Tools to Detect Risk of Death by Suicide: A Systematic Review and Meta-Analysis

Abstract

Objective: There is limited knowledge about the ability of instruments to detect risk of suicide in a range of settings. Prior reviews have not considered whether the utility of instruments depends on prior probability of risk. We performed a systematic review to determine the diagnostic accuracy of instruments to detect risk of suicide in adults using likelihood ratio analysis. This method aids evaluation of prior probabilities of risk.

Data Sources: We searched MEDLINE, Cochrane Database of Systematic Reviews, PsycINFO, EMBASE, and Scopus from inception through January 19, 2021.

Study Selection: We included clinical trials, observational studies, and quasi-experimental studies assessing the diagnostic accuracy of instruments to detect risk of suicide in adults. There were no language restrictions.

Data Extraction: Three reviewers in duplicate assessed full texts to determine eligibility and extracted data from included studies. Positive (LR+) and negative likelihood ratio (LR-) and 95% CIs were calculated for each instrument.

Results: Thirty studies met inclusion criteria. Most instruments showed minimal utility to detect or rule out risk of suicide, with LR+ ≤ 2.0 and LR- ≥ 0.5. A few instruments had a high utility for improving risk detection in emergency department, inpatient mental health, and prison settings when patients scored above the cutoff (LR+ > 10). For example, among patients discharged from an emergency department, the Columbia Suicide Severity Rating Scale-Clinical Practice Screener had a LR+ of 10.3 (95% CI, 6.3-16.8) at 3-month follow-up. The clinical utility of the instruments depends on the pretest probability of suicide in the setting. Because studies spanned over 6 decades, the findings are at risk for secular trends.

Discussion: We identified several instruments that may hold promise for detecting risk of suicide in emergency department, inpatient mental health, or prison settings. The utility of the instrument hinges, in part, on baseline suicide risk.

Registration: PROSPERO: CRD42021285528.

Figure 1:

Prisma Flow Diagram

Figure 2:

Ability of instruments to detect risk of suicide when patients score at or above the cutoff. CI = Confidence Interval; Clin-Dem = Clinical and/or demographic characteristics; m = months; MH = Mental health; SI/SB = Suicidal ideation and/or suicidal behavior; SN = Sensitivity; SP = Specificity; LR = Likelihood Ratio; ^a The studies found that LR+ were similar across derivation and validation sets.

Figure 3:

Ability of instruments to rule out risk of suicide when patients score below the cutoff. CI = Confidence Interval; Clin-Dem = Clinical and/or demographic characteristics; m = months; MH = Mental health; SI/SB = Suicidal ideation and/or suicidal behavior; SN = Sensitivity; SP = Specificity; LR = Likelihood Ratio; ^a The studies found that LR− were similar across derivation and validation sets.

Figure 4:

Likelihood ratio scattergram of instruments to detect or rule out risk of suicide.^{a a} To ease the visual interpretation of the results, we have reversed the order of the LR negative values (log scale) such that results are presented from highest to lowest values (i.e., 1.0 – 0.01).