Clinical Characteristics, Frailty, and Prognostic Predictors in Patients Aged 75 and Older With Acute Coronary Syndrome

This observational study will evaluate clinical characteristics,frailty, and prognostic predictors in patients aged 75 years and older hospitalized with acute coronary syndrome (ACS). The study is designed with two complementary components: Retrospective cohort (≈350 patients): Data will be collected from electronic medical records of patients previously hospitalized with ACS. Variables include demographics, comorbidities, laboratory findings (hematology, biochemistry, cardiac biomarkers), ECG changes, echocardiographic parameters, and coronary angiography results. Standard risk scores (TIMI, GRACE, Syntax) will be compared with observed outcomes. Data integrity will be ensured through double-entry verification, and missing values will be addressed using multiple imputation. Prospective cohort (≈800 patients): Patients will be consecutively enrolled at admission with ACS. Data collection will include the same parameters as in the retrospective cohort, with additional dynamic laboratory monitoring and frailty assesment. Frailty will be assessed within 48 hours of admission using the Rockwood Frailty Scale, performed by trained investigators. Echocardiography and coronary angiography will be conducted according to institutional protocols. Patients will be followed during hospitalization and 6 months after discharge, using structured case report forms and telephone interviews. Outcomes will include major adverse cardiovascular events (MACE), all-cause mortality, rehospitalizations, PCI-related complications (vascular, gastrointestinal bleeding, neurological), and treatment adherence. Data management and statistical analysis: All data will be entered into a secure, password-protected database with regular quality control checks. Statistical analyses will be performed using SPSS v.27 and R. Methods include descriptive statistics, univariate and multivariate logistic regression, ROC curve analysis, and comparison of AUC values. Predictors identified in the retrospective cohort will be validated in the prospective cohort. The study team consists of cardiologists, statisticians, and trained research staff responsible for patient enrollment, frailty assessment, and data monitoring. Complications and adverse events will be defined according to standardized cardiology guidelines and adjudicated by an independent committee. The study is conducted in accordance with the Declaration of Helsinki. Retrospective data collection does not require informed consent, while prospective participants will provide written informed consent. The expected contribution is improved risk stratification and more personalized therapeutic approaches for elderly patients with ACS.