Ab1544-HPR Pulmonary Functions and Respiratory Muscle Strength in Rheumatoid Arthritis: A Case-Control Study

Background: Joint involvement is the most prominent feature of the rheumatoid arthritis (RA); however, respiratory system may also be affected due to parenchyma and pleura involvement, systemic inflammation, and possible side-effects of the pharmaceutical treatment. Although restrictive decrements in lung functions have been previously documented [1,2], no studies were conducted to explore if respiratory muscle strength is affected in patients with RA. Objectives: The aim of this study was to compare pulmonary functions and respiratory muscle strengths between patients with RA and their healthy peers. Methods: Forty-one patients with RA (28 females) and 41 sex, age, body mass index (BMI) matched apparently healthy adults were tested for pulmonary functions and respiratory muscle strength by using a portable device (Cosmed Pony FX, Rome, Italy). Pulmonary function testing included measurements of forced vital capacity (FVC), forced expiratory volume in the 1st second (FEV₁), and FEV₁/FVC ratios. Maximal inspiratory (PImax) and expiratory (PEmax) mouth pressure measurements were used for determining respiratory muscle strength. Smoking history and dyspnea perception were questioned in both groups. Results: Group characteristics are presented at Table. RA group reported significantly higher dyspnea perception compared to healthy controls (p<0.05, Table 1). FVC, FEV₁, PImax, and PEmax values were significantly lower in RA group. Conclusion: According to our results and compatible with the existing literature [1,2] patients with RA present restricted lung functions. This restrictive pattern is also accompanied by decreased inspiratory and expiratory muscle strength. The underlying causes of respiratory muscle weakness and possible management strategies should be elaborated in patients with RA. REFERENCES: [1] Prisco L, Moll M, Wang J, Hobbs BD, Huang W, Martin LW, Kronzer VL, Huang S, Silverman EK, Doyle TJ, Cho MH, Sparks JA. Relationship Between Rheumatoid Arthritis and Pulmonary Function Measures on Spirometry in the UK Biobank. Arthritis Rheumatol. 2021;73(11):1994-2002. [2] Huang S, He X, Doyle TJ, Zaccardelli A, Marshall AA, Friedlander HM, Blaustein RB, Smith EA, Cui J, Iannaccone CK, Mahmoud TG, Weinblatt ME, Dellaripa PF, Shadick NA, Sparks JA. Association of rheumatoid arthritis-related autoantibodies with pulmonary function test abnormalities in a rheumatoid arthritis registry. Clin Rheumatol. 2019;38(12):3401-3412. Acknowledgements: The present study was supported by the Scientific and Technological Research Council of Türkiye (TUBITAK) within the scope of the 2209-National/International Research Projects Fellowship Program for Undergraduate Students 2022/2 with grant number 1919B012218810. Disclosure of Interests: None declared.