Abstract
Disease activity refers to potentially reversible aspects of a disease. Measurement of disease activity in paediatric rheumatic diseases is a critical component of patient care and clinical research. Disease activity measures are developed systematically, often involving consensus methods. To be useful, a disease activity measure must be feasible, valid, and interpretable. There are several challenges in quantifying disease activity in paediatric rheumatology; namely, the conditions are multidimensional, the level of activity must be valuated in the context of treatment being received, there is no gold standard for disease activity, and it is often difficult to incorporate the patient's perspective of their disease activity. To date, core sets of response variables are defined for juvenile idiopathic arthritis, juvenile systemic lupus erythematosus, and juvenile dermatomyositis, as well as definitions for improvement in response to therapy. Several specific absolute disease activity measures also exist for each condition. Further work is required to determine the optimal disease activity measures in paediatric rheumatology.
Highlights
Measurement of a health state is the cornerstone of clinical practice and medical research
Across spectrum of disease activity, academic and community clinics, ideally n = 200 Clinicians deriving criteria should be different than those providing cases/controls Validated set of criteria or expert opinions For example, sensitivity/specificity, ROC curve, and regression models Feasibility, face validity, content validity, reliability, construct validity, and responsiveness Distinct validation sample disease activity in only about 40% of cases [18,19,20]
PRINTO [14]: (1) Physician global assessment of disease activity (2) Parent/patient assessment of overall wellbeing (3) Muscle strength (CMAS, MMT) (4) Functional ability (CHAQ) (5) Global disease activity tool (DAS, MDAAT) (6) HRQL (CHQ) International Myositis Assessment and Clinical Studies (IMACS) [12]: (1) Physician global assessment of disease activity (2) Muscle strength (MMT) (3) Functional ability (CHAQ, childhood myositis assessment scale (CMAS)) (4) Muscle enzymes (≥2 of CPK, aldolase LDH, AST, ALT) (5) Extramuscular disease (MDAAT) PRINTO [31]: ≥20% improvement in 3 of 6 core response variables (CRV), with ≤2 worsening by ≥20% IMACS [32]: ≥15% improvement in muscle strength and physical function, ≥20% physician and patient global and extramuscular assessments, ≥30% improvement in muscle enzymes
Summary
Measurement of a health state is the cornerstone of clinical practice and medical research. When caring for children and youth with rheumatic diseases, standardized and validated definitions of disease activity, as well as of change in disease activity in response to treatment, are critical for making decisions in clinical practice as well as for conducting clinical research studies. Over the past several years, an international collaborative effort has been made to develop and validate measures of disease activity, treatment response, inactive disease, and flare of disease in several paediatric rheumatic conditions [2]. These measures are numerous, and several new ones are emerging on an annual basis. This paper will discuss the theoretical basis of disease activity measures, methods for their development and validation, and an overview of available measures within paediatric rheumatology
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
