Discontinuation of hydroxychloroquine due to suspected retinal toxicity in systemic lupus erythematosus and the role of multimodal imaging.

Background/aim: To evaluate the effect of hydroxychloroquine (HCQ) on disease activity and damage in patients with systemic lupus erythematosus (SLE) in whom HCQ had previously been discontinued due to retinal toxicity, and to examine and reevaluate toxicity findings through a detailed ophthalmological examination.

Materials and methods: Patients with SLE who had been on HCQ for at least 3 years after achieving lupus low disease activity state (LLDAS) following remission induction, and were followed up for at least 3 years after HCQ discontinuation due to retinal toxicity diagnosed by visual field testing, were analysed. Disease activity, the number and severity of flares and damage were recorded whilst on HCQ and after cessation. All patients were examined by two ophthalmologists using multimodal imaging techniques to further analyse toxicity.

Results: Sixty-one patients (age at diagnosis 33.4 ± 10.5, 88.5% female) were included. The percentage of visits maintaining LLDAS was significantly higher during HCQ treatment (p = 0.001). A significant number of patients experienced flares after HCQ discontinuation, with the mild-moderate type predominating (p = 0.006 and p = 0.026). Mean damage scores were higher at the end of the study period (p = 0.001). In the ophthalmologic examination (mean duration after drug cessation: 70.3 ± 52.3 months), signs of HCQ toxicity were not detected in 40 patients (65.6%), and HCQ was reinitiated for these patients. Of 21 (34.4%) patients who had visual field defects in reexamination, only five (8.2%) had typical retinal toxicity by multimodal imaging. Sixteen (26.2%) patients had macular atrophy due to other causes.

Conclusion: Hydroxychloroquine is effective in controlling disease activity and preventing damage in SLE, and the opportunity for remedication is valuable. More than half of the patients who could restart HCQ after reexamination show the importance of performing multimodal imaging to diagnose retinal toxicity and to distinguish macular pathologies with different aetiological background.