Background Parenteral firstline treatments for multiple sclerosis (MS) include disease modifying therapies (DMTs): intramuscular (IM) interferon (IFN) beta-1-a, subcutaneous (SC) IFN-beta 1-a, SC IFN-beta 1-b glatiramer acetate. Long term persistence for chronic diseases is difficult for patients to achieve, and low persistence has been related to increased mortality and morbidity as well as higher costs in medical care.

Purpose The aim of this study was to analyse firstline parenteral treatment persistence in patients with MS according to the administration route.

Material and methods This was an observational, retrospective, longitudinal study. All MS adult patients starting firstline treatment with IM IFN-beta-1-a, SC IFN-beta 1-a, SC IFN-beta 1-b and glatiramer acetate from 1 September 2005 to 31 August 2015 were included. Data were collected from the pharmacy department electronic record (Farmatools). Persistence was calculated as duration of time from initiation to discontinuation of therapy and as a dichotomous variable at the first and second year of therapy. Discontinuation was defined as a gap in treatment exposure of at least 90 days. For analysis of persistence, a survival analysis with Kaplan–Meier estimator was used. The log rank test was used to compare survival times between administration routes. The influence of covariables (age, gender, treatment, compliance) was tested according to a Cox regression model. Persistence at first and second year was compared using a χ² test. Statistical analysis were performed using SPSS.

Results 176 patients were included, 67.6% women and 32.4% men. Mean age (±SD) was 36.27±11 years. Treatment distribution: 36.4% SC IFN-beta 1-a, 10.2% SC IFN-beta 1-b, 39.2% IM IFN-beta-1-a, 14.2% glatiramer acetate. Mean compliance was 93.6%±16.5%. Mean overall persistence was 2043 (95% CI 1827–2260; p=0.217). Mean persistence times were 2007 days (95% CI 1580–2927) for the IM route and 2302 days (95% CI 1799–2805) for the SC route(p=0.751). 81.2% versus 75.7% (p=0.506) of patients were persistent in the first year for the IM and SC routes, respectively, and 68.2% versus 31.8% for the second year. Cox model showed no influence of age, gender, treatment or compliance.

Conclusion There were no differences regarding persistence between IM or SC firstline therapies in MS patients.

No conflict of interest