Hydroxychloroquine and mortality risk of patients with COVID-19: a systematic review and meta-analysis of human comparative studies

Abstract Background Global COVID-19 deaths reached at least 400,000 fatalities. Hydroxychloroquine is an antimalarial drug that elicit immunomodulatory effects and had shown in vitro antiviral effects against SRAS-CoV-2. This drug divided opinion worldwide in the medical community but also in the press, the general public and in public health policies. The aim of this systematic review and this meta-analysis was to bring a new overview on this controversial drug and to assess whether hydroxychloroquine could reduce COVID-19 mortality risk in hospitalized patients. Methods and Findings Pubmed, Web of Science, Cochrane Library, MedRxiv and grey literature were searched until 10 June 2020. Only studies of COVID-19 patients treated with hydroxychloroquine (with or without azithromycin) compared with a comparative standard care group and with full-text articles in English were included. Studies reporting effect sizes as Odds Ratios, Hazard Ratio and Relative Risk for mortality risk and the number of deaths per groups were included. This meta-analysis was conducted following PRISMA guidelines and registered on PROSPERO (Registration number: CRD42020190801). Independent extraction has been performed by two independent reviewers. Effect sizes were pooled using a random-effects model. The initial search leaded to 112 articles, from which 16 articles met our inclusion criteria. 15 studies were retained for association between hydroxychloroquine and COVID-19 survival including 15,081 patients (8,072 patients in the hydroxychloroquine arm and 7,009 patients in the standard care arm with respectively, 1,578 deaths and 1,423 deaths). 6 studies were retained for hydroxychloroquine with azithromycin. Hydroxychloroquine was not significantly associated with mortality risk (pooled Relative Risk RR=0.82 (95% Confidence Interval: 0.62-1.07, I 2 =82, P heterogeneity <0.01, n=15)) within hospitalized patients, nor in association with azithromycin (pooled Relative Risk RR=1.33 (95% CI: 0.92-1.92, I 2 =75%, P heterogeneity <0.01, n=6)), nor in the numerous subgroup analysis by study design, median age population, published studies (vs unpublished articles), level of bias risk. However, stratified analysis by continents, we found a significant decreased risk of mortality associated with hydroxychlroquine alone but not with azithromycin among European (RR= 0.62 (95%CI: 0.41-0.93, n=7)) and Asian studies (RR=0.36 (95%CI:0.18-0.73, n=1)), with heterogeneity detected across continent (P heterogeneity between =0.003). These finding should be interpreted with caution since several included studies had a low quality of evidence with a small sample size, a lack of adjustment on potential confounders or selection and intervention biases. Conclusion Our meta-analysis does not support the use of hydroxychloroquine with or without azithromycin to reduce COVID-19 mortality in hospitalized patients. It raises the question of the hydroxychloroquine use outside of clinical trial. Additional results from larger randomised controlled trials are needed