Background Physical activity is a cornerstone in treatment of ankylosing spondylitis (AS). We have previously shown that AS patients have lower cardio-respiratory fitness (CRF) than population controls. CRF is inversely associated with cardiovascular (CV) mortality and morbidity in the general population. Patients with AS have increased risk of cardiovascular disease (CVD), but the etiology is not clear. Lower CRF may be associated with increased risk of CV in AS. Arterial stiffness is a marker of CVD, and associations between CRF and arterial stiffness has not been explored previously in patients with AS.
Objectives To evaluate associations between CRF and arterial stiffness.
Methods This is a cross-sectional study on AS patients (mNY criteria). Information on demographics and medication was assessed from questionnaires. Arterial stiffness, measured as Pulse Wave Velocity (PWV) and Augmentation Index (AIx,) was recorded using the Sphygmocor apparatus (AtCor). CRF was assessed as peak oxygen uptake (VO2peak) by a maximal walking treadmill test (modified Balke protocol). Statistics were performed using SPSS version 21. Univariate associations between lnPWV/AIx (dependent variable) and VO2peak as well as possible confounders/factors, were analyzed in separate linear regression models adjusted for age and gender. Variables with a p-value of less than 0.25 were included in a backwards multivariate linear regression models.
Results The 113 AS patients had the following characteristics: Mean (SD) age 48.4 (11.3) years, 72 (64%) males, 18 (16%) smokers, mean (SD) BMI 25.6 (3.5) (kg/m2), 73 (65%) used NSAIDs, 24 (21%) used TNF-inhibitors, 14 (12%) used statins, 28 (25%) used antihypertensive medication and median (IQR) CRP (mg/l) 3 (2-10). In regression models VO2peak was significantly inversely associated with lnPWV independent of other factors (table). Similar results were found for AIx: (beta(95%CI)) -0.33 (-0.55- -0.10), p=0.01.
Conclusions CRF measured by VO2peak was inversely associated with arterial stiffness indicating that reduced CRF can be related to increased risk for CVD in AS patients. Studies on the effect of increasing CRF on risk of CVD in AS patients are warranted.
Disclosure of Interest : None declared