Increased knee-extension strength and steps per day after a novel post-hospitalization rehabilitative program in older adults (65+): Secondary analyses of a randomized controlled single-blinded trial using an expanded sample size

Introduction

Older adults are at risk of developing new or worsened disability when hospitalized for acute medical illness. This study is a secondary analysis of the STAND-Cph trial on the effect of a simple strength training intervention initiated during hospitalization and continued after discharge. We investigated the between-group difference in change in functional performance outcomes, the characteristics of patients who experienced a relevant effect of the intervention, and the characteristics of those who were compliant with the intervention, using an expanded sample size as protocolized.

Methods

The STAND-Cph was a randomized controlled trial conducted at a major Danish university hospital. Acutely admitted older adult patients (65+) from the Emergency Department were randomized to the intervention group receiving progressive strength training and a protein supplement during and after hospitalization (12 sessions over 4 weeks) or control group receiving usual care. The primary outcome was the de Morton Mobility Index assessed at baseline and 4 weeks after discharge. The secondary outcomes were 24-h mobility (assessed by ActivPAL accelerometers), isometric knee-extension strength, 30 s. sit-to-stand performance, and habitual gait speed.

Results

Between September 2013 and September 2018, a total of 158 patients were included and randomized to either the intervention group (N = 80; mean age 79.9 ± 7.6 years) or the control group (N = 78; mean age 80.8 ± 7.4 years). We found no significant between-group difference in change in our primary outcome (p > 0.05). Both the intention-to-treat (difference in change 0.14 Nm/kg (95 % CI 0.03;0.24), p = 0.01) and the per protocol (difference in change 0.16 Nm/kg (95 % CI 0.04;0.29), p = 0.008) analyses showed that between baseline and 4 weeks, knee-extension strength increased significantly more in the intervention group than in the control group. Also, the per protocol analysis showed that the intervention group increased their daily number of steps significantly more than the control group (difference in change 1088 steps (95 % CI 44; 2132); p = 0.04). When examining subgroups of patients, we found no significant differences neither between those who experienced a clinically relevant improvement in the de Morton Mobility Index and those who did not, nor between those who were compliant and those who were not.

Conclusion

This exploratory analysis indicates that while simple progressive strength training and protein supplementation does not improve functional performance assessed by the de Morton Mobility Index, it can benefit specific facets of physical activity and muscle strength among geriatric patients.