Centers for Disease Control and Prevention National Center for Health Statistics Margaret Warner, Ph.D. Office of Analysis and Epidemiology ICE on Injury, Vienna, June 2004 Selecting a main injury from multiple causes of death: Step 1 Common Pairs

Recommendation for selecting from MRG for ICD 1) Eliminate trivial injuries and superficial injuries from consideration 2) If obvious causal sequence, select injury which led to death 3) Select from among remaining injuries using severity ranking (e.g. Precedence list) 4) Select first mentioned if several at same level of severity

Information is lost when selecting Rules can be established about priority, but what conclusions will be drawn from data? One injury may not be more important There may be combinations of injuries which are more deadly

Analyze data by pairs of injuries To determine if certain combinations commonly occur together (e.g. head and thorax injuries) If yes, Could a main injury be selected? Should a single code by used to identify combination?

Methods US multiple cause mortality data 2001 Injury as underlying cause of death More than one ICD-10 S or T code Examined unique pairs – Two nature of injury codes were treated as a unique pair regardless of the order in data Stratified by the number of injuries per death

More than one injury In US in 2001, 157,078 deaths with external underlying cause Range (0-15 injuries listed, possible 20) 1 injury listed65% of deaths 2 injuries22% 3 injuries8% injuries4%

Common pairs TRUE !!!! Certain injury pairs account for high proportion of deaths with two or more injuries listed

2 injuries listed on death certificate 35,000 deaths with 3,500 unique pairs 18,500 deaths with 55 unique pairs 55 pairs are … observed 100 times or more account for 54% of deaths with 2 injuries listed

Results Most frequent pair – occurs 3,327 times S06.9 (Intracranial injury, unspecified) and S09.9 (Unspecified injury of the head) Second most frequent – occurs 2,671 times S09.9 (Open wound of head, part unspecified) and S29.9 (Unspecified injury of the thorax)

Review of pairs We choose to review pairs based on … Frequency with which pair observed If the pair included a Superficial injury Unspecified

Preliminary conclusion Certain injury pairs account for high proportion of deaths with two or more injuries listed Some cases not clear choice -- some codes for multiple injuries may be used or added Computer algorithms easily developed for many multiple injury deaths

Next steps External cause of death should be considered if indicates something about nature e.g. Poisonings, fire/flame, drowning, suffocation Location on death certificate – Part’s I & II Unspecifieds – more specific preferred International replication of pairs!!!!!