Skip Navigation Links

Glossary of Terms

Terminology varies considerably across sources cited in the Incidence and Prevalence Database (IPD). Below are some general terms you may encounter while browsing the database. There is also a Remarks section for individual ICD-9 codes, containing definitions specific to each disease or procedure along with other useful notes. The Remarks section appears under Overview Reports on the Search Results page.

Activities of Daily Living
Ambulatory Clinic
Ambulant
Baseline
Community Hospitals
Comorbidity
Cost (Indirect Cost, Direct Cost)
Current Procedural Terminology (CPT) Codes
Disposition
Emergency Department
Emergency Service Area
Epidemiology
Etiology
Hazard Rate
Health maintenance organization (HMO)
Histology
Hospice
ICD-9-CM (International Classification of Diseases, 9th Revision, Clinical Modification)
Incidence
Length of Stay
Mean, Median, and Mode
Medicaid
Medicare
Mendelian Inheritance in Men (MIM) Number
Morbidity
Mortality
Outcome
Outpatient Department
Pathophysiology
Person-Years
Prevalence
REF Codes
Risk Factors
Relative Risk (Risk Ratio)
Short-term Hospitals
Standardized Incidence Ratio
V Codes
Visit



Activities of Daily Living

A scale to score physical activity and its limitations. Examples of activities of daily living (ADL) measures include mobility, self-care, and grooming; examples of instrumental ADL measures include handling money, doing housework, and shopping.


Ambulatory Clinic

An administrative unit that provides ambulatory medical care under the supervision of a physician. Clinics are grouped into the following six specialty groups for purposes of systematic sampling and non-response adjustment: general medicine, surgery, pediatrics, obstetrics/gynecology, substance abuse, and other.


Ambulant

Walking about or able to walk about; denoting a patient who is not confined to bed or hospital as a result of disease or surgery.


Baseline

A set of critical observations or data used for comparison or a control.


Community Hospitals

All non-federal, short-term general, and special hospitals whose facilities and services are available to the public. Short-term general and special children's hospitals are also considered to be community hospitals. A hospital may include a nursing-home or a nursing-home-type unit and still be classified short-term, provided that the majority of its patients are admitted to units where the average length of stay is less than 30 days.


Comorbidity

A concomitant but unrelated disease process; usually used in epidemiology to indicate the coexistence of two or more disease processes (e.g., a patient who has asthma and diabetes, but neither one caused the other). These can also be termed "pre-existing" or "concomitant" conditions.


Cost (Indirect Cost, Direct Cost)

The cost of disease treatment or the cost of a procedure. Costs may be direct (e.g., operating room costs, physician's costs, hospital stay costs) or indirect (e.g., lost work-time, home caregiver expense, etc.).


Current Procedural Terminology (CPT) Codes

A code used to convert the documentation of health services for billing purposes. CPT codes are linked to levels of reimbursement. The Health Care Financing Administration (HCFA) provides guidelines for assigning CPT codes.


Disposition

Where a patient goes after being discharged from health services. A few examples include a patient leaving the hospital to return home, a patient leaving the hospital by dying, and a patient leaving a mental health ward to begin outpatient treatment.


Emergency Department

Hospital facility staffed 24 hours a day for the provision of unscheduled outpatient services to patients whose conditions require immediate care.


Emergency Service Area

Area within an emergency department where emergency services are provided. This includes services provided under the “hospital as landlord” arrangement in which the hospital rents space to a physician group.


Epidemiology

The study of how disease is manifest within various populations. Includes topics like incidence, prevalence, morbidity, and mortality.


Etiology

The science and study of the causes of disease and their mode of operation.


Hazard Rate

Theoretical measure of the risk of occurrence of an event (e.g., death or new disease) at a point in time.


Health maintenance organization (HMO)

A health care organization that acts as both insurer and provider of comprehensive but specified medical services in return for prospective per capita payments.


Histology

The science concerned with the minute structure of cells, tissues, and organs in relation to their function. For example, histology is usually used to describe cancerous growth and its evolution.


Hospice

A program providing palliative care, chiefly medical relief of pain and supportive services, addressing the emotional, social, financial, and legal needs of terminally ill patients and their families. Care can be provided in a variety of settings, both inpatients and at home.


ICD-9-CM

(International Classification of Diseases, 9th Revision, Clinical Modification)
Designed for the universal classification of morbidity and mortality information for statistical purposes, and for the indexing of records by disease and operations (surgical, diagnostic, and therapeutic procedures). ICD Codes with three digits before the decimal refer to disease diagnoses, while those with two digits before the decimal refer to procedures. The number of digits after the decimal (none, one, or two) indicates the degree of specificity of the disease or procedure classification. For example, two digits following the decimal indicate a highly specific description (493.00 = Extrinsic asthma without mention of status asthmaticus); one digit is somewhat more general (493.0 = Extrinsic asthma); and no digits are used for the most general classifications (493. = Asthma). Note that codes containing a "9" immediately after the decimal tend to refer to "other and unspecified" categories within the more general classification (e.g., 493.9 = Asthma, unspecified). IMPORTANT: Statistical trend data (i.e. hospital inpatient, physician office visits, etc.) from the more specific codes are incorporated into the data for the more general codes; therefore, codes with one (or two) digits after the decimal should not be added to codes with none (or one) following the decimal. For example, statistics reported for 493. include data from 493.0, 493.2, and 493.9; likewise, 493.0 includes data from 493.00 and 493.01, and so on.


