Background/Purpose:   Lack of adherence to treatment recommendations is a serious confounder to assessment of treatment efficacy for systemic lupus erythematosus (SLE). Estimates of nonadherence with medications for SLE patients range from 10%-60%.

Methods employed to assess medication adherence in the SLE population include patient self-report questionnaires, pharmacy refill record review, physician impressions of patient adherence, and therapeutic drug monitoring; however, few studies undertake a multifactorial methodology. Mycophenolate mofetil is a viable option for induction and maintenance of lupus nephritis which lacks the gonadotoxic side effects of cyclophosphamide. However, treatment adherence is a concern. This study utilized all four methods of adherence assessment to determine the most reliable predictor of adherence for SLE patients on MMF. Methods:  Adult SLE patients enrolled under the Pathogenesis and Natural History of SLE protocol receiving mycophenolate mofetil at a stable dose ranging from 0.5 grams to 1.5 grams twice daily for at least six weeks from the NIH Clinical Center Pharmacy were included in this study. Patient self-assessment of adherence was quantified using a modified Medication Adherence Self-Report Inventory (MASRI); a study tool that has been validated in SLE patients. Physicians (blinded to the patient’s MASRI scores) scored patient adherence using a Likert scale with 0 being completely noncompliant and 10 being 100 % compliant. Pharmacy refill percentage for one year or from the initial date of prescription of MMF was calculated; a refill percentage greater than 80% was considered “adherent.” As an objective measure of adherence, serum trough mycophenolic acid (MPA) levels were drawn with undetectable levels considered nonadherent. Patients were surveyed for demographic information and other mediators possibly related to low adherence.

Results:   Adherence was assessed on 30 patients; 20 patients were considered adherent by resultant detectable MPA levels. In a univariate regression model, pharmacy refill percentage had the strongest correlation with detectable MPA levels (Pearson’s Correlation r value=0.464, p-value=0.0128), while both the MASRI and the physician rating showed only modest correlations with MPA level (Pearson’s Correlation r values of 0.227 and 0.202, respectively). There was a statistically significant (p=0.0041) difference in the refill percentages, with majority of the adherent cohort (80%) having refill percentages of 80% or greater. Patients in the adherent group were slightly older, with a mean age of 40.8 (p=0.0473) and were more likely to be married (p=0.0187).

Conclusion:   Refill percentage was the best predictor of a detectable serum MPA level and patient adherence. Older age and being married also influenced adherence to the treatment regimen. Factors such as medication side effects, total number of medications prescribed, physician’s assessment of patient adherence and educational status were not found to be significant predictors of patient adherence. Future studies are needed to more completely define specific contributors to patient nonadherence to MMF in the SLE population.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/patient-adherence-with-mycophenolate-mofetil-therapy-in-a-systemic-lupus-erythematosus-cohort-a-multi-factorial-assessment/