A Quasi-Experimental Analysis of Lethal Means Assessment and Risk for Subsequent Suicide Attempts and Deaths

Abstract

Background: Counseling on access to lethal means is highly recommended for patients with suicide risk, but there are no formal evaluations of its impact in real-world settings.

Objective: Evaluate whether lethal means assessment reduces the likelihood of suicide attempt and death outcomes.

Design: Quasi-experimental design using an instrumental variable to overcome confounding due to unmeasured patient characteristics that could influence provider decisions to deliver lethal means assessment.

Setting: Kaiser Permanente Colorado, an integrated health system serving over 600,000 members, with comprehensive capture of all electronic health records, medical claims, and death information.

Participants: Adult patients who endorsed suicide ideation on the Patient Health Questionnaire-9 (PHQ-9) depression screener administered in behavioral health and primary care settings from 2010 to 2016.

Interventions: Provider documentation of lethal means assessment in the text of clinical notes, collected using a validated Natural Language Processing program.

Measurements: Main outcome was ICD-9 or ICD-10 codes for self-inflicted injury or suicide death within 180 days of index PHQ-9 event.

Results: We found 33% of patients with suicide ideation reported on the PHQ-9 received lethal means assessment in the 30 days following identification. Lethal means assessment reduced the risk of a suicide attempt or death within 180 days from 3.3 to 0.83% (p = .034, 95% CI = .069-.9).

Limitations: Unmeasured suicide prevention practices that co-occur with lethal means assessment may contribute to the effects observed.

Conclusions: Clinicians should expand the use of counseling on access to lethal means, along with co-occurring suicide prevention practices, to all patients who report suicide ideation.