medicare Coverage on Use of Invasive Colorectal Cancer Screening Tests,”Archives of Internal Medicine162, no. 22 (2002): 2581–2586; and G.S. Cooper and S.M. Koroukian, “Racial Disparities in the Use of and Indi-cations for Colorectal Procedures in Medicare Beneficiaries,”Cancer100, no. 2 (2004): 418–424.
7. The American Gastroenterological Association considered people with one of the following risk factors at “high risk” for colorectal cancer: positive occult blood or frank bleeding, iron deficiency anemia, history of colonic adenomas, family history of colon cancer, ulcerative colitis, or history of colon cancer. People age fifty and older with no risk factors are considered “average risk.” See S. Winawer et al., “Colorectal Cancer Screening and Surveillance: Clinical Guidelines and Rationale—Update Based on New Evidence,”
Gastro-enterology124, no. 2 (2003): 544–560.
8. J.L. Freeman et al., “Measuring Breast, Colorectal, and Prostate Cancer Screening with Medicare Claims Data,”Medical Care40, no. 8 Supp. (2002): IV-36–IV-42.
9. D.N. Prajapati et al., “Volume and Yield of Screening Colonoscopy at a Tertiary Medical Center after Change in Medicare Reimbursement,”American Journal of Gastroenterology98, no. 1 (2003): 194–199; and G.C. Harewood and D.A. Lieberman, “Colonoscopy Practice Patterns since Introduction of Medicare Coverage for Average-Risk Screening,”Clinical Gastroenterology and Hepatology2, no. 1 (2004): 72–77.
10. Prajapati et al., “Volume and Yield.”
11. Harewood and Lieberman, “Colonoscopy Practice Patterns.”
12. National Center for Health Statistics, “Data File Documentation, National Health Interview Survey, 2000 (Machine Readable Data File and Documentation)” (Hyattsville, Md.: NCHS, 2002).
13. Seeff et al., “Patterns and Predictions.”
14. The income level in both the 2000 and 2003 NHIS was reported as a percentage in reference to the federal poverty level from the previous year (1999 and 2002, respectively), according to the U.S. Census Bureau. Specifically, the five income categories in the NHIS are poor/near-poor (less than 200 percent of the pov-erty level), low income (200–299 percent), middle income (300–399 percent), upper income (400 percent and above), or unknown.
15. We employed the Surveyfreq procedure in SAS 9.1 to perform comparisons across years while accounting for the complex sample design in each year of the NHIS.
16. J.S. Mandelblatt, K.R. Yabroff, and J.F. Kerner, “Equitable Access to Cancer Services: A Review of Barriers to Quality Care,”Cancer86, no. 11 (1999): 2378–2390.
17. Ibid.
18. L.A.G. Ries et al., eds.,SEER Cancer Statistics Review, 1975–2002,2005, http://seer.cancer.gov/csr/1975_2002 (accessed 24 April 2006).
19. A. Sonnenberg, F. Delco, and J.M. Inadomi, “Cost-Effectiveness of Colonoscopy in Screening for Colorectal Cancer,”Annals of Internal Medicine133, no. 8 (2000): 573–584.
20. National Colorectal Cancer Research Alliance and American Gastroenterological Association, “2004 Colorectal Cancer Legislation Report Card,” http://www.nccrt.org/Documents/NewsArticles/NCCRA ReportCardFinal.pdf (accessed 24 April 2006).
21. According to the Employee Benefit Research Institute fact sheet, “Health Insurance and the Elderly” (Au-gust 2003), Medicare covered more than 96 percent of the elderly in 2001. EBRI, “Facts from EBRI,” http:// www.ebri.org/publications/facts (accessed 24 April 2006). On representation of Hispanics, see J.W. Mold, G.E. Fryer, and C.H. Thomas, “Who Are the Uninsured Elderly in the United States?”Journal of the American
