|LETTER TO EDITOR
|Ahead of print publication
Correspondence on “assessing the risk of retinopathy in indian patients using hydroxychloroquine for rheumatic and musculoskeletal diseases: A retrospective observational study” – Reply
Arindam Nandy Roy1, Vinitha Samala2, Yarram Ashok Kumar1, Syeda Sana Fatima1
1 Department of Rheumatology, Yashoda Hospitals, Secunderabad, Telangana, India
2 Tanvi Eye Center, Secunderabad, Telangana, India
|Date of Submission||18-Jan-2020|
|Date of Acceptance||18-Jan-2021|
Arindam Nandy Roy,
Department of Rheumatology, Yashoda Hospitals, Behind Hari Hara Kala Bhavan, S. D Road, Secunderabad - 500 003, Telangana
Source of Support: None, Conflict of Interest: None
|How to cite this URL:|
Roy AN, Samala V, Kumar YA, Fatima SS. Correspondence on “assessing the risk of retinopathy in indian patients using hydroxychloroquine for rheumatic and musculoskeletal diseases: A retrospective observational study” – Reply. Indian J Rheumatol [Epub ahead of print] [cited 2021 Jul 29]. Available from: https://www.indianjrheumatol.com/preprintarticle.asp?id=321199
Dadhaniya et al. have raised several pertinent questions regarding our study which we would like to answer. This is the largest study conducted in India till date employing all the four screening modalities for hydroxychloroquine (HCQ) retinopathy as per the recommendations. We tried to dwell upon all the various aspects of HCQ retinopathy as such a study is lacking in this country. We would like to reiterate the fact that as there is no evidence of a gold standard test to identify HCQ retinopathy, the consensus is to combine results of structural (Spectral Domain Optical Coherence Tomography (SD-OCT) and Fundus autofluorescence (FAF)) as well as functional tests (Humphrey visual field (HVF) and Multifocal Electroretinography (mfERG)).
The high prevalence of retinal toxicity reported by us (13.5%) points to the unidentified burden in our population. Dadhaniya et al. reported a prevalence of 6.36% employing only HVF and SD-OCT, whereas we used all the screening modalities, viz., HVF, SD-OCT, FAF, and mfERG, which must have contributed to the increased prevalence. Further combining both “possible” and “definite” retinopathy cases also gave rise to increased numbers. We did not find any statistical difference between the retinopathy and nonretinopathy group as far as mean dose/day/kg body weight is concerned though the median duration of usage between the groups was significant.
There are hardly any studies to suggest a low prevalence of HCQ retinopathy below 5 years, especially in the Indian context. Recently, Pandey et al. noted the presence of macular defect in a case using 4 mg/kg/day, a case of “definite” retinopathy even at 1 year and two cases of “possible” retinopathy below 5 years in their case series without even using mfERG and FAF. We believe that until and unless a prospective study in this area is duly conducted, the exact incidence of this retinopathy will not be known. Further, these guidelines were primarily made in the Western population, and hence, India centric guidelines are much needed.
We agree that mfERG has high sensitivity and variable specificity and should primarily be employed in patients having reproducible HVF abnormalities consistent with HCQ retinopathy in a patient with normal SD-OCT and FAF imaging as it has a good correlation to 10-2 visual field testing., We too found a good correlation of HVF abnormalities with mfERG. Further, three of our patients for whom mfERG was repeated after 6 months demonstrated reversibility and thus reiterates the significance of this modality as a sensitive functional indicator for early retinal abnormalities induced by HCQ as well as changes observed after treatment withdrawal.,
As per the previous recommendations, 10-2 HVF was done in most of our patients. We have clearly mentioned the number of patients who underwent the various field patterns [Table 4]. We too found a high prevalence of retinal abnormalities with the wider field patterns which correlated with mfERG.
Finally, we clearly mentioned in our discussion that we need to be cautious in interpreting these abnormalities lest we over diagnose patients with retinopathy and stop important drug like HCQ.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
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