Definition Purpose: To assist state, local, tribal, territorial, and federal public health practitioners in identifying emergency department (ED) visits for suspected suicide attempts. The definition can be used to supplement case-finding using syndromic surveillance data, monitor trends, and detect outbreaks of suspected suicide attempts.
New or Revised Definition: Revision of CDC Suicide Attempt v1
Date Added to ESSENCE: December 7, 2022
Justification for New Version: This definition was developed in response to findings from users of suicide-related syndrome definitions. As part of a cooperative agreement through the Emergency Department Surveillance of Nonfatal Suicide-Related Outcomes (ED-SNSRO), funded programs conducted quarterly validation testing of several suicide-related outcomes syndrome definitions (SDC Suicide Related v1, CDC Suicidal Ideation v1, and CDC Suicide Attempt v1). ED-SNSRO program recipients noted that CDC Suicide Attempt v1 had poor sensitivity and was non-specific on suicidal intent as the definition included ED visits due to non-suicidal self-harm. ED-SNSRO recipients expressed interest in a narrower definition for suicide attempt that would exclude visits for non-suicidal self-harm.
Development Methods: The CDC team, composed of subject matter experts from CDC’s National Center for Injury Prevention and Control (NCIPC) Division of Injury Prevention (DIP), Division of Violence Prevention (DVP), and Division of Overdose Prevention (DOP), worked with syndromic surveillance analysts and epidemiologists in state and local health departments as well as suicide experts and suicide prevention programs and organizations to review revisions to the v1 definition. The CDC team also worked with ED-SNSRO Programs from Ohio, Oregon, and Rhode Island, and the Tri-County Health Department in Colorado to pilot revisions to the v1 definition using visit data from 2020, 2021, and 2022.
1. The CDC team used CDC Suicide Attempt v1 as a base definition, including the discharge diagnosis codes and chief complaint terms. The CDC team reviewed chief complaint terms used for inclusion and exclusion criteria in the definition and determined what new terms to add and what terms to remove in the revision.
2. The CDC team assessed additional diagnosis codes (International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) and Systematized Nomenclature of Medicine (SNOMED) concepts that were necessary for identifying a suspected suicide attempt that were not present in v1.
3. The CDC team applied the revised queries, then reviewed ED visits pulled by each revised query to identify chief complaint terms that should be kept as an inclusion or exclusion term or removed from the revised definition.
4. Syndromic surveillance users of suicide-related syndrome definitions provided discharge diagnosis codes and chief complaint terms for consideration throughout the revision process.
5. The structure of the definition was modified to apply a two-tier process (see description, tables, and figure below) that prioritizes discharge diagnosis codes (that is, ICD-10-CM code for suicide attempt, T14.91), combining specific chief complaint terms, and includes updated exclusion terms.
The development of this syndrome definition was achieved through an iterative process of applying the new query in the Electronic Surveillance System for the Early Notification of Community-Based Epidemics, or ESSENCE, manually reviewing the visits that were pulled, refining the query, and obtaining feedback from syndromic surveillance users based on validation methods outlined in the Syndrome Definition Committee’s (SDC) guidance on developing, evaluating, and disseminating definitions for syndrome surveillance in public health practice. Participating jurisdictions classified visits into true or false positives and compared visits identified by the new definition (v2) to those identified by the v1 definition. Multiple sub-versions of the v2 definition were iteratively analyzed and refined by the CDC team until the current v2 (described in detail below) was finalized.
Definition Fields and Structure: The Chief Complaint History field (also labeled as Chief Complaint Updates when exported from ESSENCE) and the Discharge Diagnosis History field (also labeled as Discharge Diagnosis Updates when exported from ESSENCE) are used to query both the discharge diagnosis codes and chief complaint free text, with exclusions applied when necessary, to develop the syndrome definition. See Figure 1 for a visual depiction of the decision rules for the CDC suicide attempt v2 syndrome definition.
