The prevalence of nonmalignant gastrointestinal disease in patients with iron deficiency anemia: a systematic review and meta-analysis.

[OBJECTIVE] Gastrointestinal pathology is a major cause of iron deficiency anemia (IDA). While previous studies have focused on establishing the prevalence of malignant gastrointestinal disease, the prevalence of nonmalignant gastrointestinal disease in patients with IDA has not been analyzed systematically. We performed a systematic review and meta-analysis to determine the prevalence of normal findings, individual nonmalignant 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 gastrointestinal pathologies among 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 nonmalignant and malignant gastrointestinal 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 gastrointestinal finding was Helicobacter pylori gastritis (27.0%), and the most prevalent lower gastrointestinal finding was hemorrhoids (10.0%). The overall prevalence of upper gastrointestinal malignancy was 5.0%, and the prevalence of colorectal cancer was 8.0%. A total of 52.0% of upper gastrointestinal endoscopies and 66.0% of lower gastrointestinal endoscopies did not detect any abnormalities.

[CONCLUSION] The estimated prevalence of individual malignant and nonmalignant gastrointestinal disease will serve as a guide in the context of clinical decision making before endoscopy in patients with IDA. Further population-based studies are needed, particularly among relevant subgroups.