Relationship Between Adherence for Multiple Sclerosis Medications and Health Care Costs
Medication adherence has been shown to be associated with lower medical and overall healthcare cost in some chronic diseases such as hypertension and high cholesterol disease.
The purpose of this research is to observe patients taking specialty medications for multiple sclerosis (MS) and determine if patients adherent to their MS drugs have lower medical and/or overall healthcare costs than MS patients who are non-adherent.
Retrospective analysis using data from commercial claims files from Truven Health Analytics Marketscan® Databases from 2012 and 2013. Patients with an index MS drug claim in the last 6 months of 2012 and at least one ICD-9 code for MS in the 180 days prior to the first claim were included. Patients also had to be continuously enrolled in the 6 months prior to and 12 months after the index date. Outcome variables include MS medication costs and related medical and overall healthcare costs in 365 days following the index date. Multivariate modeling included independent variables such as MS medication adherence, as measured by the proportion of days covered (PDC), and other patient level factors that may influence outcomes. Adherence was categorized into the ranges 1-19%, 20-39%, 40-59%, 60-79%, and 80-100%.
The final sample for the analysis consisted of 15,298 patients that met all inclusion criteria. The number of patients in each of the adherence categories (1-19%, 20-39%, 40-59%, 60-79%, and 80-100%) was 202, 820, 1,295, 2,348, and 10,633 respectively. Average patient cost for medications in each category were $11,248, $18,820, $30,750, $43,291, and $58,301 respectively. Adjusted MS related medical costs for each category were $23,253, $20,486, $20,266, $18,063, and $17,814 respectively. MS medication and medical costs contributed to an adjusted overall MS related healthcare cost for each adherence category of $34,501, $39,306, $51,016, $61,354, and $76,115 respectively.
Increased adherence to MS medications was found to be associated with a decrease in adjusted MS related medical costs. And while total health care costs increased with adherence (due to the fact that decreases in medical costs were not enough to offset the increase in MS prescription medication costs), it is imperative for patients to maintain appropriate levels of medication adherence in order to manage their MS disease progression and severity.