Aspirin 50 mg vs. 100 mg in Elderly Cardiovascular Disease Patients

Elderly patients with cardiovascular disease face a high risk of both thrombotic and bleeding events when receiving antithrombotic therapy. The optimal dose of aspirin for secondary prevention in this population remains uncertain, particularly in Chinese elderly individuals. This multicenter, prospective cohort study aims to evaluate the effectiveness and safety of a lower dose of aspirin (50 mg daily) compared with the standard dose (100 mg daily) for secondary prevention of atherosclerotic cardiovascular disease (ASCVD) in Chinese patients aged 60 years and older. The study is an extension of the existing LAPIS cohort (ChiCTR1900021980), which has enrolled 5,448 participants receiving long-term aspirin for secondary prevention. Participants will be followed for an additional 2 years (total follow-up up to approximately 6 years) through telephone, clinic visits, and electronic medical records. The primary effectiveness outcome is the first occurrence of major adverse cardiovascular events (MACE), including non-fatal myocardial infarction, unstable angina, need for revascularization, non-fatal stroke, transient ischemic attack, and cardiovascular death (excluding intracranial bleeding). The primary safety outcome is the first occurrence of bleeding events (classified by BARC criteria). A secondary aim is to develop and validate a risk prediction model (nomogram) for thrombotic and bleeding events specifically for elderly Chinese patients receiving antithrombotic therapy, using LASSO regression and Cox proportional hazards models. The study will provide real-world evidence to guide individualized antithrombotic management in the aging Chinese population.

Background: Atherosclerotic cardiovascular disease (ASCVD) is a leading cause of mortality and disability in elderly individuals in China. Antithrombotic therapy, particularly aspirin, is the cornerstone of ASCVD secondary prevention. However, advancing age increases both thrombotic and bleeding risks. Current guidelines recommend aspirin 75-100 mg daily for secondary prevention, but evidence from Western populations may not fully apply to Chinese elderly, who have different body weights, comorbidities, and polypharmacy patterns. Preliminary data from the investigators' prior single-center studies suggested that a lower dose of aspirin (40-50 mg daily) provides comparable antiplatelet effects with fewer gastrointestinal adverse events in Chinese elderly. The ongoing LAPIS study (Low-dose Aspirin in the Prevention and Management of Cardiovascular Disease in Elderly Patients; ChiCTR1900021980) is a nationwide, multicenter, prospective cohort that has enrolled 7,611 participants (including 5,448 for secondary prevention) since April 2019. This protocol represents a 2-year extension of the LAPIS secondary prevention cohort to further assess the long-term effectiveness and safety of 50 mg daily versus 100 mg daily aspirin, and to develop a risk prediction model tailored to elderly Chinese patients receiving antithrombotic therapy. Primary Objectives: To compare the effectiveness (prevention of major adverse cardiovascular events, MACE) and safety (bleeding events) of aspirin 50 mg daily versus 100 mg daily in elderly Chinese patients (≥60 years) with established ASCVD receiving long-term aspirin for secondary prevention. Secondary Objective: To develop and internally/externally validate a prognostic model (nomogram) for predicting thrombotic events (MACE) and bleeding events in elderly Chinese patients on antithrombotic therapy, integrating demographic characteristics, comorbidities, polypharmacy, laboratory parameters, and other risk factors. Study Design: Multicenter, prospective, observational cohort study. No intervention is assigned; aspirin dose is determined by routine clinical practice. Study Population: Chinese patients aged ≥60 years with established ASCVD (including acute coronary syndrome, stable coronary artery disease, post-revascularization, ischemic cardiomyopathy, ischemic stroke, transient ischemic attack, or peripheral artery disease) who are on long-term aspirin (≥1 year) for secondary prevention. Participants were previously enrolled in the LAPIS study. Exposure: Participants are categorized into two groups according to their long-term daily aspirin dose: 50 mg daily group 100 mg daily group Dose categorization is based on the stable dose taken at baseline and maintained for at least 1 year. Number of Participants: 5,448 participants from the LAPIS secondary prevention cohort. Follow-up Duration: An additional 2 years of follow-up (after the original LAPIS follow-up), leading to a total follow-up period of up to Покажи пълното описание...

Inclusion Criteria: 1. Age ≥ 60 years. 2. Diagnosis of established atherosclerotic cardiovascular disease (ASCVD), including acute coronary syndrome, stable coronary artery disease, post-revascularization (percutaneous coronary intervention or coronary artery bypass grafting), ischemic cardiomyopathy, ischemic stroke, transient ischemic attack, or peripheral artery disease. 3. Long-term use of aspirin (≥1 year) for secondary prevention of ASCVD. 4. Available laboratory tests (within the past 3 months): complete blood count, urinalysis, routine stool examination and occult blood test, liver and kidney function, electrolytes, glucose, lipids, uric acid, coagulation function, etc. 5. Willing to provide written informed consent. Exclusion Criteria: 1. Hypersensitivity to aspirin or other salicylates, or any other component of the drug product; history of asthma induced by salicylates or nonsteroidal anti-inflammatory drugs (NSAIDs), or any other condition that, in the clinical judgment, makes the patient unsuitable for study participation. 2. Life expectancy ≤ 2 years due to non-cardiovascular causes. 3. Poor compliance (unable to adhere to prescribed medication or follow scheduled follow-up visits as judged by the investigator).