biostudies-literatureXu FChinese Academy of Medical Sciences (CAMS) Innovation Fund for Medical SciencesChina-Japan Friendship HospitalNational Key Research and Development Program of ChinaChinese Academy of Medical Sciences (CAMS) Innovation Fund for Medical Sciences (CIFMS)800https://www.ebi.ac.uk/biostudies/studies/S-EPMC12376747biostudies-literatureUnknown30(1)<h4>Background</h4>Individuals aged 80 and older face a notably increased risk of venous thromboembolism (VTE) and mortality after SARS-CoV-2 infection. Clinical guidelines recommend routine pharmacological thromboprophylaxis, yet its application in oldest-old patients remains insufficiently studied.<h4>Aims</h4>To assess the efficacy and safety of low-molecular-weight heparin (LMWH) thromboprophylaxis in hospitalized COVID-19 patients aged 80 years and older.<h4>Methods</h4>We conducted a multicenter, prospective cohort study enrolling in-hospital COVID-19 patients aged ≥ 80 years from six tertiary hospitals in China between December 2022 and January 2023. The clinical outcomes were VTE, all-cause mortality and bleeding events. Patients were followed up for 3 months after discharge. Multivariate Cox regression models were used to identify risk factors and evaluate the impact of LMWH prophylaxis on clinical outcomes.<h4>Results</h4>Among 1526 patients aged ≥ 80 years, 41.6% received LMWH prophylaxis. LMWH prophylaxis significantly reduced VTE risk by 50% (HR 0.50, 95% CI 0.33-0.75) and mortality risk by 20% (HR 0.80, 95% CI 0.65-0.99), without increasing bleeding risk (HR 0.90, 95% CI 0.60-1.34). Male, history of stroke, critical illness on admission and hemoglobin < 90 g/L were identified as risk factors of bleeding. LMWH prophylaxis remained effective in preventing VTE and demonstrated favorable safety particularly in male patients and patients with hemoglobin < 90 g/L.<h4>Discussion and conclusion</h4>LMWH may be safe and effective for thromboprophylaxis in the oldest-old COVID-19 patients, even in patients with high bleeding risk. Further studies are needed to verify our findings.European journal of medical researchImpact of prophylactic anticoagulation on hospitalized COVID-19 patients aged over 80 years: a multicenter prospective cohort study.PMC12376747ZRJY2023-QM202021-I2M-1-0492023YFC25072012021-I2M-1-001Xie WWang BWang CChen LWang DXu FZhai ZZhang SLiu WDeng CFan GZhang ZTao YZhang YYang PWan JHan JWang YWu WfalseImpact of prophylactic anticoagulation on hospitalized COVID-19 patients aged over 80 years: a multicenter prospective cohort study.<h4>Background</h4>Individuals aged 80 and older face a notably increased risk of venous thromboembolism (VTE) and mortality after SARS-CoV-2 infection. Clinical guidelines recommend routine pharmacological thromboprophylaxis, yet its application in oldest-old patients remains insufficiently studied.<h4>Aims</h4>To assess the efficacy and safety of low-molecular-weight heparin (LMWH) thromboprophylaxis in hospitalized COVID-19 patients aged 80 years and older.<h4>Methods</h4>We conducted a multicenter, prospective cohort study enrolling in-hospital COVID-19 patients aged ≥ 80 years from six tertiary hospitals in China between December 2022 and January 2023. The clinical outcomes were VTE, all-cause mortality and bleeding events. Patients were followed up for 3 months after discharge. Multivariate Cox regression models were used to identify risk factors and evaluate the impact of LMWH prophylaxis on clinical outcomes.<h4>Results</h4>Among 1526 patients aged ≥ 80 years, 41.6% received LMWH prophylaxis. LMWH prophylaxis significantly reduced VTE risk by 50% (HR 0.50, 95% CI 0.33-0.75) and mortality risk by 20% (HR 0.80, 95% CI 0.65-0.99), without increasing bleeding risk (HR 0.90, 95% CI 0.60-1.34). Male, history of stroke, critical illness on admission and hemoglobin < 90 g/L were identified as risk factors of bleeding. LMWH prophylaxis remained effective in preventing VTE and demonstrated favorable safety particularly in male patients and patients with hemoglobin < 90 g/L.<h4>Discussion and conclusion</h4>LMWH may be safe and effective for thromboprophylaxis in the oldest-old COVID-19 patients, even in patients with high bleeding risk. Further studies are needed to verify our findings.2025-01-01T00:00:00Z2025 Aug2026-06-01T13:52:37.876Z2026-04-08T13:06:01.582ZS-EPMC123767474085533310.1186/s40001-025-03041-0