Arthritis, Lupus Patients Demonstrate Increased Resilience to Hydroxychloroquine Retinal Toxicity

People with rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE) demonstrated a relatively high resilience to hydroxychloroquine toxicity, according to research presented at the Association for Research in Vision and Ophthalmology (ARVO) 2021 Annual Meeting, held virtually May 1 to 7, 2021. 

To evaluate whether people with RA and SLE differed in terms of their resilience to hydroxychloroquine toxicity — which can cause irreversible retinopathy — researchers conducted a prospective study of patients with RA and SLE at the Eye Institute of Alberta over a 20-month period. 

The total cohort included 169 patients (RA n=118, SLE n=51) who underwent multifocal electroretinography (mfERG), fundus photography, fundus autofluorescence and spectral-domain optical coherence tomography (OCT) imaging. Patients who received a ≥2 kg dose of hydroxychloroquine and presented with no evidence of retinopathy were classified as the “resilient group” (n=36). 

Patients in the resilient group received a significantly higher total dose of hydroxychloroquine (2.36±0.45 kg vs 1.10±0.54 kg), daily dose (4.70±1.53 mg/kg/body weight vs 3.98±1.29 mg/kg/body weight), duration of use (20.01±5.23 years vs 10.60±5.11 years) and included a higher proportion of people with SLE (50% vs 25%). 

In a comparison between the RA and SLE groups, investigators found that those in the SLE group received a significantly higher total dose and duration of use, as well as a higher percentage of resilient patients. These patients were also 5 years younger and included more women. 

No significant difference was seen in the percentage of resilient patients in different age groups (younger than 50 years vs 50 to 69 years vs 70 years or older) or between sexes. 

Within the RA group, there were 5 suspected cases of hydroxychloroquine retinopathy, 1 likely case, and 3 confirmed cases of toxicity; the SLE group had only 1 likely case and no cases that were suspected or confirmed. 

“While this is a small study, there would appear to be a significant difference between RA and SLE patients as to their relative resilience to [hydroxychloroquine] toxicity based on their underlying clinical diagnosis,” the research says. 

Reference

Xu M, MacDonald IM. How do RA and SLE patients differ while on long-term hydroxychloroquine therapy? Presented at: Association for Research in Vision and Ophthalmology (ARVO) 2021 Annual Meeting; May 1-7, 2021. Abstract 3531087.