Abstract
BACKGROUND: The fecal immunochemistry test (FIT) has been proposed as a surrogate marker of intestinal inflammation. Psoriasis is a chronic inflammatory skin disease that is linked to underlying systemic inflammatory conditions, including inflammatory bowel disease. METHODS: We investigated the association between occult blood in feces and the risk of psoriasis using data from the National Health Insurance System. This study was conducted involving 1,395,147 individuals who underwent health examinations from January 2009 to December 2012 and were followed up until the end of 2017. RESULTS: The incidence of psoriasis (per 1,000 person-years) was 3.76 versus 4.14 (FIT-negative versus FIT-positive group) during a median follow-up of 6.68 years. In the multivariable-adjusted model, the hazard ratios for psoriasis were 1.03 for one positive FIT result, 1.12 for two positive FIT results, and 1.34 for three positive FIT results compared with negative FIT results. CONCLUSION: The risk of psoriasis was significantly increased in patients with positive FIT results compared to the FIT-negative population.