Background There are calls to integrate serial recordings of health related quality of life (HRQoL) into routine care, clinical trials and prognosis. Little is known about the relationship between change in HRQoL and outcomes in heart failure (HF) patients by age, sex and HF subtype. Method From the Swedish Heart Failure Registry (SwedeHF; 2008-2019), patients were categorised by reduced (<40%, HFrEF), mildly-reduced (40-49%, HFmrEF) and preserved (>= 50%, HFpEF) ejection fraction. HRQoL was measured using Euro-QoL-5D visual analogue scale (EQ5D-vas), collected at baseline and 1-year. Baseline EQ5Dvas scores were categorised by: "best" (76-100), "good" (51-75), "bad" (26-50), and "worst" (0-25). Change in EQ5D-vas was categorised as 'no significant change' (<5 points increase/decrease); some worsening (5-9 points decrease); considerable worsening (>= 10 points decrease); some improvement (5-9 points increase); considerable improvement (>= 10 points increase). Associations with admission and death were estimated and interactions with patient sub-groups tested. Findings Among 23,553 patients (median age 74 [66-81] years, 8000 [34%] female), baseline EQ5D-vas was worse in older patients, women, and those with HFpEF compared to their respective counterparts. Compared to patients with the "best" EQ5D-vas, the adjusted associations for admission for those with "good", "bad" and "worst" EQ5D-vas were, respectively: HR 1.09 (1.04, 1.14), 1.27 (1.21, 1.33) and 1.39 (1.28, 1.51). Compared to no significant change in EQ5D-vas, the adjusted estimates for admission following some improvement, considerable improvement, some worsening and considerable worsening were, respectively: HR 0.91 (0.82, 1.01), 0.75 (0.70, 0.81), 1.04 (0.92, 1.16) and 1.25 (1.16, 1.35). Results were similar amongst groups and for HF admission and death. Interpretation Change in HRQoL was an independent indicator of risk of admission and death in people with all HF subtypes, irrespective of age and sex.