Background/Purpose

Patient self-management should become a key component of rheumatology care. Development of modalities using personal technologies resources represents an attractive way to assess periodic disease’s activity. We previously developed a Smartphone application and a software to measure the dominant handgrip strength in rheumatoid arthritis (RA) patients. This pilot-study was performed in healthy and RA volunteers for testing and calibrating the system with a classical dynamometer. Then using this novel handheld device, we conducted an exploratory study to correlate RA disease activity with handgrip strength. Here we present our preliminary results.

Methods

We included 50 patients with RA. All patients fulfilled the 2010 ACR/EULAR criteria for RA. We excluded patients with health issues that could affect the test (hand or wrist surgery, myopathy, carpal tunnel syndrome, etc). Patients received visual and audio instructions from the Smartphone application and one-trained operator was present. The 28-joint disease activity score (DAS28) and modified Health Assessment Questionnaire (mHAQ) were measured for all participants. Linear regression and Two-Way ANOVA test were performed. The results were adjusted by age and sex

Results

96% of patients were females. Mean age was 62,59 + 12,9. Mean DAS28 was 3,41 ± 1,38 and 38% of patients were in remission (DAS28<2,6). 22% were treated with Methotrexate or Leflunomide and 76% were treated with a bDMARD in association or not with a sDMARD. No patients reported difficulties or pain performing the test. Mean duration of the test was 3.5 minutes ± 0.22 and handgrip strength level was 9,63 ± 5,49 Kg. A significantly negative correlation between the index of handgrip strength test and DAS28 was identified (r=-0.79,-0.85 to -0.34, p<0,01). We observed a significant correlation with the mHAQ (r=0.85, 0,67 to 0,96, p<0,01). In a subgroup of 15 patients we evaluated the handgrip strength after treatment modifications or disease flare-up exacerbations and we founded a significantly correlation with DAS28 changes (r=-0.93, -0.76 to -0.54, p<0.001). Ultimately we observed a tendency to correlate index of handgrip strength, adjusted by age and sex, and the presence of ultrasonography synovitis in a subgroup of 10 patients (p=0.076)

Conclusion

Our preliminary data showed that Smartphone self-evaluation of handgrip strength is a feasible way to assess RA disease activity. Moreover, we will continue to follow longitudinally our RA patients in order to determinate if this test could be used to detect flare-up or response to treatment. Then, we will validate this simple tool of self-assessment RA activity in a larger outpatients cohort

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/self-assessment-tool-of-rheumatoid-arthritis-disease-activity-handgrip-strength-measured-by-a-smartphone-connected-to-a-dynamometer/