P780 Proteinuria is associated with the development of Crohn’s disease: a nationwide population-based study

Abstract

Abstract Background Proteinuria has been identified as a sign of systemic endothelial dysfunction and chronic inflammation, and associated with the development of several systemic inflammatory diseases. However, the impact of proteinuria and its severity on the incidence of inflammatory bowel disease (IBD) has not been studied yet. The aim of this study was to determine the association between proteinuria measured by urine dipstick test and the development of IBD. Methods We conducted a nationwide population-based cohort study using claims data from the National Health Insurance (NHI) database, a mandatory health insurance programme covering about 97% of the Korean population. A total of 9,917,400 people aged 20 years or older who had undergone a national health examination conducted by NHI in 2009 were followed until 2017. The study population was classified into four groups, negative, trace, 1+, and ≥2+, depending on the degree of proteinuria measured by urine dipstick test. The primary endpoint was the newly diagnosed IBD, Crohn’s disease (CD) or ulcerative colitis (UC) during the follow-up period, which was detected by both ICD-10 (K50 and K51) and the rare intractable disease registration programme codes which provide co-payment reduction of up to 90% in South Korea. Results The incidence of CD significantly increased according to the degree of proteinuria (adjusted hazard ratio [aHR] with 95% confidence interval [CI], 1.01(0.703–1.451), 1.515(1.058–2.162), and 2.053(1.301–3.24) in trace, 1+, and ≥2+ dipstick groups, respectively) as compared with the dipstick-negative group. However, there was no significant difference in the incidence of UC among the degrees of proteinuria (aHR with 95% CI, 1.12(0.949–1.323), 0.947(0.764–1.174), 1.009(0.741–1.373 in trace, 1+, and ≥2+ dipstick groups, respectively). In subgroup analysis, dipstick-positive proteinuria independently increased the incidence of CD regardless of subgroups. However, in the development of UC, dipstick-positive proteinuria increased the risk of UC in those with diabetes mellitus (DM), but not in those without DM (aHR, 1.527 vs. 0.846; interaction p-value 0.004). Conclusion Proteinuria, measured by dipstick test, may be associated with the development of CD.