Characteristics and outcomes of emergency patients with self-inflicted injuries: a report from ambulance records in Osaka City, Japan

BACKGROUND: Few studies have evaluated the actual situations of emergency patients with self-inflicted injuries treated by emergency-medical-service (EMS) personnel. METHODS: This study retrospectively reviewed population-based ambulance records in Osaka City, Japan, between January 2010 and December 2012, and enrolled emergency patients who suffered from self-inflicted injuries such as poisoning by drugs or gas, cutting/piercing skin, jumping from heights, hanging, and drowning. The endpoint was the annual incidence per 100,000 populations in Osaka City of emergency patients who presented with self-inflicted injuries by age and sex. Their outcomes including deaths at the scene and hospital arrival were also evaluated. RESULTS: During the study period, a total of 8,671 patients with 9,424 incidents of self-inflicted injuries were documented. The annual incidence of self-inflicted injuries was higher among women than men in the whole population and in the age group < =49 years (136.9 versus 82.6, and 214.8 versus 93.3, both Ps < 0.001), but it was inversely lower among women in the age group > =50 years (49.0 versus 68.9, P < 0.001). The total number of self-inflicted deaths was 1,564 (16.6 %), and the overall proportion of self-inflicted deaths was greater among men than women (32.2 % [1075/3340] vs. 7.5 % [451/6027], P < 0.001). The proportion of self-inflicted hanging was 76.7 % [1142/1489], followed by poisoning by carbon monoxide at 57.1 % [56/98] and jumping to death at 47.6 % [254/534]. DISCUSSION: Using large-scale EMS records, we investigated characteristics and outcomes of emergency patients with self-inflicted injuries treated by EMS personnel. Our findings suggested the gender paradox that the proportion of self-inflicted deaths was higher among men than women, while the proportion of non-fatal self-inflicted injuries was higher among women than among men, particularly in the group aged <=49 years. Our findings showing the importance of the prevention for self-inflicted injuries as well as the gender paradox of self-inflicted injuries will provide important epidemiological information to improve psychiatric cares in prehospital emergency settings. CONCLUSIONS: In the total population, the annual incidence of self-inflicted injuries responded to by EMS personnel was higher among women than among men. However, the proportion of self-inflicted deaths was greater among men than women, and the most frequent manner among deceased patients was by hanging.