Different Responses to Pulmonary Rehabilitation in COPD Patients with Different Work Efficiencies

Abstract

Background

Chronic obstructive pulmonary disease (COPD) often involves the cardiopulmonary dysfunction that deteriorates health-related quality of life (HRQL) and exercise capacity. Work efficiency (WE) indicates the efficiency of overall oxygen consumption (VO₂) during exercise. This study investigated whether different WEs have different effects on pulmonary rehabilitation (PR).

Methods

Forty-five patients with stable COPD were scheduled for PR. The PR programs consisted of twice-weekly sessions for three months. These patients were comprehensively evaluated by cardiopulmonary exercise testing and COPD assessment test (CAT) before and after PR. We compared these parameters between patients with a normal versus poor WE.

Results

Twenty-one patients had a normal WE and twenty-four patients had a poor WE (<8.6 mL/min/watt). Patients with a poor WE had earlier anaerobic metabolism, a poorer oxygen pulse, lower exercise capacity, more exertional dyspnea, and a poorer HRQL than those with a normal WE. PR improved exercise capacity, HRQL, anaerobic threshold, exertional dyspnea and leg fatigue in patients with either normal or poor WE. However, significant improvement of WE, oxygen pulse, respiratory frequency (Rf) during exercise, chest tightness, activity and sleepiness by CAT were noted only in patients with a poor WE. Among the patients with a poor WE, 29% patients had WE returned to normal after PR.

Conclusion

Patients with different WE had different responses to PR. PR improved exercise capacity and HRQL regardless of a normal or poor WE. However, WE, oxygen pulse, Rf during exercise, chest tightness, activity and sleepiness were only improved in patients with a poor WE.

Keywords:

• chronic obstructive pulmonary disease
• exercise intolerance
• pulmonary rehabilitation
• work efficiency

Data Sharing Statement

The datasets used during the current study are available from the corresponding author on reasonable request.

Ethics Approval and Informed Consent

The ethics committee of Taipei Tzu-Chi Hospital approved the study. All participants were informed about the purpose of the study, in accordance with the Declaration of Helsinki. Patient’s written consent has been obtained.

Disclosure

The authors disclose no financial or other potential conflicts of interest in this work.

Additional information

Funding

This study was supported by grants from the Taipei Tzu Chi Hospital and the Buddhist Tzu Chi Medical Foundation (TCRD-TPE-109-59 and TCRD-TPE-109-24(2/3), respectively).