Hospitalization in the United States, 1997--HCUP Fact Book No. 1

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Foreword

The unprecedented volume and pace of change in the U.S. health care system requires new information on health care and its delivery. The mission of the Agency for Healthcare Research and Quality (AHRQ) is to provide information on the health care system—on quality, outcomes, access, cost, and utilization—that decisionmakers can use to improve health care. To help fulfill this mission, the Agency develops and sponsors a number of databases, including the powerful Healthcare Cost and Utilization Project (HCUP). HCUP is a Federal-State-Industry partnership to build a standardized, multi-State health data system.

Through HCUP, AHRQ has taken a lead in developing databases, software tools, and statistical reports to inform policymakers, health system leaders, and researchers at the Federal, regional, and State levels. (Select for more information on HCUP.) But for data to be useful, they must be disseminated in a timely, accessible way. Recently AHRQ launched HCUPnet, an interactive, Internet-based tool for identifying, tracking, analyzing, and comparing statistics on hospital utilization, outcomes, and charges. Menu-driven HCUPnet guides users in tailoring specific queries about hospital care online; and, with a click of a button, users receive answers within seconds.

With Hospitalization in the United States, 1997, AHRQ launches a new strategy intended to provide timely data about hospital care in the United States in an easy-to-use, readily accessible format. Each Fact Book in the series will provide information about specific aspects of hospital care—the single largest component of our health care dollar.

This first Fact Book provides a general overview of hospital care:

What types of conditions are treated?
Who is admitted to the hospital through emergency departments?
What are the most expensive conditions treated in the hospital?
Who is billed for hospital care?
What are the outcomes of care?

Subsequent Fact Books will examine other topics such as the types of procedures performed in U.S. hospitals and hospital care for children and for women.

We invite you to tell us how you are using this Fact Book and other HCUP data and tools and to share suggestions on how HCUP products might be enhanced to further meet your needs. Please email us at hcup@ahrq.gov or send a letter to the address below:

Irene Fraser, Ph.D.
Director
Center for Delivery, Organization, and Markets
Agency for Healthcare Research and Quality, Suite 5000
540 Gaither Road
Rockville MD 20850

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Contributors

Without the following State partner organizations, the Healthcare Cost and Utilization Project would not be possible:

Arizona Department of Health Services.
California Office of Statewide Health Planning and Development.
Colorado Health and Hospital Association.
Connecticut Hospital Association (CHIME).
Florida Agency for Health Care Administration.
Georgia Hospital Association.
Hawaii Health Information Corporation.
Illinois Health Care Cost Containment Council.
Association of Iowa Hospitals and Health Systems.
Kansas Hospital Association.
Maryland Health Services Cost Review Commission.
Massachusetts Division of Health Care Finance and Policy.
Missouri Hospital Industry Data Institute.
New Jersey Department of Health and Senior Services.
New York State Department of Health.
Oregon Association of Hospitals and Health Systems and Office for Oregon Health Plan Policy and Research.
Pennsylvania Health Care Cost Containment Council.
South Carolina State Budget and Control Board.
Tennessee Hospital Association.
Utah Department of Health.
Washington State Department of Health.
Wisconsin Department of Health and Family Services.

In May 2000, the 22 HCUP State partners and AHRQ received the Secretary of Health and Human Services' Award for Distinguished Service for "leadership, teamwork, and creative thinking in increasing availability, utility, and value of data for policy-makers and researchers concerned with hospital quality, utilization and cost."

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Introduction

About 40 percent of personal health care expenditures in the United States go towards hospital care,¹ making it the most expensive component of the health care sector. This report gives an overview of hospital care during 1997, providing insight for anyone interested in a better understanding of services provided by hospitals and the characteristics of patients who receive them.

This report summarizes information from the Nationwide Inpatient Sample, or NIS, a database maintained by the Agency for Healthcare Research and Quality (AHRQ). The NIS is uniquely suited to provide a comprehensive picture of hospital care.

Because of its tremendous size (7 million records), the NIS can provide information on relatively uncommon diagnoses and procedures, as well as on subpopulations, such as various age groups. The NIS covers all types of patients discharged from hospitals, including the uninsured, those covered by public payers (Medicare and Medicaid), and those with private insurance. It also provides information on total hospital charges for all patients, unlike any other data source in the United States.

The NIS includes short-term, non-Federal, community hospitals—general and specialty hospitals (such as pediatric, obstetrics-gynecology, short-term rehabilitation, and oncology hospitals) are included, but long-term care and psychiatric hospitals are excluded.

This report provides information on:

Age and gender of hospitalized patients.
Sources of admission to the hospital.
Emergency admissions to the hospital.
Most frequent reasons for hospitalization.
Types of comorbidities, or coexisting conditions, seen in the hospital.
Charges for hospitalizations, by type of condition.
Conditions with the longest lengths of hospitalization.
Expected sources of payment for hospitalizations.
Discharges from the hospital.
Conditions with the highest in-hospital mortality.

