Multiple cause of death data and poisoning

Cleo Rooney &

Multiple cause of injury workgroup

April 2001

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

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

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

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

Number of injury codes per deathCox, Rooney, Fingerhut ICE 2000

country mean no. of injurycodes

percent of deaths by number ofinjuries coded

1 2 3+ Total %

USA 1.74 50.8 31.9 16.5 99.1

SWEDEN 1.48 61.7 27.9 10.4 100.0

SCOTLAND 1.26 74.7 21.0 3.0 98.7

E&W 1.34 74.5 19.3 6.2 100.0

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

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

USA Sweden Scotland England Nature of main Injury & Wales

Skull/neck # 2.4 2.9 1.9 2.4Int Inj chest abd pelvis 7.8 1.7 4.4 3.2# face, spine, trunk 3.5 4.1 6.2 4.5Other head, OW neck,chest 35 8.8 12.6 17.8

amputat'n limbs, spinal cordFracture of limbs 34.2 80.1 68.9 60.5Burn 0.1 0.1 0 0Other 17.1 2.3 6 11.6

Countries that submitted multicause data in ICD-9• USA

• Sweden

• Scotland

• E&W

• More volunteers?

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

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

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

Comparability study data

• Countries which can contribute

– Send copies of comparability study reports– individual level data– tabulated data / special analyses

• Volunteers?

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

Multi-substance poisonings

• Main injury and underlying cause – combination codes

• Multicause codes

• Text of certificate

• more detail

• ?? How to present it

Deaths from drugs and poisonings[poisonings 960-989, abuse & dep 304, 305]

• Number of deaths alone in combination

by substance

• all substances x y

• heroin/morphineA B

• paracetamol C D

• antidepressants E F

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