Rethinking the Hydroxychloroquine Dosing and Retinopathy Screening Guidelines

Cone Density Distribution and Related Factors in Patients Receiving Hydroxychloroquine Treatment

Purpose

Hydroxychloroquine is an effective treatment for rheumatic diseases; however, retinal damage is a possible side effect. We aimed to identify the retinal area and related risk factors associated with cone density reduction caused by hydroxychloroquine.

Methods

We recorded the retinal images of patients with rheumatic diseases taking hydroxychloroquine (n = 44) and compared them with images of healthy controls (n = 107). Cone density was obtained in vertical and horizontal axes. Regions of decreased cone density and associations between age, rheumatic disease type, dosage for ideal body weight, and cone density were evaluated.

Results

Cone densities were significantly lower in hydroxychloroquine-treated patients than in sex- and age-matched controls in the vertical axis (P < 0.001), with no significant difference in the horizontal axis (P = 0.120); in healthy elderly than in healthy young people in the horizontal axis (P < 0.001), with no significant difference in the vertical axis (P = 0.100); in hydroxychloroquine-treated elderly than in hydroxychloroquine-treated young patients in both axes (both P < 0.05); among patients with different rheumatic disease types, with no significant difference in the vertical axis (P = 0.294). The daily dose was negatively correlated with cone density in the vertical axis and inferior quadrant.

Conclusions

Hydroxychloroquine reduces retinal cone cell density in the vertical axis. Cone density loss in the horizontal axis increases with age; further, hydroxychloroquine dosage is negatively correlated with cone density in the vertical axis and inferior quadrant. Early screening of hydroxychloroquine-related retinal injury should consider changes in cone density in the vertical axis.

Pharmacokinetics of hydroxychloroquine in Japanese systemic lupus erythematosus patients with renal impairment

OBJECTIVES

Reduction of the hydroxychloroquine (HCQ) dosage is recommended in systemic lupus erythematosus (SLE) patients with renal impairment, but a pharmacokinetics (PK) study of patients with renal impairment has not yet been performed.

METHODS

We investigated the PK of both single and multiple doses of HCQ and its metabolites in SLE patients with renal impairment who newly started HCQ at a daily dose of 300 mg based on an ideal body weight dosage of 6.5 mg/kg. Population PK analysis was performed using a non-linear mixed-effects model.

RESULTS

In total, 219 samples from 21 patients were analysed. The PK of HCQ in blood after single and multiple oral administrations followed the two-compartment model. At steady state, the concentration ratio of HCQ to each metabolite was HCQ:desethylhydroxychloroquine:desethylchloroquine:bisdesethylchloroquine = 1:0.28:0.1:0.06. The HCQ concentration correlated positively with that of each metabolite. The estimated values (relative standard error) of the population PK parameters were the total clearance at 110 l/h (31%) and a central volume of distribution of 398 l (19%). Co-administration of prednisolone and age, but not renal impairment, were factors affecting the total clearance of HCQ.

CONCLUSIONS

From the PK perspective, a dosage reduction is unnecessary in SLE patients with impaired renal function.

Understanding Ocular Findings and Manifestations of Systemic Lupus Erythematosus: Update Review of the Literature

Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disease. Up to one-third of patients suffering from SLE have various ocular manifestations. The ocular findings may represent the initial manifestation of the systemic disease and may lead to severe ocular complications, and even loss of vision. Ocular manifestations are often associated with degree of systemic inflammation, but also can precede the occurrence of systemic symptoms. Early diagnosis and adequate management of patients with SLE are crucial and require cooperation between various specialists. Proper preparation of ophthalmologists can help to differentiate between complication of SLE and other ocular disorders. New therapies for SLE are promising for potential benefits, however, ocular side effects are still unknown.

Risk of hydroxychloroquine retinopathy in the community

OBJECTIVES

We aimed to estimate the risk of HCQ retinopathy and its risk factors among incident users in the community.

METHODS

Using the Rochester Epidemiology Project, a record-linkage system, a cohort of incident users of HCQ was identified from 27 counties in the American upper Midwest. HCQ retinopathy was defined based on characteristic paracentral automated 10-2 visual field (10-2 AVF) defects and parafoveal retinal photoreceptor layer changes on spectral domain optical coherence tomography. Cumulative incidence rates were estimated adjusting for competing risk of death. Risk factors for HCQ retinopathy were examined using Cox models.

