National Ambulatory Care Reporting System (NACRS)

• Ambulatory care visits are a source of morbidity information available through IntelliHEALTH beginning with the 2001/2002 fiscal (2002 calendar) year. Note that the fiscal year is the MOHLTC's fiscal year (April 1 - March 31).
• Ambulatory visits include emergency visits as well as other hospital-based outpatient clinics (e.g., renal dialysis, day/night surgery). Other components of morbidity include hospitalizations (from CIHI) and medical services (from OHIP Approved Claims files). Both are also available through IntelliHEALTH.
• The first areas or visit functional centres (VFCs) to report to NACRS in the fiscal year 2001/2002 (2002 calendar year) were the hospital emergency departments (ED) and urgent care centres (both considered ED).  The other VFCs (i.e. hospital-based outpatient units, such as day/night surgery and renal dialysis units) began reporting to NACRS in 2003/2004. Note that day/night surgery units reported to the DAD from the 1996/1997 to 2002/2003 fiscal years, but they were the only VFCs to do so.
• To select only unscheduled emergency visits, qualify Ambulatory Case Type = EMG (or select predefined filter ‘unscheduled ED visits'). Note that this case type is already selected in the Ambulatory Emergency  External Cause (Chapter 20) data source in IntelliHEALTH. The AM case type field is based on the Main Visit Functional Centre (VFC) for the visit. It is used to categorize NACRS visits into groups based on the functional area of the hospital. The types are: EMG - emergency Cases; EMS: Emergency schedule visits (i.e. ED is being used for non‐emergencies); DSU - day/night surgery; CCL: cardiac catherization clinic (outpatient); ONC - Oncology (outpatient); REN - renal Dialysis (outpatient); OTH - Other hospital-based outpatient units.
• The "Main Problem" represents the patient's main problem or diagnosis as determined during the ED visit. All visits have one main problem and up to nine other problems. Unlike the inpatient data, the only diagnosis types available are ‘main' or ‘other'. Problems/diagnoses are reported using ICD-10-CA.
• 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: whether a patient complains of chest pains on arrival in ED and is found to be suffering from an AMI (acute myocardial infarction/heart attack), the AMI would be coded as the "main problem" and the chest pain diagnosis is reported in both the ‘reason for the visit' and ‘other' diagnosis fields.
• NACRS also contains a ‘Disposition Status' indicator - which indicates the flow of patients after they leave the emergency department, e.g. if the patient is discharged home or admitted to hospital.  Disposition status equal to 6 or 7 (transfers to inpatient care in the reporting hospital) can be used to provide more timely data on hospitalization rates since hospital stays are only reported at discharge. It also allows reporting of hospitalizations for patients that are admitted to an adult psychiatric bed.
• Note that there are no decimal places for ICD-10 codes in IntelliHEALTH  (i.e., Z37.1 is Z371).  
• Hospitals report data to CIHI and data can be reported by hospital but in general, these data should be reported by residence of the patient for the health unit reporting.
• Both fiscal and calendar year are available in the IntelliHEALTH NACRS sources. Data are submitted by fiscal year but calendar year is generally used for the health unit reporting.
• The IntelliHEALTH licensing agreement does not require suppression of small cells, but limits reporting at a level that could identify individuals, e.g. reporting at the postal code level by age and sex, regardless of the cell size. Aggregation (e.g. combining years, age groups, categories) should also be done when small numbers result in unstable rates.

1. Ontario Ministry of Health and Long-Term Care. IntelliHEALTH Ambulatory Visits User Guide. Toronto, ON: Ontario Ministry of Health and Long-Term Care, 2010. Available from: http://www.intellihealth.moh.gov.on.ca/ (after log in by licensed users).
2. Macpherson AK, Schull M, Manuel D, Cernat G, Redelmeier DA, Laupacis A. Injuries in Ontario. ICES atlas. Toronto: Institute for Clinical Evaluative Sciences, 2005. Available from: http://www.ices.on.ca/webpage.cfm?site_id=1&org_id=67&morg_id=0&gsec_id=0&item_id=3053&type=atlas
3. Canadian Institute for Health Information (CIHI). Ontario Trauma Registry Analytic Bulletin: Injury Hospitalizations and Emergency Visits by County and Health Planning Region in Ontario, 2002–2003. Toronto (ON): CIHI, 2005. Available from: http://secure.cihi.ca/cihiweb/en/downloads/bl_OTR_May_Regional%20Analysis_e.pdf