The relationship between patient-reported and objective measures of physical function among cancer survivors receiving rehabilitation care: A correlation analysis

Abstract

Background: Physical function is associated with cancer-related quality of life and survival. The correlation of patient-reported and objective measures of physical function has not been quantified previously in the cancer rehabilitation medicine setting.

Objective: To correlate patient-reported physical function with objective measures of physical function. The secondary aim is to correlate fatigue and social participation levels with objective measures of physical function.

Design: Retrospective.

Setting: Tertiary university cancer center.

Participants: A total of 226 cancer survivors referred to an outpatient cancer rehabilitation medicine clinic.

Intervention: Not applicable.

Main outcome measure: Correlation of Patient-Reported Outcomes Measurement Information System (PROMIS) Cancer Function Brief 3D Profile domains with objective physical function measured by the 30-second sit-to-stand and hand grip strength.

Results: Pearson correlation analysis revealed a moderate correlation between patient-reported physical function and the 30-second sit-to-stand test (r = 0.57; p <.001), and a weak correlation of patient-reported physical function and handgrip strength (r = 0.27; p <.001). Multivariable regression modeling controlling for age, gender, and receipt of systemic therapy demonstrated a significant association between patient-reported physical function and the 30-second sit-to-stand test (estimated confidence interval 0.76 [0.60, 0.92], p < .01), in addition to patient-reported function and handgrip strength (estimated 0.22 [0.10, 0.34], p < .01). Multiple myeloma but no other cancer type was inversely associated with lower physical function.

Conclusions: Patient-reported physical function correlated moderately with the 30-second sit-to-stand test, whereas hand grip strength demonstrated a weak correlation. The 30-second sit-to-stand test is a suitable substitute for patient-reported physical function. Further work evaluating how measures relate to each other across cancer populations is needed before recommending a standardized set of outcome measures.