The prevalence of non-malignant gastrointestinal (GI) disease in patients with iron deficiency anemia (IDA): a systematic review and meta-analysis

Objective: Gastrointestinal pathology is a major cause of iron deficiency anemia (IDA). Whilst previous studies have focused on establishing the prevalence of malignant gastrointestinal (GI) disease, the prevalence of non-malignant GI disease in patients with IDA has not been analysed systematically. We performed a systematic review and meta-analysis to determine the prevalence of normal findings, individual non-malignant findings and malignancy in patients with IDA.

Methods: We searched Medline, Embase and Scopus from inception for observational studies that reported the prevalence of individual upper and lower GI pathologies amongst adults (≥18 years) with confirmed IDA who underwent endoscopic investigation. We also sought to establish the prevalence of normal endoscopic findings within the IDA population as well as the prevalence of non-malignant and malignant GI pathology amongst clinically relevant subgroups. Results were synthesized using a random effects meta-analysis.

Results: A total of 8563 citations were screened and 39 articles were included from four continents comprising 9807 patients with IDA. Overall, the most prevalent upper GI finding was H. pylori gastritis (27.0%); and the most prevalent lower GI finding was hemorrhoids (10.0%). The overall prevalence of upper GI malignancy was 5.0% and the prevalence of colorectal cancer was 8.0%. 52.0% of upper GI endoscopies and 66.0% of lower GI endoscopies did not detect any abnormalities.

Conclusions: The estimated prevalence of individual malignant and non-malignant GI disease will serve as guide in the context of clinical decision making prior to endoscopy in patients with IDA. Further population-based studies are needed, particularly amongst relevant subgroups.