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. 2022 Feb 17;12(2):e053852.
doi: 10.1136/bmjopen-2021-053852.

RetINal Toxicity And HydroxyChloroquine Therapy (INTACT): protocol for a prospective population-based cohort study

Narsis Daftarian  1   2 , Adriana Lima  1 , Shelby Marozoff  1 , Dami Ojo  1 , Steve D Levasseur  3 , David A L Maberley  3 , Alison Hoens  4   5 , John Esdaile  1   6 , Martin Dawes  7 , J Antonio Aviña-Zubieta  8   6 , Beatrice Adante  3 , Ravinder Dennis Bhui  3 , Suruchi B Bhui  3 , Michael Butler  3 , Lica Chui  3 , Murray Erasmus  3   9 , Mahyar Etminan  10 , Derek Godinho  3 , Elizabeth Hay  11 , Hussein Hollands  3 , Malvinder Hoonjan  3 , Aaron Joe  12 , Andrew Lukaris  3 , Zaid Mammo  3 , Eduardo Navajas  3 , Kaivon Pakzad-Vaezi  3 , Suren Sanmugasunderam  3 , Kam Shojania  1   6 ; Investigators of INTACT study group
Collaborators, Affiliations

RetINal Toxicity And HydroxyChloroquine Therapy (INTACT): protocol for a prospective population-based cohort study

Narsis Daftarian et al. BMJ Open. .

Abstract

Purpose: Hydroxychloroquine (HCQ) is an important medication for patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and other rheumatic diseases. Although it is well-tolerated and cost-effective, the risk of HCQ retinal toxicity is of increasing concern. The aim of this study is to re-examine the HCQ retinal toxicity incidence rate, risk factors and clinical course after discontinuation.

Methods: We designed a prospective population-based cohort study in adult patients with SLE or RA, currently receiving HCQ for five or more years, who are residents of British Columbia (BC), Canada. Based on administrative data, we identified 5508 eligible participants (1346 SLE and 4162 RA). They will participate in annual or biannual retinal screening over 5 years in alignment with the recently revised American Academy of Ophthalmology guidelines. To standardise procedures for retinal screening, imaging, diagnostic criteria, severity staging and data transfer, a consensus meeting was convened in December 2019 with participation of BC retinal specialists and the research team. Agreement was attained on: use of spectral domain-optical coherence tomography as the primary objective screening modality; classification of images into categories of normal, equivocal or abnormal; and transferring the equivocal and abnormal images plus corresponding subjective test results via cloud-based server from each clinic to a reading centre. Confirmation of HCQ retinal toxicity diagnoses and severity staging will be performed by three independent and masked reviewers. The incidence of HCQ retinal toxicity will be calculated, accounting for the competing risk of death. Hazard ratios for each risk factor will be calculated for the risk of HCQ retinopathy, after adjusting for confounders. We will also estimate the risk of HCQ retinal toxicity progression over 5 years.

Ethics and dissemination: This study has received approval from the University of British Columbia Clinical Research Ethics Board (H20-00736) and the Vancouver Coastal Health Research Institute.

Keywords: epidemiology; medical retina; rheumatology; toxicity; vetreoretinal.

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Conflict of interest statement

Competing interests: None declared.

Figures

Figure 1
Figure 1
HCQ retinal toxicity screening protocol flowchart for RetINal Toxicity And HydroxyChloroquine Therapy (INTACT) study: the consensus results. HCQ, hydroxychloroquine; RA, rheumatoid arthritis; SLE, systemic lupus erythematosus.
See this image and copyright information in PMC

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