Association between Respiratory Failure and Clinical Outcomes in Patients with Acute Heart Failure: Analysis of 5 Pooled Clinical Trials

Background: Despite a temporal increase in respiratory failure in patients hospitalized with acute heart failure (HF), clinical trials have largely not reported the incidence or associated clinical outcomes for patients requiring mechanical ventilation.

Methods and results: After pooling 5 acute HF clinical trials, we used multivariable logistic regression adjusted for demographics, comorbidities, examinations, and laboratory findings to assess associations between mechanical ventilation and clinical outcomes. Among the 8296 patients, 210 (2.5%) required mechanical ventilation. Age, sex, smoking history, baseline ejection fraction, HF etiology, and the proportion of patients randomized to treatment or placebo in the original clinical trial were similar between groups (all, P > 0.05). Baseline diabetes mellitus was more common in the mechanical ventilation group (P = 0.02), but other comorbidities, including chronic lung disease, were otherwise similar (all P > 0.05). HF rehospitalization at 30 days (12.7% vs 6.6%, P < 0.001) and all-cause 60-day mortality (33.3% vs 6.1%, P < 0.001) was higher among patients requiring mechanical ventilation. After multivariable adjustment, mechanical ventilation use was associated with an increased 30-day HF rehospitalization (odds ratio 2.03; 95% confidence interval, 1.29-3.21, P = 0.002), 30-day mortality (odds ratio 10.40; 95% confidence interval, 7.22-14.98, P < 0.001), and 60-day mortality (odds ratio 7.68; 95% confidence interval, 5.50-10.74, P < 0.001). The influence of mechanical ventilation did not differ by HF etiology or baseline ejection fraction (both, interaction P > 0.20).

Conclusions: Respiratory failure during an index hospitalization for acute HF was associated with increased rehospitalization and all-cause mortality. The development of respiratory failure during an acute HF admission identifies a particularly vulnerable population, which should be identified for closer monitoring.