Associations between cardiac rehabilitation and clinical outcomes in patients with heart failure and cognitive frailty
Authors: Nozaki K , Hamazaki N , Yamashita M , Kamiya K , Koseki S , Uchida S , Noda T , Ueno K , Ogura K , Miki T , Maekawa E , Matsunaga A , Yamaoka-Tojo M , Ako J 
Published: October 2024

Abstract

Introduction
Patients with heart failure (HF) often contend with various comorbidities, including cognitive impairment. Cognitive impairment has been increasingly recognised as cognitive frailty, which is reportedly associated with poor outcomes. On the other hand, cardiac rehabilitation (CR) for HF contributes to improved clinical outcomes. However, very few reports have examined whether CR is effective in patients with HF who have cognitive frailty.

Purpose
The present study aimed to investigate whether CR is associated with clinical outcomes in patients with HF, even in the presence of cognitive frailty.

Methods
This observational study analysed 1404 consecutive patients who admitted to a university hospital for the treatment of HF and received CR during hospitalisation. Patients who had dementia, did not perform the cognitive function evaluation, or died during hospitalisation were excluded from this study. All patients were encouraged to continue outpatient CR after hospital discharge. Cognitive function was assessed using the Mini-Cog© and a score ≤2 points was defined as the cognitive frailty. As physical function, quadriceps isometric strength (QIS) and 6-min walking distance (6MWD) were measured at the discharge and at the end of outpatient CR. The primary outcome was composite events, comprising all-cause death and re-admission due to HF. The secondary outcome was the change in physical function (ΔQIS and Δ6MWD) following outpatient CR. The association between participation in outpatient CR and composite events was assessed using the multivariate Cox proportional hazard models. We also compared the physical function changes between the presence or absence of cognitive frailty using analysis of covariance.

Results
The median age of the patients was 75 (interquartile range [IQR]: 66–81) years and 62.3% were males. Among them, 23.4% were identified as cognitive frailty. While 45.1% of overall population participated in outpatient CR, the cognitive frailty was relevant to a lower participation rate (P &lt;0.001). Over a median follow-up period of 1.0 years (IQR: 0.3–2.4 years), a total of 544 composite events occurred. Participation in outpatient CR was associated with a reduced incidence of composite events in both the cognitive frailty and non-cognitive frailty, as well as in the overall patient population (Figure 1). Additionally, ΔQIS and Δ6MWD did not significantly differ between the cognitive frailty status (P = 0.655 and 0.573, respectively).

Conclusions
Participating in outpatient CR was linked to reduced rates of composite events and improved physical function in patients with HF, regardless of the presence or absence of cognitive frailty. Encouraging active participation in outpatient CR, even among patients with cognitive frailty, is essential as it is associated with favourable clinical outcomes.Survival analysisANCOVA