Pos1513-HPR the Use of Supramaximal Verification Testing for Determining a ‘True’ Maximal Effort During Cardiopulmonary Exercise Testing in People With Rheumatoid Arthritis and Physically Inactive Non-Ra Controls

Background: A cardiopulmonary exercise test (CPET) constitutes a non-invasive and safe assessment of the interplay between the cardiovascular and pulmonary systems to supply oxygen to the exercising muscles which makes it an important tool in clinical practice. The supramaximal verification protocol with a CPET for determining a 'true' VO2max is a useful method in the general population to confirm the attainment of maximal effort. However, in patients with Rheumatoid Arthritis (RA) there is dearth of such studies. Consequently, the evaluation of exercise intolerance, disability diagnosis, response to treatment, exercise prescription, and efficacy of interventions targeted to improve VO2max may not be optimal in RA. Objectives: To investigate in people living with RA compared with non-RA controls (a) the prevalence of 'true' maximal CPETs as confirmed by a verification phase; (b) the diagnostic accuracy of the VO₂ plateau and secondary criteria [i.e., maximal values of heart rate (HR), respiratory exchange ratio (RER), and rate of perceived exertion (RPE)] for determining a 'true' maximal CPET; and (c) the safety of a combined CPET with a verification phase protocol. Methods: We recruited 85 adults for the present study: 42 were people with RA (53.5 ± 11.5 years; 27.3 ± 5.8 kg·m2; 36 females and 6 males) and 43 were non-RA controls (51.7 ± 6.3 years; 27.4 ± 5.2 kg·m2; 29 females and 14 males). All participants were physically inactive (exercising for < 30 minutes, 3 times/week or less). Participants were asked to perform a CPET protocol (modified Bruce) and, following a 20-minute recovery, a verification phase protocol (at 105% of the maximal speed and gradient at CPET). For evidence of a maximal CPET, we first investigated the presence of a plateau in VO₂, defined as a change in 15-sec averaged VO₂ ≤2.1 ml/kg/min between the last two stages. The following secondary criteria were then assessed: a) maximal heart rate (HRmax) ≥ 95% age predicted HRmax, b) maximal RER ≥ 1.15, and c) maximal RPE >18. A maximal effort was agreed to be 'verified' if the difference between the CPET and the verification phase protocol was no more than ±3%. The diagnostic accuracy of the plateau and secondary criteria during CPET to detect a 'verified' maximal effort was assessed via calculating test sensitivity, specificity, positive likelihood ratio (LH⁺), negative likelihood ratio (LH⁻), and diagnostic odds ratio (DOR). Safety was evaluated via monitoring electrocardiogram, blood pressure measurement, RPE, and acceptability (assessed via participants' self-reported willingness to proceed with the verification protocol). Results: Only 29% (n=12) of RA individuals and the 44% (n=19) of non-RA controls achieved a verified 'true' maximal CPET. On an individual level, the plateau criterion and the secondary criteria (assessed independently and combined) offered poor utility in determining whether a participant is likely to have a verified or unverified VO2max test result for both people with RA and non- RA controls (LHR+ <10 and LHR- >0.1 and DOR<20). No participant experienced any adverse effects during both CPET and verification phase or presented unwillingness to exercise further in both groups. Conclusion: Commonly used secondary criteria failed to accurately 'diagnose' a verified maximal CPET in both people with RA and physically inactive non-RA controls. Therefore, failure to use the verification phase, a safe and acceptable procedure for both of our study groups, may affect the clinical and research practice relevant to the CPET's result application either in people with RA or in physically inactive non-RA controls. REFERENCES: [1] Metsios G, Koutedakis Y, Veldhuijzen van Zanten J, Stavropoulos-Kalino glou A, Vitalis P, Duda J, et al. Cardiorespiratory fitness levels and their association with cardiovascular profile in patients with rheumatoid arthritis: a cross-sectional study. Rheumatology 2015;54(12):2215–2220. Acknowledgements: NIL. Disclosure of Interests: None declared.