Objective: To evaluate the reliability, validity, feasibility and psychometric performance of the Lupus Impact Tracker (LIT) as a patient reported outcome (PRO) measure tool in pediatric systemic lupus erythematosus (pSLE).
Methods: This is a prospective, observational, pilot study where patients aged between 12 and 25 years, fulfilling the 1997 ACR classification criteria for SLE, were enrolled. Over 3 consecutive, routine, clinical visits, the patients completed the LIT alongside the Patient-Reported Outcomes Measurement Information System-Short Forms (PROMIS-SFs), Childhood Health Assessment Questionnaire (CHAQ). Rheumatologists completed the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) and the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC-ACR) Damage Index. Demographic, clinical and laboratory data were also collected.
Results: Of 46 patients enrolled, 38 patients completed 2 visits and 31 completed all 3 visits. Seventy-eight percent were female, 33% African American, 28% Asian, 15% Caucasian and 17% Hispanic. The mean (SD) age was 17.2 (2.7) years, with a mean (SD) disease duration of 4.6 (3.1) years. The mean (SD) SLEDAI-2K at enrollment was 3.54 (2.96). In the 38 patients who completed two or more visits, intra-class correlation coefficient and Cronbach alpha were calculated to be 0.70 and 0.91 respectively, signifying good reliability of LIT. The LIT showed positive correlation with CHAQ-Disability Index and majority of the PROMIS-SFs parameters. Construct validity was established against clinical disease activity (SLEDAI-2K).
Conclusion: The preliminary results indicate that the LIT is a reliable and valid instrument to capture PRO in p-SLE. Prospective validation with a larger, multicenter cohort is the next step.
Keywords: Lupus impact tracker; patient reported outcomes; pediatric lupus.