Prevalence, predictors, and prognostic significance of respiratory failure in hospitalised heart failure patients

Background

Respiratory failure is a serious complication in patients with heart failure (HF) and is associated with worse in-hospital outcomes. Despite its clinical relevance, data on its prevalence, clinical predictors, and prognostic impact in hospitalised HF populations remain limited.

Purpose

To evaluate the prevalence, severity, clinical predictors, and prognostic significance of respiratory failure in patients hospitalised with HF.

Methods

This single-centre observational study included 517 consecutive patients admitted with a primary diagnosis of HF. Respiratory failure was defined by the presence of resting dyspnoea or orthopnoea, oxygen saturation <90% on room air, arterial blood gas abnormalities when available, and the need for supplemental oxygen, non-invasive ventilation (NIV), or invasive mechanical ventilation (IMV). Data collected included age, sex, HF phenotype, New York Heart Association (NYHA) class, echocardiographic parameters, laboratory markers, and comorbidities. Primary outcomes were in-hospital mortality and major adverse events. Independent predictors were identified using multivariable logistic regression (p<0.05 considered significant).

Results

Clinically significant respiratory failure occurred in 4–5% of patients (21–26/517). The mean age was 67 ± 12 years, and 58% were male. Mean left ventricular ejection fraction (LVEF) was 38 ± 9%; median hospital stay was 7 [5–10] days. Common comorbidities included hypertension (72%), ischaemic heart disease (65%), chronic lung disease (28%), diabetes mellitus (32%), and chronic kidney disease (21%).

Independent predictors of respiratory failure were older age (OR 1.05; 95% CI 1.02–1.08; p = 0.001), NYHA class III–IV (OR 2.3; 95% CI 1.4–3.8; p = 0.002), reduced LVEF (OR 1.08; 95% CI 1.03–1.12; p = 0.004), chronic lung disease (OR 1.9; 95% CI 1.1–3.2; p = 0.02), renal dysfunction (OR 1.7; 95% CI 1.1–2.8; p = 0.03), and anaemia (OR 1.6; 95% CI 1.0–2.6; p = 0.04).

In-hospital mortality was 27–38% for patients requiring IMV, 5–9% with NIV, and approximately 2% in those without respiratory failure. Greater severity of respiratory failure was associated with longer hospitalisation and increased adverse events.

Conclusions

Respiratory failure affects a clinically meaningful proportion of hospitalised HF patients and is independently associated with increased disease severity and in-hospital mortality. Early recognition of at-risk patients may improve risk stratification and guide acute care management.