Abstract Background The impact of SGLT2 inhibitors on generic quality of life in heart failure (HF) has not been evaluated. Purpose To quantify individual dimension scores and the Level Sum Score of the EQ-5D-5L (EQ-5D-LSS) in patients with HFrEF and HFmrEF/HFpEF, the association between these scores and outcomes, and the impact of treatment with dapagliflozin on these scores. Methods The 5 dimensions of the descriptive section of the EQ-5D-5L include mobility ("walking around"), self-care ("washing or dressing self"), usual activities ("e.g., work, study, housework, family or leisure activities"), pain/discomfort ("pain or discomfort"), and anxiety/depression ("anxious or depressed"). Each dimension is divided into 5 levels (1-5) i.e., no problem, slight problem, moderate problem, severe problem, and extreme problem (cannot do activity/extreme symptom). All dimensions and severity levels contribute equally when calculating the LSS. The individual dimension scores and the LSS were analyzed in patients with HFrEF and HFmrEF/HFpEF in the DAPA-HF and DELIVER trials, which compared dapagliflozin to placebo. Results Scores varied markedly by question with 37/30/33% of patients reporting no, a slight, or a moderate or greater problem for mobility; 67/20/13% for self-care; 40/33/27% for usual activities; 45/32/23% for pain/discomfort; and 57/27/16% for anxiety/depression. Compared to lower (better) LSS, patients with higher (worse) LSS were more often female, had more comorbidities, and had worse HF status. Compared to patients free from any problem across all dimensions (i.e. LSS of 5), the hazard ratios (95% CI) for time to first cardiovascular death or worsening HF were 1.27 (1.10-1.47), 1.70 (1.46-1.98), and 2.31 (1.88-2.85) in those with LSSs of 6-10, 11-15, 16-25 points, respectively. Patients randomized to dapagliflozin experienced greater improvement and less worsening across all EQ-5D-5L dimensions except pain/discomfort (Figure). Conclusions The EQ-5D-5L individual dimension questions revealed problems not often associated with (pain) or quantified in (anxiety/depression) HF and demonstrated the marked limitation of ordinary activities experienced by many patients with HF. Most EQ-5D-5L domain questions, including anxiety/depression, improved with dapagliflozin. The LSS, incorporating these domains was associated with clinical outcomes.