Analysis

All jurisdictions used a standardized SAS program to summarize results from the matched data sets. Aggregate data from each jurisdiction were combined. Coinfections were defined as both HIV and viral hepatitis (HBV or HCV) infections in the same person. We examined characteristics of coinfections within three cohorts: (1) persons living with diagnosed HIV as of 31 December 2014; (2) persons ever reported with HBV; and (3) persons ever reported with HCV. When assessing coinfections among persons living with diagnosed HIV infection, HIV cases were restricted to those among persons meeting the following criteria: (1) HIV infection diagnosis date on or before 31 December 2014; (2) alive as of 31 December 2014; and (3) most recent known address on or before 31 December 2014 was in the jurisdiction. When assessing coinfections among persons with a viral hepatitis condition, HIV cases were restricted to persons with HIV infection diagnosed on or before 31 December 2014 who were reported to the jurisdiction regardless of vital status and residence. When assessing coinfections among all three cohorts described previously, viral hepatitis cases were restricted to those with a condition event date on or before 31 December 2014 reported to the jurisdiction regardless of residence or vital status. Among persons with multiple reported HBV conditions (e.g., reported with both an acute and a chronic condition), the HBV condition with the earliest event date was used when summarizing the coinfection; the same method was used among persons with multiple reported HCV conditions. When assessing coinfections among persons living with diagnosed HIV as of 31 December 2014, we included persons ever diagnosed with a viral hepatitis condition and reported with a condition event date on or before 31 December 2014; due to limitations of viral hepatitis surveillance data we could not determine whether individuals had cleared their viral hepatitis infections before 31 December 2014. Because the number of persons coinfected with HIV, HBV, and HCV was expected to be low, our analysis was not designed to identify these coinfections. If a person was coinfected with all three conditions, both the HIV and HBV coinfection information and the HIV and HCV coinfection information would be summarised.

Age group was based on age at diagnosis of HIV or viral hepatitis infection; age for coinfections was based on age at diagnosis of the second reported virus. Transmission category was selected from the most likely route of transmission of HIV on the basis of a hierarchy of reported risk information [1]. Among coinfected persons, sex and race/ethnicity were first derived from the HIV data set, and supplemented with information from the hepatitis data set if missing from the HIV data set. For HIV infection, sex indicated sex at birth. For viral hepatitis cases, sex was not uniformly defined across all jurisdictions and indicated sex at birth, sex at time of viral hepatitis event, or current sex at the time the data were extracted depending on the jurisdiction. Among coinfected persons, timing of when coinfection became known was determined by comparing the HIV diagnosis date and hepatitis event date. This represented the earliest known date associated with each virus, but might not reflect the true order of infection.