Helicobacter pylori Screening After Acute Myocardial Infarction: The Cluster Randomized Crossover HELP-MI SWEDEHEART Trial.

Importance: Upper gastrointestinal bleeding is common after myocardial infarction.

Objective: To determine whether routine screening for Helicobacter pylori infection during hospitalization for myocardial infarction reduces bleeding events and improves clinical outcomes.

Design, Setting, And Participants: A nationwide, open-label, 2-period, 2-sequence, cluster randomized, crossover clinical trial using a clinical registry for study population definition and data collection merged with national Swedish health data registries. From November 17, 2021, through January 17, 2024, thirty-five Swedish hospitals grouped into 18 clusters were randomized to a sequence of 1 year with routine H pylori screening of all patients with acute myocardial infarction followed by a washout period of 2 months before crossing over to 1 year with usual care or vice versa. Patients were followed up until January 17, 2025.

Intervention: Routine addition of H pylori screening by urea breath test to standard care in all patients hospitalized for myocardial infarction during the screening periods.

Main Outcome And Measure: Upper gastrointestinal bleeding, analyzed by a negative binomial model in the intention-to-treat population.

Results: A total of 18 466 patients (median age, 71 years [IQR, 61-79], 13 138 males [71%]) with myocardial infarction were followed up: 9245 during the screening periods and 9221 during the nonscreening periods. At admission, 2284 during the screening periods and 2275 during the nonscreening periods (both 24.7%) reported proton pump inhibitor use. During screening periods, 6480 patients (70%) had undergone testing, of those 1532 (23.6%) tested positive for H pylori. After a median follow-up of 1.9 years, 299 patients in the screening group (incidence rate, 16.8 events per 1000 person-years; cumulative hazard at 3 years, 4.1%) and 336 in the usual care group (incidence rate, 19.2 events per 1000 person-years; cumulative hazard at 3 years, 4.6%) experienced the primary end point of upper gastrointestinal bleeding (rate ratio [RR], 0.90; 95% CI, 0.77-1.05; P = .18). Predefined nonmultiplicity adjusted subgroup analyses showed a heterogeneous intervention effect; for no anemia (RR, 0.98; 95% CI, 0.80-1.21), mild anemia (RR, 0.64; 95% CI, 0.42-0.98), and moderate to severe anemia (RR, 0.44; 95% CI, 0.23-0.87; P for interaction = .03).

Conclusions And Relevance: Among unselected patients with acute myocardial infarction, routine H pylori screening did not significantly reduce the risk of upper gastrointestinal bleeding.

Trial Registration: ClinicalTrials.gov Identifier: NCT05024864.