Migraine treatment and work absence trends before and after introduction of calcitonin gene-related peptide monoclonal antibodies (CGRP mAbs): A nationwide Swedish register study

Aim Calcitonin gene-related peptide monoclonal antibodies (CGRP mAbs) are an important new preventative medication class for migraine treatment. While clinical efficacy of CGRP mAbs is well established, less is known about their impact on treatment patterns and work absence. This study examined migraine treatment and work absence patterns before and after CGRP mAbs were reimbursed in 2019 in Sweden. Methods We conducted a nationwide non-interventional observational study using Swedish administrative data. Patients with a hospital diagnosis of migraine between 2015 and 2021 were included and split into three cohorts based on the year of their diagnosis: 2015–2016, 2017–2018 and 2019–2021. We assessed time to new treatments after diagnosis using inverse probability weights to adjust for baseline differences. Work absence due to sick leave and disability was assessed via a two-part regression model of the estimated probability of any work absence and the average number of absence days conditional on non-zero absence days in the year following diagnosis. Results In total, 40,247 patients were included. The proportion dispensed a new preventative treatment after diagnosis rose from 16.2% in the 2015–2016 cohort to 22.4% in the 2019–2021 cohort. Patients diagnosed in 2019–2021 initiated more new preventative treatments compared to earlier cohorts. CGRP mAbs composed a substantial part of the treatment landscape for those diagnosed in 2019–2021, with 9.2% of patients receiving them as the first new treatment after diagnosis. The regression models showed a lower probability of work absence in the 2019–2021 cohort compared to the earlier cohorts, however the total number of absence days conditional on non-zero days varied across the study cohorts. Conclusions After market entry of CGRP mAbs, newly diagnosed patients with migraine initiated and cycled through preventative migraine medications more rapidly than those diagnosed in earlier years. These changes were accompanied by a modest decline in the probability of work absence. Faster cycling through preventative medication after the entry of CGRP mAbs in Sweden may indicate that patients and physicians want to start CGRP mAb treatment as early as possible.