title: Handgrip strength measured by a dynamometer connected to a smartphone: a new applied health technology solution for the self-assessment of rheumatoid arthritis disease activity.
abstract: OBJECTIVE
  The aim was to analyse the accuracy of a hand dynamometer connected to a smartphone to assess RA disease activity through the measurement of handgrip strength (HGS).
  
  
  METHODS
  Eighty-two RA patients participated in this prospective study. Three types of HGS were assessed: power (Po), pinch (Pi) and tripod (T). An interactive mobile application was developed to capture grip measures. A unilinear regression analysis between HGS and DAS28 was performed. A multivariate regression analysis to identify independent variables related to HGS was also conducted.
  
  
  RESULTS
  Sixty-three patients (76.8%) were female. Mean age was 61.3 years. At baseline, a negative correlation between the three HGS measures and DAS28 score was found, as follows: Po, r = -0.65 (95% CI: -0.76, -0.51, P < 0.001); Pi, r= -0.42 (95% CI: -0.59, -0.23, P < 0.001); and T, r = -0.47 (95% CI: -0.63, -0.29, P < 0.001). In a longitudinal analysis of 32 patients, a negative correlation between ΔPo grip and ΔDAS28 was found (r = -0.76, 95% CI: -0.88, -0.56). Po grip was independently correlated with male sex (95% CI: 1.49, 4.14, P = 0.002), whereas variables inversely correlated with Po grip were disease duration (95% CI: -2.71, -1.34, P = 0.03), patient global assessment (95% CI: -2.41, -1.1, P < 0.001) and CRP level (95% CI: -3.56, -1.08, P < 0.001).
  
  
  CONCLUSIONS
  HGS assessed by a hand dynamometer connected to a smartphone represents an innovative health technology solution that could prompt the self-assessment of RA disease activity in an outpatient setting.
authors: Clinical Immunology and Osteoarticular Diseases Therapeutic Unit, Lapeyronie University Hospital, Montpellier.
authors: Francisco
authors: F
authors: Espinoza
authors: Clinical Immunology and Osteoarticular Diseases Therapeutic Unit, Lapeyronie University Hospital, Montpellier.
authors: Pierre
authors: P
authors: Le Blay
authors: Bodysens, Nimes and.
authors: Denis
authors: D
authors: Coulon
authors: Bodysens, Nimes and.
authors: Sylvain
authors: S
authors: Lieu
authors: Optimal Medicine, Montpellier, France.
authors: Janet
authors: J
authors: Munro
authors: Clinical Immunology and Osteoarticular Diseases Therapeutic Unit, Lapeyronie University Hospital, Montpellier.
authors: Christian
authors: C
authors: Jorgensen
authors: Clinical Immunology and Osteoarticular Diseases Therapeutic Unit, Lapeyronie University Hospital, Montpellier, ympers2000@yahoo.fr.
authors: Yves-Marie
authors: YM
authors: Pers
mesh_terms: D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000503:physiopathology; D059026:Diagnostic Self Evaluation; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index; D000068997:Smartphone; D013673:Technology Assessment, Biomedical / Q000379:methods; D017216:Telemedicine / Q000295:instrumentation / Q000379:methods
keywords: biomedical technology; hand strength; rheumatoid arthritis; telemedicine