SummaryWe describe the trends over time in patient’s diagnoses, case-complexity, case-severity, length of stay and mortality rate during the last 15 years in an academic division of general internal medicine (GIM). Our study shows that GIM patients presented with a broad spectrum of diseases. Moreover important changes were observed in the patient characteristics, i.e. a progressive increase in urgent admissions, severe medical conditions and elderly population. This evolution was associated with a significant rise in case-severity and case-complexity which explains the observed increase in hospital mortality rate. These variables should be accounted for when analyzing processes and outcomes of inpatient medical care in internal medicine.