1. Multiple cause of death data and poisoning Cleo Rooney & Multiple cause of injury workgroup April 2001

2. Discussions Uses of multiple cause coded mortality data and selecting main injury –explaining differences in underlying cause data between places, times –‘correcting’ unspecified underlying cause Difficulties classifying poisonings with multiple substances Changes in ICD-10 and comparability studies

3. Main injury in mortality data Encourage publication of multiple cause data- ~ 15 countries / 65 contribute data to WHO ICD-9 precedence list provided for choosing main injury Skull Fracture and broken neck Internal Injury of chest, abdomen, pelvis Fracture of face, spine, trunk Other head injury, open wounds of neck&chest, amputation of limbs, spinal cord lesion Fracture of limbs Burn Other

4. Main Injury in ICD-10 ICD-10 –Sequence and rules provided as for other deaths –If no sequence, choose first mentioned –Combination codes could be selected Problems: –In injury events there may not be a time sequence –Do certifiers know sequence matters? –Loss of specificity/detail if use combination code Selection rule is not WHO mandated

5. Israel method of choosing main injury Presented way of classifying injury morbidity data by severity (AIS), nature and body region Allowed main / most serious injury selection for trauma registry / hospital admission Requires ICD codes and AIS scores ? use to test selection of main injury

6. Number of injury codes per death Cox, Rooney, Fingerhut ICE 2000

7. Proposed analyses of multicause Compare main injury chosen by –Precedence list –First listed –ICD-10 rules –Combination codes –Diagnostic matrix Redistribute ‘unspecified accident’ deaths using injury information

8. Injury deaths of unspecified mechanism by ICD-9 main injury precedence list Cox, Rooney, Fingerhut ICE 2000

9. Countries that submitted multicause data in ICD-9 USA Sweden Scotland E&W More volunteers?

10. Changes in coding injury deaths in ICD-10 Main Injury –No precedence list for injuries –Combination codes for injuries Underlying cause –Fracture unspecified cause > unspecified accident –Fractures / falls can be due to osteoporosis –Rule 3

11. Comparability studies -multicountry Injury deaths ratios All injuries By matrix groups Differences between countires ?pooled ratios across countries Are ICD-10 data more comparable? Israel and US results yesterday- –broadly reassuring

12. Deaths from falls, fractures and osteoporosis Comparability ratios v different in USA, Israel and Sweden E887 > unspecified accident can be due to osteoporosis rule 3 and pneumonias Quantify net change by country –? Differences in each effect –certification or coding

13. Comparability study data Countries which can contribute –Send copies of comparability study reports –individual level data –tabulated data / special analyses Volunteers?

14. Poisonings c50% of deaths have more than one substance Can’t identify which of several substances primarily responsible for death combination codes may be confusing for data users need finer classification of substances meaningful classification for clinicians and toxicologists as well as epidemiologists

15. Multi-substance poisonings Main injury and underlying cause –combination codes Multicause codes Text of certificate more detail ?? How to present it

16. Deaths from drugs and poisonings [poisonings 960-989, abuse & dep 304, 305] Number of deathsalonein combination by substance all substancesx y heroin/morphineAB paracetamolCD antidepressantsEF

17. Projects for Montreal Compare selection of main injury by different methods –Redistribute unspecified accident deaths using injury codes Collate comparability study data ICD-9/ 10 across participating countries –changes in classification of deaths from falls, fractures and osteoporosis ? Poisoning later ? volunteers