Validation of a Core Patient-Reported Outcome Measure for Life Participation in Kidney Transplant Recipients: the SONG Life Participation Instrument.

INTRODUCTION: Life participation has been established as a critically important core for trials in kidney transplantation. We aimed to validate a patient-reported outcome measure for life participation in kidney transplant recipients.

METHODS: A psychometric evaluation of the Standardized Outcomes in Nephrology life participation (SONG-LP) measure was conducted in adult kidney transplant recipients. The measure includes 4 items of life participation (leisure, family, work, and social) each with a 5-point Likert scale. Each item is scored from 0 (never) to 4 (always) and the summary measure score the average of each item.

RESULTS: A total of 249 adult kidney transplant recipients from 20 countries participated. The SONG-LP instrument demonstrated internal consistency (Cronbach's α = 0.87; 95% confidence intervals [CI]: 0.83-0.90, baseline) and test-retest reliability over 1 week (intraclass correlation coefficient of 0.62; 95% CI: 0.54-0.70). There was moderate to high correlation (0.65; 95% CI: 0.57-0.72) with the PROMIS Ability to Participate in Social Roles and Activities Short Form 8a that assessed a similar construct, and moderate correlation with measures that assessed related concepts (i.e., EQ5D 0.57; 95% CI: 0.49-0.65), PROMIS Cognitive Functional Abilities Subset Short Form 4a (0.40; 95% CI: 0.29-0.50).

CONCLUSION: The SONG-LP instrument is a simple, internally consistent, reliable measure for kidney transplant recipients and correlates with similar measures. Routine incorporation in clinical trials will ensure consistent and appropriate assessment of life participation for informed patient-centered decision-making.