Background and aims

Physical performance is an important predictor of quality of life among the elderly. A valid and sensitive measure of physical performance is needed in order to evaluate possible interventions. The aim of this study was to examine the validity and reliability of the Continuous Summary Physical Performance Score (CSPPS) and its relationship to the Quartile Summary Physical Performance Score (QSPPS).

Methods

This cross-sectional study of an elderly cohort from 5 centers in the US and Europe included men and women (> age 65) reporting at least two domains of disability. Subjects completed assessments of mobility and ability to perform activities of daily living (ADLs), the physical component of the SF-36, and a self-rating of physical performance. Timed physical performance tests were used to calculate the CSPPS and QSPPS.

Results

216 subjects took part (mean age = 81 years). The distribution of CSPPS scores was similar for men and women, with a mean of 59.2 (SD 17.8), median of 64.3, and range from 1.3 to 91. Subjects with older age, higher degree of disability, and lower self-rated physical performance had lower CSPPS scores. The CSPPS had good test-retest reliability (r = 0.92), and CSPPS and QSPPS are highly correlated (r = 0.94, p < 0.001). However, the QSPPS appears to lack the linearity, and the ranges of the CSPPS for each score of the QSPPS overlap substantially.

Conclusions

In a cohort with moderate to severe disability, the CSPPS appears to be a valid, reproducible measure that can discriminate smaller yet clinically meaningful differences in physical function, as compared with the QSPPS.