1. Hospital separations selection of records for injury surveillance Susan G. Mackenzie Public Health Agency of Canada Presented at ICE meeting in Cuernavaca June 2005

2. Selection of hospital separation records for analysis of external causes What differences are there between (and within) countries? What differences are there between (and within) countries? Is there a generally preferred, or most common, approach? Is there a generally preferred, or most common, approach?

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

4. External cause on record PresentNot present ICD-9 Diagnosis chapter 17- Injury & poisoning Other 14,772 0 4,499 (30%) (30%) 8,254 (56%) (56%)2,019 (14%) (14%)

5. Exclude invalid diagnoses (chapter 17) and external causes Invalid diagnoses – only in the US Invalid diagnoses – only in the US Complications of care, adverse effects, allergic and anaphylactic reactions, others 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. 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 Invalid external causes – in Canada and the US Adverse effects Adverse effects Centers for Disease Control and Prevention. Recommended framework for presenting injury mortality data. MMWR 1997;46 (No. RR-14) Centers for Disease Control and Prevention. Recommended framework for presenting injury mortality data. MMWR 1997;46 (No. RR-14)

6. External cause on record PresentNot present ICD-9 Diagnosis chapter 17- Injury & poisoning Other 14,772 0 7,785129 110230 8,2542,019 4,499 7,785129 None has a valid injury diagnosis Valid Invalid Valid Injury diagnosis 8,2542,019

7. External cause on record PresentNot present ICD-9 Diagnosis chapter 17- Injury & poisoning Other 14,772 0 7,785129 110230 2,0501,560 80485 1-16 8,2542,019 4,499 7,785129 None has a valid injury diagnosis Valid Invalid Valid V-code Invalid Valid Injury diagnosis 8,2542,019 Diagnosis chapter

8. External cause on record Present Not present ICD-9 Diagnosis chapter 17- Injury & poisoning Other 14,772 0 7,785129 110230 2,0501,560 80485 1-16 CA 8,2542,019 4,499 US 7,785129 None has a valid injury diagnosis Valid V-code Invalid Diagnosis chapter Total records retained from Manitoba 2000-01 hospital separation data CA approach 10,749 US approach 7,785 Valid Injury diagnosis 8,2542,019 Invalid

9. 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 causes100 678.7937.1 Unintentional (U-) Fall46.247.6313.8446.2 U-MV traffic crash9.98.567.580.0 U-MV non-traffic crash3.32.622.123.9 U-Other transport2.52.016.718.6 U-Poisoning2.02.414.022.2 U-Late effects0.22.11.619.5 Self-inflicted6.67.645.271.0 Assault7.16.048.456.2

10. Most frequent groups of records kept only with the Canadian approach N=2,964 External cause group Diagnosis chapter Percentage FallV-code20.3 Self-inflicted Mental disorder 8.8 FallCirculatory6.6 FallSymptoms3.8 Fall 3.5 FallMusculoskeletal3.2 FallRespiratory3.0 Other accident Musculoskeletal2.9 Late effects Musculoskeletal2.4 MVTCV-code2.3 Other accident Skin2.2 V-code1.8

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

12. Two approaches used in Canada Canadian Institute for Health Information Canadian Institute for Health Information Acute care Acute care No serious errors No serious errors Adverse effects excluded Adverse effects excluded Newborns included Newborns included Other exclusions Other exclusions Poisoning, choking, late effects, travel & motion, hunger, thirst, exposure, neglect Poisoning, choking, late effects, travel & motion, hunger, thirst, exposure, neglect Public Health Agency of Canada Same Newborns excluded None

13. Compare overall results of the two Canadian approaches CIHIPHAC Initial number of records selected 14,77314,772 Records that include an E-code 12,75412,753 Records with a “valid” E-code 9,38910,749