Journal Article Annotations
2018, 2nd Quarter

Infectious Diseases

Annotation by Aum Pathare, MD
July 2018

Both localized and systemic bacterial infections are predicted by injection drug use: a prospective follow-up study in Swedish criminal justice clients

PUBLICATION #1 — Infectious Diseases

Both localized and systemic bacterial infections are predicted by injection drug use: a prospective follow-up study in Swedish criminal justice clients

Dahlman D, Berge J, Björkman P, Nilsson AC, Håkansson A

Abstract: PLoS One 2018 May 31; 13(5):e0196944

BACKGROUND: Both skin and soft tissue infections (SSTI) and systemic bacterial infections are common in people who inject drugs (PWID), but data on incidence and risk factors are lacking. We compared registered diagnoses for such infections in Swedish criminal justice clients with regard to injecting drug use.

METHODS: Baseline interview data from the Swedish Prison and Probation Service on drug use in PWID and non-PWID with problematic alcohol use were linked to follow-up data from national Swedish registers on hospital diagnoses and/or death. Associations between drug use and later diagnosis of SSTI and systemic bacterial infection (septicemia or bacterial infection of the heart, bone/joints or central nervous system) were analyzed by Cox regression.

RESULTS: Incidence rates of SSTI was 28.3 per 1,000 person-years for PWID (n = 2,444) and 10.0 for non-PWID with problematic alcohol use (n = 735). Incidence rates of systemic bacterial infection was 9.1 per 1,000 person-years for PWID and 2.7 per 1,000 person-years for non-PWID. Injection drug use was associated with a significantly increased risk of bacterial infections, for main drugs heroin (SSTI: Hazard ratio [HR] 2.45; systemic infection: HR 2.75), amphetamine (SSTI: HR 1.60; systemic infection: HR 2.19), and polysubstance use (SSTI: HR 1.92; systemic infection: HR 2.01). In relation to injection use of amphetamine and polysubstance use, PWID mainly using heroin had higher risk of SSTI.

CONCLUSIONS: Injection drug use predicted both SSTI and systemic bacterial infection, with a particularly high risk of SSTI in PWID mainly using heroin. The results imply the need for increased attention to bacterial infections among PWID, in terms of clinical management, prevention and research.

On PubMed: PLoS One 2018 May 31; 13(5):e0196944

Annotation

Type of study: Prospective cohort study

The finding: The risk of skin and soft tissue infection (SSTI), as well as systemic bacterial infections, increases with injection drug use. Heroin use poses higher risk for SSTIs, whereas no difference was noted between heroin, amphetamines, and polysubstance use for systemic infections. Homelessness and hepatitis C were associated with an increased risk for SSTI and systemic infection, whereas residence in a large city, previous overdose, were associated with increased risk of SSTI alone. Incarceration was associated with decreased risk for both conditions.

Strength and weaknesses: A relatively large sample, the reliability of the addiction severity index (ASI) scale, and use of a similar population with alcohol use as references, instead of healthy controls, are the study’s strengths.

The lack of data for factors such as frequency of use, living and injection conditions, HIV status, and diabetes are limitations. As criminal justice clients are the subjects, the sample is an enriched one, and might not be representative of the general population.

Relevance: Bacterial infections in patients who inject drugs are a recognized, but ill studied and poorly characterized issue. Heroin use has a distinctly higher contribution to infection, with the US opioid-use epidemic potentially amplifying the problem. Opioid substitution thus becomes an important strategy in reducing the risk of infection for this population, in addition to harm reduction through access to clean injection equipment. Reduction in stigma against use of psychoactive drugs, expansion of services to effectively address HCV transmission and overdose, are other methods that are globally underutilized and vital to prevent infections. As these infections are the most common reason for injectable drug users to seek medical care, C-L psychiatrists can be involved early in the management of substance use, and collaborate with outpatient providers and community programs to ensure continuity of treatment through mechanisms such as “warm handoff” programs.