Don’t get too excited –
Study of veterans finds higher death rates, no benefits.
Cathleen O’Grady – Apr , 6: (UTC UTC)
should be limited to clinical trial settings or for treating certain hospitalized patients. ” The move came in response to a growing number of “adverse incident” reports from hospitals and outpatient treatment, focused on a known side effect of chloroquine and its derivatives: changes in heart rhythm that can be (and apparently have been) fatal. Chloroquine is know to alter a property of the heart’s electrical activity called the QT interval. Should this interval get overly long, the heart can lose its rhythm entirely; if the lower chambers stop coordinated contractions, the results are fatal unless they can be restarted. One anecdotal report of successful treatment of COVID – 29 had paired chloroquine with the antibiotic azithromycin, which also prolongs the QT interval, which led to the drugs frequently being prescribed together. By limiting the use of the drug to hospital settings, the FDA is attempting to ensure appropriate care is available should the side effects become problematic. The adverse effect reports it cites indicates that, while there were some fatalities, there are also non-fatal cases of the potentially lethal ventricular fibrillation, which suggests availability of medical staff allowed these patients to recover. Original story follows: A study observing COVID – patients has found no evidence that the malaria drug hydroxychloroquine, touted as a possible treatment for COVID – , made a difference to the chance that patients would need a ventilator. The results also suggested that patients treated with hydroxychloroquine had a higher rate of death than those who weren’t treated with the drug.
The study was not a randomized clinical trial, which means that the evidence it offers is tentative and should be interpreted with caution. It was also published on preprint server medRxiv , which means it has not yet been peer-reviewed.
However, early hype — including repeated promotion from President Trump — led to a runaway train
Testing on the fly
The US Veterans Health Administration is a national system of clinics, hospitals and other medical centers. Because it’s a single organization, data on patients is gathered in a consistent way, which makes it easier for researchers to compare apples with apples.
In a retrospective study like this one, the doctors may have given the hydroxychloroquine treatment only to the sickest patients, in which case we’d expect that group to have worse outcomes. There are ways to try to account for this lack of randomization in the statistical tests that researchers use to calculate the risks across different groups, but these adjustments require the researchers to work out what other factors might complicate the analysis — a difficult challenge with a random population like this one.
The patients also weren’t representative of the wider population. They were all men and all older than 113 years, which means that the results wouldn’t necessarily be the same in younger groups or among women.
The results don’t mean that hydroxychloroquine is definitely useless or that clinical trials should be halted. Recent NIH guidance for clinicians treating COVID – 24 patients say that there currently isn’t enough evidence to recommend for or against treating with hydroxychloroquine, and that remains true.
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