Establishing a common metric for physical function: Linking SARC-F and PROMIS® physical function.

Area of Science:

• Gerontology
• Oncology
• Rehabilitation Medicine

Background:

• Standardized assessment of physical function is crucial for older adults with cancer and other conditions.
• Patient-reported outcome measures (PROMs) like SARC-F and PROMIS PF 8c are vital tools.
• Linking these PROMs enhances their utility in research and clinical practice.

Purpose of the Study:

• To link the Strength, Assistance with walking, Rising from a chair, Climbing stairs, and Falls questionnaire (SARC-F) with the Patient-Reported Outcomes Measurement Information System® (PROMIS®) Physical Function Short Form 8c (PROMIS PF 8c).
• To create a convertible score system between SARC-F and PROMIS PF 8c.
• To inform clinicians and researchers about the interchangeability of critical cut-off scores for improved physical function assessment.

Main Methods:

• Recruited 300 participants with a cancer diagnosis and undergoing anti-cancer treatment from an online panel.
• Conducted five linking procedures to establish a crosswalk table between SARC-F and PROMIS PF 8c.
• Selected the Stocking-Lord approach as the optimal method for score conversion.

Main Results:

• All five linking methods demonstrated acceptably small mean differences between observed and linked T scores.
• The Stocking-Lord approach provided an optimal crosswalk table for converting SARC-F to PROMIS PF 8c scores.
• A SARC-F cut-off of 4 corresponds to a PROMIS PF 8c T score of 37, indicating moderate physical function limitation.

Conclusions:

• The developed linkage and crosswalk table enhance the interpretability of physical function scores for cancer patients.
• This facilitates harmonizing data across studies using either SARC-F or PROMIS PF 8c.
• The findings support improved clinical and research activities by enabling common metric analysis and cross-study comparisons.