Abstract: GeroScience https://doi.org/10.1007/s11357-021-00499-8 ORIGINAL ARTICLE Premorbid aspirin use is not associated with lower mortality in older inpatients with SARS‑CoV‑2 pneumonia Coralie Sullerot · Kevin Bouiller · Caroline Laborde · Marine Gilis · Amélie Fèvre · Arthur Hacquin · Patrick Manckoundia · Florence Hoefler · Messaline Bermejo · Aline Mendes · Christine Serratrice · Virginie Prendki · Stéphane Sanchez · Alain Putot · On behalf of ESGIE (European Society of Clinical Microbiology, European Society of Clinical Microbiological and Infectious Diseases, Study Group for Infections in the Elderly) Received: 21 September 2021 / Accepted: 13 December 2021 © The Author(s), under exclusive licence to American Aging Association 2021 Abstract Platelet aggregation has been associated with COVID-19 pathogenesis. In older patients hospitalized for SARS-CoV-2 pneumonia, we aimed to investigate the association between aspirin use before admission and the risk of in-hospital all-cause mortality. We performed a retrospective international cohort study in five COVID-19 geriatric units in France and Switzerland. Among 1,357 consecutive hospitalized patients aged 75 or older and testing positive for SARS-CoV-2, we included 1,072 with radiologically confirmed pneumonia. To adjust for confounders, a propensity score for treatment was created, and stabilized inverse probability of treatment weighting (SIPTW) was applied. To assess the association between aspirin use and in-hospital 30-day mortality, SIPTW-adjusted Kaplan–Meier and Cox proportional hazards regression analyses were performed. Of the 1047 patients with SARS-CoV-2 pneumonia and median age 86 years, 301 (28.7%) were taking aspirin treatment before admission. One hundred forty-seven (34.3%) patients who had taken aspirin died in hospital within 1 month vs 118 patients (30.7%) without aspirin. After SIPTW, aspirin treatment was not significantly associated with lower mortality (adjusted hazard ratio: 1.10 [0.81–1.49], P = .52). Moreover, patients on aspirin had a longer hospital stay and were C. Sullerot · A. Hacquin · P. Manckoundia · A. Putot Department of Geriatric Internal Medicine, Dijon University Hospital, Dijon, France A. Mendes Division of Geriatrics, Geneva University Hospitals, Geneva, Switzerland K. Bouiller Department of Infectious Diseases, Besançon University Hospital, Besançon, France C. Serratrice · V. Prendki Division of Internal Medicine for the Aged, Geneva University Hospitals, Geneva, Switzerland C. Laborde · A. Fèvre Department of Geriatric Internal Medicine, Nimes University Hospital, Nimes, France V. Prendki Division of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland M. Gilis Department of Geriatrics, Besançon University Hospital, Besançon, France S. Sanchez Department of Clinical Research, Troyes Hospital, Troyes, France F. Hoefler · M. Bermejo Department of Internal Medicine and Infectious Diseases, Troyes Hospital, Troyes, France A. Putot (*) Service de Médecine Interne Gériatrie, Hôpital de Champmaillot CHU, 21079 Dijon Cedex, France e-mail: alain.putot@chu-dijon.fr Vol.: (0123456789) 13 GeroScience more frequently transferred to the intensive care unit. In a large multicenter cohort of older inpatients with SARS-CoV-2 pneumonia, aspirin use before admission did not appear to be associated with an improved prognosis. Keywords Aspirin · Antiplatelet · Pneumonia · Coronavirus · COVID-19 · Aged · Mortality