Critical analysis of the effects of proton pump inhibitors on inflammatory bowel disease: An updated review.

This letter critically evaluates the effects of proton pump inhibitors (PPIs) on inflammatory bowel disease, particularly focusing on Crohn's disease (CD) and ulcerative colitis (UC), as discussed in Liang et al's recent review. While the review provides significant insights, it relies heavily on cross-sectional and observational studies, which limits the ability to draw causal inferences. The heterogeneous study populations and inconsistent definitions of long-term PPI use further complicate the findings. This letter also highlights the need for rigorous control of confounding factors and considers the potential publication bias in the existing literature. The implications of these issues are discussed in the context of both CD and UC, and future research directions are proposed to address these shortcomings.