BACKGROUND: Poor adherence to treatment is difficult to diagnose accurately. Hydroxychloroquine (HCQ) has a long elimination half-life and its concentration in whole blood can be measured easily. OBJECTIVE: To evaluate the utility of a very low blood HCQ concentration as a marker of poor compliance in patients with systemic lupus erythematosus (SLE). METHODS: HCQ concentrations were determined on a blinded basis in 203 unselected patients with SLE. At the end of the study, the patients were informed of the results and retrospectively interviewed about their adherence to treatment. RESULTS: 14 (7%) patients said that they had stopped taking HCQ (n = 8) or had taken it no more than once or twice a week (n = 6). Their mean (SD) HCQ concentration was 26 (46) ng/ml. range (0-129 ng/ml) By contrast, the other patients had a mean HCQ concentration of 1079 ng/ml range (205-2629 ng/ml). The principal barriers to adherence were related to HCQ treatment characteristics. Adherence subsequently improved in 10 of the 12 patients whose blood HCQ concentrations were remeasured. CONCLUSIONS: Very low whole-blood HCQ concentrations are an objective marker of prolonged poor compliance in patients with SLE. Regular drug assays might help doctors in detect non-compliance and serve as a basis for counselling and supporting these patients.
BACKGROUND: Poor adherence to treatment is difficult to diagnose accurately. Hydroxychloroquine (HCQ) has a long elimination half-life and its concentration in whole blood can be measured easily. OBJECTIVE: To evaluate the utility of a very low blood HCQ concentration as a marker of poor compliance in patients with systemic lupus erythematosus (SLE). METHODS:HCQ concentrations were determined on a blinded basis in 203 unselected patients with SLE. At the end of the study, the patients were informed of the results and retrospectively interviewed about their adherence to treatment. RESULTS: 14 (7%) patients said that they had stopped taking HCQ (n = 8) or had taken it no more than once or twice a week (n = 6). Their mean (SD) HCQ concentration was 26 (46) ng/ml. range (0-129 ng/ml) By contrast, the other patients had a mean HCQ concentration of 1079 ng/ml range (205-2629 ng/ml). The principal barriers to adherence were related to HCQ treatment characteristics. Adherence subsequently improved in 10 of the 12 patients whose blood HCQ concentrations were remeasured. CONCLUSIONS: Very low whole-blood HCQ concentrations are an objective marker of prolonged poor compliance in patients with SLE. Regular drug assays might help doctors in detect non-compliance and serve as a basis for counselling and supporting these patients.
Authors: América G Uribe; Graciela S Alarcón; Martha L Sanchez; Gerald McGwin; Robert Sandoval; Barri J Fessler; Holly M Bastian; Alan W Friedman; Bruce A Baethge; John D Reveille Journal: Arthritis Rheum Date: 2004-04-15
Authors: Daniel J Wallace; Vineet S Gudsoorkar; Michael H Weisman; Swamy R Venuturupalli Journal: Nat Rev Rheumatol Date: 2012-07-17 Impact factor: 20.543
Authors: Stephen J Balevic; Michael Cohen-Wolkowiez; Amanda M Eudy; Thomas P Green; Laura E Schanberg; Megan E B Clowse Journal: J Rheumatol Date: 2018-10-01 Impact factor: 4.666
Authors: Jacob H Rand; Xiao-Xuan Wu; Anthony S Quinn; Anthony W Ashton; Pojen P Chen; James J Hathcock; Harry A M Andree; Douglas J Taatjes Journal: Blood Date: 2009-11-30 Impact factor: 22.113
Authors: Jacob H Rand; Xiao-Xuan Wu; Anthony S Quinn; Pojen P Chen; James J Hathcock; Douglas J Taatjes Journal: Blood Date: 2008-06-24 Impact factor: 22.113