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Executive Summary

Age and Gender

Nearly 60 percent of hospital stays are for women. Among individuals 18 to 44 years of age, there are nearly three times as many women in the hospital as men.
People age 65 and older make up about 13 percent of the U.S. population but account for about 36 percent of all hospital stays.

Admissions Through the Emergency Department (ED)

Over a third of all hospital admissions are through the ED.
Five of the top 10 conditions for which people are admitted through the ED are heart problems, like heart attack.
Two of the top 10 conditions are infections: pneumonia and blood infection (septicemia).
Nearly 55 percent of hospital stays for the very old (80 years and older) start in the ED, compared with 45 percent for younger age groups.

Most Frequent Reasons for Hospitalization

Eleven percent of all hospital stays are for infants born in the hospital.
Depression is one of the top 10 conditions treated in short-term hospitals.
Heart attack, hardening of the arteries, and congestive heart failure are in the top 10 conditions for all age groups 45 and older.
Pneumonia is a top 10 condition for all age groups.
Excluding pregnancy-related conditions, 4 of the top 10 conditions among people ages 18-44 are related to mental illness or substance abuse.

Comorbidities

Comorbidities are coexisting conditions that are not the main reason for the hospital stay. Comorbidities can make a hospital stay more expensive and complicated.
High blood pressure (hypertension) is the most common comorbidity. Other common comorbidities are lung disease and diabetes.
Over half of all hospitalized patients have at least one comorbidity. About a third of patients have two or more.
Drug abuse, psychoses and depression are present as top 10 comorbidities for adolescents and adults up to age 44.
Alcohol abuse is a top 10 comorbidity for adults ages 18-64.

Most Expensive and Longest Hospital Stays

The average charge for a hospital stay is over $11,000 and the average hospital stay is about 5 days long.
Infant respiratory distress is the most expensive condition treated in the hospital, with an average charge of $68,000.
Four of the top 10 most expensive conditions are related to the care of infants: respiratory distress, prematurity and low birth weight, heart defects, and lack of oxygen (intrauterine hypoxia).
Two of the top 10 most expensive conditions are traumas: spinal cord injury ($53,000) and burns ($34,000).
Even though long lengths of stay can result in high expense, four of the most expensive reasons for hospital stays are NOT among the longest stays: heart valve disorders, cardiac congenital anomalies, aneurysms, and burns.

Insurance and Hospital Stays

Government (Medicare and Medicaid) is billed for over half (54 percent) of all hospital stays.
About 13 percent of the U.S. population is over 65, but about 35 percent of all hospital stays are paid by Medicare, the most common insurer for the elderly.
About 17 percent of the U.S. population is uninsured, and about 5 percent of all hospital patients are uninsured.
Among uninsured patients, 3 of the top 10 conditions are for substance abuse or mental health. It is not possible to determine if this is because insurance does not pay for these conditions or if these conditions occur more frequently among uninsured patients.
Nearly 20 percent of hospital stays for alcohol-related mental disorders, and 23 percent of stays for substance abuse are uninsured.
Almost 12 percent of the U.S. population is covered by Medicaid; however, Medicaid is billed for:
- Over a third of all stays for babies born in the hospital.
- Over a third of all stays for fetal distress.
- Nearly 42 percent of all stays for complicated pregnancy.
- Over a fourth of all stays for depression and half of all stays for schizophrenia.

Discharges from the Hospital

Nearly 11 percent of patients discharged from the hospital go to some sort of long-term care: skilled nursing facilities, intermediate care, or nursing homes.

In-Hospital Mortality

Some patients are admitted to the hospital for end-of-life care; therefore, mortality for some conditions is expected to be high.
About 2.5 percent of hospital stays end in death.
Four of the top 10 conditions with the highest rates of in-hospital death are related to cancer.

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Findings

Age and Gender

How Old Are Patients in U.S. Hospitals?

In 1997, the average age for patients hospitalized in the United States was about 47 years.
People ages 18-44 accounted for more hospital stays than any other age group in 1997, followed closely by people ages 65-79.
The high percentage of hospitalizations for those 18-44 is due to pregnancy and childbirth. Nearly 45 percent of all hospital stays in this age group are for pregnancy and childbirth.
The high percentage of hospitalizations for children less than 1 year is because newborn infants are included in this category. About 85 percent of all discharges in this age group are for newborn infants.
Select Figure 1 (12 KB), Percent of Patients in Hospitals.
People ages 18-44 make up about 41 percent of the U.S. population and account for 27 percent of all hospital stays.
Select Figure 2 (17 KB), Age of U.S. Population and Patients in Hospitals.
People 65 and older make up about 13 percent of the U.S. population, but account for about 36 percent of all hospital stays.

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What Is the Gender of Patients in U.S. Hospitals?

