LIVERPOOL, ENGLAND – , but long-term follow-up is much more important, according to data presented at the British Society for Rheumatology annual conference.
In just one specialist rheumatology center in England, which treats more than 8,000 patients annually, the cost of the first year’s optical coherence tomography (OCT) assessment would be more than $60,000. Additional costs would be incurred to screen those who had been on the drug for more than 5 years ,who were known to be at greater risk of hydroxychloroquine-induced retinopathy. This is within the National Health Service in England where the cost of a single OCT scan is around $70; in the private health sector, the cost of one test can be as high as $400.
Dr. Mark Yates
Indeed, of 887 hydroxychloroquine users identified, 44% had at least one risk factor for hydroxychloroquine-induced retinopathy. These included being older than 60 years of age (30% of all users), having renal (10%) or hepatic (2%) impairment, retinal disease at baseline (8%), or using high (more than 6.5 mg/kg) doses of the drug based on their actual (9%) or ideal (4%) body weight.
“The retinal toxicity of hydroxychloroquine is a bit of a hot topic at the moment,” Dr. Yates said at the conference. While the drug has been around for years and used successfully to treat many patients with rheumatoid arthritis and systemic lupus erythematosus (SLE), a known side effect is retinal toxicity.
Traditionally, retinopathy has been quoted as being a relatively rare side effect, affecting around 0.5%-2% of the treated population. Recent data (JAMA Ophthalmol. 2014;132[12]:1453-60) suggest, however, that is probably a vast underestimate, with 7.5% of patients taking hydroxychloroquine for more than 5 years likely to be affected, as are up to 20% of those taking the drug for up to 20 years of treatment.
Dr. Yates and associates wanted to assess the burden of hydroxychloroquine use at their center and look at the risk factors and impact of the recent screening guidelines issued by the British Society for Rheumatology (Rheumatology [Oxford]. 2017;56[6]:865-8) in 2017 and by the Royal College of Ophthalmologists in 2018. These state that patients should have a formal baseline ophthalmic examination, ideally including OCT, within 6-12 months of starting therapy and an annual eye assessment with repeat OCT thereafter for the following 5 years; the ophthalmology guidelines recommending annual screening for the duration of therapy.