Concept: Methamphetamine Use in Manitoba

Introduction

This concept describes the definition of methamphetamine, data sources used at MCHP and various methods used in the MCHP research to identify individuals with administrative record that documented their methamphetamine use.

Definition

Methamphetamine is a central nervous stimulant known by several street names including meth, crystal meth and rock. Methamphetamine can be injected, inhaled, snorted or taken orally. Methamphetamine use results in wakefulness, vigor, euphoria and reduced appetite, and contributes to severe physical health complications that may include lethal hyperthermia, myocardial infarction (heart attack), stroke, seizure and death.

Data Sources

The data sources used in this MCHP research to identify individuals with methamphetamine use included:


• Winnipeg Fire and Paramedic Service
  
• Emergency Department Information System
  
• Hospital Discharge Abstract Database
  
• Medical Claims
  
• Diagnostic Services Manitoba

Methods

The following methods were used to identify Methamphetamine use in different databases:

1. Hospital Discharge Abstract Database

ICD-10 and ICD-9 codes for amphetamine-related disorders; harms related to amphetamine use (e.g., poisoning from amphetamine). The codes used include:



ICD-10-CA	ICD-9-CM	Issue
F15.0	292.89	Amphetamine intoxication
F15.1	305.7-305.73,305.9-305.93	Methamphetamine use
F15.2	304.4-304.43,305.7	Methamphetamine addiction
F15.3	292	Amphetamine withdrawal
F15.5	292.11,292.12	Amphetamine and psychostimulant induced psychotic disorder with delusions
F15.8	292.84,292.85,292.89	Amphetamine induced anxiety disorder
F15.9	292.9	Amphetamine related mental disorder
T43.6	969.7-969.73,969.79,970.89,970.9	Overdose of psychostimulant
T50.9	970.9,977,977.9	Drug overdose
T65.9	No code	Poisoning
Y49.7	E939.7	Adverse effect of amphetamine
Y63.9	E873.8	Underdose of amphetamine
Z86.48	305.73	History of methamphetamine abuse
Z91.8	V15.6	History of poisoning


To see the complete list of codes refer to Appendix Table1.1

2.Medical Claim Databse

5 digits of several ICD-9 codes were used to identify individuals who used methamphetamine in the Medical Claims Database. They included:

• 304.4X: Amphetamine and other psychostimulant dependence
  
• 305.7X: Amphetamine abuse
  
• 969.72: Poisoning by amphetamines

3.Emergency Department Information System (EDIS)

Keyword searches in triage notes to identify people presenting with an indication of having used methamphetamine. These data were limited to Winnipeg.
To see the complete list of search terms refer to Appendix Table 1.2

4.Winnipeg Fire Paramedic Service (WFPS) Database

Indications searches of Methamphetamine use in the database of WFPS electronic patient care reports were used. This database consists of core and subsidiary datasets corresponding to parts of the patient record, including patient assessments, vital signs, interventions and a free text narrative. In consultation with the principal investigator, two research team members did a preliminary review of approximately 15% of comments to develop inclusion criteria. All remaining records were reviewed by one team member with assistance from WFPS analyst. A portion (10%) of these records was randomly selected to be independently coded by both reviewers; decisions on these records showed very good agreement: kappa=0.865(95% CI 0.814-0.916),p<0.0005)

5.Diagnostic Services Manitoba (DSM)

Diagnostic tests where methamphetamine use identified. Two drug tests were considered.

• TEST_CODE=1663(methamphetamine)
  
• TEST_CODE=1605(drug screen)

NOTE: To construct the cohort, all the records documenting methamphetamine use from 5 databases were combined. If an individual had records from the multiple sources indicating methamphetamine use on the same date, their records were sorted into the following chronological order:(1)WFPS, (2)EDIS, (3)Hospital, (4)Medical Claims and (5)DSM. This was done to identify a person's "first point of contact" for methamphetamine use documentation based on the expected flow through the health system. Figure 2.1 in the deliverable presents a flow chart illustrating the process used to construct the cohort.

To see the details of these methods refer to Methods in the deliverable.

Exclusions

The following exclusions were applied to the cohort:

• Anyone lacking a valid PHIN and anyone not covered by Manitoba Health at the date of their methamphetamine use were excluded because without the PHIN or healthcare coverage, records across databases cannot be linked.
  
• Individuals diagnosed with ADHD and had been dispensed prescription medication for amphetamine use were also excluded. ADHD was defined using a previously established algorithm in the deliverable Mental Illness Among Adult Manitobans by Chartier et al. (2018) . The full case definition is provided in Appendix Table 1.1 These individuals were excluded because their health care contact could have been due to an adverse reaction to the ADHD medications and not the methamphetamine use.
  
• People younger than 10 years old from the health service were also excluded because there were so few children in the cohort under the age of 10 that their results would be unstable and would need to be suppressed to protect their identity.

Cautions

Absence of emergency department and paramedic service data from regions beyond Winnipeg, restricts the ability to offer a comprehensive provincial perspective.