Azathioprine and Mycophenolate Mofetil Adherence Patterns and Predictors Among Medicaid Beneficiaries With Systemic Lupus Erythematosus

Abstract

Objective. Azathioprine (AZA) and mycophenolate mofetil (MMF) are immunosuppressants frequently used in the treatment of moderate-to-severe systemic lupus erythematosus (SLE). We studied longitudinal patterns and predictors of adherence to AZA and MMF in a nationwide US SLE cohort.Methods. In the Medicaid Analytic eXtract (2000-2010) database, we identified patients with SLE who initiated AZA or MMF (no use in the prior 6 months) with ≥12 months of continuous follow-up. We dichotomized adherence at 80%, with ≥24 of 30 days per month considered adherent. We used group-based trajectory models to estimate monthly adherence patterns and multivariable multinomial logistic regression to determine the association between demographic, SLE and utilization-related predictors, and the odds ratios (OR) of belonging to a nonadherent versus the adherent trajectory, separately for AZA and MMF.Results. We identified 2,309 AZA initiators and 2,070 MMF initiators with SLE. Four-group trajectory models classified 17% of AZA and 21% of MMF initiators as adherent. AZA and MMF nonadherers followed similar trajectory patterns. African American race (OR 1.67 [95% confidence interval (95% CI) 1.20-2.31]) and Hispanic ethnicity (OR 1.58 [95% CI 1.06-2.35]) increased odds of AZA nonadherence; there were no significant associations between race/ ethnicity and MMF nonadherence. Male sex and polypharmacy were associated with lower odds of nonadherence to both medications; lupus nephritis was associated with lower odds of nonadherence to MMF (OR 0.74 [95% CI 0.55-0.99]).Conclusion. Adherence to AZA or MMF over the first year of use was rare. Race, sex, and lupus nephritis were modestly associated with adherence, but the magnitude, direction, and significance of predictors differed by medication, suggesting the complexity of predicting adherence behavior.

Area‐Level Predictors of Medication Nonadherence Among US Medicaid Beneficiaries With Lupus: A Multilevel Study

“…In this vulnerable population of patients with SLE among whom only 15% were adherent to HCQ treatment over the first year of use, we observed significant relationships between individual and contextual factors and adherence. Although it is challenging to compare across studies given differences in populations (e.g., academic‐based cohorts versus public insurance beneficiaries) and in adherence measures (e.g., self‐reported surveys versus claims‐based prescription refill data), our findings were similar to estimates of adherence to other SLE‐related medications in the Medicaid population (). In line with prior studies, younger age, black race, Hispanic ethnicity, and antidepressant use were associated with poorer adherence ().…”

Dynamic patterns and predictors of hydroxychloroquine nonadherence among Medicaid beneficiaries with systemic lupus erythematosus

“…In order to investigate whether patterns of adherence are distinct by drug, we have separately used group-based trajectory models to examine adherence to azathioprine and mycophenolate mofetil also within the Medicaid SLE population. (39) Interestingly, while we similarly noted poor nonadherence to both drugs with fewer than 20% of individuals characterized as adherent to either drug, we found that each drug had a pattern of adherence that differed from that of HCQ. While both drugs had subsets of the population who were persistent adherers and persistent nonadherers, the paths of the intermediate nonadherers were distinct.…”

Real-world treatment patterns, healthcare resource utilisation and costs in patients with systemic lupus erythematosus treated with belimumab: a retrospective analysis of claims data in the USA

“…A literature review of medication utilisation in SLE found the percentage of non-adherent patients ranged from 43% to 75%, with studies consistently reporting that >50% of patients were non-adherent 28. Studies of specific SLE treatments, many of which are considered the cornerstone of SLE treatment (hydroxychloroquine, azathioprine, mycophenolate mofetil and immunosuppressive medications), have also consistently shown adherence rates of <25% and medication possession ratios well below the accepted threshold of 80% 29–32. Adherence may have been suboptimal due to hospitalisation as belimumab treatment may have been suspended.…”