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Source of Data for This Report
The results presented in this report are drawn from the Healthcare Cost and Utilization Project (HCUP), a Federal-State-Industry partnership to build a multi-State health care data system. This partnership is sponsored by the Agency for Healthcare Research and Quality (AHRQ) and is managed by staff in AHRQ's Center for Delivery, Organization, and Markets (CDOM). HCUP is based on data collected by individual State Partner organizations (including State departments of health, hospital associations, and private agencies), which provide the data to AHRQ. HCUP would not be possible without statewide data collection projects and their partnership with AHRQ.
For the year 2004, 37 State Partner organizations contributed their data to AHRQ, where all files were validated and converted into a uniform format. The uniform HCUP databases enable comparative studies of health care services and the use and cost of hospital care, including:
- Effects of market forces on hospitals and the care they provide.
- Variations in medical practice.
- Effectiveness of medical technology and treatments.
- Use of services by special populations.
HCUP includes short-term, non-Federal, community hospitals as defined by the American Hospital Association (AHA). This definition includes general hospitals and specialty facilities, such as pediatric, obstetrics-gynecology, short-term rehabilitation, and oncology hospitals. Long-term care and psychiatric hospitals are excluded, as are substance abuse treatment facilities.
This report is based on data from the 2004 Nationwide Inpatient Sample (NIS). The NIS is the largest all-payer inpatient care database that is publicly available in the United States. The database contains data from 8 million hospital stays from roughly 1,000 hospitals sampled to approximate a 20-percent stratified sample of U.S. community hospitals. The data are weighted to obtain estimates that represent the total number of inpatient hospital discharges in the United States. Weighted discharges for adults approximate 31.9 million discharges.
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This Fact Book is based on data from the 2004 HCUP Nationwide Inpatient Sample (NIS) database. The NIS data are weighted to obtain estimates representing the total number of inpatient hospital discharges in the United States; in 2004, this figure totaled 38,661,786. The analyses presented here are limited to 31,928,948 discharges for adults in U.S. community hospitals. Because the NIS is limited to community hospital data, disorders treated in outpatient or ambulatory care settings, long-term care facilities, psychiatric hospitals, and substance-abuse treatment facilities are not reflected in this report. In addition, due to concerns regarding reimbursement and stigma associated with MSHA diagnoses, it is important to note that MHSA diagnoses are likely under-coded in the hospital discharge records. A brief discussion of selected methodological issues pertaining to this Fact Book follows.
Unit of Analysis
For this report, the unit of analysis is the inpatient stay in a community hospital rather than the patient or the procedure. For example, a patient admitted four times to the hospital is included four times in the NIS data. Thus, the same individual can account for more than one hospital stay. Frequencies and rankings of diagnoses are indicated as either principal (first-listed) diagnosis, which is defined as “the condition established after study to be chiefly responsible for occasioning the admission of the patient to the hospital,” 8 or secondary diagnosis, which includes all additional diagnoses on the record. “All-listed diagnoses” indicates that both principal and secondary diagnoses have been included in the analysis. All discharges from the NIS have been weighted to produce national estimates.
Diagnoses, Clinical Classification Software (CCS), and Mental Health and Substance Abuse Clinical Classification Software (CCS-MHSA)
Diagnoses are recorded within the NIS using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM).9 Although ICD-9-CM codes may be used to provide descriptive statistics, the granular nature of ICD-9-CM reporting is difficult to summarize. Thus, for this Fact Book, the AHRQ-developed Mental Health and Substance Abuse Clinical Classification Software (CCSMHSA) is applied. The CCS-MHSA, derived primarily from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition10 is used to aggregate ICD-9-CM MHSA diagnostic codes into a limited number of clinically meaningful categories. As shown in Appendix
A, the CCS-MHSA assigns mental and substance-use ICD-9-CM codes to 1 of the 14 categories shown in the following table.
Select for Table 12, Codes for Mental Health or Substance Abuse Disorders.