RESULTS

The study included 634 incident HCQ users (mean age at initial HCQ use was 53.7 years, 79% females, 91% white). Most common indications for HCQ were RA (57%) and SLE (19%). The average follow-up length was 7.6 years. Eleven patients developed HCQ retinopathy (91% females, 91% white). The majority used HCQ for RA (91%). The cumulative incidence rate at year 5 was 0%, which increased to 3.9% (95% CI 2.0, 7.4) by 10 years. Taking an HCQ dose ≥5 mg/kg was associated with a hazard ratio (HR) of 3.59 (95% CI 1.09, 11.84) compared with lower doses. There was a 48% increase [HR 1.48 (95% CI 1.03, 2.14)] in the risk of HCQ retinopathy for each 100 g of HCQ cumulative dose.

CONCLUSION

The risk of HCQ retinopathy at 10 years of use is lower compared with previous prevalence-based estimations. A dose ≥5 mg/kg was associated with higher HCQ retinopathy risk.

Compliance With Hydroxychloroquine Screening Guidelines at a Large Academic Medical Center

Purpose:

Long-term hydroxychloroquine use can result in irreversible maculopathy and vision loss. New screening guidelines to identify early maculopathy were issued by American Academy of Ophthalmology (AAO) in 2016; however, few studies have evaluated compliance with these updated guidelines.

Methods:

This cross-sectional study evaluated compliance with hydroxychloroquine maculopathy screening examinations at a large academic institution. Patients seen in the ophthalmology department who were prescribed hydroxychloroquine between 2011 and 2021 were included. This retrospective chart review included patients screened for hydroxychloroquine toxicity between 2011 and 2021. The main outcome measure was compliance with AAO screening guidelines (based on 2011 guidelines for patients screened between 2011 and 2015 and on 2016 guidelines for those screened in 2016 and later).

Results:

Of the 419 patients included, 239 were evaluated between 2011 and 2015 and 357 between 2016 and 2021. Only 60.7% of patients screened before 2016 met the recommended screening examination frequency, while 40.6% received adequate visual field screenings. Of patients screened after 2016, 55.3% met the recommended examination screening frequency, 46.4% received screening with macula ocular coherence tomography at the recommended interval, and 21.0% received appropriate visual field screening. One third of patients were prescribed higher than the recommended 5 mg/kg/day of hydroxychloroquine. Ten patients developed definite macular toxicity; most had concomitant risk factors for toxicity.

Conclusions:

Despite clear guidelines set forth by AAO in 2011 and 2016, compliance with screening was suboptimal. Hydroxychloroquine prescribers and eye care providers must collaborate to ensure patients are not overdosed and that they receive appropriate maculopathy screening.

Advances in the clinical use of hydroxychloroquine levels

PURPOSE OF REVIEW

This review summarizes the recent literature exploring hydroxychloroquine levels and their relationship with disease activity and risk of toxicity.

RECENT FINDINGS

There is no clear correlation between weight-based dosing of hydroxychloroquine and the resulting blood levels of the medication. Recent studies have shown that increased hydroxychloroquine levels are associated with lower lupus disease activity and likely also increased risk of medication toxicity.

SUMMARY

Mounting evidence supports use of hydroxychloroquine levels in clinical practice to document adherence and ensure safety.

Update on Retinal Drug Toxicities

Purpose of Review

This review aims to provide an update on the clinical presentations and diagnostic findings of drug-induced retinal toxicities.

Recent Findings

Several newly FDA-approved medications have been associated with acute retinal toxicities, including brolucizumab, MEK inhibitors, ulixertinib, and FGFR inhibitors. Additionally, as previously believed-to-be well-tolerated medications, such as pentosan sulfate sodium, anti-retroviral therapies, and certain intraoperative ocular medications, are used more frequently or for longer periods of time, associated toxic retinopathies and inflammatory reactions have been reported. Finally, advances in ocular imaging have revealed novel findings in hydroxychloroquine and tamoxifen maculopathies.