Incidence

The number of new cases of a disease or procedure among a given group of people for a defined period of time (usually 1 year).


Length of Stay

Length of time (usually measured in days) that a patient stays in the hospital, intensive care unit, or other health service.


Long-term hospitals

Hospitals where the average patient length of stay is 30 days or more.


Mean, Median, and Mode

The mean is the statistical measurement of central tendency or average of a set of values, usually assumed to be the arithmetic mean unless otherwise specified. The median is the middle value in a set of measurements; like the mean, a measure of central tendency. The mode is the value which appears most frequently in a set of measurements.


Medicaid

Medicaid is a program that pays for medical assistance for certain individuals and families with low incomes and resources. This program became law in 1965 and is jointly funded by the Federal and State governments (including the District of Columbia and the Territories) to assist States in providing medical long-term care assistance to people who meet certain eligibility criteria. Medicaid is the largest source of funding for medical and health-related services for people with limited income.


Medicare

The Centers for Medicare and Medicaid Services (CMS) administers Medicare, the nation's largest health insurance program, which covers nearly 40 million Americans. Medicare is for people 65 years of age and older, some disabled people under 65 years of age, and people with end-stage renal disease (permanent kidney failure treated with dialysis or a transplant).


Mendelian Inheritance in Men (MIM) Number

The catalog assignment for a mendelian trait in the MIM system. If the initial digit is 1, the trait is deemed autosomal dominant; if 2, autosomal recessive; if 3, X-linked. Wherever a trait defined in this dictionary has a MIM number, the number from the 12th edition of MIM, is given in square brackets with or without an asterisk (asterisks indicate that the mode of inheritance is known; a number symbol (#) before an entry number means that the phenotype can be caused by mutation in any of 2 or more genes) as appropriate e.g., Pelizaeus-Merzbacher disease [MIM*169500] is a well-established, autosomal, dominant, mendelian disorder.


Morbidity

A diseased state or the ratio of sick to well in a community. It can also describe the frequency of complications following a surgical procedure or other treatment. It can describe the resulting disability of someone who has suffered an acute disease episode. For instance, someone suffering a stroke might experience speech problems, dementia, palsy, etc. as a result. This would be considered "stroke morbidity."


Mortality

A fatal outcome; the proportion of a given population that dies. Mortality rates can also be called "fatality rates" or "death rates."


Outcome

A medical industry term for the short- and long-term results of an illness, a treatment, or a procedure.


Outpatient Department

Hospital facility where non-urgent ambulatory medical care is provided under the supervision of a physician.


Pathophysiology

Derangement of function seen in disease; alteration in function as distinguished from structural defects.


Person-Years

The product of the number of years multiplied by the number of members of a population who have been affected by a certain condition; e.g., years of treatment with a certain drug.


Prevalence

The number of people in a defined group who are reported to have a given disease.


REF Codes

Special codes created by Thomson Reuters (See codes REF.1 and REF.89 through REF.99 in the complete edition). REF.89 through REF.99 provide valuable overviews about nursing homes, HMOs, managed care, plus other general topics not classified by the standard ICD Codes. REF.1 specifically contains profiles and descriptions of data sources used in the IPD.


Risk Factors

Conditions that predispose a patient to a condition (i.e., smoking as a risk factor for lung cancer). A risk factor can be "predictive" (i.e., it will cause the condition) or "protective" (i.e., it will protect against the condition).


Relative Risk (Risk Ratio)

The ratio of the risk of disease among those exposed to a risk factor to the risk among those not exposed.


Short-term hospitals

Hospitals where the average patient length of stay is less than 30 days.


Standardized Incidence Ratio

The ratio of the number of events observed in a population to the number that would be expected if the population had the same distribution as the general population.


V Codes

Occasions or circumstances other than a disease or injury classifiable to ICD Codes 001-999. These can arise mainly in three ways: (1) when a person who is not currently sick encounters the health services for some specific purpose, such as organ donation, vaccination, or discussion of a problem which in itself is not a disease or injury; (2) when a person with a known disease or injury, whether it is current or resolving, encounters the health care system for a specific treatment (e.g., dialysis, chemotherapy, cast change); and (3) when some problem is present which influences the person's health status but is not in itself a current illness or injury.


Visit

A direct, personal exchange between a patient and a physician, or a staff member acting under a physician’s direction, for the purpose of seeking care and rendering health services.