Technical Notes
EPIDEMIOLOGICAL SURVEILLANCE – DATA QUALITY AND SOURCES
HIV/AIDS REPORTING SYSTEM (eHARS)
The Minnesota Department of Health (MDH) collects confidential name-based case reports of
HIV infection (since 1985) and AIDS diagnoses (since 1982) through a passive and active HIV/AIDS
surveillance system. In Minnesota, laboratory-confirmed infections of human immunodeficiency
virus (HIV) are monitored by MDH through this active and passive surveillance system. State law
(Minnesota Rule 4605.7040) requires both physicians and laboratories to report all cases of HIV
infection (HIV or AIDS) directly to MDH (passive surveillance). 1 Additionally, regular contact is
maintained with the following clinical sites to help ensure completeness of reporting (active
surveillance): Hennepin County Medical Center and Veterans Administration. Demographic,
exposure, and clinical data are collected on each case 2 and entered into Minnesota’s HIV/AIDS
Reporting System (eHARS) database developed by the U.S. Centers for Disease Control and
Prevention (CDC).
Factors that impact the completeness and accuracy of HIV/AIDS surveillance data include:
compliance with case reporting, timeliness of case reporting, test-seeking behaviors of HIVinfected individuals, the availability and targeting of HIV testing services, and the willingness of
persons recently diagnosed with HIV to be interviewed by DIS.
Given the long period of time between infection with HIV and the clinical manifestation of AIDS,
patterns of new HIV case reports are believed to describe the current epidemic more accurately
than AIDS case reports. The introduction of highly active antiretroviral therapies in the mid-1990s
further delayed the onset of AIDS for many patients and makes AIDS case reporting a weak tool
for describing the present epidemic. Including AIDS case reports is useful for looking at the whole
epidemic or trends over time.
While HIV case reports do represent persons more recently infected than AIDS case reports, there
are still several limitations that affect the completeness and timeliness of the data. There are
multiple ways for a case to be undetected by the state surveillance system promptly after
seroconversion.
First, CDC estimates that about 20% of HIV-infected individuals are unaware of their status. And
for gay/bisexual men, evidence suggests this percentage is much higher (77%) 3. This is partly
because early HIV infection does not produce severe nor distinct symptoms and so delays in
Tribal health centers are exempt from this reporting requirement. However, a recent survey of tribal health directors found that most of these
facilities report new HIV cases on a regular basis (data not published) (MDH, 2005).
2 CDC has refined the case definition for AIDS over the years. The most recent change to the case definition occurred in 1993 when (in
conjunction with confirmed HIV infection) tuberculosis, recurring pneumonia, invasive cervical cancer, or a CD4 count of less than 200 (or
below 14% of lymphocytes) joined 23 other AIDS-defining infections/conditions.
3
MacKellar DA, Valleroy LA, Secura GM, Bartholow BN, McFarland W, Shehan D, Ford W, LaLota M, Celentano DD, Koblin BA, Torian LV, Thomas
E, Janssen RS, Young Men’s Survey Group. Repeat HIV testing, risk behaviors, and HIV seroconversion among young men who have sex with
men: a call to monitor and improve the practice of prevention. Journal of Acquired Immune Deficiency Syndromes, 29(1):76-85, 2002
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Minnesota HIV/AIDS Epidemiologic Profile – Technical Notes
December 2015
testing are common. Additionally, many people acknowledge avoiding testing for fear of a
positive test result or because they believe that they are not at risk.
Second, cases of new HIV infection can also go undetected by disease surveillance due to the
availability of anonymous testing. Once a person begins care, however, other HIV/AIDS
surveillance reporting mechanisms would Annual HIV/AIDS Surveillance Summaries
most likely detect the case. Thus, although Annual HIV/AIDS surveillance summaries for
HIV case reporting is our best estimate of Minnesota are available on the MDH
new HIV infections, the system does not website:
capture all new cases and there are varying http://www.health.state.mn.us/divs/idepc/
amounts of delay between infection, diseases/hiv/hivsurvrpts.html
testing, and reporting.
New testing methodologies are becoming more widely available and will enable more timely
descriptions of the epidemic as it continues to unfold. In addition, continued efforts to encourage
testing and counseling help limit the amount of undiagnosed HIV infection.
