Background Non-adherence to treatment, a major cause of continued lupus activity and flares, may be difficult to recognize.
Objectives In this international prospective study, we evaluated adherence to hydroxychloroquine (HCQ) in SLE patients with flares (NCT01509989).
Methods This study included 305 SLE patients (SLICC criteria) from 10 countries, all of whom had been prescribed HCQ for ≥2 months and were having a disease flare (SELENA-SLEDAI Flare Index). Adherence to HCQ was assessed by self-questionnaires (MASRI, Morisky), physician's assessment (VAS 0–100), and blood concentrations of HCQ and its main metabolite desethylchloroquine ([HCQ] and [DCQ]). Non-adherence was defined by MASRI <80%, Morisky<6, [HCQ] <200ng/ml and/or undetectable [DCQ].
Results 305 patients (288 women; mean age 38 ± 12ys) met the inclusion criteria. The median SLE duration was 11ys [range 1–46]; 108 patients (35%) had a history of lupus nephritis.
At enrollment, the median SELENA-SLEDAI score was 8 [2–30] and the flare was considered severe in 43%. The HCQ dosage was 400mg/d in 72%, 200mg/d in 15%, or another dosage in 13%. The median [HCQ] was 718ng/ml [0–4345]. In addition, steroids were prescribed in 76%, and immunosuppressives in 46%.
Severe non-adherence defined by [HCQ] <200ng/ml was found in 44 patients (14.4%). 12 additional patients with very low median [HCQ] of 235ng/ml [210–343] had an undetectable [DCQ] indicating a very recent resumption of treatment. Thus, 56 patients (18.4%) were objectively defined as severely non-adherent. Table 1 shows that the treating physician believed that 75% of these non-adherent patients were taking at least 50% of their prescribed HCQ dose, strongly suggesting that doctors were often unaware of non-adherence. The median VAS evaluating the adherence from the doctor's point of view was 75 [0–98] in objectively non-adherent patients vs 87 [0–100] in other patients. The doctor's opinion, therefore, was poorly informative.
Good adherence to treatment with HCQ (MASRI ≥80%) was self-reported by 77% of the patients, including by 43% of those objectively severely non-adherent.
On the other hand, the investigators felt that only 12% of patients took less than 50% of HCQ, with severe non-adherence confirmed in 39%. Conversely, while intake was estimated at ≥75% (65%), 15% of these patients were objectively severely non-adherent.
Non-adherent patients defined by self-questionnaires (MASRI<80% or Morisky <6) and/or drug blood levels, represented 47% of this cohort.
Conclusions These data demonstrate that blood HCQ and DCQ measurements objectively identify significant non-adherence to HCQ in nearly 20% of SLE patients. Non-adherence was often unrecognized by the doctor, suggesting usefulness of blood assays to more accurately determine adherence.
Disclosure of Interest None declared