The relationship between lifestyle factors and outcome of treatment with TNFα inhibitors in axial spondyloarthritis - results from 14 European countries

To quantify the influence of lifestyle factors on tumour necrosis factor inhibitor (TNFi) treatment response, in axial spondyloarthritis (axSpA). Data on biologics-naïve adults with axSpA were captured from European rheumatology registries. Information on lifestyle factors (smoking, overweight/obesity, and/or alcohol consumption) were identified ± 30 days of commencing their first TNFi. Treatment response (BASDAI-50, ASDAS or ASAS response criteria) was determined at 3 and 12 months. In separate models, the relationship between treatment response and baseline smoking, BMI and alcohol was assessed using logistic regression, adjusted for age, sex, country, calendar year of treatment initiation, disease duration and baseline disease activity. From 14 registries, 14,885 patients were included. Of those with available data, 29% were current smokers, 49% current drinkers, 37% were overweight and 21% were obese. At 12 months, smokers were less likely to achieve BASDAI-50 treatment response compared to non-smokers (adjusted odds ratio: 0.77; 95%CI: 0.68-0.86). A similar effect was observed among overweight (0.76; 0.66-0.87) or obese patients (0.53; 0.45-0.63). In contrast, alcohol drinkers experienced a seemingly beneficial effect (1.47; 1.16-1.87). These associations were also observed with other measures of treatment response and were robust to further adjustment for clinical characteristics. Smoking and high BMI decrease the odds of bDMARD treatment success in axSpA. Rheumatologists should consider referral to smoking cessation and/or weight management interventions at the time of commencing therapy, to enhance treatment response. The relationship between alcohol and treatment response is unlikely to be causal and warrants further investigation. What is already known about this subject? It has been shown that adverse lifestyle factors (smoking, high body mass index, alcohol consumption) are associated with poorer outcomes in axial spondyloarthritis, but there are no robust estimates that quantify the impact on anti-TNF treatment response. What does this study add? Our findings, pooling data from 14 national registries, demonstrate that patients who smoke experience a 20–25% decrease in the likelihood of meeting treatment response criteria, 12 months after commencing their first TNF inhibitor, an effect that was consistent across multiple outcome measures. Overweight/obese patients experience a 50% decrease in the odds of meeting such treatment criteria. For alcohol consumption, results were reversed, with current alcohol-users more likely to experience positive outcomes. This result was not supported by sensitivity analysis imputing missing values, and thus warrants further investigation. How might this impact on clinical practice or future developments? This paper quantifies the deleterious effect of smoking and obesity on the likelihood of treatment response in axial spondyloarthritis. As an adjunct to pharmacological management, lifestyle interventions might be considered as a way of optimising patient outcomes.