January 19, 2021
Paper published in BMC Infectious Diseases documents association between hydroxychloroquine exposure and reduced hospitalization rates in mildly symptomatic outpatients with COVID-19
Researchers from Hackensack Meridian Health John Theurer Cancer Center (JTCC), a member of the Georgetown Lombardi Comprehensive Cancer Center consortium, have published results from a multi-center, retrospective, observational study suggesting a possible role for the use of hydroxychloroquine, an antimalarial agent with antiviral and anti-inflammatory properties, as an outpatient treatment for COVID-19.
In a paper published in the current issue of BMC Infectious Diseases, the JTCC researchers report that hydroxychloroquine use in the outpatient setting was associated with a reduction in hospitalization rates in mildly symptomatic individuals with COVID-19, compared to those not given to hydroxychloroquine. They called for additional exploration of hydroxychloroquine to clarify its role in the outpatient treatment of COVID-19.
“We were very pleased to see a statistically significant reduction in the risk of subsequent hospitalization in mildly symptomatic outpatients treated with hydroxychloroquine,” said lead investigator Andrew Ip, MD, MS, Director of the Division of Outcomes and Value Research at JTCC, and an attending physician in the Division of Lymphoma and Division of Myeloma at JTCC. “The results are especially encouraging in light of previous observational studies in which hydroxychloroquine did not appear to reduce the risk of death in hospitalized patients with COVID-19. We hope our findings lead to further investigation of this drug as a potentially viable oral outpatient therapy for early-stage COVID-19.” Ip is an associate member of Georgetown Lombardi.
Dr. Ip and colleagues collected and evaluated data from 1,274 outpatients identified through electronic health records as having documented COVID-19 infection, of whom 97 (7.6%) were prescribed hydroxychloroquine prior to any COVID-19-related hospitalization. They also constructed a propensity-matched sample of 1,067 patients, consisting of 97 who were exposed to hydroxychloroquine in the outpatient setting and 970 without such exposure. A total of 326 (30.6%) patients in the propensity-matched cohort subsequently required hospitalization, including 21 (21.6%) treated with hydroxychloroquine and 305 (31.4%) patients not exposed to the drug. In the primary multivariable logistic regression analysis with propensity matching, exposure to hydroxychloroquine was associated with a reduced rate of hospitalization related to progressive COVID-19 illness (odds ratio 0.53; 95% confidence interval, 0.29, 0.95). Sensitivity analyses revealed similar associations.
“The odds ratio of 0.53 means that outpatients treated with hydroxychloroquine had about half the odds of subsequent hospitalization compared to those who didn’t receive the drug, and this finding was statistically significant,” Dr. Ip explained. “At a time of surging rates of COVID-19 cases and hospitalizations, keeping patients out of the hospital becomes a public health imperative.”
Safety events in the study were minimal, with 2% of patients experiencing asymptomatic QTc prolongation (a measure of delayed ventricular repolarization, indicating that the heart muscle takes longer than normal to recharge between beats) and none experiencing arrhythmia.
The 30.6% subsequent hospitalization rate in the observational cohort is higher than current state and national hospitalization rates, the researchers noted. “We conducted this study early in the course of the pandemic in the United States, during a timeframe when testing for COVID-19 was largely limited to symptomatic individuals,” noted Dr. Ip. “We therefore suspect that the observational cohort was biased toward individuals with more advanced disease and a higher likelihood of hospitalization than the general population of those infected with the virus that causes COVID-19.”
Additional limitations to the study included the relatively small sample size, the lack of confirmation of prescription filling or of full adherence to the complete course of hydroxychloroquine therapy, and the inability to account for hospitalization outside the Hackensack Meridian Health network. The researchers further caution that results from an observational study cannot be used to assert a causal relationship, and that the findings need to be validated in a randomized controlled clinical trial.
“I am very proud of all the efforts by our JTCC team, in particular initiating a registry of COVID patients during the early days of the pandemic. With it, we can now inform on potential treatment benefits for subsets of patients,” commented Andre Goy, MD, MS, Chairman and Director of JTCC, and a co-author of the BMC Infectious Diseases paper. “There has been a lot of debate around hydroxychloroquine with mixed results. Part of the reason was due to using it at different phases of the infection and/or in different patient populations. Efforts to mitigate the course of disease and reduce hospitalization are obviously critical in COVID19 to improve patient outcomes while presumably easing the strain on overburdened health systems.”
For more information about the JTCC observational study and the BMC Infectious Diseases publication, visit: https://rdcu.be/cdAX0.