Clostridium difficile Infection Is Associated With Decreased Prostate Cancer Risk: A Retrospective Cohort Study.

Background () is one of the most common hospital-acquired infections and causes the release of various cytokines. Prostate cancer (PC) is the second most common cancer in men worldwide. As infections have been associated with decreased cancer risk, the effects of on the risk of developing PC were analyzed. Methodology Using the PearlDiver national database, a retrospective cohort analysis was performed to evaluate the relationship between a prior history of infection and subsequent development of PC. International Classification of Disease Ninth and Tenth Revision codes were used to evaluate the incidence of PC between January 2010 and December 2019 in patients with and without a history of infection. The groups were matched by age range, Charlson Comorbidity Index (CCI), and antibiotic treatment exposure. Standard statistical methods, including relative risk and odds ratio (OR) analyses, were utilized to test for significance. Demographic information was subsequently analyzed and compared between experimental and control groups. Results A total of 79,226 patients were identified in both the infected and control groups matched by age and CCI. The incidence of PC was 1,827 (2.56%) in the group and 5,565 (7.79%) in the control group (p < 2.2 × 10; OR = 0.390, 95% confidence interval (CI) = 0.372-0.409). Subsequent matching by antibiotic treatment resulted in two groups of 16,772 patients. PC incidence was 272 (1.62%) in the group and 663 (3.95%) in the control group (p < 2.2 × 10; OR = 0.467, 95% CI = 0.431-0.507). Conclusions Results from this retrospective cohort study demonstrate that infection is associated with a reduced incidence of PC. Future studies are recommended to investigate the potential effect of the immune system and cytokines related to infection on PC.