University of California, San Francisco Logo

University of California, San Francisco | About UCSF | Search UCSF | UCSF Medical Center

Population-based monitoring of HIV drug resistance in Namibia with early warning indicators
Global Health Sciences Literature Digest
Published December 13, 2010
Journal Article

Hong SY, Jonas A, Dumeni E, Badi A, Pereko D, Blom A, et al. Population-based monitoring of HIV drug resistance in Namibia with early warning indicators. J Acquir Immune Defic Syndr. 2010 Dec 1;55(4):27-31.

In Context

The widespread and increasing use of antiretroviral therapy (ART) in resource-constrained areas is likely to be associated with the development of HIV drug resistance and an increased risk of death.(1) However, monitoring of resistance in resource-constrained areas is restricted by cost and limited laboratory capacity. The World Health Organization (WHO) developed a series of non-laboratory-based indicators that can be used to supplement periodic HIV drug resistance testing as markers suggestive of development of HIV drug-resistance within a population.(2, 3)


To measure the completeness of reporting on five WHO early warning indicators (EWIs) of HIV drug resistance.(2, 3, 4)


Nine national ART sites in Namibia. Clinic records from patients prescribed ART.


Nine of the 15 Namibia ART sites were randomly selected. Records from consecutive patients who initiated ART for the first time beginning January 1, 2007 (for indicators 1-3) and records from patients consecutively returning for additional supply of ART beginning October 1, 2007 were abstracted. A total of 180 records for each indicator were abstracted. To measure continuity of drug supply, data were abstracted on stock-outs of each type of ART in use from January 1, 2008 through December 31, 2008 using pharmacy stock cards at each site.


Data from 3,240 patients were abstracted. The data to evaluate ART pick-up and supply continuity were insufficiently complete or inaccurate to analyze these outcomes. All patients at all sites were prescribed first line ART according to national protocols. Eight of the sites met the WHO target of 20% or less of patients lost to follow-up at 12 months. The site not meeting this target had lost 42% of patients at 12 months. Although not included as an EWI, 20.8% of patients at all sites combined, had a median of 2.3 months period of absence from the clinic during the first 12 months on treatment. Six of the nine clinics met the target of 100% of patients remaining on the first-line ART 12 months after initiation of treatment. A single patient at each of two sites was appropriately switched to second-line ART after virological failure while at one site a patient was change to a non-recommended triple NRTI regimen. There was only one site with usable data for analysis of on-time pick-up of medication and the site did not meet the target of 90% or more obtaining medications on time as only 72% achieved this goal. None of the sites had data that could be abstracted to measure continuity of ART supply. In response to these findings, Namibia strengthened ART record keeping which should allow for future assessment of the EWIs.


This review of EWIs found that some, but not all, indicator targets were met. Poor record keeping prevented measuring two of the five EWIs selected in the evaluation.

Study Quality

The study included the majority of ART sites and the sites included were randomly selected, providing excellent representativeness. The sample size was appropriately calculated and met. Quality assurance measures to ensure accurate data abstraction were very good, although the authors did not describe how discrepant findings identified during validation were rectified. A key limitation of this evaluation is that it only included public ART sites. Information regarding EWIs in the private sector would strengthen the study and provide a more comprehensive understanding of the risk of developing HIV drug resistance in this population as well as potentially identifying additional sites in need of better record keeping.

Programmatic Implications

The most important finding from this study is that ART sites were in need of better record keeping. There are likely many reasons for poor record keeping in resource constrained areas including high patient load and insufficient staffing. Changes to data management systems may facilitate record keeping. In addition, training of staff on the importance of accurate and complete documentation of patient medical care and outcomes is probably necessary in many resource-constrained care sites. Increased monitoring of record keeping through supportive supervision should be prioritized.


  1. Hogg RS, Bangsberg DR, Lima VD, et al. Emergence of drug resistance is associated with an increased risk of death among patients first starting HAART. PLoS Med. 2006;3:e356.
  2. Bennett DE, Bertagnolio S, Sutherland D, et al. The World Health Organization's global strategy for prevention and assessment of HIV drug resistance. Antivir Ther. 2008;13(Suppl 2):1-13.Accessed July 20, 2010.
  3. HIV Drug resistance Early Warning Indicators. World Health Organization indicators to monitor HIV drug resistance prevention at antiretroviral treatment sites. April 2010. Accessed July 20, 2010.
  4. World Health Organization. HIV Drug resistance Early Warning Indicator Briefing. April 2008.