[Impact of aging on hospital caseload]

The progressive ageing of the population has led to a rise in the number of hospital admissions among people older than 64 years. The present study analyses the impact of this phenomenon comparing the case-mix of patients older and younger than 65 years.

An analysis of the case-mix of all patients admitted to two acute hospitals of Barcelona Spain has been performed using the minimum basic data set of hospital discharges during 1997. The patients were grouped according to diagnosis-related groups (DRG). The characteristics of disease severity and complexity (admissions through emergencies department, DRG average weight, Charlson comorbidity index, average length of stay adjusted by case-mix, percentage of patients with an abnormal length of stay, readmissions and mortality rates were compared between the group of patients of 0-64 years and the group of 65 years and over. A further analysis was carried out for three subgroups of the aged patient population: 65-74, 75-84 and > 84 years.

The patients group of 65 years and over presented, in comparison with the younger than 65 qulaction, a higher average weight (1.16 vs 0.96), a higher percentage of admissions through emergency department (49.2% vs 44.4%), more comorbidity (Charlson's Index of 0.98 vs 0.66), a higher average length of stay adjusted DRG (9.4 vs 8.1), a higher percentage of patients with an abnormal length of stay (4.7% vs 3.2%), a higher readmissions percentage (8.6% vs 7.5%) and a higher mortality (6.3% vs 1.6%). All observed differences between the two groups were statistically significant. The analysis of the three subgroups of patients of 65 years and over showed that the variables admissions through the emergency department, length of stay and rate of mortality were significantly related to ageing, while the factor of complexity of comorbidity remained stable for all the subgroup of patients.

The case-mix of patients older than 65 years presents some characteristics associated with a higher complexity, severity and comorbidity, which imply more hospitalization days in relation to younger patients. Hospitals and the health care system at large should design specific strategies to face the fast and progressive ageing of patients admitted to hospitals, since this means a relevant change of the case-mix and the profile of health care requirements.