Summary

Discovery of new medications, increased frequency of use, and longer-term use have led to increased reports of retinal toxicities. Advances in retinal imaging have allowed for earlier detection of subclinical changes associated with these medications, which may help prevent progression of disease. However, more research is needed to determine the point at which vision loss becomes irreversible. Risks and benefits must be assessed prior to discontinuation of the offending, but potentially lifesaving, therapy.

Hydroxychloroquine's Early Impact on Cone Density

Purpose

To evaluate early effects of hydroxychloroquine (HCQ) on the retina using adaptive optics (AO).

Methods

This was a prospective observational single-center study of 29 eyes of 29 patients who had been treated with HCQ for the first time and followed with AO for a minimum of two years. Cone counting was performed in 4 quadrants, nasal, temporal, superior, and inferior, at 0.75 mm from the foveal center. The changes of cone density on AO, visual acuity, and foveal thickness within two years of use were analyzed. The changes of mean cone density of patients whose cumulative dose was over 200 g in 2 years were also assessed. We evaluated the correlation between cone density and cumulative dose of HCQ.

Results

There was no significant decrease in cone density in the first 2 years of HCQ use. VA and foveal thickness did not show obvious change, either. Among 9 patients whose cumulative dose was over 200 g in 2 years, the mean cone density showed no significant change at 6, 12, 18, and 24 months compared with baseline (P=0.381, P=0.380, P=0.281, and P=0.534, respectively). There was no correlation between cone density and cumulative dose of HCQ at two years (Spearman's correlation coefficient, r = −0.0553, P=0.780; n = 29).

Conclusion

AO showed no change in cone density in the first two years of HCQ use.

Ocular findings in Japanese patients with hydroxychloroquine retinopathy developing within 3 years of treatment

PURPOSE

To describe the characteristics of Japanese patients with hydroxychloroquine (HCQ) retinopathy developing within 3 years of treatment outset.

STUDY DESIGN

Retrospective case series METHODS: Three patients with HCQ retinopathy developing within 3 years of treatment outset have been identified in Japan since HCQ became available in 2015. Their medical charts, containing optical coherence tomography (OCT), fundus autofluorescence imaging, and visual field tests, were reviewed.

RESULTS

The treatment durations and cumulative doses until onset were 29-36 months and 182-326 g, respectively. The first patient had possible pre-existing maculopathy, although the abnormalities were ambiguous. The second and third patients had impaired renal function. The patients did not complain of severe visual disturbance at diagnosis, but visual field loss and disruption of the outer retinal segments consisting of a parafoveal pattern in the first case and a pericentral pattern (localized, 8 or more degrees from the center of the fovea) in the second and third cases were clearly observed on OCT. Even after HCQ discontinuation, their retinopathy showed slight progression on the visual field tests and OCT images. A blood sample was obtained from 1 patient on the day after HCQ discontinuation, and the whole blood level of HCQ was measured using validated liquid chromatography-tandem mass spectrometry. The HCQ level 27 h after the last dose was high, at 2240 ng/mL (suggested threshold > 1733 ng/mL).

CONCLUSION

Ophthalmologic screening from the initiation of HCQ treatment detected 3 cases of HCQ retinopathy developing within 3 years of treatment outset, including a patient with a high blood level of HCQ.

Stargardt disease masquerades

PURPOSE OF REVIEW

Stargardt disease is the most common inherited macular dystrophy but has a wide clinical spectrum, and several inherited macular dystrophies have phenotypic similarities that can make clinical diagnosis challenging. This review seeks to highlight key clinical and multimodal imaging features to aid clinicians in accurate diagnosis.

RECENT FINDINGS

Multimodal imaging has provided additional information to aid in the diagnosis of Stargardt disease and its masquerades. These data from multimodal imaging are important to correlate with findings from clinical examination to help support the clinical diagnosis or guide molecular investigations.

SUMMARY

This review highlights the key similarities and differences, in history, clinical examination and multimodal imaging, to help distinguish between Stargardt disease and other macular dystrophies. These findings can help direct a focused molecular analysis for accurate diagnosis, which is critical in the era of gene and stem cell therapies.