Persistence, adherence, healthcare resource utilisation and costs for interferon Beta in multiple sclerosis: a population-based study in the Campania region (southern Italy)

BackgroundTo differentiate five formulations of Interferon Beta for the treatment of multiple sclerosis (MS) in clinical practice, by analysing persistence, adherence, healthcare resource utilisation and costs at population level.MethodsIn this population-based study, we included individuals with MS living in the Campania Region of Italy from 2015 to 2017, on treatment with intramuscular Interferon Beta-1a (Avonex (R) =618), subcutaneous pegylated Interferon Beta-1a (Plegridy (R) =259), subcutaneous Interferon Beta-1a (Rebif (R) =1220), and subcutaneous Interferon Beta-1b (Betaferon (R) =348; and Extavia (R) =69). We recorded healthcare resource utilisation from administrative databases (hospital discharges, drug prescriptions, MS-related outpatients), and derived costs from the Regional formulary. We classified hospital admissions into MS-related and non-MS-related. Persistence (time to switch to other disease modifying treatments (DMTs)), and adherence (medication possession ratio (MPR)=medication supply obtained/medication supply expected during follow-up period) were calculated.ResultsPatients treated with Rebif (R) were younger, when compared with other Interferon Beta formulations (p