Feldman CH, Collins J, Zhang Z, et al. - A total of 2,309 azathioprine (AZA) initiators and 2,070 mycophenolate mofetil (MMF) initiators with SLE were recognized in order to examine longitudinal patterns and predictors of adherence to AZA and MMF in a nationwide US SLE cohort. Four-group trajectory models classified 17% and 21% of AZA and MMF initiators as adherent, respectively. AZA and MMF nonadherers followed comparable trajectory patterns. African American race and Hispanic ethnicity raised odds of AZA nonadherence and no important relationships between race/ethnicity and MMF nonadherence were found. Male gender and polypharmacy were related to lower odds of nonadherence to both medications and lupus nephritis was correlated with lower odds of nonadherence to MMF. In conclusion, over the first year of use, adherence to AZA or MMF was rare. Race, gender, and lupus nephritis were moderately related to adherence, however, the magnitude, direction, and importance of predictors varied by medication, implying the difficulty in prognosticating adherence behavior.