The groupings for MHSA stays are based on principal (or first-listed) and secondary diagnoses with CCS-MHSA codes in the ranges of 650-653, 655-661. Stays are considered to have at least one MHSA diagnosis if the discharge record includes only a “principal MHSA diagnosis,” “principal and secondary MHSA diagnosis,” or only “secondary MHSA diagnoses.” All other hospital stays are considered unrelated to MHSA conditions and are classified as non-MHSA.
Additionally, hospital stays are classified as dual diagnosis if both a substance abuse disorder (CCS-MHSA = 660) and a mental health disorder (CCS-MHSA codes = 650-653, 655-661) are listed. Hospital stays for maternal conditions were identified using the Clinical Classifications Software (CCS) that encompasses all conditions (not just MHSA disorders; CCS code = 176-196), Major Diagnostic Categories (MDC) code 14, and a recorded gender of female. More detailed information on CCS-MHSA and the CCS can be downloaded from the HCUP User Support Web site at: http://www.hcup-us.ahrq.gov/tools_software.jsp.
In Appendix B, non-MHSA conditions were classified as chronic or not chronic, using the AHRQ-developed Chronic Condition Indicator. A chronic condition is defined as a condition that lasts 12 months or longer and meets one or both of the following tests:
- It places limitations on self-care, independent living, and social interactions.
- It results in the need for ongoing intervention with medical products, services, and special equipment. More detailed information on the Chronic Condition Indicator can be found at: http://www.hcup-us.ahrq.gov/toolssoftware/chronic/chronic.jsp.
Expected Primary Payer
Each hospitalization and its related hospital bill are attributed to the payer who was expected by the hospital to pay the major portion of the bill (i.e., the expected primary payer). The expected primary source of payment at admission may not be the ultimate primary payer. To make coding uniform across all HCUP data sources, the payer variable combines detailed payers into more general groups:
- Medicaid includes fee-for-service and managed care Medicaid patients.
- Medicare includes fee-for-service and managed care Medicare patients.
- Private insurance includes Blue Cross, commercial carriers, and private HMOs and PPOs.
- Other includes Workers' Compensation, TRICARE/VA, Title V, and other government programs.
- Uninsured includes an insurance status of “self-pay” and “no charge.”
This categorization of payer differs from previous Fact Books. Previous Fact Books have assumed that payer is a proxy for socioeconomic status, placing more emphasis on Medicaid as an expected source of payment. This Fact Book relies only on expected primary payer, a decision based on several important factors. Individuals with impairments related to MHSA disorders may be eligible for disability and Medicaid, suggesting that it would be important to account for dual eligibility rules. Claims data such as HCUP, however, do not contain information about an individual's disability status. Therefore, it is not possible to determine the reason a hospital bill was submitted to Medicaid. In addition, expected secondary payer was missing in 62 percent of discharges, making it difficult to determine if patients would quality for dual eligibility.
Charges and Costs
Total hospital charges were converted to costs using HCUP Cost-to-Charge Ratio Files based on hospital accounting reports from the Centers for Medicare & 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 do not include professional (physician) fees. For the purposes of this Fact Book, costs are reported to the nearest hundreds. More information on the HCUP Cost-to-Charge Ratio Files can be found at: http://www.hcup-us.ahrq.gov/db/state/costtocharge.jsp.
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1. U.S. Department of Health and Human Services. Mental Health: A Report of the Surgeon General. Rockville, MD: Substance Abuse and Mental Health Services Administration, Center for Mental Health Services and National Institutes of Health, National Institute of Mental Health; 1999.
2. Institute of Medicine, Committee on Crossing the Quality Chasm. Improving the Quality of Health Care for Mental and Substance-Use Conditions. Washington, DC: National Academies Press; 2006.
3. U.S. Department of Health and Human Services. Mental Health, United States, 2002. Rockville, MD: Substance Abuse and Mental Health Services Administration, Center for Mental Health Services; 2004.
4. American Hospital Association. AHA Hospital Statistics, 2006 Edition. Chicago, IL: Health Forum; 2005.
5. Centers for Disease Control and Prevention, National Center for Injury Prevention and Control. Suicide: Fact Sheet. Available at: http://www.cdc.gov/ncipc/dvp/suicide/ (Accessed September 27, 2006).
