Risk factors for suicide and other deaths following hospital treated self-poisoning in Australia

Abstract

Objective: To analyze the risk factors for suicide, premature death and all-cause death in a representative population of hospital-treated deliberate self-poisoning patients.

Method: A prospective cohort study using data-linkage between the Hunter Area Toxicology Service Database and the National Death Index of the Australian Institute of Health and Welfare, from January 1991 to December 2000.

Results: There were 4105 subjects, of whom 228 (5.6%) died, 122 (2.9%) by premature death and 58 (1.4%) by suicide. The probability of suicide after 10 years follow-up was 2%. The adjusted hazard ratios (95% CI) for suicide were: 'disorders usually diagnosed in infancy, childhood and adolescence', 5.28 (95% CI = 2.04-13.65): male gender, 4.25 (95% CI = 2.21-8.14); discharge to involuntary psychiatric hospital admission, 3.20 (95% CI = 1.78-5.76); and increasing age, 1.02 (95% CI = 1.01-1.04). Men and women showed different patterns of multivariate risks, although increased risk with increasing age and discharge to an involuntary psychiatric admission was true for both. The standardized all-cause mortality ratio (95% CI) was: for men, 6.42 (95% CI = 5.44-7.57), and for women 4.39 (95% CI = 3.56-5.41). The standardized suicide mortality ratio (95% CI) was: for men, 20.55 (95% CI = 15.24-27.73), and for women 22.95 (95% CI = 13.82-38.11).

Conclusions: Men and women have different risk factors for subsequent suicide after self-poisoning. Hospital-treated self-poisoning patients have increased risk of subsequent suicide, premature and all-cause death. Psychiatric assessment, leading to discharge decisions, is worthwhile in identifying patients at long-term risk of suicide, premature and all-cause death.