AN EQUATION FOR ESTIMATED CARDIORESPIRATORY FITNESS IN RHEUMATOID ARTHRITIS PATIENTS IS NEEDED

Background: RA patients are deconditioned and on average have decreased cardiorespiratory fitness (CRF, peak oxygen uptake) compared to the general population (1). This may contribute to an increased risk of cardiovascular disease (CVD). Because CRF is associated with cardiovascular health, it is important to assess. For the general population, various equations exist for estimation of CRF (eCRF) without the need of a resource-intensive cardiopulmonary exercise test. Objectives: Compare eCRF of people without RA to eCRF of RA patients, using recognized equations for eCRF (2,3) based on gender, age, resting heart rate, waist circumference and self-reported physical activity. Methods: Among participants with self-reported RA in the second and third surveys of the Norwegian population-based Nord-Trøndelag Health Study (HUNT2 and 3)(4), RA patients were identified from hospital case files using standardized diagnostic criteria (5). The mean eCRF of participants with and without RA were calculated and the 95% confidence intervals (CI) compared. Table 1 Mean eCRF (mL/(kg x min)) and 95% CIs of RA patients and participants without RA attending HUNT2 and 3. Age categories with n<8 RA patients in grey. HUNT2 Men (no RA) Men (RA) Women (no RA) Women (RA) Mean eCRF (CI), n Mean eCRF (CI), n Mean eCRF (CI), n Mean eCRF (CI), n 30-39 years 50.3(50.2-50.5), 5,134 49.5(45.6-53.4), 8 40.3(40.2-40.4), 5,623 38.7(37.2-40.1), 25 40-49 years 46.2(46.1-46.3), 6,104 46.7(44.8-48.6), 22 36.6(36.5-36.7), 6,496 36.2(35.2-37.2), 72 50-59 years 42.2(42.0-42.3), 4,910 40.9(39.6-42.3), 50 32.9(32.8-33.1), 4,994 31.5(30.7-32.4), 75 60-69 years 38.3(38.2-38.5), 3,600 39.2(37.7-40.6), 40 29.0(28.9-29.1), 3,441 28.6(27.7-29.5), 71 70-79 years 34.7(34.5-34.9), 2,678 34.3(31.9-36.6), 20 25.3(25.2-25.5), 2,608 25.3(23.9-26.7), 32 80-89 years 30.4(30.0-30.8), 677 n=0 22.1(21.9-22.4), 871 24.0(18.1-29.9), 4 HUNT3 Men (no RA) Men (RA) Women (no RA) Women (RA) Mean eCRF (CI), n Mean eCRF (CI), n Mean eCRF (CI), n Mean eCRF (CI), n 30-39 years 46.6(46.4-46.9), 2,069 47.3(-24.5-119.0), 2 37.1(36.9-37.2), 3,189 34.7(30.8-38.5), 9 40-49 years 43.3(43.1-43.5), 3,406 46.5(10.2-82.9), 2 34.8(34.7-34.9), 4,668 34.9(32.9-36.8), 21 50-59 years 39.5(39.4-39.7), 4,153 39.5(37.4-41.5), 19 31.5(31.4-31.7), 4,994 30.2(29.1-31.4), 56 60-69 years 36.2(36.0-36.3), 3,764 33.1(31.3-34.8), 41 28.2(28.1-28.4), 4,222 27.5(26.5-28.6), 58 70-79 years 33.0(32.8-33.2), 2,149 34.3(32.4-36.1), 35 24.9(24.8-25.1), 2,284 24.4(23.2-25.5), 41 80-89 years 29.7(29.4-30.1), 708 28.3(24.5-32.0), 8 22.6(22.3-22.8), 812 22.8(21.2-24.3), 14 Conclusion: The eCRF CIs of RA patients and participants without RA were overlapping in all age categories except for men aged 60-69 years in HUNT 3 ( Table1 ). This is contradictory to previous findings where RA patients were deconditioned compared to healthy controls (1). A probable explanation is that equations for eCRF were developed from healthy populations, and therefore overestimate eCRF in RA patients. For better CVD risk management including CRF as an important risk factor, an equation for eCRF developed specifically for RA patients is needed. REFERENCES: [1] Munsterman T, et al. BMC Musculoskelet Disord. 2012;13:202. [2] Nes BM, et al. Med Sci Sports Exerc. 2014;46(6):1159-65. [3] Nauman J, et al. Mayo Clin Proc. 2017;92(2):218-27. [4] Krokstad S, et al. Int J Epidemiol. 2013;42(4):968-77. [5] Videm V, et al. J Rheumatol. 2017;44(8):1134-41 Disclosure of Interests: None declared DOI: 10.1136/annrheumdis-2019-eular.1472Citation: Ann Rheum Dis, volume 78, supplement 2, year 2019, page A689Session: Rheumatoid arthritis - comorbidity and clinical aspects (Scientific Abstracts)