Abstract

Background: Alzheimer’s disease (AD) may be the most critical medical condition of the 21st century in part because it affects more than 5 million Americans, including one out of eight Americans aged 65 or older, and nearly half of those being over the age of 85. It is also recognized that cardiovascular disease (CVD) risks can catalyze the development of AD. AD and congestive heart failure (CHF) often occur together and thus increase the cost of care and health resources. We investigated the prevalence of AD in patients hospitalized with CHF. In addition, factors that affect the outcomes of this special population were determined.
Methods: Data from the National Inpatient Samples (NIS) were extracted and analyzed using ICD 9 codes (CHF 428, PD 331) for the main diagnosis. For continuous variables, we calculated the mean and standard deviations and evaluated significant differences of these factors by Alzheimer disease status using the t-test. For categorical variables, we obtained the counts (proportions) and evaluated significant differences using the Chi-square and Fisher’s exact test Propensity score was utilized to match age, gender and race using logistic model for hospital death and generalized linear model for length of stay (LOS) and hospital charges.
Results: The overall characteristics of matched participants with CHF and AD status showed that average age of inpatients was ~84 (SD=6.31). The prevalence of inpatients with both CHF and AD was significant (p < .0001) for females, 62.91% (n = 12,054) and for males, 37.09% (n = 7,107). White patients with CHF and AD were predominant with 76.20% (14,600) when compared with other races. While diabetes (26.05%), obstructive sleep apnea (5.67%), morbid-obesity (3.36%) were prevalent for inpatient without AD, renal insufficiency (3.60%) and stroke (2.10%) were prevalent in patient with AD. Patients with low income ($1 - $38,999) were admitted more with 6,290 (33.40%) than those with higher income ($39,000 - > $63,000). Finally, patient with CHF and AD stayed longer with higher mortality rates than those without AD, p< 0.0001. Age and race significantly affected all the outcomes, p< 0.0001 while gender showed significance for hospital death and charges (p< 0.0001). Hospital death was not affected by patient’s household income but its interesting to note that LOS was affected by patients with household income between $39,000 - $62,999 and hospital charge by patients with higher household incomes from $48.000 and above. Stroke was the only comorbidity that significantly (p<0.0001) affected hospital death while diabetes significantly (p< 0.0001) affected LOS. However, diabetes, stroke and morbid obesity significantly (p< 0.0068) influenced the patient hospital charges. For hospital characteristics, it is important to note that LOS and hospital charge were significantly (p =0.0001) affected irrespective of the hospital teaching status.
Conclusion: The prevalence of CHF and AD may be higher in females than males, with white patients admitted more often than other races. Patient age, gender, comorbidities, economic status, LOS and mortality rates play a significant role in the prevalence of CHF and AD. In addition, this study has confirmed that Alzheimer's disease and CHF may occur together and increase the cost of care and health resource utilization. Impaired cognition in AD patients may lead to more frequent hospital readmissions with CHF patients and even more for patients with comorbidities such as diabetes, stroke and morbid obesity. Readmission leads to increase in length of stay and increased mortality rates for this population.