Population Trends in Substances Used in Deliberate Self-Poisoning Leading to Intensive Care Unit Admissions From 2000 to 2010

Objective: To examine population trends in serious intentional overdoses leading to admission to intensive care units (ICUs) in Winnipeg, Manitoba, Canada.

Method: Participants consisted of 1,011 individuals presenting to any of the 11 ICUs in Winnipeg, Canada, with deliberate self-poisonings from January 2000 to December 2010. Eight categories of substances were created: poisons, over-the-counter medications, prescription medications, tricyclic antidepressants (TCAs), sedatives and antidepressants, anticonvulsants, lithium, and cocaine. Using the population of Winnipeg as the denominator, we conducted generalized linear model regression analyses using the Poisson distribution with log link to determine significance of linear trends in overdoses by substance over time.

Results: Women accounted for more presentations than men (57.8%), and the largest percentage of overdoses occurred among individuals in the 35- to 54-year age range. A large proportion of admissions were due to multiple overdoses, which accounted for 65.7% of ICU admissions. At the population level, multiple overdoses increased slightly over time (incidence rate ratio [IRR] = 1.02, P < .05), whereas use of poisons (IRR = 0.897, P < .01), over-the-counter medications (IRR = 0.910, P < .01), nonpsychotropic prescription medications (IRR = 0.913, P < .01), anticonvulsants (IRR = 0.880, P < .01), and TCAs (IRR = 0.920, P < .01) decreased over time. Overdoses did not change over time as a function of age or sex. However, severity of overdoses classified by length of stay increased over time (IRR = 1.08, P < .01).

Conclusions: It is important for physicians to exercise vigilance while prescribing medication, including being aware of other medications their patients have access to.