The Impact of Dementia on Patients Admitted with Acute Respiratory Failure: A Nationwide Study

Abstract

PURPOSE: Acute respiratory failure (ARF) is one of the leading causes of mortality and morbidity in the United States. Dementia is prevalent in the elderly population and its impact as an independent risk factor for worse clinical outcomes for patients admitted with ARF on a nationwide scale has yet to be determined. METHODS: Using the National Inpatient Sample (NIS) Database from 2017 to 2020, a retrospective study of adult patients with principal diagnosis of ARF (hypoxic or hypercapnic failure) with secondary diagnosis with or without dementia according to ICD-10 codes. Several comorbidities and demographics, including age, race, and gender, were analyzed. The primary endpoint was mortality, while the secondary endpoints included mechanical ventilation, tracheostomy, and length of stay in days. Multivariate logistic regression model analysis was used to adjust for confounders, with a p value less than 0.05 considered statically significant. Odds ratio was adjusted for age, gender, race, insurance status, charlson comorbidity index, in-hospital sepsis, diabetes mellitus, hypertension, supraventricular tachycardia, and obesity. RESULTS: The study included 1,795,630 patients admitted with ARF, 112,175 of which had dementia. The Mean age in the dementia group was 80 years vs. 65 years in the control group. In the dementia group, 62% were females compared to 55% in the other group. 73% of both groups were Caucasian white. Statistically significant comorbidities noticed in the dementia group included Diabetes Mellitus (36% vs. 35%), Hypertension (81% vs. 72%), sepsis (6% vs. 5%), and supraventricular tachycardia (29% vs. 20%) (p value less than 0.01). Rates and odds of mortality were higher in the dementia group (15,704 (14%) vs. 151,511 (9%), p value <0.01, aOR 1.08, p value <0.01). Regarding secondary outcomes, in-hosital mechanical ventilation, patients with dementia had lower rates however higher adjusted odds (30,287 (27%) vs. 471,367 (28%), p value <0.01, aOR +1.2 p value <0.01). For tracheostomy patients with dementia had lower rates and adjusted odds (762 (0.7) vs. 16,834 (1), p value <0.01, aOR 0.91 p value 0.33). Length of stay (LOS) in days was higher in the dementia group 6.5 vs 6.2 with an adjusted means of +0.3 days, p value <0.01. CONCLUSIONS: Clinicians should be aware that dementia was found to be an independent risk factor for mortality in patients admitted with ARF. CLINICAL IMPLICATIONS: Patients with dementia that are admitted with acute respiratory failure were found to be sicker and likely would require a higher level of care. Clinicians should be aware of this independent risk factor and promptly identify signs and symptoms of clinical deterioration in this high-risk group. Even though patients with dementia had lower rates of in-hospital mechanical ventilation. This can be explained by the fact that patients with dementia are older and might have a "Do Not Intubate" advanced directive or family deciding not to proceed with more aggressive care. However, it is very important to point out that even though the rates were lower, dementia was found to be an independent risk factor for in-hospital mechanical ventilation through the multivariate regression analysis.