about emergency department data
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- For each data source, information about data collection and analytical methods, limitations, the citation and additional resources can be found on the Data Sources and Methods page.
Original Source: Canadian Institute for Health Information (CIHI)
Cite as: National Ambulatory Care Reporting System Data 2004-2013, IntelliHEALTH Ontario, Ministry of Health and Long-Term Care.
Data Collection Methods
- Hospital emergency departments report patient visit information into the National Ambulatory Care Reporting System (NACRS), which began in July 2000. Data are not considered to be reliable until the fiscal year 2002/2003.
- The first areas or visit functional centres (VFCs) to report to NACRS were the hospital Emergency Rooms in fiscal year 2002/2003. In fiscal year 2003/2004 other major ambulatory VFCs within the hospital such as Day Surgery, Medical Day/Night Care and specified high-cost clinics such as renal dialysis and cancer clinics etc. were also included.
- All data presented for emergency department visits on this site are based on the patients 'main problem or diagnosis as determined by the emergency department.' All visits have one main problem (and up to nine other problems). Unlike the inpatient data, there is no diagnosis type for complications, secondary diagnoses etc. All other problems are assigned a problem type of 'other'. The main problem variable is coded using International Statistical Classification of Diseases and Related Health Problems, Canada, Version 10, 2007 (ICD-10-CA) codes starting with A through U. A second set of codes for external causes (e-codes ) (those starting with V, W, X or Y) are used in the case of an injury to classify the environmental events, circumstances and conditions that caused the injury, for example a motor vehicle traffic injury. E-codes are the principal means of classifying injury deaths, but are not used as a most responsible diagnosis for hospitalizations, so they need to be examined separately. Z-codes are excluded from analysis. The ICD-10-CA codes used in these analyses are available electronically.
- Data in tables are presented as follows:
- ED visit by year
- ED visit by sex and year
- ED visit by age group (and sex if applicable) for most current year and over time if data are available
- Beginning in 2003/2004 there is an indicator to identify the problem code that was considered to be the 'Reason for the Visit' or the reason or symptom that caused the patient to visit the hospital in the first place. For example: if a patient complains of chest pain on arrival at the ER and is found to be suffering from a myocardial infarction/heart attack (MI), the MI would be coded as the 'main problem' and the chest pain as one of the other problems and the Reason for the Visit.
- Age-specific and crude rates and proportions based on counts less than five (5) are suppressed and presented in tables or graphs with the acronym 'NR' – not releasable due to small numbers.
- When calculating directly standardized rates, cell counts of less than 20 are suppressed and presented in tables or graphs with the acronym 'NR' – not releasable due to small numbers.
- Emergency department visit rates are calculated using two methods:
- Peel and Peel municipalities compared to Ontario
- Crude rates are calculated using population estimates as follows:
- #ED visits/Total population X 100,000
- Age-standardized rates are calculated using the 1991 Canadian population with population estimates as the denominator, and using the direct method of standardization.
- Peel data zones compared to Peel and Peel municipalities
- Crude rates are calculated using the population from individual tax filer data for 2006 to 2011 as the denominator as follows:
- # ED visits/Total population X 100,000
- Age-standardized rates are calculated using the 1991 Canadian population and using the population from individual tax filer data for 2006 to 2011 as the denominator, and using the direct method of standardization.
- The number of emergency department visits reported may differ slightly from other sources due to differences in methodology. The counts presented here represent the number of distinct visits and not the number of distinct individuals, as an individual may have multiple visits during the time period examined. In addition, records which have a main problem code of Z00-Z99 (Chapter XXI – Factors influencing health status and contact with health services) are not included in any of the tables or graphs presented here.
- Ambulatory visit data provide only a crude measure of the condition being quantified since a person may not seek care at an emergency department, or may visit several times for the same disease or injury event, or may visit more than one hospital for the same disease or injury event (i.e., they get transferred to another hospital, thus two visits are recorded for the same injury or event).
- Data are influenced by factors that are unrelated to health status such as availability and accessibility of care, and administrative policies and procedures. This may influence comparisons between areas and over time.
- Ontario residents visiting hospitals outside of the province are excluded. Areas bordering other provinces may be more affected.
REFERENCES AND RESOURCES
- APHEO website