Predictive value of three nutritional indexes for disease activity in patients with inflammatory bowel disease.

Background: Malnutrition is prevalent in patients with inflammatory bowel disease (IBD); however, its ability to predict the disease activity in IBD remains unexplored. Therefore, this study aimed to explore the association between malnutrition and disease activity in IBD.

Methods: In this retrospective study, we enrolled 1006 patients diagnosed with IBD from the First Affiliated Hospital of Wenzhou Medical University from 2011 to 2022. Malnutrition was assessed based on the prognostic nutritional index (PNI), geriatric nutritional risk index (GNRI), and controlling nutritional status (CONUT) scores. Logistic regression analyses were performed to identify predictors for disease activity. Restricted cubic spline analysis was performed to evaluate the possible nonlinear relations, and subgroup analysis was performed to explore potential interactions. Additionally, prediction performances were compared through receiver operating characteristic curves, net reclassification improvement, and integrated discrimination improvement.

Results: The prevalence of malnutrition calculated by the PNI, GNRI, and CONUT scores in IBD was 16.9%, 72.1%, and 75.6%, respectively and significant correlations were observed among them. Multivariate logistic regression analysis showed that PNI, GNRI, and CONUT were independent risk factors for disease activity, and no significant nonlinear relationship was observed between disease activity and all three indexes. No statistically significant interactive effect was found in nearly all the subgroups. GNRI showed the highest predictive value compared with PNI and CONUT. Additionally, combining any of the three indexes improved the ability of C-reactive protein to predict IBD activity.

Conclusions: All three nutritional indexes evaluated malnutrition to be an independent risk factor for IBD activity.