6. Finkelman AW. Mental health policy: Implications for newborns, infants and families. Newborn and Infant Nursing Reviews 2003;3(1):18-26.
7. Agency for Healthcare Research and Quality. Evidence Report/Technology Assessment No. 119, Prenatal Depression: Prevalence, Screening, Accuracy, and Screening Outcomes. Rockville, MD: Agency for Healthcare Research and Quality; 2005.
8. Centers for Medicare & Medicaid Services and National Center for Health Statistics. ICD-9-CM Official Guidelines for Coding and Reporting, Effective April 1, 2005. .
9. International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). Reno, NV: Channel Publishing, 2003.
10. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Washington, DC: American Psychiatric Association; 1994.
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Adjustment disorders—A group of diagnoses characterized by emotional or behavioral symptoms beyond what would be expected in response to an identifiable event or stressful situation. (CCS-MHSA code = 650)
Anxiety disorders—A group of diagnoses characterized by overwhelming apprehension and fear in response to a perceived threat. Symptoms are physical as well as psychological. (CCS-MHSA code = 651)
Attention-deficit and attention-deficit/hyperactivity disorder (ADD, ADHD)—Persistent inattention and/or hyperactive, impulsive behavior that is more frequent and more severe than that typical of age or developmental level. Symptoms must be present in at least two settings, typically home and school. ADD and ADHD are included in the CCS-MHSA code 652 or “Disruptive behavior disorders.”
Bipolar disorders—A group of mood disorders characterized by extreme swings between emotional highs and lows. Highs, or manic episodes, are periods of elevated energy, increased activity, and distractible or irritable mood. Lows, or depressive episodes, are characterized by periods of depressed mood, disinterest, lethargy, and fatigue. Bipolar disorders are included in the CCS-MHSA code 657 or “Mood disorders.”
Conduct disorder—An inappropriate and persistent pattern of behavior that violates others. This includes aggression to people and animals, destruction of property, deceitfulness, theft, and a serious violation of rules. Conduct disorder is included in the CCS-MHSA code 652 or “Disruptive behavior disorders.”
Delirium, dementia and amnestic and other cognitive disorders—The development of multiple cognitive disturbances and deficits, including memory impairment, and occurring as a result of a general medical condition or substance use. Dementia represents a loss of previous functioning and is characterized by gradual onset and continuing decline. Delirium is characterized by a short, fluctuating disturbance of mental status and amnestic disorders entails memory impairment not occurring during dementia or delirium. (CCS-MHSA code = 653)
Depressive disorders—A group of mood disorders characterized by a persistent low mood, profound sadness, and a lack of interest in enjoyable activities. Physical symptoms including weight loss or gain, fatigue, and sleep disturbances are common. Depressive disorders are included in the CCS code 657 or “Mood disorders.”
Disorders usually diagnosed in infancy, childhood, or adolescence—A group of diagnoses characterized by the time period in which first diagnosis typically, although not necessarily, occurs. Disorders include elimination disorders, separation anxiety disorders, pervasive development disorders, tic disorders, feeding and eating disorders of early childhood, mutism, and stereotypic movement disorder. (CCS-MHSA code = 655)
Disruptive behavior disorders—A group of diagnoses including attention-deficit disorder, attention-deficit/hyperactivity disorder, conduct disorder, and oppositional defiant disorder. (CCS-MHSA code = 652)
Dissociative disorders—A group of diagnoses characterized by a disintegration of consciousness, memory, identity, and/or perception. The presentation may be sudden or gradual, transient or chronic. Symptoms do not occur in the course of another mental disorder or as a result of a general medical condition or substance use. Dissociative disorders are included in the CCS-MHSA 661 or “Miscellaneous mental disorders.”
Dual diagnosis—The presence of both a substance-related diagnosis and a mental health diagnosis.
