Abstract
We thank Luis Ayerbe and colleagues for the opportunity to further discuss our Article.1 The choice of our study population—individuals with rheumatoid arthritis or systemic lupus erythematosus—was made to minimise the potential for confounding by indication when estimating the effectiveness of hydroxychloroquine use rather than investigating how to prevent severe COVID-19 in this population. The key question is whether our study had sufficient statistical power to detect a real difference in mortality, if one existed? As stated in the Article, the CIs around our key estimate (hazard ratio 1·03 [95% CI 0·80–1·33]) suggested that we could exclude substantial benefit, although a modest benefit or harm on a relative scale could not be ruled out; therefore, trials were warranted.
Highlights
An observational study published in The Lancet Rheumatology by Christopher T Rentsch and colleagues[1] showed no association between preexposure use of hydroxychloroquine and reduced mortality in patients with COVID-19 who have systemic lupus erythematosus or rheumatoid arthritis. 138 440 (71·1%) participants were women, and the study population was relatively young, with 50% of the participants younger than 66 years
Even when hydroxy chloroquine is used at maximum dose, patients with systemic lupus erythematosus (SLE) or rheumatoid arthritis do not receive doses as high as those used in patients with COVID-19 in studies that showed an association between hydroxychloroquine and reduced mortality (800 mg on day 1 followed by 400 mg a day for four days).[3,4]
Like Rentsch and colleagues,[1] we think that additional studies are required on the potential benefit of hydroxychloroquine, which is economical, has not proven to be harmful at the dose used for COVID-19, and could be prescribed to ambulatory patients right after the diagnosis before they develop respiratory distress
Summary
An observational study published in The Lancet Rheumatology by Christopher T Rentsch and colleagues[1] showed no association between preexposure use of hydroxychloroquine and reduced mortality in patients with COVID-19 who have systemic lupus erythematosus or rheumatoid arthritis. 138 440 (71·1%) participants were women, and the study population was relatively young, with 50% of the participants younger than 66 years. Hydroxychloroquine treatment does not Published Online January 27, 2021 https://doi.org/10.1016/ S2665-9913(21)00030-8 reduce COVID-19 mortality; underdosing to the wrong patients?
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