||Background: The Patient Reported Outcomes Measurement Information System (PROMIS) provides generalizable and universal measures of various domains of patient reported outcomes. The PROMIS-57 and PROMIS-29 questionnaires have not been tested among kidney transplant recipients (KTR). Here, we validate the PROMIS-57 and the PROMIS-29, questionnaire among KTR.
Methods: A cross-sectional sample of stable KTR was recruited. Each participant completed PROMIS-57, a 57 question instrument measuring 7 domains ? physical function, anxiety, depression, fatigue, pain, sleep disturbance, and social functioning ? alongside validated legacy questionnaires (Patient Health Questionnaire(PHQ9), General Anxiety Disorder(GAD7), Edmonton Symptom Assessment Scale(ESAS), and Kidney Disease Quality of Life(KDQoL-36)). PROMIS-29, a 29 question instrument is nested within PROMIS-57 and measures the same domains. Structural validity of PROMIS was assessed with confirmatory factor analysis, reported using the Tucker Lewis Index (TLI) and Comparative fit index (CFI). Construct validity was assessed with known group comparisons. Internal consistency was assessed with Cronbach?s ? and convergent validity was assessed with Spearman?s Rho. Test-retest reliability was assessed through the intraclass coefficient (ICC).
Results: Mean(SD) age of the 179 participants was 51(17), 57% were male and 55% Caucasian. Internal consistency of each domain was high (Cronbach?s ?>0.90). Confirmatory factor analysis showed good structural validity (TLI and CFI > 0.95). PROMIS anxiety demonstrated strong correlation with GAD7 (PROMIS-57:rho=0.76, 95%CI:0.68-0.82; PROMIS-29:rho=0.73, 95%CI:0.65-0.80). PROMIS depression demonstrated correlation with PHQ9 (PROMIS-57:rho=0.68, 95%CI:0.58-0.76; PROMIS-29:rho=0.63, 95%CI:0.53-0.72). PROMIS physical function demonstrated strong correlation with the KDQol-36 physical composite (PROMIS-57:rho=0.81, 95%CI:0.75-0.85; PROMIS-29:rho=0.79, 95%CI:0.72-0.84). PROMIS fatigue demonstrated strong correlation with ESAS fatigue (PROMIS-57:rho=0.72, 95%CI:0.64-0.79; PROMIS-29:rho=0.73, 95%CI:0.64-0.79). Test-retest reliability indicated good agreement (ICC>0.6). Transplanted patients had better scores in all domains relative to a dialysis cohort supporting known group construct validity (p<0.05).
Conclusions: Our results confirm that PROMIS-57 and PROMIS-29 profile are reliable and valid instruments and are valuable tools to assess the disease experience among KTR.