Abstract
Background: To understand fully the economic impact of interventions designed to manage relapsing-remitting multiple sclerosis (RRMS), the impact of medication adherence on patient outcomes needs to be understood. This study examines the associations between adherence to commonly used disease modifying agents (DMAs) and employment or work disability among patients with RRMS.
Methods: We used automated medical and pharmaceutical claims data along with data from patient charts to identify eligible study participants with RRMS and their adherence to DMAs. A mixed mailed/telephone survey administered to a cohort of 224 HMO insured patients with RRMS was used to solicit information on employment status and socio-demographic characteristics. A continuous measure of medication availability (CMA) expressed as the ratio of the cumulative days supply of DMA dispensed over 365 days was constructed for the year preceding survey administration. CMA ≥80% was used to identify patients who were adherent. We used multivariable logistic regressions to examine the associations between adherence and the probability of employment or work disability. Models controlled for patient age, gender, race, and comorbidities.
Results: One hundred seventy patients responded to the survey (response rate: 76%). Our final sample was comprised of 111 patients who had been dispensed a DMA in the year preceding survey administration. Among these, 57% reported working at the time of the survey and 21% reported they were work disabled (i.e., had an impairment or a health problem that kept them from working). In the multivariable logistic model predicting employment status, being therapy adherent was associated with a greater likelihood of working (OR, 3.18; P<0.05). In the multivariable model predicting work disability, being therapy adherent was associated with a decreased likelihood of work disability (OR, 0.37; P<0.10).
Conclusions: Our findings suggest that adherence to DMAs among RRMS patients is associated with a greater probability of employment and a lesser probability of work disability. In the assessment of the cost-effectiveness of interventions to improve medication adherence, the effects on employment and work disability of medication adherence should be considered along with those of medical care costs and other outcomes.
- Received September 11, 2008.
