Pulmonary rehabilitation for chronic obstructive pulmonary disease patients with underlying Alpha-1 antitrypsin deficiency: a systematic review and practical recommendations

Background: Alpha-1 antitrypsin deficiency (AATD) is an often-overlooked genetic condition that makes individuals susceptible to early onset of chronic obstructive pulmonary disease (COPD). The established benefits of exercise-based pulmonary rehabilitation (PR) for usual COPD patients are unclear for those with underlying AATD, especially given potentially differing muscle adaptations to exercise. This review seeks to compare PR outcomes between AATD and usual COPD patients and to consolidate current knowledge on exercise intervention outcomes for the AATD population. Methods: A thorough search of 4 databases (Ovid, Medline, CINAHL, CENTRAL) was conducted based on 3 search concepts: (1) alpha-1 antitrypsin deficiency, (2) pulmonary rehabilitation OR exercise, and (3) muscle morphology. A dual review process and quality assessment were independently implemented throughout all stages of the review. Results: Four studies highlighted modest exercise capacity and quality of life in AATD patients undergoing PR. However, one study reported unique muscle and mitochondrial responses compared to usual COPD patients. Additionally, a moderate exercise session did not alter pro-inflammatory cytokine levels in AATD patients, despite higher levels of tumor necrosis factor-α levels in muscle biopsies compared to usual COPD patients. Conclusions: The current literature base insufficiently addresses the efficacy of PR on AATD, with indications that exercise adaptation may deviate from that of usual COPD patients. Further research is needed to optimize PR, particularly in identifying the most suitable exercise intensity, and delivery setting, and addressing specific educational needs for individuals with AATD.