The Efficacy of H. pylori Eradication Therapy in H. pylori-Infected and Uninfected Patients with Immune Thrombocytopenic Purpura: A Systematic Review.
Authors: Arnold Donald M. , Bernotas Ashley , Nazi Ishac , Stasi Roberto , Kuwana Masataka , Kelton John G. , Crowther Mark A. 
Published: October 2019

Abstract
Introduction: Helicobacter pylori eradication therapy results in the improvement of thrombocytopenia in up to 60% of patients with chronic immune thrombocytopenic purpura (ITP). Whether this effect is directly linked to H. pylori eradication, or to other effects of the treatment such as immune modulation or the eradication of other commensal bacteria, remains uncertain. We performed a systematic review of the literature to determine the independent effect of H. pylori eradication therapy on the platelet count in ITP by comparing its efficacy in H. pylori-infected and uninfected patients.
Methods: All studies examining the platelet response following H. pylori eradication therapy in patient with ITP who were, and who were not, infected with H. pylori were included. No language or age restrictions were applied. Article selection, data abstraction and assessment of study quality were performed in duplicate. We searched MEDLINE, EMBASE, Cochrane central registry, abstracts from the American Society of Hematology (from 2003), canvassed experts and hand searched bibliographies of relevant articles.
Results: The initial search yielded 265 citations of which 101 were excluded after screening for relevance, and an additional 154 were excluded because they did not meet eligibility criteria. Ten studies (8 from Japan), were included. In total, 333 patients were enrolled, 68.2% female, mean (+/− SD) age 51.6 +/− 17 years. Mean baseline platelet count was 42 +/− 26 x109/L, mean prior duration of ITP was 30.7 +/− 49 months, and 38 patients (11.4%) had undergone splenectomy. H. Pylori infection was confirmed by the urea breath test, and eradication therapy consisted of amoxicillin 750 – 1500mg twice daily, clarithromycin 200 – 400mg twice daily, and a proton pump inhibitor for 7 days in most studies. We identified 201 H. pylori-positive and 59 H. pylori-negative patients treated with eradication therapy. Eradication was achieved in 164 (94.3%) H. pylori infected patients. The overall platelet count response (variably defined) following eradication therapy for H. pylori-positive, eradicated, and negative patients was 52.7%, 54.3% and 3.4%, respectively (p <0.0001 for eradicated vs. negative). Similarly, pooling the results of only those studies employing a homogeneous response criteria (platelet count increase to 40 x109/L or higher at 3 – 6 months), the overall response for H. pylori-positive (n=121), eradicated (n=116), and negative (n=39) patients was 50.4%, 51.7% and 5.1% respectively (p<0.0001). Of the 10 reported patients with non-eradicated H. pylori infection, 2 achieved a platelet count response following eradication therapy. Mean time to response was 2.4 weeks, and mean duration of response was 15.7 months. Mild adverse events were reported in 12 patients.
Conclusion: Our findings suggest that the benefit derived from H. pylori eradication therapy on platelet count response in patients with ITP is mostly due to H. pylori eradication, and not to the treatment itself. Eradication therapy should be offered only to those patients with confirmed H. pylori infection. Randomized trials in consecutive ITP patients are needed to confirm this observation.