Non-suicidal deaths following hospital-treated self-poisoning

Abstract

Objective: To quantify the non-suicidal mortality subsequent to hospital treated self-poisoning, and to identify risk factors for non-suicidal death.

Method: A prospective longitudinal cohort design was used, with data-linkage between the Hunter Area Toxicology Service database and the National Death Index. All patients with deliberate self-poisoning for a 10-year period (1991-2000) were studied and the first episode in the period was used as the index episode. The outcomes were: accidental, 'natural' and non-suicidal death, with follow-up for the study duration.

Results: There were 4044 patients studied, and 170 (4.2%) of these had non-suicidal death; 64 were accidental and 106 were 'natural' cause deaths. The standardized mortality ratio (95% CI) for non-suicidal death for males, females and combined were 4.98 (4.08-6.07), 3.78 (3.0-4.75) and 4.20 (3.62-4.88), respectively. The increased mortality was apparent for both males and females, and was more marked in the younger age groups. For non-suicidal death the adjusted hazard ratio (95% CI) for increased risk were: increasing age 1.07 (1.06-1.08), male gender 1.77 (1.24-2.52), psychiatric diagnosis of substance related disorder 1.49 (1.03-2.16), prescription of a respiratory drug 2.69 (1.31-5.55), and prescription of an anti-diabetic drug 1.95 (0.93-4.07), while psychiatric diagnosis of adjustment disorder 0.64 (0.38-1.053) was associated with decreased risk.

Conclusions: Patients who present with self-poisoning have increased mortality from accidental and 'natural' causes. Long-term treatment goals for these patients need to address non-suicide mortality in addition to suicide mortality.