Meta-Analysis of Longitudinal Cohort Studies of Suicide Risk Assessment among Psychiatric Patients: Heterogeneity in Results and Lack of Improvement over Time.
OBJECTIVE
It is widely assumed that the clinical care of psychiatric patients can be guided by estimates of suicide risk and by using patient characteristics to define a group of high-risk patients. However, the statistical strength and reliability of suicide risk categorization is unknown. Our objective was to investigate the odds of suicide in high-risk compared to lower-risk categories and the suicide rates in high-risk and lower-risk groups.


METHODS
We located longitudinal cohort studies where psychiatric patients or people who had made suicide attempts were stratified into high-risk and lower-risk groups for suicide with suicide mortality as the outcome by searching for peer reviewed publications indexed in PubMed or PsychINFO. Electronic searches were supplemented by hand searching of included studies and relevant review articles. Two authors independently extracted data regarding effect size, study population and study design from 53 samples of risk-assessed patients reported in 37 studies.


RESULTS
The pooled odds of suicide among high-risk patients compared to lower-risk patients calculated by random effects meta-analysis was of 4.84 (95% Confidence Interval (CI) 3.79-6.20). Between-study heterogeneity was very high (I2 = 93.3). There was no evidence that more recent studies had greater statistical strength than older studies. Over an average follow up period of 63 months the proportion of suicides among the high-risk patients was 5.5% and was 0.9% among lower-risk patients. The meta-analytically derived sensitivity and specificity of a high-risk categorization were 56% and 79% respectively. There was evidence of publication bias in favour of studies that inflated the pooled odds of suicide in high-risk patients.


CONCLUSIONS
The strength of suicide risk categorizations based on the presence of multiple risk factors does not greatly exceed the association between individual suicide risk factors and suicide. A statistically strong and reliable method to usefully distinguish patients with a high-risk of suicide remains elusive.
School of Psychiatry, University of New South Wales, Randwick, Australia.|Prince of Wales Hospital, Randwick, Australia.
Matthew
M
Large
Faculty of Medicine, University of New South Wales, Randwick, Australia.
Muthusamy
M
Kaneson
The Queen Elizabeth Hospital, Woodville South, Australia.
Nicholas
N
Myles
Discipline of Psychiatry, School of Medicine, The University of Adelaide, SA, Australia.|Country Health SA Mental Health, SA, Australia.
Hannah
H
Myles
Prince of Wales Hospital, Randwick, Australia.
Pramudie
P
Gunaratne
Discipline of Psychiatry and Centre for Values Ethics and the Law in Medicine, University of Sydney, Sydney, Australia.|Department of Psychiatry, Westmead Hospital, Westmead, NSW, Australia.
Christopher
C
Ryan
D015331:Cohort Studies; D006801:Humans; D008137:Longitudinal Studies; D001523:Mental Disorders / Q000453:epidemiology*; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D059020:Suicidal Ideation; D013405:Suicide / Q000706:statistics & numerical data*; D013406:Suicide, Attempted / Q000706:statistics & numerical data; D013997:Time Factors; D000092864:Suicide Prevention