Profile of insurance coverage in a national inpatient sample

Background: Contributing factors to the erosion of Americans' health insurance coverage include rising healthcare costs, stringent utilization review, restriction in choices, and lower payments and more restrictive billing from Medicaid and other public programs. This erosion has led to an unprecedented increase in the number of uninsured Americans and a general increase of “underinsurance” among working age adults. To identify the hospitals most strongly impacted by health insurance trends, this study investigated the relationships between hospital characteristics and patterns of insurance coverage in a national inpatient sample. Methods: Data came from the 2007 Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project, a stratified probability sample containing over 8 million inpatient hospital stays from 1,044 hospitals in 40 states and representing approximately 20% of US community hospitals. Outcomes were the percentage of patients relying on Medicare, Medicaid, private/commercial (HMO and non-HMO), or their own payment out-of-pocket (i.e., without insurance coverage for the visit). Categorical predictors in a multivariate analysis of variance (MANOVA) included bed size, location, teaching status, and region. Continuous predictors included percentages of patients 21-64 years old, 65+ years old, female, Black, Hispanic, Asian/Pacific Islander, Native American, other race, and from zip codes in the top three income quartiles. Reference classes included percentages of patients < 21 years, male, white, and in the lowest income quartile. Results: Hospitals reported an average of 47% of visits expected to be paid by Medicare, 16.2% by Medicaid, 28.6% by private insurance, and 5% of visits uncovered. However, payers showed a wide range of percentages, with hospitals reporting up to 61.5% of visits from uninsured patients. Significant multivariate differences in insurance coverage resulted from bed size, location, region, and patient age, gender, racial, and socioeconomic distributions. Urban and Southern hospitals serving adults, men, and lowest income patients had greater Medicare coverage. Medicaid was common among hospitals that were medium-sized, located in the West or Northeast, and served proportionally more children, women, Black, Hispanic, and lowest-income patients. Hospitals serving proportionally more female, white, and higher-income patients were more likely to be paid by private insurance. Hospitals in the Northeast and South, rural hospitals, and hospitals serving adults 21-64 were most likely to see uninsured patients. Conclusions: Hospital characteristics were associated with significant variations in the distribution of insurance coverage across the country. Findings suggest that programmatic changes may disproportionally impact certain hospitals based on their characteristics and the patients they serve.