Hydroxychloroquine: positive effect on return home, not mortality, study finds

Patients hospitalized for Covid-19 and treated with hydroxychloroquine are more likely to return home one month after the start of treatment, according to a French study, which concludes, however, that it is not effective to reduce mortality.

Read also: Taking hydroxychloroquine as a preventive would not be effective

" Significantly higher rates of discharge from hospital have been observed in patients treated with hydroxychloroquine ", concludes this study published online on Saturday but not yet published. The rate of patients returning home 28 days after starting treatment is 11 points higher than those who did not receive this drug, a derivative of the antimalarial chloroquine and usually used to treat autoimmune diseases such as lupus . This represents a 25% relative increase in the likelihood of being discharged from hospital, the study said.

This result, which had not been highlighted in previous research on hydroxychloroquine, " deserves to be replicated in other large studies " to be confirmed, said one of the authors, Émilie Sbidian, interviewed by AFP.

" No significant difference in mortality "

However, the study concluded that "there was no statistically significant difference in 28-day mortality " between the patients who received hydroxychloroquine and the control group, " after taking confounding factors into account . As for those who received the antibiotic azithromycin in addition to hydroxychloroquine, the study did not observe any difference in the rate of discharge from hospital and " a possible excess risk of mortality ".

Read also: Containment, masks, chloroquine ... A doctor accuses

The researchers analyzed the medical records of approximately 4,642 patients hospitalized for Covid-19 in one of the 39 AP-HP hospitals between February 1 and April 6. They excluded those who had received another drug currently tested against the coronavirus, such as the antiviral remdesivir or the immunosuppressants tocilizumab and sarilumab. The results have been statistically corrected to take account of " confounding factors ", and in particular the difference in composition of the three groups.

" Regarding the data from our study, we can see that patients on hydroxychloroquine or hydroxychloroquine / azithromycin had obesity, diabetes and smoking (poor prognosis factors) rates higher by around 5% to 15% , but that they were also much younger than patients not treated with hydroxychloroquine (on the order of 6 to 8 years younger), which can also greatly influence the results since the mortality from coronavirus infection is the more important the higher the age , ”explains Émilie Sbidian.

" It is therefore very important not to stop at the raw results to judge the effectiveness or ineffectiveness " of the treatment, adds the researcher, dermatologist at Henri-Mondor Hospital in Créteil. The authorization to prescribe hydroxychloroquine in hospitals, outside of clinical trials, was withdrawn on May 4.