Hand grip strength in juvenile idiopathic arthritis as predictor of disease activity and disability in clinical practice

Abstract

Background: JIA is a chronic inflammatory disease resulting in joints arthritis and deformities in the hands and fingers. This leads to decrease of joint mobility and strength of the hands which can lead to physical and functional hand disability and subsequent reduction in daily living activities. Despite the presence of indices to assess the hand function, grip strength assessment remains the strong predictor of both hand and upper limb function. Hand grip strength (HGS) can be measured quantitatively using a hand dynamometer. Although the role of HGS in evaluating hand function in JIA has been studied, the use of HGS as a predictor of disease activity and disability in JIA has not been explored. The aim of the study was to evaluate the HGS in JIA patients using electronic hand dynamometer and to assess its relationship with JIA disease activity, disability and quality of life. Methods: Twenty-three patients with JIA (14 girls and 9 boys) diagnosed according to ILAR classification criteria and 59 healthy children were enrolled in the study. The disease activity was assessed using Juvenile DAS (JDAS27). The Juvenile Arthritis Functionality Scale (JAFS) and Paediatric QOL Inventory (PedsQL) were used to assess physical function and quality of life respectively. HGS was tested three times in each hand of every patient and control using an electronic hand dynamometer and the mean value was considered. Results: Patients with JIA showed low HGS in one or both hands compared with healthy children (P=0.001). Grip strength showed a significant inverse correlation with JDAS27 (P=0.003, r=-0.591) and with JAFS (total and after exclusion of hand component; P=0.001 and 0.002, r=-0.650 and -0.608, respectively). Significant correlations were observed between HGS and PedsQL (P=0.036). Conclusion: Patients with JIA have reduced HGS when compared with healthy children. HGS may be considered as a noninvasive predictor of JIA disease activity and disability. Paediatric quality of life is adversely affected with decrease in HGS. HGS testing might be used a simple screening for disease activity in patients with JIA.