Patient characteristics and exposure assessment
A total of 422 consecutive RA patients were enrolled; mean age was 58.2 years and mean disease duration was 16.1 years. The other demographic data and disease characteristics are reported in Table 1. RA patients were stratified in three subgroups according to their ongoing treatment: 1) 25 subjects without an ongoing DMARDs (e.g. drug washout for side effects or comorbidities, long-standing remission, or programmed therapy switch); 2) 108 treated with csDMARDs; 3) 289 patients treated with b/tsDMARDs. Based on the main demographic and clinical characteristics, the three groups were similar, except for smoking habits and positivity for RF and/or ACPA that were higher in the b/tsDMARDs group. Disease activity indexes were similar in the 3 groups, except for PhGA (p=0.05) and TJC (p=0.036) that were higher in patients with no therapy.
Daily concentrations of PM10, PM2.5, O3 and NO2 at patients’ municipality are reported in Supplementary Table S1-S4. A map representation of the four pollutants is reported in figure 1. Each map reports the mean value, over the entire study period, for each municipality, and the subjects of the study georeferenced to their residential address.