The impact of smoking on response to tumor necrosis factor-α inhibitor treatment in patients with ankylosing spondylitis.

BACKGROUND

To investigate the impact of smoking on disease activity, treatment retention, and response in patients with ankylosing spondylitis (AS) treated with their first tumor necrosis factor-α inhibitor (TNFi).

METHODS

AS patients who started their first TNFi treatment for the active axial disease (BASDAI ≥ 4) from TURKBIO Registry were included. Treatment response of smoker (current and ex-smokers) and nonsmoker (never smoker) patients were primarily evaluated as achievement of BASDAI50 or improvement in BASDAI at least 20 mm at 3 months and 6 months compared to baseline.

RESULTS

There were 322 patients with AS (60% male, 59% smoker, mean age: 38.3 years). The median follow-up time was 2.8 years (Q1- Q3: 1.3-3.8), and disease duration was 3.5 years (Q1-Q3: 0.7-8.2). Smokers had male predominance (p < 0.001), lower ESR (p = 0.03), higher BASDAI (p = 0.02), BASFI (p = 0.05), HAQ-AS (p = 0.007), and ASDAS-CRP (p = 0.04) compared with nonsmokers at baseline. In the multivariate analysis, male gender [OR 2.7 (95%CI 1.4-5), p = 0.002], and concomitant conventional synthetic disease-modifying antirheumatic drug use [OR 2.4 (95%CI 1.1-5.2), p = 0.03] were associated with better treatment response. There was an association of male gender [HR 2.4 (95%CI 1.6-3.7), p < 0.001], older age (≥30years) [HR 1.8 (95%CI 1.1-2.8), p = 0.01], and response to treatment [HR 1.8 (95%CI 1.2-2.9), p = 0.008] with better treatment retention. No impact of smoking status was found on treatment retention and response in univariate and multivariate analyses.

DISCUSSION: This study suggested that smoking was associated with poorer patient-reported outcomes in biologic naïve AS patients initiating their first TNFi treatment, but it had no impact on the TNFi treatment response and retention rate.