Effect of pre-existing medical conditions on in-hospital mortality: analysis of 20,257 trauma patients in Japan

Abstract

Background: The average life expectancy of Japanese individuals is the longest in the world. The mortality rate from injury is increasing among older people. There have been no detailed reports on the relationship between pre-existing medical conditions (PMCs) and mortality from trauma among elderly people in Japan.

Study design: 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.

Results: 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.

Conclusions: 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.