Juvenile Dermatomyositis: what comes next? Long-term outcomes in childhood myositis from a patient perspective

Abstract

Background: To describe long-term outcomes in JDM using patient questionnaires and link to longitudinal, prospectively collected data for each patient within the Juvenile Dermatomyositis Cohort and Biomarker Study, UK and Ireland (JDCBS) to determine outcome predictors. METHODS: JDCBS participants aged ≥ 16y completed the SF36, HAQ and a questionnaire regarding current disease features, medications, education and employment. Data collected from the JDCBS included disease subtype, demographics, clinical and laboratory features. Intensity indices were calculated for physician VAS, modified skin DAS, CMAS and MMT8 by dividing area under the curve (AUC) from longitudinal score trajectories by duration of study follow-up (y). Relationships between questionnaire and JDCBS clinical / laboratory data were investigated fitting statistical models appropriate for cross sectional and longitudinal data.

Results: Of 190 questionnaires sent, 84 (44%) were returned. Average age of respondents was 20.6 years (SD 3.9), time since diagnosis was 12.4 years (SD 5.0), age at onset was 9.2 years (SD 4.3), female to male ratio 4.25:1. Forty-nine (59%) self-reported persistently active disease, 54 (65%) were still taking immunosuppressive medication. 14/32 at school/higher education reported myositis adversely affecting academic results. 18-24 year-olds were twice as likely to be unemployed compared the UK population (OR = 0.456, 95% CI 0.24, 0.84, p = 0.001). Participants ≥ 18 years were three times as likely to be living with a parent/guardian (OR = 3.39, p < 0.001). SF36 MCS and MMT8 intensity index scores were significantly correlated (ρ = 0.328, p = 0.007).

Conclusions: After 12.4 years, questionnaire responders reported self-perceived high rates of persistently active disease and medication use, reduced rates of employment and were more likely to live with a parent/guardian. Perceived persistently active muscle disease appeared to affect quality of life in these patients and was the most significant contributor to long-term outcomes. Our findings highlight the importance of including the patient perspective in the assessment of long term outcomes, so that that we can start to target initial management strategies more effectively based on a combination of clinical and patient-reported data.

Keywords: Adolescent; Juvenile; Myositis dermatomyositis; Outcome; Young adult.

Fig. 1

One individual longitudinal trajectory dataset. Data from one representative individual from visits over time are plotted for four variables; CMAS, modified skin DAS, MMT8 and Physician’s global VAS, showing variation in disease activity from age 8 years to 23 years of age

Fig. 2

Intensity indices of disease activity data in questionnaire responders and questionnaire non- responders. Intensity index data for four variables, (CMAS, MMT8 modified skin DAS, and Physician’s global VAS as shown), comparing data for questionnaire responders and questionnaire non-responders as shown. Box plots show IQR values, line represents median value. Note that disease burden for MMT8 and CMAS indices is higher in those with a low index score; while for Physician’s global VAS and modified skin DAS a greater burden is indicated by a high index score