# Presentation: 677599

## Hospital separations selection of records for injury surveillance

- Susan G. Mackenzie
- Public Health Agency of Canada

- Presented at ICE meeting in Cuernavaca June 2005

## Selection of hospital separation records for analysis of external causes 

- What differences are there between (and within) countries?
- Is there a generally preferred, or most common, approach?

## Compare results of Canadian and US approaches using the same data set

- Data set
- All acute care separations from the province of Manitoba for 2000-01, excluding newborns and records with serious errors.
-  N=126,217
- Select all records where
- The **tabulating diagnosis is an injury** (in chapter 17 of ICD-9)    **or**
- There is an **external cause on the record**
**N=14,772**

## 0

**External cause on record**

**Present**

**Not present**

**ICD-9 ****Diagnosis**** ****chapter**

**17- Injury & poisoning**

**Other**

**14,772**

**0**

**4,499**
** ****(30%)**

**8,254**
** ****(56%)**

**2,019**
** ****(14%)**

## Exclude invalid diagnoses (chapter 17) and external causes

- Invalid diagnoses – only in the US
- Complications of care, adverse effects, allergic and anaphylactic reactions, others
- Injury Surveillance Workgroup. Consensus recommendations for using hospital discharge data for injury surveillance. Marietta (GA): State and Territorial Injury Prevention Directors Association; 2003.
- Invalid external causes – in Canada and the US
- Adverse effects
- Centers for Disease Control and Prevention. Recommended framework for presenting injury mortality data . MMWR 1997;46 (No. RR-14)

## External cause on record

**External cause on record**

**Present**

**Not present**

**ICD-9 ****Diagnosis**** ****chapter**

**17- Injury & poisoning**

**Other**

**14,772**

**0**

- 7,785

- 129

**110**

**230**

**8,254**

**2,019**

**4,499**

**7,785**

**129**

**None has a valid injury diagnosis**

**Valid**

**Invalid**

**Invalid**

**Valid**

**Injury diagnosis**

**8,254**

**2,019**

## External cause on record

**External cause on record**

**Present**

**Not present**

**ICD-9 Diagnosis chapter**

**17- Injury & poisoning**

**Other**

**14,772**

**0**

- 7,785

- 129

**110**

**230**

**2,050**

**1,560**

**804**

**85**

-  **1-16**

**8,254**

**2,019**

**4,499**

**7,785**

**129**

**None has a valid injury diagnosis**

**Valid**

**Invalid**

**Valid**

**V-code**

**Invalid**

**Invalid**

**Valid**

**Injury diagnosis**

**8,254**

**2,019**

**Diagnosis chapter**

## External cause on record

**External cause on record**

**Present**

**Not present**

**ICD-9**** ****Diagnosis**** ****chapter**

**17- Injury & poisoning**

**Other**

**14,772**

**0**

- 7,785

- 129

**110**

**230**

**2,050**

**1,560**

**804**

**85**

-  **1-16**

**CA**

**CA**

**CA**

**CA**

**8,254**

**2,019**

**4,499**

**US**

**7,785**

**129**

**None has a valid injury diagnosis**

**Valid**

**Valid**

**V-code**

**Invalid**

**Invalid**

**Diagnosis** **chapter**

**Total records retained from Manitoba 2000-01 hospital separation data**
**CA approach   10,749**
**US approach     7,785**
** **

**Valid**

**Injury diagnosis**

**8,254**

**2,019**

**Invalid**

## Distribution of selected external cause groups  using US and CA approaches data from Manitoba 2000-01

|  
    External cause  |          Percentages 
   N=7,785            N=10,749
US approach     CA approach |  |  
      Rates/100,000
US approach    CA approach |  |
| --- | --- | --- | --- | --- |
| All external causes | 100 | 100 | 678.7 | 937.1 |
| Unintentional (U-) Fall | 46.2 | 47.6 | 313.8 | 446.2 |
| U-MV traffic crash | 9.9 | 8.5 | 67.5 | 80.0 |
| U-MV non-traffic crash | 3.3 | 2.6 | 22.1 | 23.9 |
| U-Other transport | 2.5 | 2.0 | 16.7 | 18.6 |
| U-Poisoning | 2.0 | 2.4 | 14.0 | 22.2 |
| U-Late effects | 0.2 | 2.1 | 1.6 | 19.5 |
| Self-inflicted | 6.6 | 7.6 | 45.2 | 71.0 |
| Assault | 7.1 | 6.0 | 48.4 | 56.2 |

## Most frequent groups of records kept only with the Canadian approach   N=2,964

| External cause group | Diagnosis chapter | Percentage |
| --- | --- | --- |
| Fall | V-code | 20.3 |
| Self-inflicted | Mental disorder | 8.8 |
| Fall | Circulatory | 6.6 |
| Fall  | Symptoms | 3.8 |
| Fall | Mental disorder | 3.5 |
| Fall | Musculoskeletal | 3.2 |
| Fall | Respiratory | 3.0 |
| Other accident | Musculoskeletal | 2.9 |
| Late effects | Musculoskeletal | 2.4 |
| MVTC | V-code | 2.3 |
| Other accident | Skin | 2.2 |
| Other accident | V-code | 1.8 |

## Summary

- US selection based on
- Valid injury diagnoses and valid external causes
- Canadian selection based on
- Valid external causes
- Canadian approach yields more records
- There are quite large differences in the rates for some external cause groups
- Other countries?

## Two approaches used in Canada

**Canadian Institute for Health Information**
- Acute care
- No serious errors
- Adverse effects excluded
- Newborns included
- Other exclusions
- Poisoning, choking, late effects, travel & motion, hunger, thirst, exposure, neglect

**Public Health Agency of Canada**
- Same
- Same
- Same
- Newborns excluded
- None

## Compare overall results of the two Canadian approaches

|  | 
CIHI | 
PHAC |
| --- | --- | --- |
| Initial number of records selected | 
14,773 | 
14,772 |
| Records that include an E-code | 
12,754 | 
12,753 |
| Records with a “valid” E-code | 
9,389 | 
10,749 |