Impact of body mass index on length of stay in patients with inflammatory bowel disease: A retrospective study
Yi Xiang, Yiquan Zhou, Renying Xu, Yi FengAbstract
Background
The association between body mass index (BMI) and clinical outcomes in inflammatory bowel disease (IBD) remains controversial. We aimed to investigate whether BMI independently predicts length of stay (LOS) or if its impact is mediated by nutritional and inflammatory markers.
Methods
This retrospective study included 2545 patients hospitalized with Crohn's disease (CD) and 721 with ulcerative colitis (UC). Patients were categorized into four groups: underweight, normal weight, overweight, and obese. Restricted cubic splines were used to visualize the non‐linear relationship between BMI and LOS. Multivariable linear regression models were applied to identify independent predictors of LOS.
Results
Univariate analysis showed that in patients with CD, both underweight and obese patients had longer hospital stays than those with normal weight ( P = 0.009). BMI showed a U‐shaped correlation with serum albumin (ALB) and hemoglobin (Hb). However, in the multivariate model, after adjusting for ALB, Hb, C ‐reactive protein (CRP), and comorbidities, BMI was no longer a significant predictor of LOS in patients with CD ( P = 0.082 to 0.4) or UC ( P = 0.2 to 0.9). Instead, lower ALB ( P < 0.001) and higher CRP ( P < 0.001) were significantly associated with prolonged hospital stays.
Conclusion
While BMI is associated with LOS in IBD patients, it is not an independent driver. BMI serves as a phenotypic reflection of the underlying inflammatory status. Clinical management should prioritize the correction of inflammation rather than focusing solely on BMI.