Researchers have found that the drug hydroxychloroquine — with or without the antibiotic azithromycin — did not reduce the risk of ventilation or death, and was associated with longer length of hospital stay in COVID-19 patients.
The analysis, published in the journal Med, is the first in the US to report data on hydroxychloroquine (HCQ) outcomes for COVID-19 from a nationwide integrated health system.
"Among patients hospitalised with COVID-19, this retrospective study did not identify any significant reduction in mortality or in the need for mechanical ventilation with hydroxychloroquine treatment with or without azithromycin," the researchers noted.
According to the scientists, including those from the University of Virginia School of Medicine in the US, the research assessed data from 807 people hospitalised with COVID-19 at Veterans Affairs medical centers around the country.
They said about half of the patients, did not receive HCQ at any time during their hospitalisation.
Among those who did, the study noted that 198 patients were treated with HCQ and 214 were treated with both hydroxychloroquine and azithromycin.
It said about 86 per cent of the patients given HCQ received it before being put on a mechanical ventilator.
After adjusting for other clinical characteristics, the scientists said the risk of death from any cause was higher in the HCQ group but not in the 'hydroxychloroquine + azithromycin' group when these were compared with the no-hydroxychloroquine group.
The researchers also found that the length of hospital stay was 33 per cent longer in the HCQ group and 38 per cent longer in the 'hydroxychloroquine + azithromycin' group than in the no-HCQ group.
They said pre-existing conditions like cardiovascular disease, chronic obstructive pulmonary disease, and diabetes were relatively common and similar across all groups.
The study, according to the scientists, had strengths that earlier research did not have.
Citing an example, they said the current study employed data from comprehensive electronic medical records, rather than administrative health insurance claims.
With this, the researchers said, they were able to apply rigorously identified patient outcomes.
Since the data came from an integrated national healthcare system, they said the findings were less susceptible to biases that might occur in a single-center or regional study.
Mentioning the limitations of the research, they said the median age in their study was about the same age as that in other studies of hospitalised patients -- 70 years -- but since the patients were older, the findings might not apply to younger people with COVID-19.
However, the scientists said a quarter of patients ranged from 22 to 60 years old.
The patients in the study were also overwhelmingly male -- nearly 96 per cent -- they said, reflecting the demographics of veterans.
According to the researchers, the findings don't provide insight into the use of these drugs in the outpatient setting or as prophylaxis.
They added that the US Food and Drug Administration, and the National Institutes of Health have both advised against the use of hydroxychloroquine outside of clinical trials.