Depression in Alzheimer’s disease hospitalized patients: A descriptive analysis of a nationwide database

Background Alzheimer’s disease (AD) is the leading cause of dementia worldwide. About 40‐50% of AD patients are also affected by depression, with mounting evidence suggesting its association with worse disease prognosis and negative outcomes, such as lower quality of life, higher mortality, and more hospitalizations, with a prolonged length of stay (LoS) and greater socioeconomic burden. This study aimed to describe the main sociodemographic characteristics and hospitalization outcomes of AD patients with a register of depression. Method A retrospective observational study was conducted using a Portuguese nationwide hospitalization database from all mainland public hospitals. All episodes of inpatients ≥65 years old with a primary or secondary diagnosis of AD (ICD‐9‐CM code 331.0), with a concomitant register of depression at any diagnostic position (codes 296.2X, 296.3X and 311), discharged between 2008‐2015, were selected. Descriptive statistics were performed using SPSS IBM v26®. Result A total of 1.637 hospitalizations were analysed. An upward trend has been registered from 65 (2008) to 407 episodes (2015), with most episodes occurring in female patients (73,7%), with a mean age of 80±6 (SD) years. Pneumonia (15,0%), urinary tract infections (8,5%), fracture of neck of femur/hip (6,5%), acute cerebrovascular disease (5,3%), and delirium, dementia, amnestic and other cognitive disorders (4,4%) were the most frequent primary diagnoses. A median LoS of 8 days (Q1‐Q3: 5‐14) was observed and a total of 162 (9,9%) patients died during hospitalization. Each episode had a mean estimated hospitalization charge of 3.219,15€, which represents a sum of 5.269.750,98€ for the total episodes analysed. Conclusion The increased register of depression can be explained by the improvement in the quality of hospital‐coded data, particularly secondary coding. Moreover, the data raises awareness of depression impact in the number, duration, and cost of hospitalized patients with AD, which could conduce to more diligent healthcare interventions.