Objective. To develop the first composite disease activity score for juvenile dermatomyositis (JDM) and provide preliminary evidence of its validity. Methods. The Juvenile DermatoMyositis Activity Index (JDMAI) is composed of four items: physician’s global assessment of overall disease activity; parent’s/child’s global assessment of child’s wellbeing; measurement of muscle strength; and assessment of skin disease activity. The score of the JDMAI is the arithmetic sum of the scores of each individual component. Six preliminary versions of the JDMAI were tested, which differed in the tools used to assess the third and fourth items. Validation procedures were conducted using three large multinational patient samples including a total of 627 patients. Furthermore, a preliminary longitudinal validation was conducted on 57 patients enrolled at disease onset or at a follow-up visit in standard clinical care. Results. The JDMAI was found to possess face and content validity, good construct validity, satisfactory internal consistency (Cronbach’s alpha = 0.58-0.89), fair responsiveness to clinically important change (standardized response mean = 0.82-3.12 among patients improved) and strong capacity to discriminate patients judged as being in the state of inactive disease or low, moderate or high disease activity by the physician (P<0.001) or whose parents were satisfied or not satisfied with the course of their child’s illness (P<0.001). Similar results were obtained in the sample of patients prospectively enrolled for the aim of the study. Overall, the six versions of the JDMAI showed similar metrological performances in validation analyses. Conclusion. The JDMAI was found to possess good measurement properties in a large population of patients with a wide range of disease activity, and is, therefore, suitable for use in both clinical and research settings. The final version of the JDMAI will be selected after its large-scale prospective validation.

Development and validation of a composite disease activity score for juvenile dermatomyositis

ROSINA, SILVIA
2019-05-22

Abstract

Objective. To develop the first composite disease activity score for juvenile dermatomyositis (JDM) and provide preliminary evidence of its validity. Methods. The Juvenile DermatoMyositis Activity Index (JDMAI) is composed of four items: physician’s global assessment of overall disease activity; parent’s/child’s global assessment of child’s wellbeing; measurement of muscle strength; and assessment of skin disease activity. The score of the JDMAI is the arithmetic sum of the scores of each individual component. Six preliminary versions of the JDMAI were tested, which differed in the tools used to assess the third and fourth items. Validation procedures were conducted using three large multinational patient samples including a total of 627 patients. Furthermore, a preliminary longitudinal validation was conducted on 57 patients enrolled at disease onset or at a follow-up visit in standard clinical care. Results. The JDMAI was found to possess face and content validity, good construct validity, satisfactory internal consistency (Cronbach’s alpha = 0.58-0.89), fair responsiveness to clinically important change (standardized response mean = 0.82-3.12 among patients improved) and strong capacity to discriminate patients judged as being in the state of inactive disease or low, moderate or high disease activity by the physician (P<0.001) or whose parents were satisfied or not satisfied with the course of their child’s illness (P<0.001). Similar results were obtained in the sample of patients prospectively enrolled for the aim of the study. Overall, the six versions of the JDMAI showed similar metrological performances in validation analyses. Conclusion. The JDMAI was found to possess good measurement properties in a large population of patients with a wide range of disease activity, and is, therefore, suitable for use in both clinical and research settings. The final version of the JDMAI will be selected after its large-scale prospective validation.
22-mag-2019
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/945551
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