Annex 7.4. Attachment G: Using Surveillance Data to Document Need and Initiate Referrals

Annex 7.4. Attachment G: Using Surveillance Data to Document Need and Initiate Referrals

Annex 7.4. Attachment G, continued

Annex 7.4. Attachment G, continued

Annex 7.4. Attachment G, continued

Annex 7.4. Attachment G, continued

Annex 7.4. Attachment G, continued

Annex 7.4. Attachment G, continued

Annex 7.4. Attachment G, continued

Annex 7.4. Attachment G, continued

Annex 7.4. Attachment G, continued

Annex 7.4. Attachment G, continued

Unit 8

Analysis, Interpretation, and Dissemination

of HIV Surveillance Data

Overview

What this

unit is about

This unit describes the key stages in the HIV disease natural history that should be tracked by HIV surveillance activities and how the data are analysed and summarised. It describes the different analyses that can be preformed from HIV case surveillance data. Finally, it summarises the types of reports should be generated and disseminated.

questions

1. 
   List three elements of an HIV surveillance report.
   

a.
b.

2. 
   True or false? The conclusion section of an HIV surveillance report is an optional element.
   

3. 
   True or false? Changes in reporting practises may result in a spurious increase or decrease in AIDS incidence.
   

4. 
   When describing the HIV epidemic, why is it preferable to perform analysis based on date of diagnosis versus date of report?
   

5. 
   True or false? Increases in the number of persons receiving ART can result in a decrease in AIDS incidence, regardless of the number of new HIV infections occurring.
   

True False

6. 
   Which of the following are potential target audiences for surveillance reports on HIV?
   

1. 
   people who contribute to collecting the surveillance data
   
2. 
   healthcare workers
   
3. 
   public health officials at the district, provincial, national and international levels
   
4. 
   all of the above
   

Introduction

What you

By the end of this unit, you should be able to:

• 
  summarise data obtained from surveillance activities
  
• 
  interpret HIV case surveillance data
  
• 
  describe the basic elements of an annual HIV Surveillance Report
  
• 
  describe the elements in an annual Epidemiologic Profile.
  

HIV epidemic

In order to fully understand the HIV epidemic, several key stages in the disease should be monitored. These include:

• 
  HIV incidence (that is, the number or rate of new HIV infections)
  
• 
  HIV prevalence (that is, the number or rate of all persons living with HIV, regardless of how long they have been infected or whether or not they are aware of their infection)
  
• 
  incidence of advanced HIV disease
  
• 
  incidence of AIDS
  
• 
  prevalence of advanced HIV disease
  
• 
  prevalence of AIDS
  
• 
  HIV-related deaths
  

These target points for HIV surveillance are described in Unit 4.

Decisions regarding public health are dependent on quality data. Accurate surveillance data are central to the effective monitoring of trends in HIV infection, identification of risk behaviours within populations, and the successful development and evaluation of HIV intervention and prevention programs. It is also important that surveillance data be presented in a manner that facilitates their use for public health action. Therefore, it is essential that HIV surveillance data meet certain criteria for quality before being analysed and disseminated.

case surveillance

data

The introduction of HIV case surveillance is necessary due to the increased availability of ART in developed countries, which has markedly altered the natural history of HIV infection.

• 
  Without ART, it takes an average of eight to ten years for an HIV-infected person to develop AIDS.
  
• 
  With ART, the progression to AIDS is delayed or possibly prevented.
  

In this situation, relying just on AIDS case surveillance will miss many HIV-infected persons. The current method of estimating HIV prevalence in developing countries is to conduct unlinked anonymous HIV sero-prevalence surveys in women attending antenatal clinics and/or high-risk populations. While these have been reasonable methods of estimating HIV prevalence, WHO encourages countries to conduct HIV case surveillance, as described in Unit 4: HIV Case Surveillance.

