Abstract
Purpose :
The long-term use of hydroxychloroquine (HCQ) can cause irreversible retinopathy. We performed a prospective study to investigate whether rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) patients differ in their resilience to HCQ toxicity.
Methods :
Patients with RA and SLE referred to the Eye Institute of Alberta and screened for HCQ retinopathy were identified prospectively over a 20-month period. All patients underwent multifocal electroretinography (mfERG), fundus photography, fundus autofluorescence and spectral-domain optical coherence tomographic (OCT) imaging as part of their visits. Data collected included clinical diagnosis, age, sex, HCQ use (daily dose, total dose, duration of use), co-morbid maculopathy, and tamoxifen use. Patients with co-morbid maculopathy were excluded from the analysis. Patients who received a total dose of ≥2kg of HCQ and had no evidence of retinopathy were a priori referred as the “resilient group”.
Results :
A total of 177 patients were recruited in the study; 8 were excluded due to co-morbid maculopathy, leaving 169 (118 RA and 51 SLE) for analysis. Thirty-six patients were in the resilient group. This group had received a significantly higher total dose (2.36±0.45 vs 1.10±0.54 Kg), duration of use (20.01±5.23 vs 10.60±5.11 years), daily dose (4.70±1.53 vs 3.98±1.29 mg/kg body weight), and had a higher proportion of SLE patients (50% vs 25%) compared to the rest of the cohort (all p<0.05). Comparison between RA and SLE patients reveals that the SLE group had received a significantly higher total dose, duration of use, and had a higher percentage of resilient patients (all p<0.05); they were also 5 years younger on average and had more females (both p<0.05). Nevertheless, no significant difference was found in the percentage of resilient patients among different age groups (<50 vs 50-69 vs ≥ 70 years) and between genders (both p>0.05). In terms of HCQ retinopathy cases, the RA group (n=118) had 5 (4.2%) suspect, 1 (0.8%) likely, and 3 (2.5%) confirmed cases of toxicity, whereas, the SLE group (n=51) had only 1 (2.0%) likely case and no suspect or confirmed cases.
Conclusions :
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 HCQ toxicity based on their underlying clinical diagnosis.
This is a 2021 ARVO Annual Meeting abstract.