Eating disorders—A group of diagnoses characterized by a severe disturbance in eating behavior. This includes anorexia nervosa (excessive weight loss), bulimia nervosa (repeated episodes of binging and purging), pica (persistent eating of nonnutritive substances), and rumination disorder (repeated regurgitation and re-chewing of food). Eating disorders are included in the CCS-MHSA 661 or “Miscellaneous mental disorders.”
Elimination disorders—Repeated urination (enuresis) or defecation (encopresis) in inappropriate places beyond an appropriate developmental age. Episodes may be intentional or involuntary. Elimination disorders are included in the CCS-MHSA 655 or “Disorders typically diagnosed in childhood.”
Factitious disorders—A group of diagnoses characterized by intentionally producing or feigning physical or psychological symptoms in the absence of external incentives such as economic gain or avoiding legal responsibility. Factitious disorders are included in the CCS-MHSA 661 or “Miscellaneous mental disorders.”
Impulse control disorders—A group of diagnoses characterized by the repeated failure to resist the urge to perform an act that is harmful to the self or others. This includes assault, theft, fire-setting, pathological gambling, and hair-pulling. Increased arousal is usually experienced before acting, and pleasure, gratification, or relief are felt while committing the act. (CCS-MHSA code = 656)
Mental disorders due to general medical condition, not elsewhere classified—Includes personality changes, anxiety disorders, and unspecified transient mental health disorders where the disturbance is the result of a general medical condition. These disorders are included in the CCS-MHSA 661 or “Miscellaneous mental disorders.”
Miscellaneous mental disorders—A group of diagnoses that include dissociative disorders, eating disorders, factitious disorders, mental disorders due to general medical condition, not elsewhere classified, psychogenic disorders, sexual and gender identity disorders, sleep disorders, somatoform disorders, and other miscellaneous mental health disorders. (CCS-MHSA code = 661)
Mood disorders—A group of diagnoses including bipolar disorders and depressive disorders. (CCS-MHSA code = 657)
Oppositional defiant disorder—A pattern of negative, angry, defiant, disobedient behaviors directed toward authority figures. These behaviors are more frequent than that typical of age or development level. Oppositional defiant disorder is included in the CCS-MHSA 652 or “Disruptive behavior disorders.”
Other disorders of infancy, childhood, or adolescence—Includes emotional, attachment, and movement related conditions impairing specific developmental tasks of childhood but not meeting diagnostic conditions for disorders classified elsewhere. These disorders are included in the CCS-MHSA 655 or “Disorders typically diagnosed in childhood.”
Personality disorders—A group of diagnoses characterized by a pattern of cognitions, emotional responses, interpersonal relations, and impulse control that deviates noticeably from cultural expectations. This pattern of cognitions and behaviors is inflexible, pervasive, and lasts over time. (CCS-MHSA code = 658)
Pervasive developmental disorders—A group of childhood diagnoses characterized by severe and pervasive impairment in social, communication, or motor skills or by the presence of stereotyped behavior, interests, and activities. The impairments represent a loss of previously acquired skills or are significantly atypical of age or developmental level. Pervasive developmental disorders are included in the CCS-MHSA 655 or “Disorders typically diagnosed in childhood.”
Psychogenic disorders—Refers to diagnoses where physical symptoms occur as a result of other diagnosed mental disorders. Symptoms may be musculoskeletal, respiratory, cardiovascular, of the skin, gastrointestinal, genitourinary,
endocrine, or unspecified. Psychogenic disorders are included in the CCS-MHSA 661 or “Miscellaneous mental disorders.”
Schizophrenia—A chronic, severe, and disabling brain disease that affects cognition, speech, emotional expression, social relations, and behavior. Symptoms include delusions (bizarre thoughts with no basis in reality); hallucinations (experiencing sensations that have no source); disordered thinking and nonsensical speech that impair effective communication; disorganized and agitated behavior; and negative symptoms including social withdrawal, extreme apathy, and blunted
affect. Other psychotic disorders include conditions that have delusions, hallucinations, and paranoia in their presentation. (CCS-MHSA code = 659)
Sexual and gender identity disorders—A group of diagnoses including psychologically based sexual dysfunctions, paraphilias (intense and unusual sexual fantasies or behaviors), and gender identity disorders (a strong cross-gender identification and persistent discomfort with one's biological sex). These disorders are included in the CCS-MHSA 661 or “Miscellaneous mental disorders.”
