Healthcare resource utilization following switch or discontinuation in multiple sclerosis patients on disease modifying drugs

Abstract

Objective: The objective of this study was to explore the cost and utilization in the period following discontinuations or switches of disease modifying drugs (DMDs) for patients with multiple sclerosis (MS). Secondary objectives included an assessment of the time to switch or discontinuation from index DMD treatment.

Methods: Cases were defined as a billed MS diagnosis in continuously enrolled patients initiated with interferon-beta1a IM, interferon-beta1b SC, glatiramer acetate, and interferon-beta1a SC found in the PharMetrics Patient-Centric Database. Information on patient demographics, diagnoses, procedures, pharmacy-dispensed drugs, and costs was extracted; reasons for discontinuation and expenses outside of the healthcare system were not available. Treatment discontinuations and switches between study drugs were defined using pharmacy prescription patterns and analyzed by descriptive and regression methods. The non-pharmacy medical costs in the 18 months following switching or discontinuation were compared to the costs in a randomly selected similar period for those patients who did not switch or discontinue these agents.

Results: A total of 5,772 MS patients were continuously enrolled and were treated with one or more of the four drugs of interest, and about half of these patients switched drugs or discontinued treatment for at least 90 days. Patients initiated with interferon-beta1b SC were more likely to discontinue treatment compared to interferon-beta1a IM users. Non-pharmaceutical medical costs were highest for those switching treatments followed by those discontinuing DMDs in the 18 months following a switch or discontinuation, compared to persistent users of these drugs. Interferon beta1b SC initiators had higher costs following changes or discontinuations, while glatiramer acetate and interferon-beta1a SC users had lower subsequent costs compared to interferon-beta1a IM users.

Limitations: Unfortunately, the reasons for stopping the initial treatment cannot be determined from analysis of an administrative claims database. Also, the MS cases followed in this analysis are billing diagnostic events unconfirmed through a review of medical records or other data sources. The results are unstratified in terms of severity and thus while treatment patterns may vary for patients with different types of MS (e.g., progressive vs. relapsing-remitting), this cannot be examined in this analysis.

Conclusion: Changing or discontinuing DMDs is common among MS patients and is associated with higher non-pharmaceutical medical costs that vary based on the initiating drug and other demographics characteristics.