Background Studies have suggested a higher risk of cardiovascular (CVD) in patients with ankylosing spondylitis (AS). The increased risk of CVD cannot be explained by traditional risk factors alone and this study evaluated the influence of disease activity on CVD risk.
Objectives To compare prevalence of established CVD between a cohort of AS patients, dichotomized according to levels of disease activity, and a population control group. Secondly we compared levels of Augmentation Index (AIx), a surrogate marker of CVD risk across the same groups
Methods In 2008-2010 159 patients with AS and 134 controls from the Oslo area were examined. The AS cohort comprise hospital-recruited patients diagnosed according to the mNew York classification criteria. The control population was randomly selected by Statistics Norway. CVD was recorded based on interview with a cardiolgist. AIx estimation, measuring arterial stiffness, was performed using a Sphygmocor apparatus. Disease activity was measured by the AS disease activity score (ASDAS) including 4 patient reported questions and CRP. The ASDAS cut-off was set at 2.1 dividing patients into low-moderate and high-very high disease activity. Statistical analyses were performed with SPSS 17.0 using bivariate tests as appropriate. Validity of the results was confirmed in logistical and linear regression models adjusted for age, gender and smoking habits.
Results The groups were comparable regarding demographic data (AS vs controls): age (50.0 vs 52.7 p=0.17), gender/male (61.6% vs 58.2% p=0.55) and current smoking (18.9% vs 22.6% p=0.44). Acute phase reactants were as expected elevated in AS vs controls (ESR median:16 vs 8, p<0.001 and CRP median:3 vs 1, p<0.001). Total cholesterol was significantly lower in the AS group compared to controls: (mean±SD) 5.42±1.12mmol/l vs 5.75±0.96mmol/l p=0.009. Odds ratio for CVD was 3.3 (CI: 1.1-9.6) p=0.03 in high-very high ASDAS groups compared to controls. AIx was significantly higher in the high-very high ASDAS groupscompared to controls: 20.2 (CI 18.1-22.3) vs 17 (CI 15.7-18.8), p=0.002. The subgroup analyses are presented in Figure 1.
Conclusions We found significantly higher odds ratio (OR) for established CVD among patients with active AS despite the total AS group having significantly lower total cholesterol. The increased risk of CVD was further confirmed by a significantly increased AIx in patients with high ASDAS.
Disclosure of Interest I. J. Berg Consultant for: MSD, A. G. Semb: None Declared, S. Provan: None Declared, H. Dagfinrud: None Declared, D. van der Heijde: None Declared, T. Kvien: None Declared