Age-Specific Differences in Non-Surgical Patients Requiring Intensive Care　― Trends and Prognostic Impact During the Past Decade ―

BACKGROUND: This study aimed to elucidate the age trends among non-surgical patients requiring intensive care over a 10-year period and the prognostic impact of aging in relation to their underlying etiologies. METHODS AND RESULTS: In all, 4,279 non-surgical patients requiring intensive care from 2012 to 2021 were enrolled in the study. Patient backgrounds and prognoses were compared among age 4 groups: Group A, age <60 years (n=910); Group B, age 60-69 years (n=1,062); Group C, age 70-79 years (n=1,355); and Group D, age ≥80 years (n=952). During the study period, the number of patients aged 60-69 years decreased significantly with time, whereas the number aged over 80 years increased significantly. A multivariate Cox regression model identified Group D as an independent predictor of 365-day all-cause mortality (hazard ratio [HR] 2.070; 95% confidence interval [CI] 1.619-2.646) relative to Group A. Multivariate logistic regression analysis indicated that the presence of sepsis was independently associated with 365-day mortality, especially in the cohort aged ≥80 years (HR 1.878; 95% CI 1.270-2.777; P=0.002). CONCLUSIONS: The mean age of patients requiring non-surgical intensive care is increasing annually, and greater age was identified as a significant factor associated with a higher 365-day mortality rate. The presence of sepsis was linked to increased 365-day mortality among older individuals.