ABSTRACT
OBJECTIVES: We examined the interrelationships between and contributions of background, cognitive, and environmental factors to colorectal cancer (CRC) screening adherence. METHODS: In this study, 2,416 average risk patients aged 50-75 from 24 Veterans Affairs medical facilities responded to a mailed survey with phone follow-up (response rate 81%). Survey data (attitudes, behaviors, demographics) were linked to facility (organizational complexity) and medical records data (diagnoses, screening history). Patients with a fecal occult blood test within 15 months, sigmoidoscopy or barium enema within 5.5 years, or colonoscopy within 11 years of the survey were considered adherent. Logistic regressions estimated the association between adherence and background, cognitive, and environmental factors. Deviance ratios examined interrelationships between factors. Population attributable risks (PAR) were used to identify intervention targets. RESULTS: The association of background factors with adherence was partially explained by cognitive and environmental factors. The association of environmental factors with adherence was partially explained by cognitive factors. Cognitive and environmental factors contributed equally to adherence. Factors with the highest PARs for non-adherence were age 50-64, less than two comorbidities, and lack of physician recommendation. CONCLUSIONS: Efforts to increase physician screening recommendations for younger, healthy patients at facilities with the lowest screening rates may improve CRC adherence in this setting.
Subject(s)
Colorectal Neoplasms/prevention & control , Health Knowledge, Attitudes, Practice , Mass Screening/statistics & numerical data , Patient Compliance/statistics & numerical data , Aged , Barium Sulfate , Colonoscopy/psychology , Colonoscopy/statistics & numerical data , Enema/psychology , Enema/statistics & numerical data , Female , Humans , Male , Mass Screening/psychology , Middle Aged , Occult Blood , Patient Compliance/psychology , Social Support , Socioeconomic FactorsABSTRACT
OBJECTIVE: The aim of the study was to validate self-reported colorectal cancer (CRC) screening using the National Cancer Institute Colorectal Cancer Screening questionnaire. MATERIALS AND METHODS: 890 patients, ages 50 to 75 years, from the Minneapolis Veterans Affairs (VA) Medical Center were surveyed by mail. Phone administration was attempted with mail nonresponders. VA and non-VA records were combined for the reference standard. Sensitivity, specificity, concordance, and report-to-records ratio (R2R) were estimated for overall and test-specific CRC adherence among respondents providing complete medical records. Secondary analyses examined variation in estimates by patient characteristics, treatment of missing and uncertain responses, and whether a strict or liberal time interval was used for assessing concordance. RESULTS: Complete medical records were available for 345 of the 686 survey responders. For overall adherence, sensitivity was 0.98, specificity was 0.59, concordance was 0.88, and R2R was 1.14. Sensitivity was 0.82 for fecal occult blood test (FOBT), 0.75 for sigmoidoscopy, 0.97 for colonoscopy, and 0.63 for double-contrast barium enema (DCBE). Specificity was 0.89 for FOBT, 0.76 for sigmoidoscopy, 0.72 for colonoscopy, and 0.85 for DCBE. Concordance was >0.80 for all tests other than sigmoidoscopy (0.76). R2R was 1.31 for FOBT, 1.33 for sigmoidoscopy, 1.42 for colonoscopy, and 6.13 for DCBE. The R2R was lower for a combined sigmoidoscopy and colonoscopy measure. Overreporting was more pronounced for older, less-educated individuals with no family history of CRC. Sensitivity and R2R improved using a liberal interval and treating uncertain responses as nonadherent (versus missing), but differences were not statistically significant. CONCLUSIONS: Self-reported CRC screening validity is generally acceptable and robust across definitional decisions, but varies by screening test and patient characteristics.