General findings

The number of uninsured hospitalizations in America grew steadily from 1998 to 2007 (table 1). In 1998, there were 1.8 million uninsured stays compared to more than 2.3 million uninsured stays in 2007—a 31 percent increase in 10 years (figure 1). During the same time period, hospitalizations billed to Medicaid (the public insurance program for low-income individuals) increased by 33 percent, stays billed to Medicare (the public insurance program for the elderly and disabled) increased by 13 percent, and the number of privately insured stays remained relatively stable (figure 2). The overall growth in all hospital stays was about 13 percent.

Table 1

Characteristics of uninsured hospital stays, 1998–2007.

Figure 1

The percentage of uninsured hospital stays increased by 31 percent, 1998–2007^*. ^* Note: The rate of growth of all hospital stays from 1998 to 2007 was 13 percent. Source: AHRQ, Center for Delivery, Organization, and Markets, Healthcare Cost and (more...)

Figure 2

The number of uninsured, Medicaid, and Medicare hospital stays increased while the number of privately-insured stays remained steady, 1998–2007. Source: AHRQ, Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project, (more...)

Hospital charges and costs for uninsured stays, 1998–2007

Hospital charges reflect the amount the hospital billed for the hospital stay. While these charges generally are discounted for insured patients, the uninsured population typically has been billed the full amount. From 1998 to 2007, hospital charges for the uninsured increased substantially with an 88 percent growth in average charges, from $11,400 to $21,400 per stay (after accounting for inflation) (table 1 and figure 3). Total charges for the uninsured in 2007 were about $50 billion. Meanwhile, the estimated hospital costs of providing care (i.e., the amount the hospital incurred to provide services) also increased for uninsured stays, but at a slower rate of about 37 percent, from $5,200 to $7,100 per stay. Total costs for the uninsured in 2007 were $16.5 billion. The increases in hospital charges and costs can not be attributed to patients staying at the hospital longer because the mean length of uninsured stays over the 10-year period remained consistent at about 4 days.

Figure 3

The hospital bill for uninsured stays increased by 88 percent while estimated hospital costs increased by 37 percent, 1998 and 2007. Note: 1998–2006 hospital charges and costs were adjusted for inflation and noted in 2007 dollars. Source: AHRQ, (more...)

Comparison of uninsured stays to hospital stays overall, 2007

Table 2 provides more detailed information about uninsured hospital stays in 2007 relative to all hospital stays. Comprising almost 6 percent of all hospital stays, uninsured hospitalizations were, on average, shorter and less expensive. Aggregate hospital costs to render uninsured hospital care totaled more than $16.5 billion in 2007—about 5 percent of hospital costs overall. The mean cost of an uninsured hospital stay was about $1,600 less expensive ($7,100 versus $8,700 per hospital stay) and shorter (4.0 versus 4.6 days) than a typical hospital stay.

Table 2

Characteristics of uninsured hospital stays compared to all hospital stays, 2007.

Uninsured patients were nearly 4 times more likely to leave against medical advice. They were 3.5 times less likely to be discharged to home health care, and slightly less likely to die in the hospital.

Uninsured hospital stays, by patient characteristics, 2007

Among uninsured hospitalizations, stays were about equally divided between men (51.4 percent) and women (48.1 percent); whereas, women accounted for a larger percentage of all hospital stays (58.7 percent) (table 3).

Table 3

Characteristics of the uninsured patient population compared to the overall patient population, 2007.

The mean age of uninsured patients was about 12 years younger than for the overall patient population (35 years versus 47 years, respectively). Individuals ages 18 to 44 years comprised about 38 percent of the total U.S. population, but accounted for nearly half of all uninsured stays (table 3).

