The term hospitalizations refers to hospital discharges of Missouri residents from non-federal and non-state short-term (average length of stay less than 30 days) general and specialty hospitals whose facilities are open to the general public.
Excluded from hospitalization data are discharges from long-term care facilities, as well as those from long-term care units within general hospitals (i.e., swing bed, skilled nursing, and intermediate care units). Also excluded are discharges from residential care facilities and residential care units within licensed hospital facilities.
Newborns are a special category of hospital discharges that are not included in this MICAs. However mothers who gave birth, as well as persons hospitalized for pregnancy and childbirth-related conditions will be included in the hospitalizations data. Users interested information on pregnancy and birth events should see the Births and Pregnancies MICAs and the community profiles on Preconception/Family Planning, Prenatal, Delivery, Infant and/or Child Health.
Hospitalization data reflect all sources of inpatient admissions, including direct admissions, transfers from emergency departments or other within-hospital units, and transfers from external facilities (i.e., other hospitals or long-term care facilities). The source of these data is the Patient Abstract System (PAS) data file, which is compiled from hospital discharge records that are filed with the Department of Health and Senior Services by state law. The reporting requirements for the PAS have been in place in Missouri continuously since 1993.
In some instances, certain data values in the patient record are missing or miscoded. Discharges with missing or miscoded data values are included in the statewide totals, but may not be included within the displayed categories of certain variables (e.g., race, county of residence). Thus, a total of all categories of a variable may not equal the statewide total for that variable. Patients with a missing state of residence were deleted from the analysis file. Those discharges records identified as Missouri residents, but missing a county identifier, are included in the statewide totals only.
Diagnoses and Procedures
Diagnoses and procedures associated with hospitalizations are classified in accordance with the Ninth Revision of the International Classification of Diseases (ICD-9). This classification is the result of close collaboration among many nations and non-governmental organizations, under the auspices of the World Health Organization. Its original use was to classify causes of mortality. Later, it was extended to include diagnoses in morbidity. For example, the "clinical modification" of the ICD is used in categorizing hospital diagnoses. In practice, the ICD has become the international standard diagnostic classification for all general epidemiological, as well as health management, purposes. The ninth revision of the ICD has been used to classify disease and procedures beginning January 1, 1979, to the present.
The diagnostic categories used are based on the principle diagnosis, which is submitted as the first of several possible diagnoses coded on the discharge record. As defined by the Uniform Hospital Discharge Data Set (UHDDS), the principal diagnosis represents the "condition established after study to be chiefly responsible for occasioning the admission of the patient to the hospital for care".
Procedure codes are used to identify significant procedures performed during the patient encounter or stay at the health care facility. Procedures that are surgical in nature, involve both procedural and anesthetic risk, and require specialized medical training. Surgery includes incision, excision, amputation, introduction, endoscopy, repair, destruction, suture, and manipulation. The MICA reports on procedures also include statistics on miscellaneous diagnostic and therapeutic procedures. These non-surgical procedures involve varying levels of risk, as well as varying levels and types of training for persons who perform the procedures.
The procedure and diagnostic groupings used in the hospitalization profiles and MICA reports are based on the Clinical Classification Software (CCS). CCS is a tool for clustering patient diagnoses and procedures into a manageable number of clinically meaningful categories. It was developed by the Agency for Healthcare Research and Quality (AHRQ - formerly known as the Agency for Health Care Policy and Research (AHCPR). The tool is updated periodically. It was originally named the Clinical Classifications for Health Policy Research (CCHPR). The CCS compresses the 12,000 diagnosis codes of the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) into 259 mutually exclusive categories. In its multi-level mode, the system further categorizes these 259 into some 26 broader groupings. The 3,500 procedure codes of the ICD are similarly compacted into 231 groups. The system can be used with any data that are coded using the ICD-9-CM. It has been shown to be helpful in understanding and analyzing patient data by managed care plans, insurers and researchers.
Further information on the clinical classification, as well as the list of diagnoses and procedures utilized by CCS, can be found at http://www.hcup-us.ahrq.gov/toolssoftware/ccs/ccs.jsp.