Exercise capacity in axial spondyloarthritis and associated factors: A cross-sectional controlled study.

Objective: To examine the associations between exercise capacity (EC), cardiovascular (CV) risk factors and disease-related variables in axial spondyloarthritis (AxSpA) patients.

Methods: In this cross-sectional controlled study, CV risk profile data, physical activity, 10-year CV event risk estimated by the Framingham model and Ankylosing Spondylitis Disease Activity Score - C-reactive protein were recorded. A maximal treadmill exercise test by Bruce protocol was administered. Analyses of covariance were performed with adjustments for age, smoking status and physical activity level. Linear regression analysis was performed to study the association between EC and related CV risk factors.

Results: Thirty-eight patients and 38 age-gender matched controls were recruited between May and October 2014. Patients had significantly lower EC than controls (MD 2.2; metabolic equivalents 0.91-3.49; P = .001). The difference remained significant after adjustments (P = .001). There were significant correlations between EC and age, 10-year CV event risk, body mass index (BMI) and waist circumference for patients and controls (P < .001 and P < .05, respectively). There was a significant relationship between EC and total cholesterol, triglycerides and heart rate recovery (HRR) in patients (P = .04, P < .001 and P = .006, respectively). High-density lipoprotein - cholesterol was significantly higher, and BMI was significantly lower in nonradiographic AxSpA patients (P = .026 and P = .03 respectively). Age and triglyceride levels were found as the significant predictors for EC in the AxSpa group (for age β = -.105, P = .003; for triglycerides β = -.016 P = .003).

Conclusion: Exercise capacity was significantly lower and attenuated HRR was significantly associated with low EC and high 10-year CV event risk in AxSpA patients.