Intentional or unintentional drug poisoning in elderly people: retrospective observational study in a tertiary care hospital in Japan

Aim Intentional or unintentional acute drug poisoning occurs even in elderly people, but little is known about the factors influencing the intention to poisoning. A retrospective study was undertaken to describe the characteristics of acute drug poisoning in elderly people according to whether the poisoning was intentional or unintentional and the responsible agents. Methods The study was carried out in a single tertiary hospital in Japan. A total of 145 patients aged ≥65 years who were transferred by an ambulance service and were diagnosed with acute drug poisoning were included. Medical records were used to collect information on the intention behind poisoning and the responsible agents. Patients were divided into two groups according to whether they experienced intentional or unintentional poisoning and were further classified according to the responsible agent. Multivariable logistic regression models were used to estimate the association between hospitalization for acute drug poisoning and the use of benzodiazepine receptor agonists (BzRAs). Results Poisoning was unintentional in 102 (70.3%) patients and intentional in 43 (29.7%) patients. In total, 65 (44.8%) patients required hospitalization. Among patients in the unintentional poisoning group, those using non-BzRAs were more likely to be hospitalized than those using BzRAs (odds ratio, 6.64; 95% confidence interval, 2.56-17.22). The length of hospital stay was significantly longer in the unintentional poisoning group than in the intentional poisoning group (13.9 vs. 6.2 days; P = 0.013). Conclusions The proportion of unintentional poisoning in the elderly is high, and particularly with respect to poisoning with non-BzRAs, the hospitalization rates are high.