Appendix III: Technical Notes

Year of Diagnosis versus Year of Report:

There are two dates associated with an HIV disease case, the date of HIV diagnosis and the date the case was reported to Orange County HIV/AIDS Surveillance and Monitoring Program. Most HIV/AIDS data reports utilize the report date to determine what year the case was reported. When showing case demographics in individual years, this data report will focus on the date that the case was diagnosed with HIV (unless this date is absent, in which case the AIDS diagnosis date will be used). Presenting data by year of diagnosis gives a clearer picture of the current nature of the epidemic and the demographics of the most newly infected individuals. Due to reporting delays, diagnosis data for 2014 is incomplete as cases diagnosed in 2014 will continue to be reported throughout 2015. By using the year of report, the number of cases reported each year should be relatively stable making it appropriate to compare the most current year of reporting to previous years. However, in recent years additional surveillance efforts were made to identify cases of HIV disease never reported to the SOA. This resulted in an increased number of cases being reported that were not reflective of an increase in the epidemic, nor were they reflective of the demographics of persons newly diagnosed.

Calculation of Rates:

 Population based rates were calculated by using population figures from California Department of

Finance data sets; the numerator represents the number of cases in a particular sub-population, period of time, or the whole population. The rate is expressed per 100,000 population.

 Percentages are calculated by dividing the number of cases in a particular group by the total number of

cases reported or diagnosed for that time period or subset. For example, the percentage of cumulative cases reported that were age 20-29 at diagnosis would be the number of cases age 20-29 at diagnosis divided by the total number of cumulated cases reported.

Data Limitations:

 Reported vs. Diagnosed cases: Data presented by demographics in this report represents the number

of HIV disease cases diagnosed in a particular year. Caution must be taken in interpreting these data, since cases will continue to be reported which were diagnosed in previous years, so diagnosis data is never “complete.” However, it does give a more accurate picture of the current epidemic and who is testing positive today.

 Attention should be given to what the numbers represent (rates, number of cases, percentages, etc.).

Please refer to the Glossary of Terms for definitions.

 Surveillance data are revised as duplicate cases are removed at the state level. Therefore, the total

numbers presented for a particular period are subject to revision.

 The number of HIV disease cases among some subgroups may be small. Small numbers may appear

misleadingly large when viewed as a rate. Therefore, large rates for some characteristics should be interpreted with caution. In addition, subgroups with fewer than five cases reported will be masked and a footnote will appear.

National HIV/AIDS Strategy Methodology:

 Goal 1: Reduce the Number of New HIV Infections o Objectives 1-1 and 1-2  HIV incidence estimates are based on algorithms developed by the Centers for Disease Control

and Prevention (CDC).

 Baseline (2010) calculation: 281 cases (incidence)/6,579 estimated prevalence (diagnosed

(5,395) + undiagnosed (1,184))*100 = 4.3 new HIV transmissions per 100 people estimated to be living with HIV.

 2014 calculation: 261 cases (incidence)/6,698 estimated prevalence (diagnosed (5,760) +

undiagnosed (938))*100 = 3.9 new HIV transmissions per 100 people estimated to be living with HIV.

 Goal 2: Increase Access to Care and Optimize Health Outcomes for People Living with HIV

Disease

o Objectives 2-1; 2-2; and 2-3  Laboratory data were used as a proxy for care visits; a care visit was defined as a CD4 and/or

viral load laboratory result reported to Orange County Health Care Agency (OCHCA).

 Newly diagnosed persons linked to care were defined as persons diagnosed with HIV infection

during a calendar year and received care within three months of their diagnosis (excluding persons who died within three months of their diagnosis).

 In continuous care was defined as having at least two care visits, as represented by a CD4

and/or viral load laboratory result, during a calendar year, where the visits were at least three months apart.

 For 2-3 the denominator included Orange County resident cases living with HIV disease at the

end of the calendar year, diagnosed by the end of the previous year, and at least 13 years old. For 2-2 the denominator included only those who are clients in the Ryan White Program.

o Objectives 2-4  Defined as HIV Care Program Ryan White clients who received at least one service during a

calendar year and reported “stable/permanent” housing (living with relatives/friends, participant-owned housing, rental housing, or rented room) as their living situation at the most recent date before the end of the calendar year. If no living situation was available prior to the end of the year, the living situation closest to that date was used.

 Data are from Orange County’s and California’s HIV Care Program client management system,

the AIDS Regional Information and Evaluation System (ARIES).

 Unknown/missing data (2.8 percent in 2010, 0.1 percent in 2014) were excluded from

denominator.

 For additional information about the Ryan White Program, please see:

http://hab.hrsa.gov/abouthab/index.html.

 Goal 3: Reduce HIV-related Health Disparities o Objectives 3-1; 3-2; and 3-3  Denominator for 2014 included current Orange County residents diagnosed with HIV disease on

or before December 31, 2013 and at least 13 years old on December 31, 2013 and were still alive on December 31, 2014.

 Persons whose most recent viral load test result was less than 200 copies/ml during January 1,

2014-December 31,2014 were considered virally suppressed and included in the numerator of those with an “undetectable viral load”.

Suggested Citation:

 County of Orange, Health Care Agency, HIV/AIDS Surveillance and Monitoring Program. Disease

Control & Epidemiology. HIV Disease Surveillance Statistics, 2014.

Disease Control & Epidemiology Division 83 HIV/AIDS Surveillance & Monitoring Program