Hepatitis C Virus Infection: Prevalence Report, 2003 Data Source: Minnesota Department of Health HCV Surveillance System P.O. Box 9441 Minneapolis, MN 55440-9441 612-676-5414, 1-877-676-5414 www.health.state.mn.us/immunize
Background The mission of the viral hepatitis program is to provide support for hepatitis C virus (HCV) prevention and control activities by monitoring disease trends; assessing burden of disease; identifying infected persons and those contacts requiring follow-up; identifying and controlling outbreaks; and disseminating educational and referral resources to affected individuals through their healthcare providers. The HCV registry, which includes an HCV chronic carrier database and an active surveillance system to identify acute cases, has been critical to reaching these goals. Methods These data describe persons living with HCV in Minnesota in 2003 by person, place, and time. Data analyses excluded persons diagnosed in federal or private correctional facilities, but include state prisoners. In addition, 206 persons of whom we have knowledge of their deaths and 144 children less than 1 year of age were also excluded. Lab results in children whose only serology was conducted prior to 1 year of age represent maternal antibody and are therefore not included in the dataset. Age is defined as the difference between date of birth and first laboratory collection date on record. If no collection date is available, age is based on date of birth and date record was created in the database. Metro consists of four categories: greater Minnesota, suburbs, Minneapolis and St. Paul. Greater Minnesota includes all counties except the 7-county metro area. Suburbs include 2
only the 7-county metro area less Minneapolis and St. Paul residents. Data cleaning and basic descriptive analysis was conducted using Intercooled STATA 8.2 (STATA Corp LP, College Station, TX). Assumptions & Limitations Some assumptions about HCV surveillance data follow: Data do not include HCV-infected persons who have not been tested for HCV. Data do not include persons whose positive test results have not been reported to MDH. Persons are assumed to be alive unless the MDH has knowledge of their death. Persons whose most recently reported state of residence was Minnesota are assumed to be currently residing in Minnesota unless MDH has knowledge of their relocation. (The ability to track changes of residence, including within the state, is limited.) Data include false-positive, resolved infections, and chronic cases of HCV. Since surveillance is based on positive reporting of disease, it is impossible to identify resolved infections, unless conscientious clinicians follow-up with these data. It is also difficult to identify false-positive results due to confusion in interpretation over HCV screening test 3
results. Most clinicians fail to order confirmatory testing, removing the ability to identify falsepositives. Signal-to-cutoff ratios greater than 3.8 are indicative of a confirmed result. Therefore, if labs can begin to report these data, cases can be confirmed in the absence of a confirmatory test being run. Risk factor data is not mutually exclusive. In addition, due to the temporal disjuncture between acquisition of disease and diagnosis of disease, it is extremely difficult to determine the exact route of transmission in chronic cases of HCV. Results As of December 31, 2003, 22,356 persons are assumed alive and living in Minnesota with HCV (Fig. 1). The median age at diagnosis is forty-three (Fig. 2). Of HCV positive individuals reported to MDH, 65% were male and 32% were female (Fig. 3). Both genders had similar median ages at time of diagnosis (Fig. 4) Of this sample, 22% reside in the suburbs; 32% live in Greater MN; 25% live in Minneapolis; and 9% live in St. Paul (Fig. 5 & 6). Median age at time of diagnosis was 43, regardless of area of residence (Fig. 7). Race breakdown was as follows: 5% were American Indian; 2% were Asian, 15% were Black or African American; 0.02% were Native Hawaiian or Pacific Islander; 44% were white; 1% were other, unspecified race; and 33% were had unreported 4
race (Fig. 8). Race breakdown by age revealed similar proportions (Fig. 9). Risk factor data was not mutually exclusive. The most commonly cited risk factor was any type of illicit drug use (Table 1). Conclusions The number of Minnesotans living with HCV reported to MDH is small proportion of the actual persons living with HCV infection. It is hoped that this snapshot will be useful for policy and planning related to HCV prevention and control. In the future, the surveillance databases can be linked with death records to more accurately remove deceased individuals. Also, algorithms will be developed based on repeated laboratory testing to determine if patients are receiving follow-up care. Finally, signal-to-cutoff ratio data will be collected to obtain confirmed HCV antibody test results. 5
Tables and Figures Fig. 1: N Newly Identified Cases of Chronic HCV Infection 0 1,000 2,000 3,000 ewly Identified Cases of Chronic HCV Infection in MN 601 N=22,356 458 36 6 381 893 by year, 1990-2003 1379 1408 1694 22 84 2695 2838 2592 2269 2498 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Fig. 2: by Age, 2003 Frequency 0 500 1000 1500 2000 2500 0 20 40 60 80 100 age 6
Fig. 3: by Gender, 2003 3% N=22,356 32% 65% Male Unreported gender Female Fig. 4: by Age and Gender, 2003 0 20 40 60 80 100 N=21,466 Male Unreported gender Female 7
Number Living with Chronic HCV 0 2,000 4,000 6,000 8,000 Fig. 5: 4996 by Residence at Diagnosis, 2003 7214 5515 N=22,356 2048 Burbs Greater MN Minneapolis St. Paul 2583. Unreported Fig. 6: by Residence at Diagnosis, 2003 N=22,356 9% 12 % 25 % 22% 32% Unreported residence Greater MN St. Paul Burbs Minneapolis 8
0 20 40 60 80 100 Fig. 7: by Age and Residence at Diagnosis, 2003 N=21,466 Burbs Minneapolis Unreported residence Greater MN St. Paul Fig. 8: by Race, 20 03 American Indian Asian N=22,356 Black or African American Native Hawaiian or Pac. Isldr White Other. Unreported 0 2,000 4,000 6,000 8,000 10,000 Number Living with Chronic HCV 9
Fig. 9: by Gender and Race, 2003 Male Female 4% 2% 6% 2% 32% 16% 0% 31% 13% 0% 2% 1% 44% 47% American Indian Black or African American White Unreported race Asian Native Hawaiian or Pac. Isldr Other Graphs by Gender Table 1: Reported Risk Factors in Persons Living with HCV in MN, 2003 (non-mutually exclusive) (n=22,356) Risk Factors Cases % Total Injection drug use 4,558 20% Intranasal cocaine 1,014 5% All illicit drug 5,658 25% Blood transfusion or products prior to 1992 1,038 5% Hemodialysis 140 1% Needlestick 219 1% Perinatal transmission 38 0% High risk sex activity (HCV+, IDU, multiple) 1,299 6% Unhygienic tattoos & body piercing 896 4% IVIG gammaguard 10 0% Incarcerated (past and current) 2,202 10% 10