Injury MICA - Variable Definitions

Record Selection for All Injuries

The injuries in this MICA are those recorded by hospitals for their emergency room patients and inpatients, as reported by the Missouri Department of Health and Senior Services Patient Abstract System (PAS).

The causes of the injuries are defined according to the external cause codes of the International Classification of Diseases-10th Revision-Clinical Modification (ICD-10-CM). This coding system is used by hospitals to record the injuries and diseases of their patients. Below are the cause and diagnoses that are used to define injury causes and determine whether the hospital visit should be included in this MICA.

Visits were selected for this MICA using a process outlined in the Centers for Disease Control and Prevention’s (CDC’s) National Health Statistics Report number 164. This report, published in September 2021, provides guidance for inpatient and outpatient injury diagnoses classification.

Injury Matrix

This MICA is structured to follow the Intent-by-Mechanism matrix recommended by the CDC. The matrix categorizes all external cause codes according to a mechanism of injury (firearm, poison, etc.) and five intentions: 1) assault: intent to injure others; 2) self-injury: intent to injure oneself; 3) legal intervention/war 3) unintentional: accidental or no intent to hurt anyone, and 4) intent undetermined: intention cannot be determined). For example, firearms can be used with the intent of injuring oneself or others or they can injure people unintentionally. If specific mechanisms are selected for display in a table, the user should understand that the mechanisms will encompass all intentions (unless an intention is selected as a qualifying variable for the table.)

Additional Information/ Considerations

Abusive Behavior

Abusive behavior, a type of assaultive behavior, does not fit very well into the intention-mechanism structure. Ideally, abusive behavior, like the other intentions, could be categorized by which mechanism was used--striking, cutting, etc.--but the external cause codes are not structured this way, and abuse can only be categorized by the types of abusive behavior--spouse abuse, child abuse, etc.

A further complication with the Abuse/Neglect/Rape category is that a record may fall into more than one category of abuse depending on the patient's age and the external cause codes and diagnosis codes on the record. For example, some records had both a cause code for spouse abuse and a diagnosis code for sexual abuse. Records with multiple codes were categorized according to the following priority: spouse abuse, sexual abuse, rape, shaken baby, physical abuse, neglect.

Motor Vehicle Crashes

External cause coding of injuries due to motor vehicle crashes can be confusing. Injury MICA for 2016 forward, groups visits into Motor Vehicle Traffic and Motor Vehicle-Non Traffic injuries. Motor Vehicle Traffic injuries are those that occur on a road network and can include car/trucks, motorcycles, and other specified or unspecified motor vehicles, as well injuries from crash involving one of this group with a bicycle or pedestrian. Motor Vehicle-Non Traffic injuries occur in parking lots, driveways and other areas that are not a part of the road network. Separate categories exist for injuries involving pedestrians and cyclists that do not involve a motor vehicle.

Multiple Records

The inpatient records and emergency room records are designed to be mutually exclusive in the PAS system and on MOPHIMS. If a person is admitted to the hospital through the emergency room, the inpatient record but not the E/R record should be included in the PAS. Only if the person is treated in the E/R and released should the E/R record be included in the PAS. Additionally, patients who return to the hospital for follow-up treatment will also have more than one E/R or inpatient record for an injury episode. The number of injury records is thus somewhat more numerous than the number of injury episodes and patients.

Injury External Cause Codes

For more detail on these categories, please consult the CDC’s National Health Statistics Report number 136, Table II.