Analysis of spectral domain Optical Coherence Tomography findings in patients with Systemic Lupus Erythematosus on Hydroxychloroquine therapy.

Abstract

Purpose: Spectral domain Optical Coherence Tomography (SD-OCT) is one of the recommended screening tests for Hydroxichloroquine (HCQ) related retinal toxicity. The aim of this study was to evaluate changes in SD-OCT in patients with Systemic Lupus Erythematosus (SLE) taking HCQ and investigate whether they are related to the cumulative dose or the duration of treatment of HCQ.

Methods: Cross-sectional study in a cohort of 156 consecutive patients with SLE on HCQ therapy. Each patient had a complete ophthalmologic examination and the following measurements with SD-OCT (Cirrus, Carl Zeiss): Macular Cube 518x128; HD 5 line raster. Two retina specialists analysed qualitatively the scans for abnormalities in the retinal pigment epithelium (RPE) and outer retina (normal, any focal thickening or atrophy). We also recorded quantitative data: average macular thickness and distribution in normative data (normal within 5-95% interval; thickened >95%; thinned <5%); thickness in each quadrant of the ETDRS grid; ganglion cell layer thickness and distribution. We then compared abnormalities in SD-OCT in relation to HCQ cumulative dose, duration of treatment, previous intake of Chloroquine (CQ) and recognised risk factors for HCQ toxicity (>1000 g cumulative dose and >8 years of treatment).

Results: 89% of the patients were female and 95% white. 19% had qualitative abnormalities of the RPE or outer retina in either eye. 3.29% had atrophy of RPE, outer retina or both. Regarding quantitative data, 12 patients (8%) had thinning in average macular thickness (<5% of normative data) in either eye. There was no statistically significant difference in the cumulative dose of HCQ between patients with atrophy of RPE/outer retina (474 ± 617.5g) and those without (507.6 ± 361.9g). The same was true for quantitative thinning of average macular thickness. There was no difference either in the frequency of atrophy between patients who had never taken CQ (3 out of 119) and patients who had taken it (2 out of 27). No difference was found in the rest of the parameters studied (HCQ> 1000g, > 8 years of treatment, duration of treatment). There was no correlation between average macular thickness and cumulative dose of HCQ.

Conclusions: In this cohort of SLE patients, there is no relationship between abnormalities in SD-OCT and dosage of HCQ. The incidence of atrophy of RPE/outer retina is low.

Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 503 drug toxicity/drug effects • 464 clinical (human) or epidemiologic studies: risk factor assessment