Nearly 60 percent of all hospital discharges are women.
Select Figure 3 (8 KB), Hospital Discharges by Gender.
Among hospital patients 17 years and younger, there are nearly equal numbers of males and females. The same is true for patients ages 45 to 64.
For the age group 18 to 44 years of age, nearly three times as many women as men are in the hospital. Seventy-three percent of all hospitalized patients in this age group are women.
Males are hospitalized more frequently in the older age groups than are females. For example, males make up 41 percent of the total U.S. population 65 years of age and older, but account for 43 percent of all hospital stays.
Select Figure 4 (22 KB), Hospital Patients and Population by Gender and Age.

Hospital Admissions

How Are Patients Admitted to the Hospital?

Over a third of all hospital admissions are through the Emergency Department (ED).
Most admissions are routine admissions to the hospital—not through the ED or from another hospital or other health facilities, such as nursing homes.
Select Figure 5 (13 KB), Hospital Admissions.

What Are the Most Frequent Reasons for Being Admitted to the Hospital Through the Emergency Department?

Five of the top 10 conditions for which patients are admitted to the hospital through the emergency department are related to heart problems.
Three of the top 10 conditions are related to respiratory problems (pneumonia, chronic obstructive lung disease, and asthma). Nearly 6 percent of all admissions to the hospital through the ED are due to pneumonia.
Two of the top 10 conditions are infections: pneumonia and blood infection (septicemia).

Table 1. Most Frequent Reasons for Hospital Admission Through the Emergency Department

Principal diagnosis	Total number of discharges (in thousands)	Percent of all hospital discharges admitted through the ED
1. Pneumonia	756	5.8
2. Congestive heart failure	652	5.0
3. Hardening of the arteries of the heart (coronary atherosclerosis)	587	4.5
4. Heart attack (acute myocardial infarction)	450	3.5
5. Stroke (acute cerebrovascular disease)	434	3.4
6. Nonspecific chest pain	396	3.1
7. Chronic obstructive lung disease	350	2.7
8. Irregular heartbeat (cardiac dysrhythmia)	312	2.4
9. Asthma	282	2.2
10. Blood infection (septicemia)	271	2.1

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How Does Hospital Admission Through the Emergency Department Differ by Age Groups?

Over 40 percent of all children's hospitalizations begin in the ED.
Over half of admissions for people age 80 and over begin in the ED (comprising over 2.6 million admissions), compared with 45 percent for people ages 65-79 years.

Select Figure 6 (13 KB), Hospital Admissions through Emergency Department by Age.

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Reasons for Hospitalization

What Are the Most Frequent Reasons for Hospitalization?

The most common reason for hospitalization is infant birth. About 11 percent of all discharges from the hospital are infants born in the hospital.
Five of the top 10 conditions are cardiovascular diseases, encompassing nearly 13 percent of all discharges.
One of the top 10 conditions treated in short-term hospitals is a mental health diagnosis—depression.

Table 2. Most Frequent Reasons for Hospitalization

Principal diagnosis	Total number of discharges (in thousands)	Percent of all discharges
1. Infants born in the hospital	3,845	10.9
2. Hardening of the arteries of the heart (coronary atherosclerosis)	1,432	4.1
3. Pneumonia	1,258	3.6
4. Congestive heart failure	1,011	2.9
5. Heart attack (acute myocardial infarction)	746	2.1
6. Trauma to perineum due to childbirth	726	2.1
7. Stroke (acute cerebrovascular disease)	638	1.8
8. Depression (affective disorders)	596	1.7
9. Irregular heartbeat (cardiac dysrhythmia)	583	1.7
10. Chronic obstructive lung disease (emphysema or chronic bronchitis)	565	1.6

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What Are the Most Common Reasons for Hospital Stays, by Body System?

Looking at the most common conditions by body system, diseases of the circulatory system are the most frequent reasons for hospitalization. These include conditions such as coronary atherosclerosis, congestive heart failure, heart attack, and cardiac dysrhythmia.
The next most common reasons for hospitalization include pregnancy and childbirth (diagnoses received by women), followed by newborns and other perinatal conditions (diagnoses received by babies).
Hospitalizations for all mental disorders combined make up about 3.5 percent of all hospital stays.

Table 3. Reasons for Hospital Stays by Body System

Reasons for hospital stay, by body system	Total number of discharges (in thousands)	Percent of all discharges
1. Diseases of the circulatory system	5,990	16.9
2. Pregnancy and childbirth	4,411	12.5
3. Newborns and perinatal conditions	3,970	11.2
4. Diseases of the respiratory system	3,588	10.1
5. Diseases of the digestive system	2,887	8.2
6. Disease of the musculoskeletal system	2.667	7.5
7. Diseases of the nervous system	2,041	5.8
8. Mental disorders	1.238	3.5
9. Diseases of the kidney and urinary tract	1,126	3.2
10. Diseases of the female reproductive system	984	2.8

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