BEHAVIORAL SURVEILLANCE
MDH collects a small amount of behavioral data as it relates to HIV and AIDS surveillance
information. For example, reports of HIV infection received by MDH include information on drug
use and sexual behaviors. Additionally, from time to time MDH will undertake special projects
with the intent of collecting behavioral data on specific populations. Examples of these are the
2001 Minnesota STD Prevalence Study (ages 12-24) and the 2004 and 2007 Twin Cities Men’s
Health Surveys (MSM 18 and older) and the 2011 Minnesota Men’s Health Study (MSM 18 and
older).
OTHER DATA SOURCES
Data regarding risk factors for acquiring HIV that are presented in this report include sexually
transmitted disease rates (Epidemiology and Surveillance Unit, STD and HIV Section, MDH), teen
pregnancy rates (Minnesota Center for Health Statistics), chemical health indicators (Minnesota
Behavioral Risk Factor Surveillance System), behavioral survey data (Minnesota Student Survey
and Minnesota Behavioral Risk Factor Surveillance System), a variety of social and economic data
from the 2010 Census (U.S. Census Bureau), and results from specific scientific studies. These
data serve to characterize the population at risk for acquiring or transmitting HIV.
MODE OF EXPOSURE
Cases can have unspecified risk for two reasons. The first is that the person has not yet been
interviewed or has refused an interview by a Disease Intervention Specialist (DIS) from MDH, and
therefore we have little information on their risk category. Disease Intervention Specialists have
reported difficulty interviewing recent cases due to language and cultural barriers, as well as
difficulty locating the individuals. Second, the person may have no obvious risk. However,
heterosexual contact as a mode of HIV transmission is only assigned when the person knows that
their partner was HIV-infected or at increased risk for HIV. Often this level of knowledge about
sexual partners (anonymous, casual, or exclusive) may be unknown. According to a study
Minnesota HIV/AIDS Epidemiologic Profile – Technical Notes
December 2015
conducted by the CDC, it is likely that at least 80% of women with unspecified risk acquired HIV
through heterosexual contact 4.
In 2004, MDH began estimating mode of exposure for cases with unspecified risk in its annual
PowerPoint summary slides 5. In 2014, estimation was done by using the risk distribution for
cases reported between 2012 and 2014 with known risk by race and gender and applying the
distribution to those with unspecified risk of the same race and gender. For females a step was
added in 2007, whereby females that were interviewed by a DIS and determined not to have
any risk other than heterosexual exposure were designated as having heterosexual mode of
transmission. There are two exceptions to this method, African-born cases and Asian/Pacific
Islander women. For both African-born and Asian/Pacific Islander women, a breakdown of 95%
heterosexual risk and 5% other risk was used. For African-born males, a breakdown of 5% maleto-male sex, 90% heterosexual risk, and 5% other risk was used. These percentages are based
on epidemiological literature and/or community experience 6.
TREATMENT CASCADE
As part of the National HIV/AIDS Strategy for the United States, MDH began calculating an HIV
treatment cascade in 2013 using HIV surveillance data. These calculation help us better
understand the HIV epidemic and the disparities that exist in the delivery of care among HIV
positive people in Minnesota.
Limitations
Laboratory data are used as a proxy for a care visit to calculate each segment of the treatment
cascade. The accuracy of the cascade depends on complete reporting of laboratory results. The
transition from voluntary reporting of CD4 and VL results to mandated reporting in 2011 has
occurred at different rates among the various reporting laboratory facilities. We have been
made aware of at least one lab in the state that has had difficulty consistently reporting all CD4
and VL results which could potentially bias the results. We also know that patients who have
laboratories drawn as part of research studies are not reported to MDH. One clinic estimates
that approximately 90 of their patients are participating in a research study.
Linkage to Care
Linkage to care is defined as those who were diagnosed in Minnesota during the year 2013 and
had a CD4 or VL test performed within 90 days of initial diagnosis. Calculation of the linkage to
care measure use a denominator that is different due to guidance from CDC that instructs local
jurisdictions to make this calculation based on one year of diagnoses. Therefore results for this
measure are displayed in a different color in the graphics.
