Background/Purpose: Patient reported outcomes (PROs) are becoming increasingly recognized as important in the care of patients with chronic diseases, such as Juvenile Dermatomyositis (JDM); however, the correlation of PROs to physician (MD) reported scores in clinical practice is unclear. We sought to assess the correlation between patient (PT) and MD reported global disease activity in JDM and examine factors associated with disparate scores.

Methods: We identified a cohort of patients with physician-diagnosed JDM through the Childhood Arthritis and Rheumatology Research Alliance registry, an IRB approved, multi-center registry developed to capture data about children with rheumatic diseases. Data were abstracted using a standardized form, including demographics, medication history, PRO measures (global disease activity on a 10 point visual analog scale (VAS), childhood health assessment questionnaire (CHAQ), pain and overall quality of life scores), and physician reported outcome measures (global disease activity VAS, subjective weakness, muscle strength scoring, muscle enzyme testing, examination findings and associated co-morbidities). We assessed the discordance between PT and MD global disease activity VAS, and defined ≥3 point difference as discordant. We then evaluated factors associated with discordance. Variables were compared using chi-square for categorical and Kruskal-Wallis analysis for continuous, with significance p<0.01.

Results: In the registry, 563 patients with JDM were identified. Mean age was 10.6 years (range 6.9-14.7) with average age of onset 5.5 (3.6-9.3). Most patients were female (403, 72%), white (442, 79%) and non-Hispanic (471, 84%). Overall, PT and MD global disease activity VAS were similar in 78% of cases. Of discordant scores, 16% of PT rated VAS ≥3 points above MD (indicating greater disease activity), while 6% of MD VAS were higher than PT VAS. When PT VAS was ≥3 points above MD, these patients had significantly worse CHAQ scores, higher pain scores, and more frequently reported poor quality of life (all p<0.01). When MD VAS was ≥3 points above PT, these patients had more frequent muscle enzyme abnormalities, weakness and lower strength score, rash, nail fold changes, calcinosis, joint involvement, and current steroid treatment (all p<0.01). Prevalence of GI/cardiac involvement tended to be higher with discordance in either direction. There was no statistical evidence that demographic factors (current age, age of onset, gender, race or ethnicity, or income level) were associated with discordant VAS scores.

Conclusion: While patients and physicians frequently agree on global disease activity VAS ratings in JDM, discordance is seen in over 20%. When patients report discordantly worse/higher scores, this is associated with worse PRO measures of functional status, pain and quality of life. When physicians report higher scores, this is associated with poorer objective measures of strength, abnormal muscle enzyme testing, more co-morbidities and physical exam findings. This study highlights the importance of incorporating PROs into the routine assessment of patients with JDM.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/comparison-of-patient-and-physician-reported-global-disease-activity-measures-in-juvenile-dermatomyositis/