Physical function measurement in older long-term cancer survivors
Jennifer Blackwood, Kateri Rybicki
Abstract
Objective: To establish reliability, validity, and minimal detectable change in measures of function in older longterm cancer survivors. Methods: Older cancer survivors were recruited to perform functional measures; 5 Times Sit-to-Stand (5xSTS), 30-second Timed Chair Rise (30sTCR), Short Physical Performance Battery (SPPB), Physical Performance Test-7 (PPT-7). Two testing sessions were completed two weeks apart. Test-retest reliability was examined using the intraclass correlation coefficient (ICC 2,1 ), convergent and discriminant validity using Spearman's rho and Minimal Detectable Change (MDC 95 ) was calculated. Results: Forty-seven older long-term cancer survivors participated. Test-retest reliability was good for 5xSTS (ICC 2,1 =0.86), 30sTCR (ICC 2,1 =0.89), and SPPB (ICC 2,1 =0.85) and poor for PPT-7 (ICC 2,1 =0.48). Both convergent and discriminant validity was established. Conclusions: SPPB, 5xSTS, and 30sTCR are reliable and valid tools to measure function in older long-term cancer survivors. MDC 95 values were larger than those reported in geriatrics and should be interpreted with caution. Residual effects of cancer treatment, comorbidity, and physical inactivity may contribute to decreased physical function in older long-term cancer survivors, therefore valid and reliable measures like SPPB and the timed chair rise tests should be used objectively measure function throughout the survivorship spectrum.