Gout may be associated with a decreased occurrence of colorectal cancer, as detected by diagnostic colonoscopy, among a population of veterans, according to study results published in the Journal of Clinical Rheumatology.
Study investigators sought to understand the relationship between gout and colorectal cancer by assessing the 10-year occurrence of colorectal cancer in patients with gout vs osteoarthritis (OA). Investigators identified data of active patients from the Computerized Patient Record System of the Veterans Affairs New York Harbor Health Care System who had at least 1 documented colonoscopy between 2000 and 2010, including 581 patients with gout and 598 patients with OA. Confirmed diagnoses, demographic risk factors for colorectal cancer, and other demographic data were collected for all patients. Incidence of colorectal cancer and nonmalignant polyps were compared between both the gout and osteoarthritis cohorts, and among patients who received nonsteroidal anti-inflammatory drugs (NSAIDs), allopurinol, and/or colchicine vs patients who did not.
Over the 10-year study period, the prevalence of colorectal cancer was significantly lower in patients with gout compared with patients with OA (0.8% vs 3.7%; P =.0008). After adjusting for NSAID use, differences in colorectal cancer rates remained significant. Furthermore, within the gout cohort, use of allopurinol and/or colchicine did not influence the rate of colorectal cancer occurrence. In a subanalysis of patients who underwent diagnostic vs screening colonoscopies, the differences in colorectal cancer rates persisted with diagnostic colonoscopy (0.5% in gout vs 4.6% in OA; P <.01) vs screening colonoscopy (0.9% in gout vs 1.1% in OA; P =1.00). There was no significant difference in the occurrence of nonmalignant colorectal polyps between cohorts (50.4% in gout vs 47.0% in OA; P =.24).
Study limitations included a relatively small sample size compared with other studies using administrative datasets, the fact that frequency of colonoscopies performed were not compared between the gout and OA groups, and that only colonoscopies performed within the New York Harbor Veterans Affairs system were evaluated. Medication use did not account for prescriptions from outside sources or those taken over the counter; the duration of medication use or medication adherence was also not reported. Finally, data on uric acid levels were incomplete, and polyp subtype or size was unaccounted for in the study analysis.
Investigators suggested that gout may exert a protective effect against cancer as indicated by the significantly lower occurrence of colorectal cancer in patients with gout compared with patients with OA. According to the researchers, reduced colorectal cancer risk was specific to patients who underwent diagnostic rather than screening colonoscopies. They also indicated that future studies should be undertaken to clarify the association between gout and colorectal cancer.