Abstract
IMPORTANCE: Heart failure (HF) hospitalization is a common end point in HF trials; however, how HF hospitalization is associated with all-cause hospitalization in terms of proportionality, correlation of treatment effects, and concomitant reporting has not been studied. OBJECTIVE: To determine the ratio of HF to all-cause hospitalizations, whether reported treatment effects on HF hospitalization are associated with treatment effects on all-cause hospitalization, and how often all-cause hospitalization is reported alongside HF hospitalization. DATA SOURCES: PubMed was searched from inception to September 2, 2024, for randomized clinical trials (RCTs) of HF treatments using MeSH (medical subject heading) terms and keywords associated with heart failure, ventricular failure, ventricular dysfunction, and cardiac failure, as well as the names of specific journals. STUDY SELECTION: RCTs of HF treatments and reporting on HF hospitalization published in 1 of 3 leading medical journals (New England Journal of Medicine, The Lancet, or JAMA). DATA EXTRACTION AND SYNTHESIS: The PRISMA guidelines were followed. Data extraction was performed by 2 reviewers, and disagreements were resolved by consensus. Trial baseline characteristics and outcome data on HF and all-cause hospitalizations were extracted. The ratio of HF to all-cause hospitalizations was calculated. The association of HF hospitalization effects with all-cause hospitalization effects was evaluated using hierarchical bayesian models with weak priors. The posterior distribution was used to calculate the HF hospitalization treatment effects that would need to be observed before a high probability (97.5%) of a reduction in all-cause hospitalization could be achieved. The proportion of trials reporting all-cause hospitalization was calculated. MAIN OUTCOMES AND MEASURES: HF and all-cause hospitalizations. RESULTS: Of 113 trials enrolling 261 068 patients (median proportion of female participants, 25.4% [IQR, 21.3%-34.2%]; median age, 66.2 [IQR, 62.8-70.0] years), 60 (53.1%) reported on all-cause hospitalization. The weighted median ratio of HF to all-cause hospitalizations was 45.9% (IQR, 30.7%-51.7%). This ratio was higher in trials with greater proportions of New York Heart Association class III or IV HF, with lower left ventricular ejection fractions, investigating nonpharmaceutical interventions, and that restricted recruitment to patients with HF and reduced ejection fraction. Reported effects on HF and all-cause hospitalizations were well-correlated (R2 = 90.1%; 95% credible interval, 62.3%-99.8%). In a large trial, the intervention would have to decrease the odds of HF hospitalization by 16% to ensure any reduction, 36% to ensure a 10% reduction, and 56% to ensure a 20% reduction in the odds of all-cause hospitalization with 97.5% probability. CONCLUSIONS AND RELEVANCE: In this meta-analysis of HF trials, all-cause hospitalization was underreported despite a large burden of non-HF hospitalizations. Large reductions in HF hospitalization must be observed before clinically relevant reductions in all-cause hospitalization can be inferred.