A systematic review and meta‐analysis of prevalence and clinical features of upper gastrointestinal (UGI) tract Crohn's disease in adults compared to non‐UGI types

BACKGROUND AND AIM: Crohn's disease is an inflammatory condition that affects the gastrointestinal (GI) system. This study aimed to determine the prevalence of upper gastrointestinal Crohn's disease (UGICD) and compare its features to non‐UGICD types. METHODS: We conducted a systematic search in the databases PubMed, Web of Science, Scopus, and Google Scholar. The heterogeneity of prevalence estimates was examined, subgroup analyses were carried out, and meta‐analyses were conducted using random‐effects modeling. Prognostic data were qualitatively reviewed and combined. RESULTS: Two‐thousand nine‐hundred and forty studies were retrieved and 32 studies were included in the final analysis. Pooled prevalence of UGICD was 15% (CI: 11–18%) among 14 509 patients. UGICD prevalence did not show any significant increase with time (P = 0.45). The most prevalent (38%, CI: 30–47%) behavior of UGICD was B1 (nonstricturing‐nonpenetrating), while the most common concurrent location was L3 (ileocolon) with a prevalence of 47% (CI: 34–59%). UGICD patients had higher stricturing phenotype (B2) compared to non‐UGICD (0.38 vs 0.30; P = 0.03). There was no significant difference in the prevalence of UGICD between patients classified according to the Montreal or Vienna classification. Stricturing phenotype was more common among Asian patients compared to Western patients (0.44 vs 0.24; P < 0.001). UGICD was a risk factor for surgery and drug therapy and was associated with an aggressive course of the disease and more resections. Pooled prevalence of UGICD was 15%. CONCLUSION: Nonstricturing‐nonpenetrating type was the most prevalent UGICD. UGICD patients had more complications and worse outcomes compared to non‐UGICD patients.