) or severe (eGFR RESULTS: A total of 0000 patients were included. Of these, 00% had moderate and 00% severe renal dysfunction. At 00 months, patients with renal dysfunction had higher rates (?0.000) of all-cause (0.0%, 0.0% and 00.0% in patients with none or mild, moderate and severe renal dysfunction, respectively) and cardiovascular mortality (0.0%, 0.0% and 00.0%, respectively). After multivariable adjustment, severe renal dysfunction was associated with a higher risk of all-cause (hazard ratio (HR) 0.00, 00% confidence interval (CI) 0.00-0.00, ?=?0.000) and cardiovascular death (HR 0.00, 00% CI 0.00-0.00, ?=?0.000), whereas non-fatal events were unaffected. Acute kidney injury incidence was significantly higher in ST-elevation myocardial infarction versus non-ST-elevation acute coronary syndrome patients (00.0% vs. 0.0%, ?=?0.000) and in those with reduced baseline renal function (?0.000), and it was associated with increased mortality independently from baseline renal function and clinical presentation. CONCLUSIONS: Baseline renal dysfunction is highly prevalent and is associated with higher mortality in elderly acute coronary syndrome patients undergoing percutaneous coronary intervention. Acute kidney injury occurs more frequently among ST-elevation myocardial infarction patients and those with pre-existing renal dysfunction and is independently associated with one-year mortality. 