Obesity Status and Physical Rehabilitation in Older Patients Hospitalized With Acute HF: Insights From REHAB-HF

Background: In the REHAB-HF (Rehabilitation Therapy in Older Acute Heart Failure Patients) trial, a novel, early, transitional, multidomain rehabilitation intervention improved physical function, frailty, quality of life (QOL), and depression in older patients hospitalized for acute decompensated heart failure (ADHF), but the potential impact of baseline obesity on this intervention has not been studied.

Objectives: This study assessed for treatment interactions by body mass index (BMI) subgroups for a novel rehabilitation intervention in ADHF.

Methods: Three-month outcomes including Short Physical Performance Battery (SPPB) (primary outcome), 6-minute walk distance (6MWD), and Kansas City Cardiomyopathy Questionnaire (KCCQ) were assessed by baseline BMI (≥30 kg/m² vs <30 kg/m²). Six-month end points included all-cause rehospitalization and death. All analyses were adjusted for age, sex, clinical site, and ejection fraction category, and 3-month outcomes were also adjusted for baseline measure. The prespecified significance level for treatment interaction by BMI category was P ≤ 0.10.

Results: Of 349 trial participants, 204 (58%) had BMI ≥30 kg/m² and 145 (42%) <30 kg/m². Compared with patients with BMI <30 kg/m², participants with BMI ≥30 kg/m² were younger (age 71 ± 7 years vs 75 ± 9 years), more frequently women (57% vs 46%), and had significantly worse baseline physical function and QOL. Although interaction P values for 3-month outcomes by BMI were not significant (interaction P > 0.15 for overall measures), adjusted SPPB effect sizes were nominally larger for participants with BMI ≥30 kg/m² compared with those with BMI <30 kg/m²: +1.7 (95% CI: 0.8-2.7) vs +1.1 (95% CI: -0.1 to 2.2). This difference in SPPB effect size was due largely to improvements in the balance component of the SPPB for participants with BMI ≥30 kg/m²: +0.6 (95% CI: 0.2-1.0) vs 0.0 (-0.6 to 0.5) for those with BMI <30 kg/m² (interaction P = 0.02). In contrast, adjusted 6MWD and KCCQ effect sizes were smaller for participants with BMI ≥30 kg/m² compared with those with BMI <30 kg/m²: +21 meters (-17 to 59) vs +53 meters (6-100), and +5.0 (-4 to 14) vs +11 (-0.5 to 22), respectively. There was no significant interaction by BMI for 6-month clinical outcomes (all interaction P > 0.30).

Conclusions: Older patients with ADHF benefit from the rehabilitation therapy regardless of BMI. Benefits for patients with obesity may be more evident in the multidomain measure of physical function (SPPB), compared with the 6MWD or KCCQ, which may be driven, in part, by the unique aspects of the novel rehabilitation intervention. (A Trial of Rehabilitation Therapy in Older Acute Heart Failure Patients [REHAB-HF]; NCT02196038).