Channeling John Snow: Investigating Injection Drug Use Related to HIV and HCV

BACKGROUND:  The 2014 outbreak of HIV associated with injection drug use in Indiana raised concerns about the ability to detect and respond to a similar outbreak in Minnesota. A workgroup at the Minnesota Department of Health (MDH) was convened with participation from both infectious disease and injury prevention units. Currently available data sources were discussed that could provide information regarding at risk communities. The goal was to identify potentially high risk areas for an outbreak of HIV or HCV, as well as where future resources for treatment and prevention of HIV or HCV should be placed within Minnesota.

METHODS:  Minnesota hospital discharge data with ICD-9 codes for poisoning, abuse, or dependency for opiates/opioids, cocaine, or amphetamine were used to identify cases of drug use from 2009 to 2014. The number of cases were first totaled per year by the patient’s county of residence, and the top ten counties for number of cases were mapped. To provide further detail, the total number of cases per year by the patient’s ZIP Code of residence were also mapped using Epi Info 7. The Minneapolis/Saint Paul seven county metropolitan area was excluded from a secondary analysis to provide information about the number and distribution of cases in greater Minnesota. The results were compared with census tract data on cases of HIV that had injection drug use as a risk factor, and acute cases of HCV under the age of 30 identified from 2009 to 2014.

RESULTS:  From 2009 to 2014, the counties in the Minneapolis/Saint Paul metropolitan and Duluth areas account for the most drug poisoning, abuse, or dependency cases. When excluding the metropolitan area counties, the counties surrounding Saint Cloud and Rochester, Minnesota have the greatest number of cases. A similar pattern is observed with the ZIP Code of residence information. The analysis of HCV and HIV cases in Minnesota identified similar areas of Minnesota, including the Minneapolis/Saint Paul metropolitan area counties, counties surrounding Duluth, and counties of north central Minnesota.

CONCLUSIONS:  Using hospital discharge data along with mapping, as well as data on newly identified HIV and HCV cases, provided insight into areas of the state that have greater injection drug use, and may be at increased risk for HIV and HCV outbreaks. These data are useful to target prevention measures, such as screening, counseling, referral to care, and syringe exchange programs.