The gold standard for a clinical trial is a double-blinded, randomized controlled trial (RCT). What this means in plain English is that the study has been designed to reduce biases that would render its results meaningless. Neither the physician nor the patients knows whether they received the drug (“double-blinded”), a safeguard that reduces the possibility that the doctor will treat the two groups differently. The researchers also do not get to choose which patients go into which group (“randomized”) and the makeup of the two groups is roughly equivalent (“controlled”).
The French hydroxychloroquine study did not follow any of these rules.
The treatment group and the control group were drawn from separate populations: the treatment group were all patients at the institution where the researchers worked, the Méditerranée Infection University Hospital Institute in Marseille, while the control patients came from other hospitals in the south of France. The treatment group (mean age 51.2) was significantly older than the control group (mean age 37.3), introducing another variable that could undermine the meaning of the results. The study was “open label”, meaning the physicians and patients knew which treatment they were receiving. The French researchers also treated some but not all of the treatment group patients with azithromycin, a common antibiotic, another complicating factor that was not randomized.
But even more important than these shortcomings in the design of the study is how the researchers chose to measure and report their results. Forty-two patients were initially included in the study. Three were transferred to the intensive care unit; one died, one left the hospital, and one stopped taking the treatment due to nausea. The other 36 eventually recovered, and those who received the drug cleared the virus from the system faster than those who did not.
If you had only heard about this study from the Fox News assertion of a “100% cure rate”, you might assume that the four patients with poor clinical outcomes (the three ICU visits and one death) had been unlucky enough to be in the group that did not receive the “cure”.
And yet, those four patients, as well as the patient with nausea and the one who left the hospital early, were all part of the treatment group. They were excluded from the topline results of the study because of the way that the researchers chose to measure and report the results: strictly based on the measurable presence of viruses in nasal swabs taken each day of the study. Since the patients were in the ICU or dead, their samples could not be taken and they were left out of the final analysis. Based on the nasal swabs of just the 36 patients who completed the study, those who received the drug cleared the virus from their systems faster than those who did not.
This is how an experiment in which 15% of the treatment group and 0% of the control had poor clinical outcomes could end up being reported as showing a “100% cure rate”.
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