POS0880 TWO-MINUTE WALK TEST AS A SIMPLE AND OBJECTIVE OUTCOME MEASURE IN IDIOPATHIC INFLAMMATORY MYOSITIS
Authors: S. K. Dunga, C. Kavadichanda, V. Negi
Journal: Annals of the Rheumatic Diseases (2021)

Background: Manual muscle testing (MMT) and Functional index 2(FI-2) are the usual methods in assessing disease activity in IIM 1 . Limitations of MMT8 include low sensitivity to change, floor/ceiling effect, and under-representation of certain important muscle groups 1 while FI-2 takes a longer time to administer. Several Timed function tests (TFTs) like the 2-minute walk test (2MWT) or 30s raise from a chair test and 30s 1kg arm rise test may be better alternatives and less time taking 2 . Data looking at the performance of these tests are limited to small controlled studies. Objectives: To assess the performance of timed function tests against MMT8 and FI-2 in assessing muscle strength and endurance at baseline, 3 and 6 months of therapy. Methods: An observational cohort study, included 41 patients with polymyositis and dermato-myositis attending OPD and IPD service of tertiary centre. MMT8, FI-2 and Timed function tests were done at baseline, at 3 months and at 6 months. (Figure 1) Figure 1. Consort diagram showing the workflow in study population Results: Forty one patients included in the study had completed three month follow-up assessment, while 17 patients achieved a six-month evaluation. Out of 41 patients, 11 (27%) were polymyositis, and 30 (73%) were dermatomyositis. The mean MMT8 of the total study population at baseline was 57±15, at three months (n=41) was 66 ±10 and at six months (n=17) was 71 ± 10, while in active subgroup was 50 ± 18, 64 ± 9 (n=41), 67 ± 9.6 (n=17)at baseline, three months and six months respectively. The change in TFTs showed a moderate to strong correlation with the change in Fi-2 among the study population at three months and six months (Table 2). Among the TFTs 2MWT showed moderate correlation with both MMT8 and FI-2 in active disease. Table 1. Spearman Rho Correlation between change in timed function tests with change in MMT8, change in FI-2 at 3 months and 6 months At 3 months (n=41 ) At 6 months (n=17 ) Active disease (n=18 ) Inactive disease (n=23 ) Active disease (n=7 ) Inactive disease (n=10 ) Correlation of Δ MMT8 with Δ30s rise form chair 0.143 0.346 0.200 0.347 Δ30s1kg arm lift 0.018 0.284 0.362 0.168 Δ2MWD 0.755* 0.313 0.482* 0.334 Correlation of ΔFI-2 with Δ30s rise form chair 0.784* 0.495* 0.486* 0.424* Δ30s1kg arm lift 0.671* 0.107 0.704* 0.301 Δ2MWD 0.834* 0.623* 0.808* 0.506* *p&lt;0.05 Conclusion: Using timed function tests can be an excellent alternative to FI-2 in assessing muscle endurance. 2-minute walk distance is a better alternative to conventional muscle testing as it measures both power and endurance, and this can overcome the ceiling effect of MMT-8. References: [1]Rider LG, Aggarwal R, Machado PM, Hogrel J-Y, Reed AM, Christopher-Stine L, et al. Update on outcome assessment in myositis. Nat. Rev. Rheumatol. 2018;14:303–18. [2]Agarwal S, Kiely PD. Two simple, reliable and valid tests of proximal muscle function, and their application to the management of idiopathic inflammatory myositis. Rheumatology. 2006 Jul 1;45(7):874-9. Acknowledgements: I would like to acknowledge my patients, my teachers, colleagues, and paraclinical staff of the department of Clinical Immunology JIPMER Disclosure of Interests: None declared