Healthcare Costs for Treating Relapsing Multiple Sclerosis and the Risk of Progression: A Retrospective Italian Cohort Study from 2001 to 2015

Abstract

Background: Disease modifying treatments (DMTs) are the main responsible for direct medical costs in multiple sclerosis (MS). The current investigation aims at evaluating possible associations between healthcare costs for treating relapsing remitting MS (RRMS) and disease evolution.

Methods: The present cohort study retrospectively included 544 newly diagnosed RRMS patients, prospectively followed up for 10.1±3.3 years. Costs for DMT administration and management were calculated for each year of observation. Following clinical endpoints were recorded: time to first relapse, 1-point EDSS progression, reaching of EDSS 4.0, reaching of EDSS 6.0, and conversion to secondary progressive MS (SP). Covariates for statistical analyses were age, gender, disease duration and EDSS at diagnosis.

Results: At time varying Cox regression models, 10% increase in annual healthcare costs was associated with 1.1% reduction in 1-point EDSS progression (HR = 0.897; p = 0.018), with 0.7% reduction in reaching EDSS 6.0 (HR = 0.925; p = 0.030), and with 1.0% reduction in SP conversion (HR = 0.902; p = 0.006).

Conclusion: Higher healthcare costs for treating MS have been associated with a milder disease evolution after 10 years, with possible reduction of long-term non-medical direct and indirect costs.

Fig 1. Patient disposition flow diagram.

Patient disposition flow diagram showing patients included, excluded or lost-to-follow-up within the study cohort. MS: Multiple Sclerosis; RRMS: Relapsing-Remitting Multiple Sclerosis.

Fig 2. Kaplan-Meier curves for the probability of relapse occurrence, of 1-point EDSS progression, of reaching of EDSS 4.0, of reaching of EDSS 6.0, and of SP conversion, in relation to annual healthcare costs before the specific study endpoint was reached.

Kaplan-Meier plots estimating the probability of relapse occurrence (A), of experiencing 1-point EDSS progression (B), of reaching of EDSS 4.0 (C), of reaching of EDSS 6.0 (D), and of SP conversion (E), in relation to the annual healthcare costs before the specific study endpoint was reached. P-values and hazard ratios (HR) are shown from time varying Cox regression models. For graphical purposes, healthcare costs have been categorized on the median value (the red line represents costs lower than the median value, whereas the blue line represents costs higher than the median value). EDSS: Expanded Disability Status Scale; HR: Hazard Ratio.

Fig 3. Scatter plot for overall annual healthcare costs and relapses.

Scatter plot showing the relationship between overall annual healthcare costs and the ARR. P-value and coefficient from Poisson regression analysis are shown; 95% confidence intervals are represented in grey shadow. ARR: Annualised Relapse Rate; Coef: Coefficient.