General characteristics of hospital stays for patients with diabetes

Table 1 presents findings for hospital stays for patients with diabetes (as a principal or secondary diagnosis), those with diabetes as a principal diagnosis, and stays without diabetes in 2008. While patients with a principal diagnosis of diabetes accounted for only 1.4 percent of all hospital stays, almost 20 percent of all hospitalizations involved patients with diabetes. This is significant because diabetes increases length of stay and therefore increases cost regardless of whether it is the primary reason for admission. Patients with diabetes were, on average, much older than patients without diabetes (65 vs. 45 years old). Females comprised nearly 53 percent of hospital stays for patients with diabetes, and 60 percent of hospital stays for patients without diabetes.

Table 1

Hospitals stays of patients with diabetes compared to those without diabetes, 2008.

Further, hospital stays for patients with diabetes as a principal or any diagnosis were more likely to originate from the emergency department compared with those for patients without diabetes (72 percent for diabetes with a principal diagnosis, 61 for all diabetes patients, and 42 percent for non-diabetes stays). Patients with diabetes as a principal or any diagnosis had a higher number of comorbidities with a mean of 2.6 for diabetes patients with any diagnosis and 2.4 for diabetes patients as a principal diagnosis compared to 1.3 for patients without diabetes.

All remaining analyses focus on all hospitalizations involving diabetes—those cases with diabetes as the principal reason for hospitalization as well as stays that involved diabetes as a secondary or comorbid condition.

Most common principal reasons for hospitalization of patients with diabetes

Table 2 shows diabetes as the most common principal reason for hospitalization among patients with diabetes recorded in the medical record. Most of the top 10 reasons for hospitalization were chronic conditions except for pneumonia and sepsis. Circulatory disorders represented five of the top 10 reasons for hospital admission: congestive heart failure, coronary atherosclerosis (hardening of the arteries), acute myocardial infarction (heart attack), nonspecific chest pain, and cardiac dysrhythmias. It is worth noting that diabetes was a coexisting condition (i.e., a comorbidity) for 42 percent of hospital stays for congestive heart failure, 38 percent of stays for hardening of the arteries, and 34 percent of stays for heart attack.

Table 2

Top 10 most common principal reasons for hospitalization among patients with diabetes, 2008.

Most common comorbidities for hospitalized patients with diabetes

Table 3 shows the 10 most common comorbidities for hospitalized patients with diabetes in 2008. Hypertension was the most common comorbidity, present among 69 percent of hospital stays for patients with diabetes compared with 30 percent of stays for patients without diabetes. Other common comorbidities included fluid and electrolyte disorders (25 percent), chronic pulmonary disease (21 percent), deficiency anemias (21 percent), renal failure (18 percent), and obesity (16 percent). Patients with diabetes experienced these comorbidities more frequently than patients without diabetes.

Table 3

Top 10 most common comorbidities for hospitalization among patients with diabetes, 2008.

Hospital stays for patients with diabetes by payer

Medicare was the most common expected payer for hospital stays for patients with diabetes (60 percent), followed by private insurance (23 percent; Table 1). For patients without diabetes, private insurance was the most common expected payer, closely followed by Medicare, and Medicaid (38, 32, and 20 percent, respectively). Figure 1 shows the percentage of total hospital stays involving patients with diabetes by expected payer. More than 30 percent of hospital stays covered by Medicare involved patients with diabetes. In contrast, patients with diabetes comprised only 10 percent of hospital stays covered by private insurance, 13 percent of stays covered by Medicaid, and 15 percent of stays by the uninsured.

Figure 1

Percentage of hospitalizations for patients with diabetes by payer, 2008. Source: AHRQ, Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project, Nationwide Inpatient Sample, 2008

Hospital stays for patients with diabetes by income quartile

Figure 2 shows the rates of hospitalization for patients with diabetes per 100,000 individuals in each income quartile⁴. Rates decrease as income quartile increases. There were 3,232 diabetes stays per 100,000 persons in the lowest income quartile, compared with 1,762 stays per 100,000 persons in the highest income quartile.

Figure 2

Rate of hospitalizations for patients with diabetes per 100,000 persons by income quartile, 2008. Source: AHRQ, Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project, Nationwide Inpatient Sample, 2008. The number of persons (more...)

Hospitalizations for patients with diabetes by region

Figure 3 shows differences in hospitalization rates for patients with diabetes per 100,000 persons in each U.S. region.⁴ The South had the highest rate of hospitalizations related to patients with diabetes (2,829 hospitalizations per 100,000 persons), followed by the Midwest (2,742 hospitalizations per 100,000 persons) and the Northeast (2,565 hospitalizations per 100,000 persons). The West had the lowest rate of hospital stays for patients with diabetes (1,866 hospitalizations per 100,000 persons).

Figure 3

Rate of hospitalizations for patients with diabetes per 100,000 persons by geographic region, 2008. Source: AHRQ, Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project, Nationwide Inpatient Sample, 2008. The number of (more...)

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.⁵ This “clinical grouper” makes it easier to quickly understand patterns of diagnoses and procedures.

Procedures and Clinical Classifications Software (CCS)

The principal procedure is the procedure that was performed for definitive treatment rather than one performed for diagnostic or exploratory purposes (i.e., the procedure that was necessary to take care of a complication). If two procedures appear to meet this definition, the procedure most related to the principal diagnosis was selected as the principal procedure.

CCS categorizes procedure codes into clinically meaningful categories.⁵ This “clinical grouper” makes it easier to quickly understand patterns of procedure use.

Case Definition

For this report diabetes hospitalizations were defined as CCS diagnosis categories:

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49: Diabetes without complication

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50: Diabetes with complications

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 hundreds.

Median community-level income

Median community-level income is the median household income of the patient’s ZIP Code of residence. The cut-offs for the quartile designation is determined using ZIP Code demographic data obtained from Claritas. The income quartile is missing for homeless and foreign patients.

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

Admission source or Point of Origin

Admission source (now known as patient’s Point of Origin) indicates where the patient was located prior to admission to the hospital. Emergency admission indicates the patient was admitted to the hospital through the emergency department. Admission from another hospital indicates the patient was admitted to this hospital from another short-term, acute-care hospital. This usually signifies that the patient required the transfer in order to obtain more specialized services that the originating hospital could not provide. Admission from long-term care facility indicates the patient was admitted from a long-term facility such as a nursing home.

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.