(Scientific Session) Comparing Patient-reported and Objective Measures of Physical Function Among Cancer Survivors: A Correlation Analysis

Background and/or Objectives: Cancer survivors experience a decline in physical function. Physical function is associated with treatment eligibility, survival and quality of life. It is unknown how physical function outcome measures relate with each other in the cancer population. The correlation of patient-reported and objective measures of physical function has not been previously quantified in the cancer rehabilitation medicine setting. The primary aim is to correlate the PROMIS physical function, a patient-reported measure, with the 30 second sit-to-stand and hand grip strength tests. The secondary aim is to correlate the PROMIS fatigue and PROMIS physical function.

Design: Retrospective study

Setting: Academic medical center

Participants: 226 subjects

Interventions: Subjects completed the PROMIS Cancer Function Brief 3D Profile, 30 second sit-to-stand and handgrip strength tests

Main Outcome Measures: Physical function and fatigue domains of the PROMIS Cancer Function Brief 3D Profile, 30 second-sit to stand test, hand grip strength

Results: The three most common cancers were breast, multiple myeloma, and gynecologic. The average PROMIS physical function T score was 44, fatigue T score was 58, hand grip was 24 kg and 30 second sit-to-stand was 12. There was a moderate correlation between the 30 second sit-to-stand test and the PROMIS physical function (r=0.57; p= < 0.001), a negligible correlation of the physical function and hand grip (r=0.27; p= < 0.001), and a mildly negative correlation between physical function and fatigue (r= -0.49; p= < 0.001).

Conclusions: The PROMIS physical function domain correlated moderately with the 30 second sit-to-stand test and did not correlate with hand grip strength. Patient-reported outcomes and objective physical function tests likely capture distinct aspects of physical function. They may not be a true substitution for each other. Further work evaluating how measures relate to each other across cancer diagnoses and their clinical significance is needed before recommending a standardized set of outcome measures in the cancer rehabilitation setting.