Major cardiovascular events after admission to intensive care units: A Danish nationwide cohort study

Abstract Background Patients admitted to the intensive care unit (ICU) present overall excess morbidity and mortality. Knowledge on the risk of major cardiovascular events (MACE) in the general ICU population is sparse. In this nationwide registry-based cohort study, we assessed the incidence of 30-day and 1-year mortality as well as MACE in ICU survivors according to pre-existing cardiovascular disease and admission specific demographics. Methods We identified all adult individuals (≥18 years) who survived a first-time admission to any ICU in Denmark from 2005 through 2017, using nationwide administrative registries. Pre-existing cardiovascular disease was defined as at least one diagnosis registered up to 10 years prior to admission. MACE was a composite of myocardial infarction (MI), stroke, coronary revascularization, or cardiovascular death. Incidence of outcomes was calculated by dividing number of events by number of patients in the study population, and the associated 95% confidence intervals (CI) were computed according to the Clopper-Pearson method. Cox proportional hazard models were used to analyze the association of admission specific demographics on time-to-first event of MACE within one year from hospital discharge. Results We identified 217,157 individuals who had survived an ICU admission, of whom 131,814 (60.7%) had no pre-existing cardiovascular disease. Of these, 10,758 (8.9%) presented with MI, stroke, or coronary revascularization, either as index diagnose or during admission. The 30-day mortality in the overall population was 6.5% (95% CI: 6.4-6.6) and increased to 17.3% (95% CI: 17.1-17.4) at one year from hospital discharge. The cumulative incidence of MACE in the entire population was 2.4% (95% CI: 2.4-2.5) at 30 days and 5.8% (95% CI: 5.7-5.9) at one year. Among patients without pre-existing cardiovascular disease and without MI, stroke, or coronary revascularization during admission, the cumulative incidence of 1-year MACE was 3.5% (95% CI: 3.4-3.6). In these patients, the incidence of MACE at one year when treated with mechanical ventilation and vasopressors/inotropes, was 5.1% (95% CI: 4.9-5.3) and 5.5% (95% CI: 5.3-5.8) in patients, respectively. The risk of 1-year MACE varied by admission diagnosis, with cardiovascular and respiratory admissions carrying the highest risks (hazard ratios (HR) (95% CI): 2.19 (2.03-2.35) and 1.28 (1.17-1.39), respectively). Patients who underwent cardiovascular surgery (other than coronary revascularization) during admission had an increased risk of 1-year MACE (HR (95% CI): 1.67 (1.41-1.97)). Conclusion In the Danish population of patients who survived admission to an intensive care unit, the incidence of MACE more than doubled from 30 days to 1 year after hospital discharge. Admissions with cardiovascular and respiratory diseases had the highest risk of 1-year MACE in patients without pre-existing cardiovascular disease and without MI, stroke, or coronary revascularization during admission.Figure 1 Figure 2