Tobacco differentially affects the clinical-biological phenotypes of ANCA-associated vasculitides

To describe the clinical-biological phenotype of ANCA-associated vasculitides (AAV) according to tobacco consumption.

We conducted a descriptive study to describe that phenotype at diagnosis according to tobacco use. AAV patients entered in the French Vasculitis Study Group database with data on smoking habits were analysed. The clinical-biological phenotypes at diagnosis were compared according to current tobacco use (current smokers) or not (including previous and never smokers).

AAV diagnoses were: granulomatosis with polyangiitis (GPA) for 583 (50%), eosinophilic granulomatosis with polyangiitis (EGPA) for 326 (28%) and microscopic polyangiitis (MPA) for 256 (22%). Among them, 973 patients (84%) never smoked, 116 (10%) were previous smokers and only 76 (6%) were current smokers. Current smokers were younger age (p=0.01), male gender (p=0.004), less frequently EGPA (p=0.017) and MPA (p=0.036), and had less frequent kidney involvement (p=0.10). Among GPA patients, current smokers, compared to non-current smokers, were younger age (p=0.02), male gender (p=0.08), more frequent skin involvement (p=0.03) and less frequent ENT involvement (p=0.06). Among EGPA patients, current smokers, compared to non-current smokers, were also younger (p=0.028) and had less frequent constitutional symptoms (p=0.02), arthralgias (p=0.04), renal involvement (p=0.025) and MPO-ANCA (p=0.02). Finally, analysis of MPA patients was impossible because only 6 (2%) were current smokers.

These results suggest that tobacco use could differentially affect GPA and EGPA clinical-biological phenotypes, and support the role of environmental exposures in AAV development and its phenotype.