What is a meaningful change in physical performance? Findings from a clinical trial in older adults (the LIFE-P study)

• Published in: The Journal of nutrition, health & aging health & aging, 2009-06, Vol.13 (6), p.538-544
• Main Authors: Kwon, S., Perera, S., Pahor, M., Katula, J. A., King, A. C., Groessl, E. J., Studenski, S. A.
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Aging; Aging - physiology; Biological and medical sciences; data analysis; Disability Evaluation; elderly; exercise; exercise test; Exercise Therapy; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; gait; Geriatrics/Gerontology; Health Education; Humans; Meaningfulness in Performance Measures; Medicine; Medicine & Public Health; Neurosciences; Nutrition; Physical Fitness; Primary Care Medicine; Quality of Life Research; randomized clinical trials; Research Design; Self Disclosure; Single-Blind Method; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Walking
• ISSN: 1279-7707; 1760-4788
• DOI: 10.1007/s12603-009-0104-z

Objective Performance measures provide important information, but the meaning of change in these measures is not well known. The purpose of this research is to 1) examine the effect of treatment assignment on the relationship between self-report and performance; 2) to estimate the magnitude of meaningful change in 400- meter walk time (400MWT), 4-meter gait speed (4MGS), and Short Physical Performance Battery (SPPB) and 3) to evaluate the effect of direction of change on estimates of magnitude. Design This is a secondary analysis of data from the LIFE-P study, a single blinded randomized clinical trial. Using change over one year, we applied distribution-based and anchor-based methods for self-reported mobility to estimate minimally important and substantial change in 400MWT, 4MGS and SPPB. Setting Four university-based clinical research sites. Participants Sedentary adults aged 70–89 whose SPPB scores were less than 10 and who were able to complete a 400MW at baseline (n=424). Interventions A structured exercise program versus health education. Measurements 400MWT, 4MGS, SPPB. Results Relationships between self-report and performance measures were consistent between treatment arms. Minimally significant change estimates were 400MWT: 20–30 seconds, 4MGS: 0.03–0.05m/s and SPPB: 0.3–0.8 points. Substantial changes were 400MWT: 50–60 seconds, 4MGS: 0.08m/s, SPPB: 0.4–1.5 points. Magnitudes of change for improvement and decline were not significantly different. Conclusions The magnitude of clinically important change in physical performance measures is reasonably consistent using several analytic techniques and appears to be achievable in clinical trials of exercise. Due to limited power, the effect of direction of change on estimates of magnitude remains uncertain.