Abstract Background Frailty is common in patients admitted with acute decompensation of heart failure (ADHF) and it is unclear how the frailty syndrome affects heart failure (HF) patients during their acute hospital admission. Understanding the interplay between frailty, impaired renal function, hospital-acquired infections (HAI), and death may be useful in optimising patient care and prognosis. Purpose The aim of this analysis was to explore the relationship between admission frailty levels and the incidence of HAI, acute kidney injury (AKI), and mortality in acute HF hospital admissions. Methods This is a retrospective analysis of data submitted from a single centre to the National HF audit between January and June 2023. Additional frailty and baseline renal function data was retrospectively collected from electronic patient health records. Patients were categorised into three groups according to their Rockwood Clinical Frailty Scale (CSF) (1): no/mild frailty (CFS 1-3), moderate frailty (CFS 4-6) and severe frailty (CFS 7-9). AKI was defined based on baseline and admission creatinine, as per KDIGO guidelines (2). Chi-squared and t-tests were used to compare baseline characteristics between frailty groups. Chi-squared tests were used to compare frailty groups in terms of: HAI, AKI, mortality. Results Between 1st January and 22nd June 2023, there were 344 acute HF hospital admissions in our centre. Most patients had moderate frailty on admission (n=256, 74.4%). Frail patients were significantly older, had a lower admission mean haemoglobin and more were female, compared to non-frail patients (Figure 1A). Patients who were more frail were more likely to experience HAI during their admission; p=0.035 (figure 1B). Furthermore, patients with HAI had a greater risk of mortality, at a median follow-up of 171 (IQR 100.25) days after admission, compared to those without HAI (p>0.001). 41.9% of acute HF admissions were associated with an AKI, and although numerically more frail patients had an AKI, this did not achieve statistical significance (p=0.084). Patients who were more frail were more likely to die, both during hospital admission and at 3 months following discharge; p<0.001 (Figure 1B). Furthermore, this trend persisted after follow-up; p<0.001 (Figure 2). Conclusions Patients with moderate or severe frailty are at greater risk of adverse events (HAI, death) during an acute HF hospital admission, than patients with no or mild frailty. It is imperative to consider the frailty status of all patients with ADHF, to be aware of the frailty-associated risks, and act proactively with targeted interventions (screen for infections, daily bloods, early conversations with patients and their families about treatment escalation plans and patient priorities) to improve outcomes and enhance the quality of care for this vulnerable patient population. Further research is warranted to explore potential interventions to address frailty-related risks in HF management.