The physiological and physical determinants of functional ability measures in children with juvenile dermatomyositis

Abstract

To study the relationships of muscle strength and maximal oxygen consumption (VO(2peak)) with Childhood Health Assessment Questionnaire (CHAQ) score, Childhood Myositis Assessment Score (CMAS) and Child Health Questionnaire [physical summary (CHQ-PhS) and psychosocial summary (CHQ-PsS)] scores in juvenile dermatomyositis. Fifteen patients (age 5-14 yr) participated. CMAS, CHAQ, CHQ, muscle strength and VO(2peak) were measured. Correlations revealed significant relationships between CHAQ and (i) muscle strength (r=-0.72) and (ii) absolute VO(2peak) (r=-0.68); between CMAS and relative VO(2peak) (r=0.73); and between CHQ-PhS and (i) muscle strength (r=0.57) and (ii) relative VO(2peak) (r=0.58). Backward regression analysis showed that muscle strength was the best indicator of variation in CHAQ. Age and relative VO(2peak) were the best indicators for CMAS. Body mass and age were the best indicators for CHQ-PsS. Body mass and muscle strength were the best indicators for CHQ-PhS. CMAS, CHAQ and CHQ correlate with muscle strength and VO(2peak). CMAS, CHAQ and CHQ depend on different physical and physiological variables.