Is the Total Score of the Hamilton Depression Rating Scale Associated with Suicide Attempts or Suicides?

Background: Most evidence behind interventions for depression is, in essence, based on the total score of the 17-item Hamilton Depression Rating Scale (HDRS). We identified no systematic review or meta-analysis examining if a total 17-item HDRS score is associated with suicide attempts or suicides in depressive patients.
Methodology: Based on a systematic literature search CENTRAL in The Cochrane Library, MEDLINE, EMBASE, PsycInfo, and Science Citation Index Expanded, we systematically reviewed and meta-analysed observational studies examining if the total 17-item HDRS score is associated with suicide attempts or suicides.
Results: We identified and included ten cohort studies - seven retrospective and three prospective. All the studies were assessed as high risk of bias. Meta-analysis on the HDRS scores from three retrospective studies showed that depressive patients with a suicide attempt during the on-going depressive episode had a significantly higher score on the HDRS compared to non-suicidal patients (mean difference 6.31 HDRS; 95% confidence interval 4.72 to 7.91; P<0.00001, I2=0). However, meta-analyses of the HDRS scores from three prospective studies and four studies reporting retrospectively lifetime suicide attempts showed no significant differences between patients with or without a suicide attempt or suicide.
Conclusion: A total score on the HDRS does not seem to be associated with past or future suicide attempts or suicides. There seems to be a need for other assessment tools to predict and explain risks of suicidality.