Impaired cardiorespiratory fitness in psoriatic arthritis: insights from cardiopulmonary exercise testing

Data on cardiorespiratory fitness (CRF) in psoriatic arthritis (PsA) are scarce. This study aimed to determine the CRF level in patients with PsA and to examine the relation between CRF and disease parameters, cardiometabolic risk profile as well as patient-reported outcome measures (PROMs).

In this cross-sectional study, CRF was measured as peak oxygen uptake (VO₂peak) during an incremental maximal cardiopulmonary exercise test and compared with reference charts of the general population using the one-sided t-test. Multivariable linear regression models were built to evaluate the associations between VO₂peak (mL/min/kg, log-transformed) and disease parameters, cardiometabolic risk parameters and PROMs. Statistical significance was defined as p<0.05 with application of Holm-Bonferroni correction in regression analysis (expressed as p*).

In 80 patients with PsA (41% females, mean age 51 years (SD=11)), mean VO₂peak was 26.03 mL/min/kg (SD=7.56) and significantly decreased compared with the physically active reference population (mean 74.01% (SD=19.19), p<0.001) with 41% having an impaired CRF. In the final multivariable linear regression model, adjusted for age and sex, disease activity (Psoriatic Arthritis Disease Activity Score: β=-0.2757, p*=0.009), waist-hip ratio (β=-0.4193, p*<0.001), patient-reported disease impact (Psoriatic Arthritis Impact of Disease 12-item questionnaire: β=-0.2385, p*=0.015), and moderate-to-vigorous physical activity during commuting and leisure time (minutes/week: β=0.1702, p*=0.015) were significantly associated with VO₂peak (adjusted R²=0.71).

The CRF level of patients with PsA was significantly decreased compared to a physically active population with 41% having an impaired CRF. A lower CRF level was substantially associated with impaired disease control, unfavourable body composition, lower self-reported physical activity as well as with higher patient-reported disease impact.