Validation of the Standardized Outcomes in Nephrology-Life Participation Instrument in People with CKD

The Standardised Outcomes in Nephrology-Life Participation instrument is valid and reliable to use in patients with CKD not yet requiring KRT. Use of the Standardised Outcomes in Nephrology-Life Participation instrument in clinical trials and publication of results will ensure consistency reporting of life participation in trials in people with CKD.

Life participation has been identified as a critically important core outcome by people with CKD not yet requiring KRT. In this study, we aimed to validate the Standardized Outcomes in Nephrology-Life Participation (SONG-LP) instrument.

A psychometric evaluation of the SONG-LP was conducted in adults with CKD not yet requiring KRT. The instrument includes four equally weighted domains of life participation including leisure, family, work, and social activities, scored on a five-point Likert scale that specifies frequency over a 1-month recall period from never (zero) to always (four) with a range of zero to four possible (calculated as a mean of the four responses). Internal consistency, test-retest reliability, convergent validity, hypothesis testing, and acceptability were assessed.

In total, 179 participants from 16 countries participated. The SONG-LP instrument demonstrated strong internal consistency (Cronbach α =0.92; 95% confidence interval [CI], 0.89 to 0.94; baseline; McDonald ω =0.93; 95% CI, 0.91 to 0.95; baseline) and strong test-retest reliability over 1 week ( n =165, intraclass correlation coefficient of 0.81; 95% CI, 0.76 to 0.86) with mean scores 2.97±0.91 and 3.07±0.92 at baseline and at week 1, respectively. There was strong positive correlation with the Patient-Reported Outcomes Measurement Information System Ability to Participate in Social Roles and Activities Short Form 8a that assesses a similar construct (0.81; 95% CI, 0.72 to 0.86), and moderate correlation with measures that assess related concepts including Euro Quality of Life-5 Dimension (0.72; 95% CI, 0.63 to 0.79) and Patient-Reported Outcomes Measurement Information System Cognitive Functional Abilities Subset Short Form 4a (0.61; 95% CI, 0.50 to 0.70).

The SONG-LP instrument is a valid, reliable and internally consistent instrument to assess life participation in people with CKD not yet requiring KRT. It can potentially facilitate routine and consistent assessment of life participation in trials and routine clinical care in people with CKD.