SynthesisNature communications2021
Mortality outcomes with hydroxychloroquine and chloroquine in COVID-19 from an international collaborative meta-analysis of randomized trials.
Synthesis in Nature communications, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Cited by 180 papers, 15 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
180 citing papers in PubMed, 15 syntheses or guidelines pooled it, 291 citations in OpenAlex.
- Exploring the long-term hydroxychloroquine's effects on COVID-19 outcomes in patients with autoimmune diseases: a systematic review and meta-analysis.European journal of clinical pharmacology · 2026Pooled it
- Efficacy of tenofovir on clinical outcomes of COVID-19 patients: a systematic review.BMC infectious diseases · 2025Pooled it
- Drug treatments for mild or moderate covid-19: systematic review and network meta-analysis.BMJ (Clinical research ed.) · 2025Pooled it
- AGIHO guideline on evidence-based management of COVID-19 in cancer patients: 2022 update on vaccination, pharmacological prophylaxis and therapy in light of the omicron variants.European journal of cancer (Oxford, England : 1990) · 2023Guideline
- Hydroxychloroquine for treatment of non-hospitalized adults with COVID-19: A meta-analysis of individual participant data of randomized trials.Clinical and translational science · 2023Pooled it
- Identifying factors contributing to increased susceptibility to COVID-19 risk: a systematic review of Mendelian randomization studies.International journal of epidemiology · 2022Pooled it
- Systematic review and meta-analysis of randomized trials of hydroxychloroquine for the prevention of COVID-19.European journal of epidemiology · 2022Pooled it
- Systematic review and meta-analysis of ivermectin for treatment of COVID-19: evidence beyond the hype.BMC infectious diseases · 2022Pooled it
- Hydroxychloroquine in the treatment of coronavirus disease 2019: Rapid updated systematic review and meta-analysis.Reviews in medical virology · 2022Pooled it
- Efficacy and safety of azithromycin in Covid-19 patients: A systematic review and meta-analysis of randomized clinical trials.Reviews in medical virology · 2022Pooled it
- Hydroxychloroquine/chloroquine for the treatment of hospitalized patients with COVID-19: An individual participant data meta-analysis.PloS one · 2022Pooled it
- The impact of therapeutics on mortality in hospitalised patients with COVID-19: systematic review and meta-analyses informing the European Respiratory Society living guideline.European respiratory review : an official journal of the European Respiratory Society · 2021Guideline
- Association between convalescent plasma treatment and mortality in COVID-19: a collaborative systematic review and meta-analysis of randomized clinical trials.BMC infectious diseases · 2021Pooled it
- Pooled it
- Update of the recommendations of the Sociedade Portuguesa de Cuidados Intensivos and the Infection and Sepsis Group for the approach to COVID-19 in Intensive Care Medicine.Revista Brasileira de terapia intensivaPooled it
- Cardiac findings in a phase II double-blind randomized placebo-controlled trial of combination therapy (HAZDPac) to treat COVID-19 patients.BMC cardiovascular disorders · 2024Trial
- Evaluation of Hydroxychloroquine as a Perpetrator on Cytochrome P450 (CYP) 3A and CYP2D6 Activity with Microdosed Probe Drugs in Healthy Volunteers.European journal of drug metabolism and pharmacokinetics · 2024Trial
- Immunosuppression by hydroxychloroquine: mechanistic proof in in vitro experiments but limited systemic activity in a randomized placebo-controlled clinical pharmacology study.Immunologic research · 2023Trial
- Trial
- Feasibility of contextualizing the Informed Health Choices learning resources in Italy: A pilot study in a primary school in Florence.F1000Research · 2022Trial
120 more citing papers are in PubMed but not listed here.
Corrections and comments
- Erratum issued
- Erratum issued
Authors and funding
94 authors at 20 institutions in 23 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Substantial COVID-19 research investment has been allocated to randomized clinical trials (RCTs) on hydroxychloroquine/chloroquine, which currently face recruitment challenges or early discontinuation. We aim to estimate the effects of hydroxychloroquine and chloroquine on survival in COVID-19 from all currently available RCT evidence, published and unpublished. We present a rapid meta-analysis of ongoing, completed, or discontinued RCTs on hydroxychloroquine or chloroquine treatment for any COVID-19 patients (protocol: https://osf.io/QESV4/ ). We systematically identified unpublished RCTs (ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, Cochrane COVID-registry up to June 11, 2020), and published RCTs (PubMed, medRxiv and bioRxiv up to October 16, 2020). All-cause mortality has been extracted (publications/preprints) or requested from investigators and combined in random-effects meta-analyses, calculating odds ratios (ORs) with 95% confidence intervals (CIs), separately for hydroxychloroquine and chloroquine. Prespecified subgroup analyses include patient setting, diagnostic confirmation, control type, and publication status. Sixty-three trials were potentially eligible. We included 14 unpublished trials (1308 patients) and 14 publications/preprints (9011 patients). Results for hydroxychloroquine are dominated by RECOVERY and WHO SOLIDARITY, two highly pragmatic trials, which employed relatively high doses and included 4716 and 1853 patients, respectively (67% of the total sample size). The combined OR on all-cause mortality for hydroxychloroquine is 1.11 (95% CI: 1.02, 1.20; I² = 0%; 26 trials; 10,012 patients) and for chloroquine 1.77 (95%CI: 0.15, 21.13, I² = 0%; 4 trials; 307 patients). We identified no subgroup effects. We found that treatment with hydroxychloroquine is associated with increased mortality in COVID-19 patients, and there is no benefit of chloroquine. Findings have unclear generalizability to outpatients, children, pregnant women, and people with comorbidities.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.