Background
Patients with heart failure (HF) often suffer from a range of comorbidities, which may affect their health status.

Objectives
To assess the impact of different comorbidities on health status in patients with HF and reduced and preserved ejection fraction (HFrEF and HFpEF).

Methods
Using individual patient data from HFrEF (ATMOSPHERE, PARADIGM-HF, DAPA-HF) and HFpEF (TOPCAT, PARAGON-HF) trials, we examined the Kansas City Cardiomyopathy Questionnaire (KCCQ) domain scores and Overall Summary Score (KCCQ-OSS) across a range of cardio-respiratory (angina, AF, stroke, COPD) and other comorbidities (obesity, DM, CKD, anaemia).

Results
Of patients with HFrEF(n=20,159), 36.2% had AF, 33.9% CKD, 33.9% diabetes, 31.4% obesity, 25.5% angina, 12.2% COPD, 8.4% stroke, and 4.4% anaemia; the corresponding proportions in HFpEF(n=6,563) were: 54.0% AF, 48.7% CKD, 43.4% diabetes, 53.3% obesity, 28.6% angina, 14.7% COPD, 10.2% stroke, and 6.5% anaemia. HFpEF patients had lower KCCQ domain scores and KCCQ-OSS (67.8 vs. 71.3) than HFrEF patients. Physical limitations, social limitations and quality of life domains were reduced more than symptom frequency and symptom burden domains. In both HFrEF and HFpEF, COPD, angina, anaemia, and obesity were associated with the lowest scores. An increasing number of comorbidities was associated with decreasing scores e.g., KCCQ-OSS 0 vs. ≥4 comorbidities: HFrEF 76.8 vs. 66.4; HFpEF 73.7 vs. 65.2.

Conclusions
Cardiac and non-cardiac comorbidities are common in both HFrEF and HFpEF patients and most are associated with reductions in health status although the impact varied among comorbidities, by the number of comorbidities, and by HF phenotype. Treating/correcting comorbidity is a therapeutic approach that may improve the health status of patients with HF.