DMD Early Adherence as Predictor of Future Adherence

San Diego—Multiple sclerosis generally presents in young adults, resulting in a greater loss of productivity and quality of life compared with other diseases. Frequency of relapses can be reduced with use of disease-modifying drugs (DMDs), yet many patients struggle to maintain adherence to their DMD regimen. Adherence rates range from 28% to 87%, percentages that are similar to rates for medication regimens that require self-administration for other diseases.

Patients who are adherent to their DMD regimen have decreased risk of relapse, emergency department visits, severe relapse, hospitalization, neuropsychological issues, and costs, as well as increased quality of life compared to patients who are nonadherent.

To date, according to researchers, managed care organizations have utilized predictive models that rely on demographic characteristics, comorbidities, or previous consumption of healthcare resources to predict future adherence. The researchers recently conducted an analysis to evaluate early adherence with DMDs as a predictor of future adherence in patients with MS. They reported results during a poster session at the AMCP meeting. The poster was titled Early Adherence with Disease-Modifying Drugs Predicts Future Adherence in Patients with Multiple Sclerosis.

The descriptive, exploratory, retrospective pharmacy and medical claims analysis included patients with commercial healthcare coverage who were selected from the IMS LifeLink Health Plan Claims Database. Patients met inclusion criteria if they received a DMD (interferon beta-1a intramuscular, interferon beta-1a subcutaneous, interferon beta-1b, or glatiramer acetate) that was billed using a National Drug Code between January 1, 2006, and May 31, 2010. Other inclusion criteria included continuous insurance eligibility for medical and pharmacy services for 12 months before and 24 months after their index date, defined as the first DMD claim date in the pharmacy billing records from January 1, 2006, to May 31, 2010, and were ≥18 years of age and ≤63 years of age.

Adherence was calculated across all DMD therapies based on dispensing dates and days supply of medication using the proportion of days covered (PDC). It was assumed that only 1 product was used and that the product was used sequentially and the dates of use were extended if the days supply overlapped within a DMD.

In all, 4606 patients met the study criteria. Average age was 46.0 years and 78.7% were female. The patients were in 2 groups: (1) existing patients (n=2268) and (2) new patients (n=2338). Slightly greater PDC was seen in the existing cohort than in the new cohort and a greater percentage of patients in the new cohort had a non-MS hospitalization compared with the existing cohort (11.0% vs 6.5%, respectively). Depression and/or anxiety diagnoses were similar between the 2 groups and occurred in 22.8% of the sample overall.

Using the first 60 days of early adherence (with no additional variables) showed an r-squared of 20.6%, whereas using only the preperiod and demographic variables to predict adherence during the postindex year yielded an adjusted r-squared of 2.3%. Adding 60 days of early adherence data increased the r-squared to 22.4%.

In summary, the researchers stated, “Predictive models that rely only on early adherence with DMDs were able to explain the variance in future adherence outcomes to a greater extent than models based solely on baseline characteristics. Early DMD adherence offers a new and simpler model approach to predict future adherence in patients with MS.”

This study was supported by EMD Serono, Inc. and Pfizer Inc.