Question
I have prepared flag variables for the DAD 2009 ICD-10 classification (which I will send to the DLI for distribution once finished; I’m still working on the CCI codes). As I was looking at the frequencies of these flag variables to see if they made sense (i.e., that the chapter headings were picked up along with the more specific heading), I encountered something peculiar: there are no ICD-10 listings for any classification of V01 through Y98 (external causes of morbidity and mortality) – no one requiring treatment for any form of accident, fall, drowning, assault, etc. Were these records suppressed on the file distributed to us, or was it random chance (through sampling) that none of these records were selected for our file, or (even less likely, there were no such discharges through the years)? I checked the specifications file for the cycle (specifications-dad-raf.pdf), and couldn’t see any note to that effect in the exclusions.
Exclusions:
- Stillbirths (ENT_CODE = S)
- Cadaveric donations (ADM_CAT = R)
- All therapeutic abortion (TA) records, defined as follows:
1) ICD-10-CA diagnosis code = O04 at the three-digit level, in any diagnosis code field; or
2) CCI intervention code = 5CA20, 5CA24, 5CA88, 5CA89 or 5CA90 at the five-digit level, in any intervention code file
Answer
ICD-10 codes for ‘external causes of morbidity and mortality’ (V01 - Y98) are recorded as a diagnosis type ‘9’. All diagnoses with a diagnosis type of ‘3', '4', '5' or '9' were removed from the records for privacy reasons. As per the file layout there are only type ‘M’, ‘1’, ‘2’, ‘W’, ‘X’ and ‘Y’ included in the file.
This is not included in the exclusion criteria of the specifications because it was not the criteria used to remove an entire record. Any record with one of the exclusions listed (Ex. stillbirths) was completely removed from the dataset. In the case of diagnoses type ‘3', '4', '5' or '9' these ICD-10 codes were only removed from the record and the record itself was retained in the dataset. This way you can still search ICD-10 codes for ‘Injury, poisoning and certain other consequences of external causes’ (S00-T98) to obtain records with a diagnosis due to an external injury – but the cause is removed.
All this information can be found in the DAD Abstracting Manuals which we provided as part of the DLI. The Group 10 – Diagnosis section contains a description of “Diagnosis Type” and how it is coded.
For example:
-“9” External Cause of Injury Code - A Diagnosis Type 9 is assigned to an external cause of injury code (Chapter XX: External Causes of Morbidity and Mortality in the Canadian Coding Standards for ICD-10-CA and CCI), place of occurrence code (U98.–Place of occurrence) or activity code (U99.–Activity). Chapter XX codes are mandatory for use with codes in the range S00 to T98Injury, poisoning and certain other consequences of external causes. Category U98.–Place of occurrence is mandatory with codes in the range W00 to Y34, with the exception of Y06 and Y07. Recording with Category U99.–(Activity) is optional.
I’ve included short description of 3, 4 and 5 below but further information on all the types and when they are coded can be found in the manual:
-“3” Secondary Diagnosis - A Diagnosis Type (3) is a secondary diagnosis or condition for which a patient may or may not have received treatment, has been assigned an ICD-10-CA code and does not satisfy the requirements for determining co-morbidity. Diagnoses that are listed only on the front sheet, discharge summary, death certificate, history and physical or pre-operative anaesthetic consults qualify as Diagnosis Type (3). A Diagnosis Type (3) is also used for ICD-10-CA codes that are assigned to provide detail that in themselves do not represent a co-morbidity.
-“4” Morphology Code - Diagnosis Type (4) morphology codes are derived from ICD-O (International Classification of Diseases—Oncology) codes describing the type and behaviour of neoplasm. These codes are found in Chapter XXII: Morphology of Neoplasms.
-“5” Admitting Diagnosis - Diagnosis Type (5) can be used to code the admitting diagnosis when it differs from the most responsible Diagnosis Code. Its use is determined at the provincial/territorial or facility level. Refer to the DAD provincial/territorial sections and facility policies to determine the use of this Diagnosis Type.
