Codes denoting drug use, including findings of drugs in blood, poisoning by drugs, and where drugs have been found to be the cause of other health conditions. The phenotype considers illegal drugs but excludes tobacco, in keeping with the literature. A phenotype for alcohol use is available separately.

ICD-10 definition

This definition is based on validated, published and comparable lists (Rees et. al., 2022; DelPozo-Banos et. al., 2018; NHS, 2018; NHS, 2019; Syed et. al., 2018; Walsh et. al., 2018) and reviewed by a clinician in the study team (Prof Ann John).

Read code definition

This definition also includes symptoms, observations, medications, behaviours (e.g., “injecting drug user”), referrals and contacts with other services. It contains prescriptions relevant to treatment for drug use disorder (naltrexone, lofexidine and methadone) as almost all recipients were found to have a history of drug use (Rees et. al., 2022); and excludes those used primarily for pain management. For buprenorphine, the list includes only prescriptions where 90% or more recipients had a history of drug use disorder, as assessed during validation (Rees et. al., 2022).

This definition is based on validated, published and comparable lists (Rees et. al., 2022; DelPozo-Banos et. al., 2018; NHS, 2018; NHS, 2019; Syed et. al., 2018; Walsh et. al., 2018) and reviewed by a clinician in the study team (Prof Ann John).

SNOMED CT definition

The SNOMED codes for drug use were developed by mapping the existing ICD-10 and Read code definitions and running complementary SNOMED CT searches. This definition excludes generic terms where the type of the drug cannot be assumed (e.g., ‘Paranoid state caused by drug’). The definition is split in the following concepts:

• Drug use: Contains all codes that determine the use of illicit drugs at the time of recording.

• Probable drug use: Contains codes that, while not confirmatory, they are indicative of drug use (e.g., screening for drug use, counselling for drug abuse, etc).

• History of drug use: Contains codes that indicate a history of drug use prior to the date of recording (e.g., abstinence from drug use).

Note: The SNOMED CT definition has not undergone validation yet.

References

DelPozo-Banos, M., John, A., Petkov, N., Berridge, D. M., Southern, K., LLoyd, K., ... & Travieso, C. M. (2018). Using neural networks with routine health records to identify suicide risk: feasibility study. JMIR mental health, 5(2), e10144.

NHS National Services Scotland (2018). Alcohol-related hospital statistics Scotland 2017/18.

NHS National Services Scotland (2019). Drug-related hospital statistics Scotland 2017/18.

Rees, S., Watkins, A., Keauffling, J., & John, A. (2022). Incidence, Mortality and Survival in Young People with Co-Occurring Mental Disorders and Substance Use: A Retrospective Linked Routine Data Study in Wales. Clinical Epidemiology, 14, 21

Syed, S., Gilbert, R., & Wolpert, M. (2018). Parental alcohol misuse and the impact on children: a rapid evidence review of service presentations and interventions.

Walsh E, Jones R, Cox S. (2018). Data mining Wales: the annual profile for substance misuse 2017–18.

Implementation

Citation Requirements

Rees, S., Watkins, A., Keauffling, J., & John, A. (2022). Incidence, mortality and survival in young people with co-occurring mental disorders and substance use: a retrospective linked routine data study in Wales. Clinical Epidemiology, 21-38.

Citation Example

A. John, S. Rees. PH1108 / 3518 - Drug use. Phenotype Library [Online]. 22 July 2024. Available from: http://phenotypes.healthdatagateway.org/phenotypes/PH1108/version/3518/detail/. [Accessed 27 July 2024]