Asthma burden according to treatment steps in the French population-based cohort CONSTANCES

International audienceBackground: Data on health care consumption and costs of asthma in the French population are scarce.Objectives: The study objective was to describe the burden of asthma according to GINA treatment steps in the CONSTANCES cohort. Methods: Data from 162,725 participants included between 2012 and 2019 were extracted. Participants were considered as current asthmatics if asthma was reported at inclusion and asthma symptoms and/or treatments were reported in 2019. Participants were classified in three categories according to GINA treatment steps. The results were compared to non-asthmatic participants matched with a propensity score calculated on age, sex, region of residence, precariousness score and year of inclusion.Results: Among 162,725 participants aged 18–69 years, 6783 asthmatics (1566 not treated for asthma, 2444 + 251 GINA steps 1 + 2, 1054 + 1315 GINA steps 3 + 4, and 153 GINA step 5) were matched with 6783 controls. Average annual ambulatory cost and average annual hospitalization cost were respectively €1925 and €719 for asthmatics versus €1376 and €511 for participants without asthma (p < 0,0001). Cardiovascular risk factors, co-morbidities, visits and hospitalizations were higher for asthma participants as compared to controls and increased with GINA steps, as well as inpatient and outpatient costs. However, for cardiovascular risk factors and co-morbidities, differences were non-significant in multivariate analyses. Pharmacy costs were ten times higher for GINA step 5 participants than for GINA steps 1–2 participants: €3187 versus €393 (p < 0,0001).Conclusion: mean cost of asthma was estimated at €757 per patient/year and increased with GINA treatment step