Sleep disorders—A group of diagnoses characterized by disturbances to healthy, normal sleep patterns that are not to the result of another mental disorder, a general medical condition, or substance use. Sleep disorders are included in the CCS code “Miscellaneous mental disorders.”
Somatoform disorders—A group of diagnoses characterized by the presence of physical symptoms suggesting a general medical condition but not accounted for by a medical diagnosis, mental health disorder, or substance use. Symptoms are not intentional or under voluntary control. Somatoform disorders are included in the CCS-MHSA 661 or “Miscellaneous mental disorders.”
Substance-related disorders—A group of diagnoses related to the abuse, dependence or withdrawal from alcohol or drugs. Abuse and dependence disorders are characterized by maladaptive patterns of use leading to increased tolerance and physical symptoms of withdrawal in the absence of the substance. (CCS-MHSA code = 660)
Suicide and intentional self-inflicted injury—Includes external cause of injury codes that indicate an attempt to voluntarily and intentionally take one's own life or to voluntarily and intentionally cause physical harm to oneself. (CCS-MHSA code = 662)
Tic disorders—A group of diagnoses characterized by the presence of sudden, rapid, recurrent, non-rhythmic, stereotyped movements or vocalizations that are not the result of a general medical condition or substance use. Tic disorders are included in the CCS-MHSA 655 or “Disorders typically diagnosed in childhood.”
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For More Information
More information regarding HCUP data is available at http://www.ahrq.gov/data/hcup, as well as on the HCUP User Support Web site at http://www.hcup-us.ahrq.gov.
Additional descriptive statistics can be viewed through HCUPnet (http://www.hcupnet.ahrq.gov/), a Web-based tool providing easy access to information on hospital stays.
NIS data are available for the following data years:
- 2004 data
- 2003 data
- 2002 data
- 2001 data
- 2000 data
- 1999 data (PB 2002-500020)
- 1998 data (PB 2001-500092)
- 1997 data, Release 6 (PB 2000-500006)
- 1996 data, Release 5 (PB 99-500480)
- 1995 data, Release 4 (PB 98-500440)
- 1994 data, Release 3 (PB 97-500433)
1993 data, Release 2 (PB 96-501325)
- 1988-1992 data, Release 1 (PB 95-503710)
NIS data can be purchased for research through the HCUP Central Distributor sponsored by AHRQ: telephone: (866) 556-4287 (toll-free), fax: 866-792-5313, or e-mail: HCUPDistributor@ahrq.gov. The HCUP Central Distributor can provide information on which States are included in both databases for any year.
Price of the data is $322 for Release 1; $160 per year for 1993 to 1999; and $200 per year for 2000 to 2004. The student price is $20 per database. Prices may be higher for customers outside the United States, Canada, and Mexico.
AHRQ is always looking for ways in which AHRQ-funded research, products, and tools have influenced clinical practice, improved policies, affected patient outcomes, and changed people's lives. Impact case studies describe AHRQ research findings in action. These case studies have been used in testimony, budget documents, and speeches. If you are aware of any impact AHRQ-funded research or products, such as HCUP, have had on health care policy, clinical practice, or patient outcomes, please let us know by using the contact information below.
Healthcare Cost and Utilization Project (HCUP)
Center for Delivery, Organization, and Markets
Agency for Healthcare Research and Quality
Phone: 866-290-HCUP (4287); E-mail: firstname.lastname@example.org
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The authors acknowledge the following individuals for their contributions to this Fact Book: Gail Eisen, Nancy Jordan and Amanda Mummert (Thomson Medstat) and DonnaRae Castillo (AHRQ) for editorial services; and The Madison Design Group (MDG) for design and layout.
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Proceed to Appendixes