Trends in prevalence and the effects on hospital outcomes of dementia in patients hospitalized with acute COPD exacerbation.

Aims: To assess changes in prevalence and the effects on hospital outcomes of dementia among patients hospitalized with an acute exacerbation of chronic obstructive pulmonary disease (AE-COPD); and to evaluate sex-differences, as well as the impact of COVID-19 pandemic in this relationship.

Methods: We used a nationwide discharge database to select patients admitted with AE-COPD in Spain from 2011 to 2020. We identified those with any type of dementia, vascular dementia (VaD) or Alzheimer's disease (AD).

Results: We identified 658,429 hospitalizations with AE-COPD (4.45% had any type of dementia, 0.79% VaD and 1.57% AD). The presence of any type of dementia remained stable from 2011 to 2015, and increased significantly between 2016 and 2020. For VaD, the time trend showed no change until 2020, when a significant increment was found. The probability of AD decreased significantly overtime. The in-hospital mortality (IHM) among patients with any type of dementia remained stable overtime until 2020, when it increased significantly. Older age, higher comorbidity, COVID-19, and use of mechanical ventilation were variables associated to IHM. Women had lower risk of dying in the hospital than men in all subgroups.

Conclusions: After a previous period of stability, the prevalence of any type of dementia increased over the last 5 years of the study, although we identified different trends depending on the specific cause of dementia. The IHM remained stable overtime until 2020, when it increased, probably related to the COVID-19 pandemic. It is remarkable the protective effect of female sex for IHM.