Short Physical Performance Battery: What Does Each Sub-Test Measure in Patients with Chronic Obstructive Pulmonary Disease?

Objective: To identify phenotypic factors associated with the Short Physical Performance Battery (SPPB) and its individual sub-tests: standing balance, 4‑meter gait speed (4mGS) and 5-repetition sit-to-stand (5STS).
Methods: The Evaluation of the Role of Inflammation in non-pulmonary disease manifestations in Chronic Airways disease (ERICA) study recruited adult participants with stable chronic obstructive pulmonary disease (COPD). Proportional odds models identified factors associated with the SPPB, and a principal component analysis (PCA) evaluated how much SPPB variance was explainable by each of its 3 sub-tests.
Results: Of 729 enrolled participants, 717 (60% male, mean age 67 years) had full SPPB data. Overall, 76% of patients had some evidence of functional limitations (SPPB total score < 12). Scores < 4 were observed in 71%, 31%, and 22% of participants for the 5STS, 4mGS, and balance sub-tests, respectively. A longer 6-minute walk test and greater quadriceps maximal voluntary contraction decreased the odds of being in a lower score category for SPPB total score and for all 3 sub-tests. Aging, self-reported hypertension and higher dyspnea increased the odds, and being married decreased the odds of being in a lower category for total score. All sub-tests contributed equally to total score.
Conclusion: Each of the 3 sub-tests contributed independent information to the SPPB, demonstrating their usefulness for assessing COPD when considered together rather than individually. The 5STS sub-test had the greatest variation in scores and may thus have the best discriminatory power for clinical COPD studies of lower limb performance where only one SPPB test is feasible.
Competing Interests: VSB, DM, NG, MA and RT-S are employees of (or were during the time of this study) and hold stock in GlaxoSmithKline. MIP has received payment to his institution or himself for advice on skeletal muscle weakness in COPD from GlaxoSmithKline, Novartis, AstraZeneca, Pfizer, Lilly and Astellas. CEB reports grants from GlaxoSmithKline and Pfizer; consultancy fees from Boehringer Ingelheim and honorarium from Chiesi in the past 3 years. JRC reports grants from Technology Strategy Board/Medical Research Council, during the conduct of the study; personal fees from GlaxoSmithKline, outside the submitted work. WM received research support from GlaxoSmithKline and Pfizer, and was on advisory committees of Almirall, GlaxoSmithKline, Novartis and Pfizer; he was a speaker for AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Janssen and Novartis. IBW reports grants from Technology Strategy Board and GlaxoSmithKline during the conduct of the study, and grants from GlaxoSmithKline outside the submitted work.
(JCOPDF © 2020.)