Phenotypic characteristics associated with reduced short physical performance battery score in COPD

Area of Science:

• Gerontology
• Pulmonology
• Rehabilitation Medicine

Background:

• The Short Physical Performance Battery (SPPB) is widely used in gerontology.
• Its determinants in Chronic Obstructive Pulmonary Disease (COPD) are not well understood.
• The impact of pulmonary COPD on SPPB's assessment of lower limb function is unknown.

Purpose of the Study:

• To evaluate the determinants of SPPB scores in patients with COPD.
• To determine if pulmonary aspects of COPD influence SPPB's validity for assessing lower limb function.
• To identify phenotypes associated with varying SPPB scores in COPD.

Main Methods:

• 109 COPD patients underwent assessment of SPPB, spirometry, 6-minute walk distance, quadriceps strength, muscle size, body composition, physical activity, and dyspnea.
• Vastus lateralis muscle biopsies were analyzed for structural characteristics in 31 patients.
• Phenotypic characteristics were compared between patients stratified by SPPB score.

Main Results:

• Quadriceps strength and 6-minute walk distance were independent predictors of SPPB score.
• Age, dyspnea, and health status were univariate predictors; FEV1 was not.
• Lower SPPB scores correlated with muscle atrophy, reduced strength, exercise capacity, and physical activity.
• Patients with SPPB < 10 showed a higher proportion of type 2 muscle fibers.

Conclusions:

• The SPPB is a valid and simple tool for assessing functional impairment in stable COPD patients.
• SPPB can identify a phenotype characterized by functional limitations, muscle mass loss, and structural muscle abnormalities.
• SPPB is useful for detecting specific phenotypes within the COPD population.