Prevalence of Comorbidities in Inflammatory Bowel Disease: An Umbrella Review of 18 Systematic Reviews

<b>Background:</b> Inflammatory bowel disease (IBD) is associated with numerous extraintestinal manifestations and systemic comorbidities; however, the certainty of prevalence estimates across multiple organ systems has not been systematically evaluated. <b>Objective:</b> To synthesize evidence from systematic reviews on the prevalence of comorbidities in patients with inflammatory bowel disease (IBD) and to assess the certainty of estimates through an umbrella review. <b>Methods:</b> In this umbrella review, we included systematic reviews reporting the prevalence of comorbidities in adults with IBD and their confidence intervals. Methodological quality was assessed using AMSTAR-2 and ROBIS, while statistical heterogeneity and certainty of evidence were evaluated using GRADE adapted for prevalence studies. <b>Results:</b> Eighteen systematic reviews published between January 2014 and September 2025 were included. The highest prevalences were sexual dysfunction 50.6% (95% CI 40.8-60.5), fecal incontinence in Crohn's disease 34.8% (27.9-41.9), non-alcoholic fatty liver disease 32% (24-40), anemia 24% (18-31), and ≥1 extraintestinal manifestation 24% (19-31). Only four comorbidities achieved moderate certainty: primary sclerosing cholangitis 2.16% (1.76-2.60), uveitis 2.38% (1.60-3.17), hepatitis B 3.3% (2.5-4.0), and hepatitis C 1.8% (1.2-2.4). Prevalence rates varied significantly by IBD subtype, geographic region, and diagnostic method. Heterogeneity was consistently high (I² > 90%), and certainty was predominantly low or very low. <b>Conclusions:</b> Comorbidities in IBD are frequent, with prevalences ranging from 1.8% to 50.6%, highlighting the importance of comorbidity awareness in clinical practice. However, the certainty of evidence is predominantly low or very low due to extreme methodological heterogeneity. These findings underscore the urgent need for studies with standardized diagnostic methods and robust statistical approaches to strengthen the evidence base and establish evidence-based surveillance protocols.