Impact of Coexisting Dementia on Inpatient Outcomes for Patients Admitted with a COPD Exacerbation.

Purpose: People with COPD are at a higher risk of cognitive dysfunction than the general population. However, the additional impact of dementia amongst such patients is not well understood, particularly in those admitted with a COPD exacerbation. We assessed the impact of coexisting dementia on inpatient mortality and length of stay (LOS) in patients admitted to hospital with a COPD exacerbation, using the United States based National Inpatient Sample database. Patients and Methods: Patients aged over 40 years and hospitalised with a primary diagnosis of COPD exacerbation from 2011 to 2015 were included. Cases were grouped into patients with and without dementia. Multivariable logistic regression analysis, stratified by age, was used to assess risk of inpatient deaths. Cox regression was carried out to compare death rates and competing risk analysis gave estimates of discharge rates with time to death a competing variable. Results: A total of 576,381 patients were included into the analysis, of which 35,372 (6.1%) had co-existent dementia. There were 6413 (1.1%) deaths recorded. The odds of inpatient death were significantly greater in younger patients with dementia (41-64 years) [OR (95% CI) dementia vs without: 1.75 (1.04-2.92), p=0.03]. Cases with dementia also had a higher inpatient mortality rate in the first 4 days [HR (95% CI) dementia vs without: 1.23 (1.08-1.41), p=0.002] and a longer LOS [sub-hazard ratio (95% CI) dementia vs without: 0.93 (0.92-0.94), p<0.001]. Conclusion: Dementia as a comorbidity is associated with worse outcomes based on inpatient deaths and LOS in patients admitted with COPD exacerbations.