General characteristics of hospital stays among patients with depression

Table 1 compares the general characteristics of hospitalizations related to depression with the characteristics of hospital stays with no mention of depression in 2005. Compared to stays with no mention of depression, depression-related stays were more likely to occur among younger patients and among females. On average, patients hospitalized principally for depression were about 16 years younger than patients without depression (41.8 years versus 58.0 years). In fact, patients aged 18 to 44 years, accounted for nearly half of all hospitalizations in which depression was the principal reason for admission. Females accounted for 58.8 percent of all hospitalizations with a principal diagnosis of depression, and 68.3 percent of stays with depression as a secondary condition. In comparison, females accounted for 53.5 percent of hospitalizations with no mention of depression.

Table 1

Differences in hospital stays related to depression, 2005.

In 2005, the hospital resources associated with depression as a secondary diagnosis and with stays unrelated to depression were similar. For example, stays with a secondary diagnosis of depression and stays with no mention of depression averaged approximately five days in length—1.5 days shorter than the mean length of stay for hospitalizations principally for depression (6.6 days). Similarly, the average hospital cost per stay was $8,100 for stays with a secondary diagnosis of depression and $9,600 for stays unrelated to depression, while average hospital costs were $4,500 among stays principally for depression. As a result, hospitalizations with a principal diagnosis of depression had an average cost per day that was 63.2 percent lower than the cost per day for stays unrelated to depression ($700 versus $1,900). The average cost per day of hospitalizations with depression listed as a secondary condition was $1,600, which is comparable to stays unrelated to depression. This pattern is likely a result of more resource intensive procedures and treatments related to the principal diagnoses in stays with depression as a coexisting condition.

Differences in hospital stays among patients with depression, by region

When adjusted for the population of each region, hospitalizations related to depression were most likely to occur in the Midwest and Northeast (table 1). Although the overall hospitalization rates for stays unrelated to depression were relatively similar in the Northeast, Midwest, and South (about 975 hospital stays per 10,000 people in each region), hospitalizations principally for depression in the Midwest (19.5 stays per 10,000 people) and Northeast (17.3 stays per 10,000 people) occurred more frequently than in the South (12.6 stays per 10,000 people). A similar pattern of hospitalization rates across regions was noted among stays with a secondary diagnosis of depression. The West had the lowest regional rate of hospitalizations related to depression (9.4 stays per 10,000 people with a principal diagnosis of depression and 62.2 stays per 10,000 people with depression as a secondary diagnosis), but also had a lower overall rate of hospitalization than the other regions (714.0 stays per 10,000 people).

Differences in hospital stays among patients with depression, by primary payer

Although the distribution of expected primary payer among stays with no mention of depression and stays with depression as a secondary condition was similar, stays principally for depression were more likely to be covered by Medicaid or be uninsured (figure 2). In 2005, Medicaid was the expected primary payer for nearly one in four hospitalizations (24.8 percent) principally for depression. In comparison, 14.2 percent of stays with depression as a secondary diagnosis and 12.1 percent of hospitalizations unrelated to depression were covered by Medicaid. Uninsured stays accounted for 9.8 percent of hospital stays principally for depression—about twice the percentage seen among stays with depression as a secondary diagnosis (4.9 percent) and stays with no mention of depression (5.7 percent). Medicare was the expected primary payer for only 24.8 percent of stays principally for depression, compared to nearly half of stays with a secondary diagnosis of depression and stays with no mention of depression (49.0 percent and 48.7 percent, respectively).

Figure 2

Distribution of hospitalizations, by payer, 2005. Source: AHRQ, Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project, Nationwide Inpatient Sample, 2005.

Most common principal conditions associated with depression

In approximately 85 percent of all hospital stays involving a diagnosis of depression, the patient was admitted principally for another condition. Table 2 lists the most common principal diagnoses for hospital stays where depression was a secondary diagnosis. One in ten depression-related stays was principally for cardio- and cerebrovascular conditions such as nonspecific chest pain, congestive heart failure, coronary atherosclerosis, cardiac dysrhythmias, and stroke. Common respiratory conditions such as pneumonia, chronic obstructive pulmonary disease, and asthma were the principal reason for admission in 7.8 percent of stays with a secondary diagnosis of depression.

Table 2

Principal diagnoses for hospital stays with a secondary diagnosis of depression, 2005.

Alcohol and substance abuse was 3.5 times more likely to be a principal reason for admission among patients with depression than those without depression. Similarly, poisoning by psychotropic agents was 9 times more likely to be a principal reason for admission, and poisoning by other medications and drugs was 5 times more likely to be a principal reason for admission among patients with depression than among those without depression.

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 12,000 ICD-9-CM diagnosis codes.

CCS categorizes ICD-9-CM diagnoses into 260 clinically meaningful categories.⁵ This “clinical grouper” makes it easier to quickly understand patterns of diagnoses and procedures.

Case definition

The ICD-9-CM codes defining depression include diagnosis codes in the following range: 293.83, 296.20–296.26, 296.30–296.36, 300.4, and 311. This analysis excludes any hospitalizations related to childbirth or the treatment of a neonate.

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).⁶ 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.

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