Hand-Held Dynamometry May Provide A Valid And Objective Method Of Muscle Strength Quantification In Adult Inflammatory Myopathy: Results From Clinical Practice In A Tertiary Centre

Abstract Background/Aims Accurate methods of muscle strength assessment are vital in the care of patients with idiopathic inflammatory myopathy (IIM). Manual muscle testing (MMT) is limited in quantification of strength and has a demonstrated 'ceiling effect'. Recent research has indicated that hand-held dynamometry (HHD) may provide a user-friendly and patient-acceptable method to quantify muscle strength without a ceiling effect. This study aims to demonstrate routine clinical application of HHD and explore the ability to predict physical function and patient-rated impact in a tertiary IIM cohort. Methods Data was collected from adult IIM patients attending a UK tertiary centre between 2016 and 2019. Bilateral HHD of knee extension, shoulder abduction and grip strength were measured by a single specialist physiotherapist. Data was also collected on function (Health Assessment Questionnaire [HAQ]), muscle strength (MMT-8) and global activity (patient global visual analogue scale [VAS]). Generalised linear modelling, adjusted for age and sex was used to quantify associations between HHD values of each movement and HAQ score, MMT-8 score and patient global activity VAS. Results Data was collected on 57 patients (60% female) with a mean age of 56 years (SD 13), mean HAQ of 1 (SD 0.85), and mean MMT-8 of 75 (SD 6) out of a maximum score of 80. Summary values of each collected measurement and modelling results are displayed in Table 1. All HHD measurements significantly correlated with HAQ, MMT-8 and patient global VAS scores. The greatest magnitude of association was seen with shoulder abduction. The collection of strength measures by the HHD method was tolerable and time-efficient for patient and clinician. Patient feedback on being able to see their objective strength measures on the HHD was also encouragingly positive, boosting their intrinsic motivation to take part in rehabilitation. P150 Table 1:Summary HHD strength values and modelling resultsMeasurement using HHDMean (SD) (kg)Association with HAQ - Coef (p-value)Association with MMT-8 - Coef (p-value)Association with patient global VAS - Coef (p-value)Grip strength22.98 (12.41)-0.04 (<0.01)0.26 (<0.01)-1.53 (<0.01)Shoulder abduction10.39 (5.51)-0.11 (<0.01)0.60 (<0.01)-2.74 (<0.01)Knee extension13.03 (7.17)-0.06 (<0.01)0.51 (<0.01)-1.53 (<0.01)SD = standard deviation, HAQ = Health Assessment Questionnaire, MMT-8 = manual muscle testing, VAS = visual analogue scale, Coef = coefficient, HHD = hand held dynamometry. Conclusion This study indicates that HHD may provide an inexpensive, user-friendly method of strength assessment in IIM patients, providing accurate insights into function, strength and global activity. Undertaking HHD in clinic and by a specialist physiotherapist allows for stratified, personalised rehabilitation intervention. Following future validation, HHD could form a method of objective muscle strength assessment, thus focusing IIM clinical care and research. Disclosure W.J. Gregory: Honoraria; W.G. has received honoraria from Abbvie, Pfizer and UCB. A. Oldroyd: None. H. Chinoy: None.