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High SLE disease activity linked to hydroxychloroquine nonadherence, improves with counseling
Patients with systemic lupus erythematosus who had low blood levels of prescribed hydroxychloroquine were more likely to have high disease activity, but counseling and ongoing blood tests improved adherence, according to recently published research.
Researchers studied 686 patients with systemic lupus erythematosus (SLE) enrolled in the Hopkins Lupus Cohort with over 2,400 recorded physician visits. A single blood level check for hydroxychloroquine was taken from 138 patients; 357 (52%) had levels checked between two and four times and 191(28%) were seen from five to 12 times. Patients were 92% women, 49% white, 42% black and 9% other ethnicities.
Nonadherence was defined as hydroxychloroquine levels below 15 mg/mL, subtherapeutic or partially adherent were defined by levels of 15 to 500 ng/mL, a therapeutic dose was defined as levels between 500 and 2,000 ng/mL and levels above 2,000 were considered to be supratherapeutic.
At baseline, 304 patients (44%) had subtherapeutic levels of hydroxychloroquine, including 88 patients with 15 ng/mL or lower. Sixteen patients had supratherapeutic levels despite weight-based dosing.
Men (71%) were more likely to have therapeutic levels compared to women (52%), and patients under 30 years or over 60 years were more likely to have levels in the therapeutic range. No differences were associated with income level or education.
Of six patients with renal failure, one had levels of hydroxychloroquine in the therapeutic range and one patients had a supratherapeutic level. Subtherapeutic levels were observed in 60% of patients with renal impairment.
No differences were seen based on disease activity, Physician’s Global Assessment while a statistically significant negative association was observed with hydroxychloroquine levels and the SLE Disease Activity Index (SLEDAI) score.
More than half (52%) of patients had vitamin D levels below 40 ng/mL, and lower levels of hydroxychloroquine were detected in those patients.
The proportion of patients who had therapeutic levels of hydroxychloroquine increased with each visit from 56% at baseline to 80% in patients who had three visits or more.
“Our work demonstrates that prior to instituting routine testing, up to 44% of our patients with SLE did not take their most important medication as prescribed,” the researchers wrote, and added, “importantly, our work demonstrates that with repeated measurement and patient counseling, adherence can be significantly improved.” – by Shirley Pulawski
Disclosure: The researchers report no relevant financial disclosures.