Clinical Characteristics and In-Hospital Outcomes of Patients Aged 90 Years or Older Admitted to an Internal Medicine Department: A Single-Center Study From Portugal.

introductionThe number of patients aged 90 years or older requiring hospital care continues to increase. However, contemporary data describing their clinical characteristics and in-hospital outcomes in Portuguese Internal Medicine departments remain limited. This study aimed to describe the demographic characteristics, functional status, chronic medication use, primary admission diagnoses, length of hospital stay, discharge disposition, and in-hospital mortality of patients aged 90 years or older admitted to an Internal Medicine Department. MATERIALS AND

methodsA single-center retrospective descriptive study was conducted including 89 consecutive patients aged 90 years or older admitted to the Internal Medicine Department of a Portuguese tertiary hospital between January and December 2025. Functional status was assessed using the Barthel Index, and comorbidity was evaluated with the Charlson Comorbidity Index.

resultsEighty patients (90%) were nonagenarians, and nine (10%) were centenarians. Most patients were female (n = 57, 64%), with a mean age of 94 ± 3.2 years. Before admission, 69 (77%) lived at home, whereas 20 (23%) were institutionalized. At admission, 48 (54%) patients were completely dependent, 30 (34%) were partially dependent, and 11 (12%) were independent in activities of daily living. Almost all patients (n = 88, 99%) were receiving chronic medication, and 54 (61%) met the criteria for polypharmacy (≥5 medications). Antihypertensive therapy was prescribed in 61 (69%) patients. Among the 32 patients treated with antihypertensive monotherapy, an angiotensin-converting enzyme inhibitor was the most prescribed drug (n = 16, 50%). Antipsychotics were prescribed in 29 (33%) patients and benzodiazepines in 24 (27%). Respiratory tract infection was the most frequent admission diagnosis (n = 47, 53%), followed by urinary tract infection (n = 22, 25%) and hyponatremia (n = 6, 7%). The mean hospital stay was 10 ± 7.8 days (range, 2-46 days). Overall, 74 (83%) patients were discharged, whereas 15 (17%) died during hospitalization. All patients who died were completely dependent at admission.

conclusionsPatients aged 90 years or older admitted to an Internal Medicine Department commonly presented with functional dependence, multiple comorbidities, and polypharmacy. Respiratory tract infections were the leading cause of hospitalization, and in-hospital mortality was 17%. These findings provide contemporary data on the characteristics and hospital outcomes of very old adults and support the importance of comprehensive clinical assessment, including regular review of chronic medication, in this growing patient population.