• 
  all previously reported cases have been entered into the HIV case surveillance database
  
• 
  case-finding for old unreported cases has been done and entered into the database
  
• 
  assessment of the HIV case surveillance system shows that it is functional (see Unit 5: Monitoring Surveillance System Quality)
  

This may take several years. This is to be sure that the data, especially trend data, are not misinterpreted. For example, in the first year of reporting, some of the newly diagnosed persons will be reported. In subsequent years, more infected people will be reported, but these reports may be from patients who were diagnosed in the past but not yet reported. Alternatively, these may be newly diagnosed persons. Once the people with long-standing HIV infection have been reported, data may be analysed in the same way that AIDS case data were analysed.

• 
  call for considering use of ART for patients at HIV clinical stage 3
  
• 
  recommend use of ART for patients at HIV clinical stage 4.
  

Using HIV case surveillance data, continued

Terms used

in analysis of

HIV case

surveillance

HIV incidence is the true number of new infections occurring in a population. See Unit 4 for methods to estimate HIV incidence.
HIV prevalence is the true prevalence of people infected with HIV. See Unit 4 for methodologies to estimate HIV prevalence.
New diagnoses of HIV includes persons with advanced HIV disease or AIDS.
New diagnoses of advanced HIV disease includes persons with AIDS. The term ‘incidence’ may be used to describe the new cases diagnosed with advanced HIV disease.
New diagnoses of AIDS includes only persons with clinical stage 4 or CD4 count less than 200. The term ‘incidence’ may be used to describe the new cases diagnosed with AIDS.
Cumulative diagnoses of HIV includes persons with advanced HIV disease or AIDS. Cumulative diagnoses include all persons diagnosed with HIV infection since the beginning of the HIV epidemic.
Cumulative diagnoses of advanced HIV disease includes persons with AIDS. Cumulative diagnoses include all persons diagnosed with advanced HIV disease (WHO clinical stage 3 or 4, or CD4 count <350 cells/uL) since the beginning of the HIV epidemic.
Terms used in analysis of HIV case surveillance, continued
Cumulative diagnoses of AIDS include all persons diagnosed with AIDS (WHO clinical stage 4 or CD4 count <200 cells/uL) since the beginning of the HIV epidemic.
Deaths among persons with HIV may or may not be attributable to HIV disease. If your vital registration system includes cause of death, this is important information to present. Bear in mind that this may be an under-representation of the actual number of deaths due to HIV-related disease.
HIV-related deaths. These are people who died from HIV-related conditions.
The number of persons living with HIV is a critical number/analysis for planning purposes. To be able accurately count how many persons are diagnosed and living with HIV, subtract number of persons who have died (all causes of death) from all those diagnosed with HIV.
Determining the number of persons living with advanced HIV disease is important for planning because it tells you how many people may need HIV care and treatment in the near future. According to WHO recommendations, these people should be receiving HIV treatment. This can also be referred to as prevalence of advanced HIV disease.
Determining the number of persons living with AIDS is important because it tells you how many people currently need treatment. You can look at the number of PLWA and see how many people are on treatment and assess whether you are meeting your treatment needs. This can also be referred to as prevalence of AIDS.
Interpreting

HIV case data

HIV, advanced HIV disease, and AIDS case data should be examined to answer the following questions:

• 
  Are new diagnoses of HIV, advanced HIV disease and AIDS increasing, decreasing or remaining stable?
  
• 
  Which parishes/regions/counties have the highest number of new diagnoses of HIV, advanced HIV disease, and AIDS?
  
• 
  What are the differences between parishes/regions/counties where new diagnoses of HIV, advanced HIV disease and AIDS is low and those where it is relatively high?
  
• 
  What are the differences between parishes/regions/counties where the new diagnoses of HIV, advanced HIV disease and AIDS is increasing and those where it is decreasing or not changing?
  

Interpreting HIV case data, continued

• 
  What proportion of persons with HIV, advanced HIV disease, and AIDS are receiving ART?
  
