A prospective international study on adherence to treatment in 305 patients with flaring SLE: assessment by drug levels and by self-administered questionnaires

摘要

Nonadherence to treatment is a major cause of lupus flares. Hydroxychloroquine (HCQ), a major medication in systemic lupus erythematosus, has a long half-life and can be quantified by HPLC.This international study evaluated nonadherence in 305 lupus patients with flares using drug levels (HCQ<200ng/ml or undetectable desethylchloroquine), and self-administered questionnaires (MASRI<80% or MMAS-8<6).Drug levels defined 18.4% of the patients as severely nonadherent. In multivariate analyses, younger age, non-use of steroids, higher BMI and unemployment were associated with nonadherence by drug level. Questionnaires classified 39.9% of patients as nonadherent. Correlations between adherence measured by questionnaires, drug level, and physician assessment were moderate.Both methods probably measured two different patterns of nonadherence: self-administered questionnaires mostly captured relatively infrequently missed tablets, while drug levels identified severe nonadherence (i.e., interruption or erratic tablet intake). The frequency with which physicians miss nonadherence, together with under-reporting by patients, suggests that therapeutic drug monitoring is useful in this setting.>Trial registration: :