Uninsured elderly care was rare given the availability of Medicare insurance coverage for the elderly. When elderly hospital stays were excluded, the mean age for uninsured patients was comparable to non-elderly patients overall (35 years compared to 32 years, respectively). Excluding elderly stays also resulted in larger differences between the percentage of uninsured versus insured hospital stays for children (ages less than 1 and 1–17 years) and smaller differences among non-elderly adults (ages 18–44 and 45–64 years).

In 2007, uninsured hospitalization rates were 1.8 times higher among populations living in the poorest areas compared to those living in other communities (10.9 versus 5.9 uninsured stays per 1,000 population, respectively). Among hospital stays overall, the rate of hospital stays in the poorest areas was 1.2 times greater than in communities.

Most common principal diagnoses associated with uninsured hospitalizations, 2007

Table 4 shows that from 1998 to 2007 newborn birth remained the most common reason for uninsured hospitalizations, accounting for more than 252,000 uninsured stays in 2007 (10.9 percent of all uninsured stays). Newborn birth was also the most frequent reason for admission among all hospital stays (11.5 percent of all stays).

Table 4

Top 10 reasons for hospital stays among the uninsured, 2007.

The number of hospital stays for skin infections, a potentially preventable event given early intervention, showed a significant change in the uninsured population between 1998 and 2007. Uninsured hospitalizations for skin infections increased sharply from about 31,000 stays in 1998 to 73,300 stays in 2007, representing nearly twice the portion of uninsured stays in 2007 (3.2 percent in 2007 compared to 1.8 percent in 1998). In 2007, skin infections were reported more than twice as frequently in uninsured stays compared to all stays.

Mental health and substance abuse conditions (mood-, alcohol-, and substance-related disorders) remained a common reason for uninsured hospital stays, collectively accounting for 213,300 stays in 2007 (9.3 percent of all uninsured stays). These conditions were more frequently cited as the main reason for hospitalization in uninsured stays compared to all hospital stays. In fact, in 2007, stays principally for alcohol and substance abuse were about 4 times more common in uninsured stays compared to all hospitalizations and stays for mood disorders were twice as common in uninsured stays.

Two of the other most common reasons for uninsured hospital stays included cardiac conditions, nonspecific chest pain and hardening of the arteries, collectively accounting for 116,100 uninsured stays (5.0 percent of all uninsured stays). While stays for nonspecific chest pain were slightly more common among uninsured hospitalizations compared to overall hospital stays, hospitalizations for hardening of the arteries were less common in uninsured stays.

Stays for pneumonia and diabetes with complications were also commonly cited in uninsured hospital stays. Uninsured stays for pneumonia decreased slightly from 1998 to 2007 and were less common than in overall hospital stays. The percentage of uninsured stays for diabetes with complications remained more common among uninsured stays representing about 2 percent of all uninsured stays over the 10-year period.

Uninsured hospital stays, by region, 1998–2007

From 1998 to 2007, uninsured hospitalization rates increased in every region except the Midwest (figure 4). The proportion of uninsured hospitalizations grew by 29.2 percent in the South, 17.2 percent in the Northeast, and 14.3 percent in the West; meanwhile, the percentage of uninsured stays decreased by 13.8 percent in the Midwest.

Figure 4

The percentage of uninsured hospital stays increased in the South and Northeast, but decreased in the Midwest, 1998, 2003, and 2007. Source: AHRQ, Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project, Nationwide Inpatient (more...)

The South consistently had the highest proportion of uninsured stays during this 10-year period, ranging from about 6 percent of all Southern hospital stays in 1998 to nearly 8 percent in 2007. In 1998, the rate of uninsured stays was the lowest in the West: 3.9 percent of all hospitalizations. The Midwest replaced the West as the region with the lowest uninsured hospitalization rate in 2007, with 4.0 percent of their hospital stays being uninsured.

Diagnoses, ICD-9-CM, and Clinical Classifications Software (CCS)

The principal diagnosis is that condition established after study to be chiefly responsible for the patient’s admission to the hospital. Secondary diagnoses are concomitant conditions that coexist at the time of admission or that develop during the stay.

