Risk Factors for Advanced Colorectal Neoplasia in Veterans

Introduction: In previous work, we showed that the risk of advanced colorectal neoplasia (AN) (advanced, precancerous polyps and colorectal cancer (CRC)) was related to age and male sex, but not race. Age and sex along with other factors could help tailor CRC screening based on risk. The study objective was to identify factors independently associated with AN that are readily available from the VA's Computerized Patient Record System (CPRS) with the goal of using these factors to improve the efficiency of screening. Methods: Through remote electronic data extraction, we identified a veteran cohort who underwent a first diagnostic or screening colonoscopy between 2002 and 2009 at one of 14 VA Medical Centers. Colonoscopies for an indication of inflammatory bowel disease or neoplasia surveillance were excluded. We used natural language processing to identify the most advanced findings and location within the colorectum as proximal (splenic flexure) or distal. Logistic regression was used to identify age- and sexadjusted factors that were independently associated with AN (CRC, adenomas or SSPs1 cm or larger, and adenomas with villous histology or high-grade dysplasia). Results: A total of 90,691 eligible colonoscopies were identified. Mean (SD) patient age was 61.7 (9.4) years; 5.2% (n=4,673) were women. Among 72,527 (80%) patients with known race, 55,180 (76.1%) were Caucasian, 14,155 (19.5%) were Black, 2,498 (3.4%) were Hispanic, and 734 (1.0%) were other. Overall prevalence of AN was 8.9% (n=8,081), of which 14.5% (n=1,171) was CRC. Independently associated with AN were: age (odds ratio [OR] 1.26 for every 10 year increase; 95% CI, 1.22-1.30), male sex (OR=1.98; CI, 1.60-2.45); current tobacco use (OR=1.24; CI, 1.15-1.33); and a current prescription or listing of aspirin (OR=0.90; CI, 0.84-0.97), COX-1 inhibitor NSAIDs (OR=0.67; CI, 0.63-0.73), and COX-2 inhibitor (OR=0.52; CI, 0.34-0.79). Conclusion: Several factors are associated with AN. These factors - all of which are available through CPRS - may be useful for identifying Veterans for whom CRC screening (i.e., use of colonoscopy or fecal immunochemical test) could be tailored based on risk of AN, with the goal of improving the efficiency of CRC screening for Veterans.