The impact of comorbidities, regional trends, and hospital factors on discharge dispositions and hospital costs after acoustic neuroma microsurgery: a United States nationwide inpatient data sample study (2005–2009)
Authors: Sonig Ashish , Khan Imad Saeed , Wadhwa Rishi , Thakur Jai Deep , Nanda Anil 
Published: September 2012

Object
Hospitalization cost and patient outcome after acoustic neuroma surgery depend on several factors. There is a paucity of data regarding the relationship between demographic features such as age, sex, race, insurance status, and patient outcome. Apart from demographic factors, there are several hospital-related factors and regional issues that can affect outcomes and hospital costs. To the authors' knowledge, no study has investigated the issue of regional disparity across the country in terms of cost of hospitalization and discharge disposition.

Methods
The authors analyzed the Nationwide Inpatient Sample (NIS) database over the years 2005–2009. Several variables were analyzed from the database, including patient demographics, comorbidities, and surgical complications. Hospital variables, such as bedsize, rural/urban location, teaching status, federal or private ownership, and the region, were also examined. Patient outcome and increased hospitalization costs were the dependent variables studied.

Results
A total of 2589 admissions from 242 hospitals were analyzed from the NIS data over the years 2005–2009. The mean age was 48.99 ± 13.861 years (± SD), and 304 (11.7%) of the patients were older than 65 years. The cumulative cost incurred by the hospitals from 2005 to 2009 was $948.77 million. The mean expenditure per admission was $76,365.09 ± $58,039.93. The mean total charges per admission rose from $59,633.00 in 2005 to $97,370.00 in 2009. The factors that predicted most significantly with other than routine (OTR) disposition outcome were age older than 65 years (OR 2.22, 95% CI 1.411–3.518; p < 0.001), aspiration pneumonia (OR 16.085, 95% CI 4.974–52.016; p < 0.001), and meningitis (OR 11.299, 95% CI 3.126–40.840; p < 0.001). When compared with patients with Medicare and Medicaid, patients with private insurance had a protective effect against OTR disposition outcome. Higher comorbidities predicted independently for OTR disposition outcome (OR 1.409, 95% CI 1.072–1.852; p = 0.014). The West region predicted negatively for OTR disposition outcome. Large hospitals were independently associated with higher hospital charges (OR 4.269, 95% CI 3.106–5.867; p < 0.001). The West region had significantly higher (p < 0.001) mean hospital charges than the other regions. Patient factors such as meningitis and aspiration pneumonia were strong independent predictors of increased hospital charges (p < 0.001). Higher comorbidities (OR 1.297, 95% CI 1.036–1.624; p = 0.023) and presence of neurofibromatosis Type 2 (OR 2.341, 95% CI 1.479–3.707; p < 0.001) were associated with higher hospital charges.

Conclusions
The authors' study shows that several factors can affect patient outcome and hospital charges for patients who have undergone acoustic neuroma surgery. Factors such as younger age, higher ZIP code income, less comorbidity, private insurance, elective surgery, and the West region predicted for better disposition outcome. However, the West region, higher comorbidities, and weekend admissions were associated with higher hospitalization costs.