Environmental Air Pollution Is a Predictor of Poor Response to Biological Drugs in Chronic Inflammatory Arthritides

BACKGROUND: There is increasing evidence that environmental air pollution is associated with the development of chronic inflammatory arthritides (CIA). The role of air pollutants on the biological treatment (biological disease‐modifying antirheumatic drugs [bDMARDs]) response of CIA is still unclear. METHODS: We retrieved longitudinal data on patients affected by CIA on biological therapies and on the daily concentration of air pollutants in the Verona area. We designed a case‐crossover study to compare the exposure to pollutants in the 60‐day period preceding a drug switch or swap due to disease progression referent to the 60‐day period preceding a visit with stable treatment for at least 6 months. RESULTS: A total of 1257 patients with CIA (863 with rheumatoid arthritis, 256 with psoriatic arthritis, and 138 with ankylosing spondylitis) with 5454 follow‐up visits were included in the study (median follow‐up 2.09 years [interquartile range: 0.82‐2.58 years]). A total of 282 patients were included in the case‐crossover study. We retrieved 13 636 daily air pollution records. We found that air pollutants’ concentrations were higher in the 60‐day period before a failure of bDMARD response and prior to a switch or swap compared with the period preceding a visit with stable bDMARD therapy for at least 6 months. CONCLUSION: We found that environmental air pollution was a determinant of poor response to bDMARDs in a cohort of patients with CIA followed over a 5‐year period. An intervention aimed at decreasing fossil combustion emissions might have beneficial effects on biologic persistence rates of patients with CIA and economic expenditures related to switches and swaps.