Association of socioeconomic status with adherence to oral agents in patients with multiple myeloma.

Abstract

8023 Background: The introduction of novel oral immunomodulatory drugs has improved the overall survival rates of patients with multiple myeloma (MM). Poor adherence to oral therapies may lead to drug resistance, poor response to treatment and other downstream effects. It is unknown if socioeconomic status (SES) mediates adherence to oral MM agents. Methods: This is a retrospective review of newly diagnosed adult patients with MM with drug coverage through a large pharmacy benefit manager (PBM) who received oral MM agents between September 1, 2016 and September 1, 2020. Patients were excluded if they were not eligible for PBM benefits for the 6 months prior to or the 12 months after the index date and if they had a stem cell transplant based on a proxy signal. Adherence was defined as an annual medication possession ratio between 0.8 and 1.2. An SES composite index was developed using ZIP code level factors in a K-means clustering algorithm. Multivariable logistic regression for adherence was conducted using the SES-index and controlled for other patient-specific demographics. Results: In total, 6,602 patients were enrolled in the study, of which, 4,211 (64.5%) were defined as adherent. There were significant unadjusted differences in age (67.89 vs 64.06, p<0.00001), ZIP code-based SES index (p=0.00049), census region (p<0.00001) and insurance plan type (p<0.00001). Results from multivariable logistic regression are shown in table. Patients residing in Very Low SES ZIP codes were significantly less likely to be adherent to oral MM agents compared to those residing in Very High SES locations. Odds of adherence increased as patient’s age increased. Increasing polypharmacy was negatively associated with oral MM agent adherence. Conclusions: Aside from patients residing in Very Low SES ZIP codes, ZIP code-based SES measures were not associated with worse adherence. Other mediating factors include younger age and number of co-prescribed medications. Further investigations of adherence to oral MM agents with clinically relevant outcomes are warranted. [Table: see text]