Association of admission frailty and frailty changes during cardiac rehabilitation with 5-year outcomes

Aims Examine the association between (1) admission frailty and (2) frailty changes during cardiac rehabilitation (CR) with 5-year outcomes (i.e. time to mortality, first hospitalization, first emergency department (ED) visit, and number of hospitalizations, hospital days, and ED visits). Methods and results Data from patients admitted to a 12-week CR programme in Halifax, Nova Scotia, from May 2005 to April 2015 (n = 3371) were analysed. A 25-item frailty index (FI) estimated frailty levels at CR admission and completion. FI improvements were determined by calculating the difference between admission and discharge FI. CR data were linked to administrative health data to examine 5-year outcomes [due to all causes and cardiovascular diseases (CVDs)]. Cox regression, Fine-Gray models, and negative binomial hurdle models were used to determine the association between FI and outcomes. On average, patients were 61.9 (SD: 10.7) years old and 74% were male. Mean admission FI scores were 0.34 (SD: 0.13), which improved by 0.07 (SD: 0.09) by CR completion. Admission FI was associated with time to mortality [HRs/IRRs per 0.01 FI increase: all causes = 1.02(95% CI 1.01,1.04); CVD = 1.03(1.02,1.05)], hospitalization [all causes = 1.02(1.01,1.02); CVD = 1.02(1.01,1.02)], ED visit [all causes = 1.01(1.00,1.01)], and the number of hospitalizations [all causes = 1.02(95% CI 1.01,1.03); CVD = 1.02(1.00,1.04)], hospital days [all causes = 1.01(1.01,1.03)], and ED visits [all causes = 1.02(1.02,1.03)]. FI improvements during CR had a protective effect regarding time to all-cause hospitalization [0.99(0.98,0.99)] but were not associated with other outcomes. Conclusion Frailty status at CR admission was related to long-term adverse outcomes. Frailty improvements during CR were associated with delayed all-cause hospitalization, in which a larger effect was associated with a greater chance of improved outcome. Lay Summary This work improves our understanding of the relationship between admission frailty and frailty changes with mortality, hospitalization, and emergency department (ED) use in a cardiac rehabilitation (CR) setting. Frailty changes during CR were related with time to hospitalization due to any cause.Higher frailty levels at admission of CR were related to lower time to death, re-hospitalization, and ED visit and to a higher total number of hospitalizations and ED visits due to all causes or due to cardiovascular diseases.Overall, this work underscores the importance of considering the degree of frailty in the CR setting for the purpose of predicting adverse outcomes.