We conducted a retrospective analysis using 20,257 cases recorded in the Japan Trauma Data Bank from 2004 to 2007. The subjects were 11,590 hospital inpatients (57.2 % ) 16 years of age or older. A logistic regression analysis was conducted for the relation between 23 PMCs and in-hospital mortality.
Overall in-hospital mortality was 10.8 % , and for people 75 years of age and older, was 17.7 % . The incidence of PMC was 4,752 (41.0 % ). Patients with PMCs of cirrhosis, active cancer, chronic obstructive pulmonary disease, hematologic disorders, anticoagulation drugs, dementia or mental retardation, or other conditions had higher in-hospital mortality. The existence of a single PMC did not increase mortality, but with 2 or more PMCs, mortality significantly increased. The existence of 2 or more PMCs in the 50- to 74-year-old age group and in the minor injury group strongly affected the odds ratio for mortality.
The existence of certain PMCs or of 2 or more PMCs increases in-hospital mortality from injury. This effect is particularly conspicuous in middle-aged patients and people with minor injuries, but was not found to be a problem among elderly people. The increased mortality from injury in elderly people in Japan is therefore not affected by the existence of PMCs.