• 
  Are there demographic differences between person receiving ART and those who are not, among those who need treatment?
  
• 
  What are the most frequent HIV-related opportunistic illnesses and are these changing over time? This is applicable if data on OI are collected.
  

Changes in HIV, advanced HIV disease and AIDS case reports may be due to factors other than a true decrease or increase in the number of infections and deaths occurring. Interpret surveillance data to understand factors that may produce spurious changes. These include:

• 
  increases or decreases in the size of the risk population
  
• 
  changes in risk behaviours; these would affect HIV transmission rates, and HIV, advanced HIV disease and AIDS incidence many years later.
  
• 
  changes in HIV testing and/or other diagnostic procedures
  
• 
  increase in VCT activities—that is, VCT campaigns or outreach programmes
  
• 
  increases or decreases in the number of healthcare facilities or other access to care issues (institution of user fees resulting in decreased clinic attendance)
  
• 
  increase in availability of ART
  
• 
  impact of ART on the slowing of the progression of HIV disease to advanced HIV disease
  
• 
  adoption of new case definitions
  
• 
  changes in case surveillance practises (for instance, private providers reporting)
  
• 
  duplicate case reports (that is, more than one report provided for an individual, leading to counting the person twice)
  

A number of factors may affect the incidence of advanced HIV disease and AIDS, including:

• 
  past HIV incidence (keeping in mind the time it takes to develop AIDS after HIV infection)
  
• 
  HIV care provided to persons early in HIV infection may decrease progression to advanced HIV disease
  
• 
  ART impact on delaying the progression of HIV to AIDS should decrease AIDS incidence
  

Because AIDS represents late-stage HIV infection, AIDS incidence rates do not provide much information on HIV incidence. HIV incidence is the leading edge of the epidemic.

Interpreting HIV case data, continued
Factors that may affect the prevalence of advanced HIV disease and AIDS cases are:

• 
  changes in incidence of AIDS due to increased availability of ART
  
• 
  changes in advanced HIV disease and AIDS mortality—for example, a decrease in AIDS mortality from ART will increase the prevalence of advanced HIV disease.
  

the figure

Look at Figure 8.1 and answer the following questions:

1. 
   What factors may explain the discrepancy in the number of HIV and AIDS cases between 1992 and 1994 (that is, high numbers of HIV cases but relatively low number of AIDS cases)?
   

2. 
   What would you expect to happen to the number of AIDS cases and deaths in the absence of ART in 2004?
   

Data should meet

minimum performance

standards

Before analysis, HIV surveillance data should meet the minimum quality standards for timeliness and completeness. Additionally, any report or presentation of the data should include discussion of the quality and limitations of the data. Data quality standards are listed Unit 5.
For example, when looking at completeness of reporting, you should note that many Caribbean countries have had AIDS case surveillance from selected healthcare facilities. HIV-infected patients may be referred from public clinics to district-level clinics or specific private facilities for specialised care. This is particularly true for patients who are receiving ART. In this situation, it is not uncommon for reporting only to be completed from the public clinic, district and reference private facility. If cases are reported from a select number of sites, this should be mentioned in the report. Additionally, methods to estimate the proportion of missing cases should be considered.
In general, limitations of the data should be mentioned in the report.

Data should meet

confidentiality

requirements

To reduce the risk of inadvertent identification of individuals, it is essential that data be presented in a way that preserves the confidentiality of persons in the HIV case surveillance database. Policies for data release should be guided by knowledge of the overall population characteristics and distribution, and of the HIV-infected population. Each area should have a written data release policy that has been reviewed and approved by the overall responsible party. In all circumstances, the primary consideration should be to maintain confidentiality in a manner consistent with making useful data available for local purposes. Data release policies should consider the purposes for which the data were originally collected, as well as the purpose of data presentation. Unit 7: Confidentiality and Data Security provides further details on the confidentiality requirements for HIV case surveillance data.