Background/Purpose: Patients with ankylosing spondylitis (AS) have a decreased life expectancy due to an increased cardiovascular risk. Cardiovascular risk factors such as smoking, dyslipidemia, overweight, male gender and hypertension are implicated in atherogenesis. However, atherogenesis is also amplified by inflammation. Anti-inflammatory treatment with tumor-necrosis factor (TNF) inhibitors decreases the incidence of cardiovascular disease, which could be due to an improvement of cardiovascular risk factors, such as atheroprotective changes in the lipid profile. Therefore, the effect of treatment with TNF inhibitors on the lipid profile in patients with AS was investigated.

Methods: We evaluated all consecutive AS patients, who fulfilled New York 1984 criteria for AS, starting either with adalimumab or etanercept at our clinic Reade, Amsterdam. A total of 107 patients started adalimumab, and 183 patients started etanercept. Clinical data and blood samples were collected at baseline, at 24 and at 52 weeks of follow-up. A response to TNF blocking therapy was defined as a decrease in C-reactive protein (CRP) levels from >10 mg/L at baseline to <10 mg/L at 24 weeks, or a decrease in erythrocyte sedimentation rate (ESR) from >20 mm/h at baseline to < 20 mm/h at 24 weeks. Systolic and diastolic blood pressure, serum glucose, CRP, ESR, total cholesterol, triglycerides, low density lipoprotein (LDL), high density lipoprotein (HDL), apolipoprotein A (ApoA) and apolipoprotein B (ApoB) were measured. The students t-test was used to calculate changes.

Results: Patients with high disease activity (CRP >10 mg/L) had decreased lipid levels compared with patients with low disease activity. Seventy-four out of 206 (35,9%) patients showed a response to anti TNF therapy within 24 weeks. Total cholesterol levels increased significantly in responding patients (figure 1). In addition,  triglycerides, HDL, LDL and ApoA levels also increased significantly. After one year of treatment this effect was still present. In non responding patients only HDL levels increased significantly after 24 weeks, but this effect disappeared  after a year.

Conclusion: In AS patients with high disease activity lipid levels are depressed to a similar extent as observed in rheumatoid arthritis. Lipid levels normalized in responding AS patients. This effect was still present after one year of therapy. Anti-inflammatory therapy with TNF-blockers normalizes lipid levels and could potentially decrease the cardiovascular risk.

Figure 1. Changes in total cholesterol levels in responding and non-responding patients (n=292).