Asthma-Related Health Care Use

Ambulatory Health Care Data and Hospital Inpatient Stays

Background

Physician office visits and emergency department visits data are provided by National Center for Health Statistics (NCHS) annually.

The National Ambulatory Medical Care Survey (NAMCS) is based on a sample of visits to non-federally employed office-based physicians who are primarily engaged in direct patient care and, starting in 2006, a separate sample of visits to community health centers. NAMCS provides objective, reliable information about the provision and use of ambulatory medical care services in the United States. Prior to 2012, NAMCS relied on paper instruments; the survey switched to an automated laptop-assisted data collection method in 2012.

The National Hospital Ambulatory Medical Care Survey (NHAMCS) collects data on the utilization and provision of ambulatory care services in hospital emergency and outpatient departments, and hospital-based ambulatory surgery centers in non-federal, general or short-stay hospitals, exclusive of federal, military, and Veterans Administration hospitals, located in the 50 States and the District of Columbia. The NHAMCS survey of hospital emergency and outpatient departments has been ongoing since 1992. Data on ambulatory surgery performed in hospitals have been collected annually, since 2009. Prior to 2012, NHAMCS relied on paper instruments; the survey switched to an automated laptop-assisted data collection method in 2012.

For additional information regarding the design of the NAMCS/NHAMCS, go to https://www.cdc.gov/nchs/ahcd/index.htm.  For the survey description, questionnaires, and related documentation, go to https://www.cdc.gov/nchs/ahcd/ahcd_questionnaires.htm.

NAMCS/NHAMCS web tables for physician office and emergency department (ED) visits with asthma as the primary diagnosis include the weighted count and rate of visits per 10,000 U.S. civilian population by selected patient characteristics. An asthma physician office or ED visit was defined as a visit with asthma as the primary diagnosis (ICD-9-CM diagnosis code of 493 until year 2016 and ICD-10-CM diagnosis code of J45 in 2016 and after).

The relative standard error (RSE) of an estimate is calculated by dividing the standard error of the estimate by the estimate itself and is expressed as a percentage of the estimate. The National Center for Health Statistics considers an estimate to be reliable if it has a relative standard error of 30 percent or less (i.e., the standard error is no more than 30 percent of the estimate).

Hospital inpatient stays with asthma, Healthcare Cost and Utilization Project (HCUP)

Background

The Healthcare Cost and Utilization Project (HCUP) is a family of healthcare databases, software tools, supplemental files, reports, and other related products developed through a federal,state, and Industry partnership and sponsored by the Agency for Healthcare Research and Quality (AHRQ). It builds on the data collection efforts of state data organizations, hospital associations, and private data organizations and is the largest collection of all-payer, encounter-level hospital care data in the United States. AHRQ transforms administrative statewide healthcare data into research-ready uniform databases with a common set of data elements. For the inpatient database, data are acquired from 48 Partners (47 states and the District of Columbia) and represents 97 percent of inpatient discharges from community hospitals to produce the National (Nationwide) Inpatient Sample (NIS).

Beginning with the 2012 data, the National Inpatient Sample (NIS) was redesigned to optimize national estimates. The nationwide statistics in HCUPnet for years prior to 2012 were regenerated using new trend weights in order to permit longitudinal analysis. The regenerated data were posted to HCUPnet on July 2, 2014. The statistics for years prior to 2012 currently on HCUPnet will differ slightly from statistics obtained prior to July 2, 2014.   For additional information regarding HCUP, go to https://www.hcup-us.ahrq.gov/overview.jspExternal.

Web tables for hospital inpatient stays with asthma as the primary diagnosis include the weighted count and rate of hospital inpatient short-stays per 10,000 U.S. civilian population by selected patient characteristics.

An asthma hospital inpatient stay was defined as a hospital inpatient stay with asthma as the primary diagnosis (ICD-9-CM diagnosis code of 493 until October 2015 and ICD-10-CM diagnosis code of J45 in October 2015 and after). The relative standard error (RSE) of an estimate is used to assess the reliability of the estimates. If an estimate has a relative standard error of 30 percent or less, the estimate is considered reliable.

Office Visits, ED Visits and Hospitalizations

201020112012201320142015

Page last reviewed: February 1, 2019