Hydroxychloroquine Blood Levels Predict Hydroxychloroquine Retinopathy.

Area of Science:

• Ophthalmology
• Rheumatology
• Clinical Pharmacology

Background:

• The American Academy of Ophthalmology updated hydroxychloroquine (HCQ) dosage recommendations in 2016, lowering the daily dose.
• The impact of this lower HCQ dose on efficacy for systemic lupus erythematosus (SLE) and cardiovascular risk remains unclear.
• Understanding HCQ retinopathy risk and the role of blood levels is crucial for patient management.

Purpose of the Study:

• To determine the frequency of HCQ retinopathy in a large SLE cohort.
• To investigate the association between HCQ blood levels and the risk of developing retinopathy.
• To identify clinical factors associated with increased HCQ toxicity.

Main Methods:

• Retrospective analysis of 537 SLE patients with repeated HCQ blood level measurements.
• Systematic testing for HCQ retinopathy.
• Statistical assessment of risk factors, including clinical characteristics and HCQ blood levels.

Main Results:

• The overall frequency of HCQ retinopathy was 4.3%.
• Risk of retinopathy increased significantly with longer duration of HCQ use (11.5% after 16-20 years).
• Higher HCQ blood levels, older age, and higher BMI were associated with increased retinopathy risk.

Conclusions:

• Assessing HCQ blood levels is a valuable tool for predicting retinopathy risk.
• Clinicians can use HCQ blood levels to adjust dosage or intensify monitoring for high-risk patients.
• This approach aids in preventing HCQ-induced retinopathy in SLE patients.