Concept: Cause of Death Coding in the MCHP Vital Statistics Mortality Registry Data

Introduction

This concept contains information on how cause of death information is collected and coded in Manitoba, and the type of data that is available in the MCHP Vital Statistics Mortality Registry. It briefly describes the process for collecting and coding cause of death information in Manitoba, identifies the cause of death data that is available in the MCHP Manitoba Vital Statistics Mortality Registry data over time, and provides a list of reference information for this concept.

Process for Collecting and Coding Cause of Death in Manitoba

Since 2004, Manitoba has sent the completed Medical Certificate of Death (referred to as the "Death Certificate" in previous MCHP research) to Statistics Canada for coding and for determination of the cause of death. Currently, this data is coded using the 10th revision of the World Health Organization (WHO) International Classification of Diseases (ICD-10) and the related international rules for mortality classification (Bulletin of the World Health Organization, April 2006, 84: 297-304). The completed data is then sent back to the Manitoba Vital Statistics Agency. This process takes approximately 6-8 weeks. Coding is done on an as-received basis and delays usually only occur if many provincial submissions are received at once.

At present, all but the largest provinces in Canada use Statistics Canada to do this work. British Columbia, Ontario and Quebec do their own coding, but utilize the same methodology. Since the implementation of ICD-10 in Canada, much of the cause of death coding has been done using an international automated system designed to select the cause of death in accordance with the WHO rules. Records not processed by the automated system for coding cause of death are handled by trained and experienced mortality classification staff at Statistics Canada or, in the case of British Columbia, Ontario and Quebec, by in-house staff.

IMPORTANT NOTE:


• Both WHO and Statistics Canada documentation refer to cause of death as the "underlying cause of death", defined as "(a) the disease or injury which initiated the train of morbid events leading directly to death, or (b) the circumstances of the accident or violence which produced the fatal injury. This underlying cause of death is selected from a number of conditions listed on the medical certificate of cause of death."
  
  (Source: cause of death definition on the Statistics Canada website, Vital Statistics Death Database - Glossary - http://www23.statcan.gc.ca/imdb-bmdi/document/3233_D4_T9_V1-eng.htm - accessed April 6, 2016).
  
  
• In the MCHP Vital Statistics Mortality Registry data, the WHO and Statistics Canada term "underlying cause of death" is recorded as the primary cause of death.

Cause of Death in the MCHP Vital Statistics Mortality Registry Data

The MCHP Vital Statistics Mortality Registry data contains ICD diagnosis data in several variables that are related to cause of death. Since January, 2000, the diagnoses are recorded using ICD-10. The variables include:


• primary cause of death - referred to as "underlying cause of death" by WHO and Statistics Canada; and
  
• underlying cause of death, 1 - 20 - up to 20 additional variables are available that identify additional factors (diagnoses) related to the cause of death from the Medical Certificate of Death.

From 1979 until the end of 1999, the Manitoba Vital Statistics Mortality Registry uses ICD-9 coding and contains only two variables related to cause of death. These are:


• primary cause of death, and
  
• underlying cause of death, - NOTE: this is only coded if there is an external cause of injury / poisoning (E-code) coded as the primary cause of death.
  
  NOTE: ICD-9 E-codes (external cause of injury and poisoning) begin with the letter "E". In the 1979-1999 Vital Statistics mortality data, the "E" is part of the injury code value recorded in the primary cause of death variable. For more information, please see the Vital Statistics - Use of ICD-9 Codes Identifying Cause of Death concept.

For data from 1970 to 1979, the same structure as the 1979 to 1999 data set is used, but cause of death codes are recorded using ICDA-8.

Reference Information

This concept contains information from a June 2014 email from Mark Smith (Associate Director of the MCHP Data Repository) in correspondence with Linda Harlos (Assistant Director of Agency Management for the Manitoba Vital Statistics Agency), and from knowledge of Data Analysts and Data Management staff at MCHP.

Information on the definition of cause of death can be found on the:


• Statistics Canada web site - Vital Statistics Death Database - Glossary - Cause of death; and
  
• World Health Organization (WHO) web site - Mortality


For reference on how Katz et al. (2019) found cause of death please read Technical Definitions of Indicators and Drug Codes from the online supplement material from Katz et al. (2019) deliverable: The Health Status of and Access to Healthcare by Registered First Nation Peoples in Manitoba .