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Incidence of COVID-19 in patients exposed to chloroquine and hydroxychloroquine: results from a population-based prospective cohort in Catalonia, Spain, 2020

Vivanco-Hidalgo et al., Eurosurveillance, doi:10.2807/1560-7917.ES.2021.26.9.2001202
Mar 2021  
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Hospitalization -46% Improvement Relative Risk Case -8% HCQ for COVID-19  Vivanco-Hidalgo et al.  Prophylaxis Is pre-exposure prophylaxis with HCQ beneficial for COVID-19? Retrospective 20,238 patients in Spain Higher hospitalization with HCQ (not stat. sig., p=0.1) Vivanco-Hidalgo et al., Eurosurveillance, Mar 2021 FavorsHCQ Favorscontrol 0 0.5 1 1.5 2+
HCQ for COVID-19
1st treatment shown to reduce risk in March 2020
*, now with p < 0.00000000001 from 411 studies, recognized in 46 countries.
No treatment is 100% effective. Protocols combine treatments. * >10% efficacy, ≥3 studies.
4,300+ studies for 75 treatments.
Retrospective database analysis of chronic HCQ users and matched control patients, failing to match or adjust for the very different baseline risk for systemic autoimmune disease patients. Other research shows that the risk of COVID-19 for systemic autoimmune disease patients is much higher overall, Ferri et al. show OR 4.42, p<0.0011.
This study is excluded in the after exclusion results of meta analysis: not fully adjusting for the different baseline risk of systemic autoimmune patients.
risk of hospitalization, 46.0% higher, RR 1.46, p = 0.10, treatment 40 of 6,746 (0.6%), control 50 of 13,492 (0.4%), adjusted per study.
risk of case, 8.0% higher, RR 1.08, p = 0.50, treatment 97 of 6,746 (1.4%), control 183 of 13,492 (1.4%), adjusted per study.
Effect extraction follows pre-specified rules prioritizing more serious outcomes. Submit updates
Vivanco-Hidalgo et al., 9 Mar 2021, retrospective, Spain, peer-reviewed, 8 authors.
This PaperHCQAll
{ 'indexed': {'date-parts': [[2024, 3, 28]], 'date-time': '2024-03-28T02:34:54Z', 'timestamp': 1711593294776}, 'reference-count': 29, 'publisher': 'European Centre for Disease Control and Prevention (ECDC)', 'issue': '9', 'license': [ { 'start': { 'date-parts': [[2021, 3, 4]], 'date-time': '2021-03-04T00:00:00Z', 'timestamp': 1614816000000}, 'content-version': 'unspecified', 'delay-in-days': 0, 'URL': ''}], 'content-domain': {'domain': [], 'crossmark-restriction': False}, 'published-print': {'date-parts': [[2021, 3, 4]]}, 'abstract': '<jats:sec>\n' ' <jats:title>Background</jats:title>\n' ' <jats:p>Several clinical trials have assessed the protective potential of ' 'chloroquine and hydroxychloroquine. Chronic exposure to such drugs might lower the risk of ' 'infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or severe ' 'coronavirus disease (COVID-19).</jats:p>\n' ' </jats:sec>\n' ' <jats:sec>\n' ' <jats:title>Aim</jats:title>\n' ' <jats:p>To assess COVID-19 incidence and risk of hospitalisation in a ' 'cohort of patients chronically taking chloroquine/hydroxychloroquine.</jats:p>\n' ' </jats:sec>\n' ' <jats:sec>\n' ' <jats:title>Methods</jats:title>\n' ' <jats:p>We used linked health administration databases to follow a cohort ' 'of patients with chronic prescription of hydroxychloroquine/chloroquine and a control cohort ' 'matched by age, sex and primary care service area, between 1 January and 30 April 2020. ' 'COVID-19 cases were identified using International Classification of Diseases 10 ' 'codes.