Moving Beyond Comorbidity: The Effect of Exercise Training in Community-Acquired Pneumonia

Abstract

Full text

To the Editor—We thank Acuña-Rocha and Zuñiga-Hernandez for their interest in our study in which we investigated the effect of supervised exercise training during admission for patients with community-acquired pneumonia (CAP) on prognosis, including length of stay, risk of 90-day readmission, and 180-day mortality [1]. In the study, patients with CAP were randomly allocated to 3 parallel groups: standard care, standard care combined with daily supervised in-bed cycling, or standard care combined with daily supervised exercise according to a booklet (booklet exercise) [2]. All patients were treated for CAP according to Danish guidelines [3, 4], including ward rounds, nursing assistance, mobilization, and physiotherapy if needed.

Acuña-Rocha and Zuñiga-Hernandez raise the issue that the patients who were randomized to daily supervised exercise training had a nonstatistically significant higher percentage of chronic cardiac and respiratory diseases, which potentially could have an impact on exercise performance and the outcomes thereof. Further, there was concern about whether these patients were compensated. To ensure that no patients were pushed beyond their point of exhaustion, we reviewed patient files daily to find their individual acceptable oxygen saturation (SpO_2_), which was based on a clinical evaluation by the attending physician. Patients were given supplementary oxygen during exercise to maintain appropriate SpO_2_ (additional details provided in the Supplementary Material in Ryrsø et al [1]).

In our protocol article [5], we prespecified which covariances to include in the analysis (ie, age, sex, number of comorbidities, the confusion, urea level, respiratory rate, blood pressure, and age ≥65 years (CURB-65) score [6], and body mass index). We agree that exercise intolerance is a cardinal feature of chronic cardiac and respiratory disease [7, 8]. Hence, it would be preferable to adjust for these in the analysis. We therefore reanalyzed the study outcomes, adjusting the models for individual comorbidities that could impact exercise performance, such as heart failure, other chronic heart diseases, chronic obstructive pulmonary disease (COPD), or other chronic respiratory diseases, rather than the number of comorbidities (0, 1, ≥2). In the sensitivity analysis, supervised in-bed cycling (−5%; 95% confidence interval [CI], −26 to 22) and booklet exercise (−1%; 95% CI, −23 to 28) had no effect on length of stay compared with standard care (Table 1). Similarly, the tendency toward a reduced 90-day readmission risk with exercise remained despite adjusting for cardiac and respiratory diseases (P = .07). The risk of 180-day mortality was similar between standard care and the exercise groups.

We estimated that daily supervised exercise training during CAP admission would be more effective than standard care in reducing the length of stay. In recent years, research has been performed with the aim of improving CAP treatment, including early discharge [9, 10]. In previous studies [11, 12], early mobilization, that is, sitting out of bed for 20 minutes, was investigated as an intervention to reduce the length of stay in CAP. Unlike earlier studies, early mobilization is now a part of standard care for CAP; therefore, we investigated the additional beneficial effect of exercise training in patients with CAP. However, this trial suggests that exercise training has the potential to reduce readmission risk in patients with CAP.