ICD-9-CM is the International Classification of Diseases, Ninth Revision, Clinical Modification, which assigns numeric codes to diagnoses. There are about 13,600 ICD-9-CM diagnosis codes.

CCS categorizes ICD-9-CM diagnoses into a manageable number of clinically meaningful categories. This “clinical grouper” makes it easier to quickly understand patterns of diagnoses and procedures.

Types of hospitals included in HCUP

HCUP is based on data from community hospitals, defined as short-term, non-Federal, general and other hospitals, excluding hospital units of other institutions (e.g., prisons). HCUP data include OB-GYN, ENT, orthopedic, cancer, pediatric, public, and academic medical hospitals. They exclude long-term care, rehabilitation, psychiatric, and alcoholism and chemical dependency hospitals, but these types of discharges are included if they are from community hospitals.

Unit of analysis

The unit of analysis is the hospital discharge (i.e., the hospital stay), not a person or patient. This means that a person who is admitted to the hospital multiple times in one year will be counted each time as a separate “discharge” from the hospital.

Costs and charges

Total hospital charges were converted to costs using HCUP Cost-to-Charge Ratios based on hospital accounting reports from the Centers for Medicare and Medicaid Services (CMS). Costs will tend to reflect the actual costs of production, while charges represent what the hospital billed for the case. For each hospital, a hospital-wide cost-to-charge ratio is used because detailed charges are not available across all HCUP States. Hospital charges reflect the amount the hospital charged for the entire hospital stay and does not include professional (physician) fees. For the purposes of this Statistical Brief, costs are reported to the nearest hundred.

For the purposes of this Statistical Brief, all charge and cost data have been presented in 2007 dollars using the Bureau of Labor Statistics Consumer Price Index All Urban Consumers (CPI-U) U.S. city average and reported to the nearest hundred. (Note: Costs for the 1998 data are imputed from the 1997 CCR file.)

Payer

Payer is the expected primary payer for the hospital stay. To make coding uniform across all HCUP data sources, payer combines detailed categories into more general groups:

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Medicare includes fee-for-service and managed care Medicare patients.

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Medicaid includes fee-for-service and managed care Medicaid patients. Patients covered by the State Children's Health Insurance Program (SCHIP) may be included here. Because most state data do not identify SCHIP patients specifically, it is not possible to present this information separately.

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Private insurance includes Blue Cross, commercial carriers, and private HMOs and PPOs.

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Other includes Worker's Compensation, TRICARE/CHAMPUS, CHAMPVA, Title V, and other government programs.

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Uninsured includes an insurance status of “self-pay” and “no charge.”

When more than one payer is listed for a hospital discharge, the first-listed payer is used.

Region

Region is one of the four regions defined by the U.S. Census Bureau:

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Northeast: Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, and Pennsylvania

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Midwest: Ohio, Indiana, Illinois, Michigan, Wisconsin, Minnesota, Iowa, Missouri, North Dakota, South Dakota, Nebraska, and Kansas

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South: Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, South Carolina, Georgia, Florida, Kentucky, Tennessee, Alabama, Mississippi, Arkansas, Louisiana, Oklahoma, and Texas

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West: Montana, Idaho, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada, Washington, Oregon, California, Alaska, and Hawaii

Median income of the patient’s ZIP Code

Median community-level income is the median household income of the patient's ZIP Code of residence. The cut-offs for the quartile designation are determined using ZIP Code demographic data obtained from Claritas. The income quartile value is missing for homeless and foreign patients. In 2007, the lowest income quartile ranged from $1–$38,999, while the highest income quartile was defined as $63,000 or above.

Discharge status

Discharge status indicates the disposition of the patient at discharge from the hospital, and includes the following six categories: routine (to home), transfer to another short-term hospital, other transfers (including skilled nursing facility, intermediate care, and another type of facility such as a nursing home), home health care, against medical advice (AMA), or died in the hospital.