</jats:p>\n' ' </jats:sec>\n' ' <jats:sec>\n' ' <jats:title>Results</jats:title>\n' ' <jats:p>We analysed a cohort of 6,746 patients (80% female) with active ' 'prescriptions for hydroxychloroquine/chloroquine, and 13,492 controls. During follow-up, ' 'there were 97 (1.4%) COVID-19 cases in the exposed cohort and 183 (1.4%) among controls. The ' 'incidence rate was very similar between the two groups (12.05 vs 11.35 cases/100,000 ' 'person-days). The exposed cohort was not at lower risk of infection compared with controls ' '(hazard ratio (HR): 1.08; 95% confidence interval (CI): 0.83–1.44; p\u2009=\u20090.50). Forty ' 'cases (0.6%) were admitted to hospital in the exposed cohort and 50 (0.4%) in the control ' 'cohort, suggesting a higher hospitalisation rate in the former, though differences were not ' 'confirmed after adjustment (HR: 1·46; 95% CI: 0.91–2.34; p\u2009=\u20090.10).</jats:p>\n' ' </jats:sec>\n' ' <jats:sec>\n' ' <jats:title>Conclusions</jats:title>\n' ' <jats:p>Patients chronically exposed to chloroquine/hydroxychloroquine did ' 'not differ in risk of COVID-19 nor hospitalisation, compared with controls. As controls were ' 'mainly female, findings might not be generalisable to a male population.</jats:p>\n' ' </jats:sec>', 'DOI': '10.2807/', 'type': 'journal-article', 'created': {'date-parts': [[2021, 3, 5]], 'date-time': '2021-03-05T11:20:18Z', 'timestamp': 1614943218000}, 'update-policy': '', 'source': 'Crossref', 'is-referenced-by-count': 8, 'title': 'Incidence of COVID-19 in patients exposed to chloroquine and hydroxychloroquine: results from a ' 'population-based prospective cohort in Catalonia, Spain, 2020', 'prefix': '10.2807', 'volume': '26', 'author': [ { 'ORCID': '', 'authenticated-orcid': False, 'given': 'Rosa Maria', 'family': 'Vivanco-Hidalgo', 'sequence': 'first', 'affiliation': [ {'name': 'These authors contributed equally'}, { 'name': 'Agència de Qualitat i Avaluació Sanitàries de Catalunya (AQuAS), ' 'Departament de Salut Generalitat de Catalunya, Carrer de Roc ' 'Boronat 81-95, Barcelona, Spain'}]}, { 'given': 'Israel', 'family': 'Molina', 'sequence': 'additional', 'affiliation': [ { 'name': 'Infectious Diseases Department, Hospital Universitario Vall ' "d'Hebron, PROSICS Barcelona, Universitat Autònoma de Barcelona, " 'Barcelona, Spain'}, {'name': 'These authors contributed equally'}]}, { 'given': 'Elisenda', 'family': 'Martinez', 'sequence': 'additional', 'affiliation': [ { 'name': 'Agència de Qualitat i Avaluació Sanitàries de Catalunya (AQuAS), ' 'Departament de Salut Generalitat de Catalunya, Carrer de Roc ' 'Boronat 81-95, Barcelona, Spain'}]}, { 'given': 'Ramón', 'family': 'Roman-Viñas', 'sequence': 'additional', 'affiliation': [ { 'name': 'Agència de Qualitat i Avaluació Sanitàries de Catalunya (AQuAS), ' 'Departament de Salut Generalitat de Catalunya, Carrer de Roc ' 'Boronat 81-95, Barcelona, Spain'}]}, { 'given': 'Adrián', 'family': 'Sánchez-Montalvá', 'sequence': 'additional', 'affiliation': [ { 'name': 'Infectious Diseases Department, Hospital Universitario Vall ' "d'Hebron, PROSICS Barcelona, Universitat Autònoma de Barcelona, " 'Barcelona, Spain'}]}, { 'given': 'Joan', 'family': 'Fibla', 'sequence': 'additional', 'affiliation': [ { 'name': 'Institut de Recerca Biomedica de Lleida, Av. Alcalde Rovira ' 'Roure, 80, 25198, Lleida, Spain'}, { 'name': 'Unitat de Genètica Humana, Departament de Ciències Mèdiques ' 'Bàsiques, Universitat de Lleida, Av. 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