Background/Purpose: Hydroxychloroquine (HCQ) is one of the main drugs used for the treatment of systemic lupus erythematosus (SLE). Nonetheless, HCQ-induced retinal toxicity remains a major concern. To reduce the risk of HCQ-induced retinopathy, in 2016 the American Academy of Ophthalmology recommended a maximum daily HCQ dose of ≤5.0 mg/kg real weight. However, it is uncertain if this recommended dose would have an impact on the clinical course and outcome of SLE patients. Thus, we compared outcome measures in a cohort of SLE patients before and after adjusting HCQ dose to ≤5mg/kg/day.

Methods: Sixty Hispanics from Puerto Rico with SLE (per 1997 revised American College of Rheumatology [ACR] criteria) treated with HCQ who were changed to HCQ ≤5.0 mg/kg/day were studied. Visits were ascertained every 6 months for 2 years prior to HCQ dose adjustment (baseline visit) and up to 2 years afterwards. Disease activity (per Systemic Lupus Disease Activity Index [SLEDAI]), SLE exacerbations, emergency room visits, hospitalizations, damage accrual (per Systemic Lupus International Collaborating Clinics/ACR Damage Index [SDI]), prednisone (or equivalent) exposure, prednisone (or equivalent) mean dose, and immunosuppressive drugs exposure were determined before and after HCQ dose change. Statistical analyses were performed using Exact McNemar’s test and Wilcoxon signed-rank test, as appropriate.

Results: At baseline visit, the mean age was 44.0 ± 14.9 years. All patients were women. The mean disease duration and HCQ treatment duration were 13.8 ± 9.1 and 12.5 ± 15.1 years, respectively. The mean daily HCQ doses before and after adjustment were 395 ± 28 mg and 256 ± 50 mg, respectively. All patients had at least 1 year of follow-up, 41 (68.3%) had 1.5 years of follow-up, and 39 (65.0%) had 2 years of follow-up after dose adjustment. Before HCQ dose adjustment, patients had more mean hospitalizations (any cause) (0.08 ± 0.20 vs. 0.02 ± 0.07, p=0.031) and mean hospitalizations attributed to SLE (0.04 ± 0.16 vs. 0.00, p=0.045) when compared to visits after HCQ dose reduction. No significant differences (p >0.05) were observed for mean SLEDAI scores (2.2 ± 2.9 vs. 2.1 ± 2.9), lupus exacerbations (0.18 ± 0.25 vs. 0.16 ± 0.25), emergency room visits (any cause) (0.06 ± 0.22 vs. 0.17 ± 0.78), emergency room visits attributed to SLE (0.02 ± 0.78 vs. 0.01 ± 0.06), and mean daily prednisone dose (7.9 ± 17.3 mg vs. 5.2 ± 5.8 mg) before and after HCQ dose adjustment. Likewise, no differences were observed for exposure to corticosteroids, mycophenolate mofetil, azathioprine, cyclophosphamide, tacrolimus, rituximab or methotrexate. Patients did not accrue more damage from baseline visit to last study visit (mean SDI score: 0.9 ± 1.4 vs. 1.0 ± 1.4, p=0.190), and no deaths occurred.

Conclusion: This study suggests that adjustment of daily HCQ dose to ≤5.0 mg/kg real weight does not have a significant impact in the short- and mid-term outcomes of SLE patients. Nevertheless, a larger number of patients and longer follow-up are necessary to reach further conclusions.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/clinical-impact-of-decreasing-hydroxychloroquine-dose-according-to-the-2016-american-academy-of-ophthalmology-guidelines-in-patients-with-systemic-lupus-erythematosus/