Background/Purpose:

Antimalarial drugs (AM) are commonly used to treat rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). AM can be associated with retinal toxicity that may result in vision loss. Current US guidelines recommend annual eye screening for all patients with ≥ 5 years of AM exposure. Our objectives were 1) to identify the pattern of retinal screening in patients with RA and SLE under AM therapy, and 2) to evaluate the association of being seen by a rheumatologist and ophthalmologist retinal screening.

Methods:

We conducted a population-based study using an administrative health database including the entire population in the province of British Columbia, Canada (over 5 million individuals). Our data included all outpatient and inpatient visits, investigations, procedure codes, demographics, vital statistics and all dispensed medications. We identified RA and SLE cases using a validated algorithm. We created 2 cohorts of AM users: 1) patients who started AM for ≥ 6 consecutive months after disease onset, and 2) a subset of cohort 1, restricted to patients with continuous AM use for ≥ 5 years, allowing gaps of < 6 months.

The unit of measurement was patient-year (PY) of AM use. The primary outcome was the number of PYs in which individuals had an ophthalmology visit with retinal screening (using billing codes for procedures), defined as either 1) fluorescein angiography of retina, 2) fundus photography, 3) visual field examination, 4) quantitative perimetry examination, 5) anterior segment gonioscopy, or 6) spectral-domain optical coherence tomography.

For objective 2, we created 18-month windows of AM exposure to assess the odds of a retinal screening visit from a previous rheumatologist visit versus not seen by a rheumatologist. We used a generalized linear model with general estimation equation to estimate the odds ratio (OR) of the events.

Results:

In cohort 1, we identified 23,868 patients (RA=20,000, SLE=3,868) . Among these, 8,119 (34.0%) patients had a history of ≥ 5 years continuous use of AM (cohort 2). The average age in RA patients was 56.2 (SD=15.7) and the average age in SLE patients was 47.3 (SD=14.9). Seventy-three percent of RA patients and 80.0% of SLE patients were female.

For cohort 1, we identified a total of 219,355 PYs. Despite guidelines suggesting eye screening every PY of AM use, only 29.7% (65,106) of PYs were associated with retinal screening. For cohort 2, a total of 44,676 PYs of AM exposure were identified with 43.4% (19,393) PYs associated with retinal screening.

For both cohort 1 and 2, there was a significant association between being seen by a rheumatologist and retinal screening (cohort 1: OR 1.63, 95% CI 1.57-1.69, P<0.0001; cohort 2: OR 1.46, 95% CI 1.37-1.56, P<0.0001).

Conclusion:

Overall, this large population-based study demonstrates that only a small proportion of patients under AM therapy undergo for retinal screening as per current guidelines. Our study shows that visits by rheumatologists improve adherence to screening guidelines, however, a huge gap still remains even in a publically funded healthcare system.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/poor-rates-of-screening-for-retinal-toxicity-in-patients-on-antimalarial-medications-a-population-based-study/