Lansky A, Fleming PL, Buyers RH, Karon JM, Wortley PM. A method for classification of HIV exposure category for women with HIV risk
information. Monthly Morbidity and Mortality Report, 50(RR-6):29-40, 2001
5 See annual reports at http://www.health.state.mn.us/divs/idepc/diseases/hiv/stats/hivsurvrpts2012.html
6 Detailed methodology available in the HIV Surveillance Technical Notes at
http://www.health.state.mn.us/divs/idepc/diseases/hiv/stats/pmtech2010.html
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Minnesota HIV/AIDS Epidemiologic Profile – Technical Notes
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GLOSSARY OF TERMS
Greater Minnesota: All counties outside of Transitional Grant Area. The counties include:
Aitkin, Becker, Beltrami, Benton, Big Stone, Blue Earth, Brown, Carlton, Cass, Chippewa, Clay,
Clearwater, Cook, Cottonwood, Crow Wing, Dodge, Douglas, Faribault, Fillmore, Freeborn,
Goodhue, Grant, Houston, Hubbard, Itasca, Jackson, Kanabec, Kandiyohi, Kittson, Koochiching,
Lac qui Parle, Lake, Lake of the Woods, Le Sueur, Lincoln, Lyon, McLeod, Mahnomen, Marshall,
Martin, Meeker, Mille Lacs, Morrison, Mower, Murray, Nicollet, Nobles, Norman, Olmsted, Otter
Tail, Pennington, Pine, Pipestone, Polk, Pope, Red Lake, Redwood, Renville, Rice, Rock, Roseau,
Saint Louis, Sibley, Stearns, Steele, Stevens, Swift, Todd, Traverse, Wabasha, Wadena, Waseca,
Watonwan, Wilkin, Winona, and Yellow Medicine counties.
HIV Infection: Includes all new cases of HIV infection, both HIV (non-AIDS) and AIDS at first
diagnosis, diagnosed within a given calendar year.
Incidence: The number of new cases of a disease that occur in a population during a certain
time period, usually a year.
Late Tester: Persons with an AIDS diagnosis within one year of initial HIV infection diagnosis
Linkage to Care: Linkage to care is defined as those who were diagnosed in Minnesota during
the year 2012 and had a CD4 or VL test performed within 90 days of initial diagnosis.
Pediatric case: Children less than 13 years of age at time of diagnosis.
People Living with HIV/AIDS (Diagnosed Prevalence): CDC estimates that between 18 and 20
percent of HIV infected individuals are not diagnosed and includes this estimate of unaware
individuals in the national treatment cascade. For local adaptations of the treatment cascade,
CDC recommends to use the diagnosed prevalence as the estimate for people living with
HIV/AIDS within their jurisdiction. This does not include an estimate of the proportion of people
living with undiagnosed HIV infection. Therefore Minnesota’s treatment cascade is not a direct
comparison to other cascades that include an estimate of positive persons with unknown
status.
To calculate the diagnosed prevalence used in this cascade, surveillance data were used to
estimate the number of people over the age of 13 living in Minnesota at the end of 2014 who
were diagnosed with HIV infection (regardless of residence at diagnosis) by the year end of
2013. This estimate serves as the underlying population for retention in care and viral
suppression measures, hence is seen on the graph as 100% as people living with HIV/AIDS in
Minnesota.
Prevalence: The total number of persons living with a specific disease or condition at a given
time.
Minnesota HIV/AIDS Epidemiologic Profile – Technical Notes
December 2015
Retention in care: The CDC defines retention in care for local adaptations of the treatment
cascade for jurisdictions without medical monitoring funding as two laboratory results at least
three months apart. This is not displayed on Minnesota’s treatment cascade because initial
analyses showed that 30% of people who were virally suppressed at the end of 2012, did not
meet this definition of retention in care. After discussing with our prevention and care partners,
it was noted that patients who are doing well on treatment may have only one laboratory
ordered each year to monitor progression of disease. Therefore, on Minnesota’s treatment
cascade, retention in care is defined as one laboratory test within the year 2014 for patients
alive and living in Minnesota at the end of 2014 who were diagnosed through year-end 2013.
Because of Minnesota’s adaptation of retention in care, use caution when comparing the
retention in care measure to the national estimate.
Transitional Grant Area: A geographical area highly impacted by HIV/AIDS that are eligible to
receive Ryan White HIV/AIDS Program Part A funds. To be an eligible TGA and area must have
reported at least 1,000 but fewer than 2,000 new AIDS cases in the most recent five years. In
Minnesota the TGA comprises the 13 counties in the Minneapolis-St. Paul-Bloomington
metropolitan statistical. This includes 11 counties in Minnesota as well as two counties in
Wisconsin. The Minnesota Counties include: Anoka, Dakota, Carver, Chisago, Hennepin, Isanti,
Ramsey, Scott, Sherburne, Washington, and Wright counties. The Wisconsin counties include
Pierce and St. Croix counties.
Viral suppression: Viral suppression is defined as a viral load test result of ≤200 copies/mL at
the most recent test during 2014.
Minnesota HIV/AIDS Epidemiologic Profile – Technical Notes
December 2015