• Inclusion based on discharge diagnosis codes (see Table 1):
o The visit is included if it contains:
1. A discharge diagnosis code of suicide attempt (that is, T14.91 or SNOMED code) OR,
2. A discharge diagnosis code of self-harm AND suicidal ideation
o There are no exclusion terms applied to the above
• Inclusion based on chief complaint terms or discharge diagnosis codes for suicide attempt or a combination of suicide-related chief complaint terms or discharge diagnosis codes (see table 2):
o The visit is included if it contains:
1. Chief complaint terms for suicide attempt ([(“attempt”, “try”, “tried”, “intentional”, ”commit”) AND (“kill herself/himself/themself/themselves”, “end life”, “suicide”)] OR “SI attempt”)
2. Concurrent chief complaint terms for suicidal ideation (“suicidal ideation”, “suicide ideation”, “want” AND “die”, “want” AND “life” AND “end”, (“plan” or “want” or “going to”) AND “self” AND “harm”, “hurt”, “inflict”, “lacera”, “mutilat”, “shoot”, “stab”, “cut”, “kill himself/herself/themself/themselves”, (“plan” or “want” or “going to”) AND “self” AND (“hang” AND NOT “chang”), “suicidal”) AND self-harm ((“attempt”, “try”, “tried”, or “intentional”) AND (“hang”, “shoot”, “overdose”, “drug overdose”, “[;] OD”, “drug ingestion”, “poisoning”, or “poison ingestion”), (“self-injury”, “self-inflicted harm”, “harm to self”, Self-Directed Violence”, “Self-harm”))
3. Concurrent discharge diagnosis codes for suicidal ideation AND chief complaint terms for self-harm ((“attempt”, “try”, “tried”, or “intentional”) AND (“hang”, “shoot”, “overdose”, “drug overdose”, “[;] OD”, “drug ingestion”, “poisoning”, or “poison ingestion”), (“self-injury”, “self-inflicted harm”, “harm to self”, “Self-Directed Violence”, “Self-harm”))
4. Concurrent discharge diagnosis codes for self-harm ((“attempt”, “try”, “tried”, or “intentional”) AND (“hang”, “shoot”, “overdose”, “drug overdose”, “[;] OD”, “drug ingestion”, “poisoning”, or “poison ingestion”), (“self-injury”, “self-inflicted harm”, “harm to self”, “Self-Directed Violence”, “Self-harm”)) AND chief complaint terms for suicidal ideation (“suicidal ideation”, “suicide ideation”, “want” AND “die”, “want” AND “life” AND “end”, (“plan” or “want” or “going to”) AND “self” AND “harm”, “hurt”, “inflict”, “lacera”, “mutilat”, “shoot”, “stab”, “cut”, “kill himself/herself/themself/themselves”, (“plan” or “want” or “going to”) AND “self” AND (“hang” ANDNOT “chang”), “suicidal”)
o The above must exclude:
1. Concurrent chief complaint terms: “deny/denying/denies/denied HI/SI”, “nonsuicidal", “no attempt”, “not attempt”, “previous attempt”, “past attempt”, “history of attempt”, “history of suicide”, “end of life”, “end of battery life”, “deny/denying/denies/denied attempt”, “deny/denying/denies/denied attempt”, “previous suicide”, “past suicide”, “history of suicide”, “deny/denying/denies/denied suicide”, “deny/denying/denies/denied ideation”, “deny/denying/denies/denied now”, “deny/denies/denied self harm/self-harm”, “deny/denies/denied self harm/self-harm”, “no self harm/self-harm”, “not self harm/self-harm”, “unintentional suicidal/suicide”, “accidental suicidal/suicide”, “non-suicidal/suicide”, “non suicidal/suicide”, “no suicidal/suicide”, “not suicidal/suicide”, “not a suicidal/suicide”, “not want_die”, “not try_die”, “not want_kill_himself/herself/themself/themselves”, “deny/denying/denies/denied_kill_himself/herself/themself/themselves”, “not try_kill_himself/herself/themself/themselves”, “not try_end_life”, “didn’t try_die”, “didn’t try_kill_himself/herself/themself/themselves”, “didn’t try_end_life”, “wasn’t try_die”, “wasn’t try kill himself/herself/themself/themselves”, “wasn’t try_end_life”, “didn’t want_end_life”, “not want_die”, “not want_kill himself/herself/themself/themselves”, “not want_end_life”, “deny/denying/denies/denied harm_self”
Validation Results: In 2021, the Colorado Tri-County Health Department, Ohio Department of Health, and Rhode Island Department of Health tested a draft of the v2 syndrome definition. Jurisdictions found that the revised definition was more specific and excluded more false positive cases compared to v1. The Colorado Tri-County Health Department applied this revised definition to ED visits from January 1 to June 30, 2020. Of the visits identified, there were 66% true positives and 34% false positives. Many of the false positive cases included terms for “non-suicidal self-harm”. The Ohio Department of Health and Rhode Island Department of Health applied this revised definition to ED visits from January 1 to December 31, 2021. Ohio observed a 41% reduction and Rhode Island observed a 48% reduction in number of visits identified by v2 compared to v1. Visits captured by v1 and not by v2 were reviewed and the majority of probable cases that should be captured by v2 included chief complaint terms for intentional self-harm and suicidal ideation. The version of the definition tested did not capture the terms “suicidal” and “SI attempt” in these cases. All jurisdictions also noted a large reduction in number of ED visits captured by v2 when compared to v1, which is expected as a large count of false positives for example, non-suicidal self-harms, were included in v1 but not in v2. Following recommendations from the Colorado Tri-County Health Department, Ohio Department of Health, and Rhode Island Department of Health, the final version of the v2 definition has exclusion terms for non-suicidal self-harm, exclusion terms for ED visits that refer to a past suicide attempt, and inclusion chief complaint terms for “SI attempt” and “suicidal” (only pulled in combination with self-harm).
Limitations: There are several limitations to be aware of when applying syndrome definitions to syndromic surveillance data and interpreting syndromic surveillance findings. For this syndrome definition, the findings may not be generalizable due to the lack of representativeness of the reporting facilities. Coding practices for suicide attempt is limited due to variation in use of discharge diagnosis codes over time and between facilities, thus, this syndrome uses a combination of diagnosis codes and chief complaint terms that relate to suicide attempts. Data collected from syndromic surveillance can under- or over- estimate suicide attempt-related emergency department visits because of the differences in coding or reporting over time, or between facilities. The syndrome definition applied has undergone a thorough validation process by CDC staff and state and local health departments conducting syndromic surveillance. Although the revised definition has resulted in a reduced number of invalid ED visits, relative to the previous definition, misclassifications remain possible and these findings should not be interpreted as exact counts or represent the full burden of a condition or outcome. Lastly, each ED visit a syndromic definition identifies is based on the parameters set when applying the query. Thus, as this definition pulls cases based on discharge diagnosis and chief complaint of suicide attempts, it is not certain that each visit identified by the query is for a true suicide attempt. Regular assessment of the data quality and validation of each syndromic definition used is recommended.