Concept: Vital Statistics - Use of ICD-9 Codes Identifying Cause of Death

Introduction

This concept describes the use of the International Classification of Disease 9th Revision (ICD-9) coding system in the "cause of death" data in the Manitoba department of Vital Statistics Mortality Registry data for the years 1979 to 1999.

1. Cause of Death Fields

In the Vital Statistics Mortality data for 1970 to 1999, there are two variables related to cause of death: PRIMARYCAUSEDEATH and UNDERLYINGCAUSE. In most cases, only the primary cause of death is coded and used to identify the medical reason of death. For example, if a person dies from a cerebral hemorrhage that was not caused by an accident, it would be coded as:


• PRIMARYCAUSEDEATH: 431 - Intracerebral hemorrhage;
  
• UNDERLYINGCAUSE: < leftblank >

If the cause of death involves an injury or poisoning, then both variables will have code values that describe the injury / poisoning that occurred. The PRIMARYCAUSEDEATH variable contains the ICD-9 E-code (ranging from E800 - E999) identifying the external cause of injury / poisoning and the UNDERLYINGCAUSE variable contains the ICD-9 code describing the medical reason of death.

NOTE: ICD-9 E-codes recorded in the PRIMARYCAUSEDEATH variable in the Vital Statistics Mortality Registry data contain the prefix "E" in the code value.

For example, if a person dies from drowning as the result of a watercraft submersion, both variables would be coded, as follows:


• PRIMARYCAUSEDEATH: E830 - Accident - watercraft submersion;
  
• UNDERLYINGCAUSE: 9941 - Drowning / nonfatal submersion

NOTE:

• Code values recorded in the file do not contain the period between the third and fourth digits in ICD-9.
  
• ICD-9 codes in the range of 800-999 are related to injury and poisoning, BUT THEY ARE NOT the same as ICD-9 E-codes in the range E800-E999. When attempting to add labels or identify codes for the Vital Statistics Mortality Registry data, this must be considered.

2. ICD-9 versus ICD-9-CM

The "cause of death" information recorded in the Vital Statistics Mortality Registry data uses ICD-9 codes, NOT ICD-9-CM codes. This can cause some confusion, for example, when we look at ICD codes in Vital Statistics data compared to diagnoses in the Hospital Abstracts or Medical Services (Physician Claims) data. A few of the noted differences between these sets of data include:


• Vital Statistics data only codes cause of death to 4 digits from 1979 to 1999.
  
• At the first 3 digit level there is no difference between ICD-9 and ICD-9-CM.
  
• At the 4 digit level there are DIFFERENCES between ICD-9 and ICD-9-CM.

NOTE: The following list of ICD-9-CM codes are examples of codes that do not exist at all in the ICD-9 codebook, and some of these have slightly different "meaning". This list is not all inclusive.


013.2 - 013.8
015.5 - 015.7
016.1 - 016.7
017.8 , 017.9
250.2 - 250.8
296.0 - 296.9
312.0 - 312.4
369.4, 441.9
644.0 - 644.2
800.1 - 800.9
801.1 - 801.9
803.1 - 803.9
804.1 - 804.9
813.0 , 813.1 , 813.8 , 813.9 823.0 , 823.1 , 823.8 , 823.9
851.0 - 851.9
852.0 - 852.5
941.4 - 941.5
942.4 - 942.5
943.4 - 943.5
944.4 - 944.5
945.4 - 945.5
946.4 - 946.5
949.4 - 949.5
E849.0 - E849.9 E850.0 - E850.7 E935.1 - E935.7

NOTE: As of 1999 data, none of these differences have any effect on the tabulated POPULIS Health Status Causes of Death if compared to a corresponding Hospital or Physician Visit diagnosis.

3. Additional Information

Additional, related information is available:


• For a more complete historical description on cause of death coding in the mortality data, please see the Cause of Death Coding in the MCHP Vital Statistics Mortality Registry Data concept.
  
  
• For more information on the variety of ICD coding systems and applicable years for relevant databases in the MCHP Data Repository, please read the International Classification of Disease (ICD) Coding in MCHP Data concept.