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Table 1 Definitions and statistical measures of suicidal behavior outcomes

From: Association between body mass index and suicidal behaviors: a systematic review protocol

Outcome Definition Measurement of variable Statistics Studies
Completed suicide Death caused by self-inflicted injurious behavior intended to end one’s own life International classification of diseases (eighth, ninth, or tenth revisions) using diagnostic codes (E950-E950: ICD8, ICD9) or (X60-X84: ICD10) Cox proportional hazard model [15-21,26-28,32]
    Linear regression  
    Logistic regression  
   In some studies, associations were also estimated with undetermined deaths (deaths where it was uncertain whether the cause was suicide; (E980-E989: ICD 8, ICD 10) or codes (Y10-Y34, ICD 10))   
  Pearson correlation (ecological analysis)
  Spearman’s rank correlation (ecological analysis)
    Wilcoxon-Mann-Whitney test  
  Verified using mortality registries (for example, National Death Registry, National Death Index), by next of kin and/or using pathology and medical records.
  Incidence rate ratio
Attempted suicide Potentially self-injurious behavior with a non-fatal outcome for which there is either explicit or implicit evidence that the person intended to kill him or herself [63]. Hospital Discharge Registries or Medical Records using aforementioned diagnostic codes for intentional injuries: (E950-E950: ICD8, ICD9) or (X60-X84: ICD10). Cox proportional hazard model [42-47]
2012 to present: [29,34,48-51]
Logistic regression
Incidence rate ratio
Self-reported using questionnaire (for example, Suicide Behaviours Questionnaire - Revised, AUDADIS, M-CIDI)
Self-reported using single-question (e.g. “How often have you already tried to take your own life”)
Suicidal ideation Having thoughts, plans, and/or impulses for suicidal behavior, including contemplation of attempting or completing suicide. Self-reported using questionnaire (for example, Depressive Symptom Index - Suicidality Subscale, Suicide Behaviors Questionnaire - Revised). Logistic regression Linear regression [42,47]
2012 to present: [48,50,52]