Association Between Keratoconus and Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis.

PURPOSE: To investigate an association between inflammatory bowel disease and keratoconus.

CLINICAL RELEVANCE: Keratoconus can be difficult to diagnose early, and because of its progressive nature, early treatment is beneficial to preserving vision. Understanding potential associations of systemic disease with keratoconus may aid the development of screening protocols and guide early management decisions.

METHODS

Our search of 5 key databases (PubMed, Ovid Medline, Scopus, Web of Science, and Embase) was conducted on October 16, 2024. The selected papers were categorized as patient studies or genetic association studies for analysis. The primary outcome was odds ratio. Meta-analysis and test of assumptions was conducted on patient studies. Bias assessments were conducted using Q-GENIE and ROBINS-E.

RESULTS

Our search yielded 299 publication titles, of which 9 were included in our systematic review and 3 were incorporated into the meta-analysis. The aggregate odds ratio of patient-focused studies was 1.39 (95% confidence interval: 0.82-2.37). In the 4 studies investigating Crohn disease, there was no significant causal association (all P-values >0.05). All 5 genetic association studies demonstrated a genetic association between either inflammatory bowel disease (as a collective) and/or ulcerative colitis and keratoconus.

CONCLUSIONS

The literature demonstrated a genetic association between ulcerative colitis and keratoconus. This association has not been consistently replicated in patient-focused studies.