Lower doses of hydroxychloroquine lead to increased SLE-related hospitalizations, the study found

Lower doses of hydroxychloroquine lead to increased SLE-related hospitalizations, the study found

New research presented this week at ACR Convergence 2022, the annual scientific meeting of the American College of Rheumatology, found that the recommended weight-based or non-weight-based dose of hydroxychloroquine resulted in more hospitalizations for flares in patients with systemic lupus erythematosus (Abstract # 1654).

Hydroxychloroquine (HCQ), the main treatment for systemic lupus erythematosus (SLE), reduces flare-ups and improves long-term outcomes. However, the appropriate dosage to prevent retinopathy has long been controversial. Ophthalmic guidelines originally recommended a HCQ dosage equal to or less than 6.5 mg/kg/day of ideal body weight. In 2016, updated guidelines recommended using 5 mg/kg/day or less based on actual body weight. In some patients this results in doses less than 400 mg per day, which have often been used to treat SLE. The effects of lower doses on SLE hospitalizations are unknown. Researchers conducted this study to determine the effect of HCQ dose on the risk of hospitalization for SLE flares.

In this case-crossover study, researchers identified SLE patients within the Massachusetts General Brigham cohort using an electronic medical record-based algorithm. These patients had at least one visit for SLE and were prescribed HCQ between January 2011 and December 2021. Patients with one or more hospitalizations for an SLE flare while taking HCQ were included in the study. The case period included the six months prior to SLE-related hospitalization; the control period was a non-overlapping period of six months that did not end in hospitalization. Patients could have up to three cases and three control periods.

We designed this as a case-crossover study because it compares patients to themselves and addressed concerns that patients were adequately matched between groups.”

Jacquelyn Nestor, MD, PhD, a rheumatology and research fellow at Massachusetts General Hospital and lead author of the study

The researchers were interested in the comparative results of lower versus higher doses of HCQ. Low-dose weight-based HCQ was defined as equal to or less than 5 mg/kg per day; a higher dose than more than 5 mg/kg per day. The low, non-weight-based daily dose was less than 400 mg versus a higher dose of 400 mg.

Of nearly 3,000 SLE patients taking HCQ, 108 were hospitalized for an SLE flare while taking the drug and had at least one control period of HCQ use during the study. The majority of patients were women, 43.5% of patients were white and 32.4% were black.

In these patients, researchers found that both the lower weight-based dose and the non-weight-based dose were associated with increased hospitalizations for SLE flares, with an adjusted odds ratio of 4.41 and 3.48, respectively.

"The results of the study confirmed our hypothesis. We know that hydroxychloroquine has many proven benefits in SLE patients, so it seemed likely that there would also be a dose effect," says Dr. Nestor. "Current guidelines address dosing of hydroxychloroquine by weight, which are in place to prevent the potential long-term side effect of blindness. However, our study shows that lower dosage results in increased SLE-related hospitalization in the short term. It may be worth reconsidering the current dosing guidelines for hydroxychloroquine to address both the to compensate for short- and long-term side effects.”

Source:

American College of Rheumatology

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