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Amplifying and Quantifying HIV-1 RNA in HIV Infected Individuals with Viral Loads Below the Limit of Detection by Standard Clinical Assays
Published on: September 26, 2011
Trends in detectable viral load by calendar year in the Australian HIV observational database
Matthew G Law1, Ian Woolley, David J Templeton
1National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, NSW, Australia. mlaw@nchecr.unsw.edu.au
Insights
Detectable viral load in patients on combination antiretroviral treatment (cART) decreased over time. However, HIV diagnoses and incidence increased in Australia during the study period.
Area of Science:
- Public Health
- Virology
- Epidemiology
Background:
- Combination antiretroviral treatment (cART) may reduce HIV transmission by lowering viral load.
- This study investigated trends in detectable viral load among cART patients in Australia.
Purpose of the Study:
- To assess calendar trends in detectable viral load (>400 copies/ml) in patients receiving cART.
- To evaluate the effectiveness of cART in reducing viral load over time within the Australian HIV Observational Database.
Main Methods:
- Analysis of viral load data from 2439 patients between 1997 and 2009.
- Utilized repeated measures logistic regression to account for patient variability.
- Predicted detectable viral load rates, accounting for patients lost to follow-up.
Main Results:
- Observed detectable viral load declined to 5.3% by early 2009.
- Predicted detectable viral load declined to 13.8% in 2009.
- Despite viral load reduction, HIV diagnoses and incidence increased in Australia.
Conclusions:
- Detectable viral load in cART patients decreased over time, though predicted levels remained higher than observed.
- The study highlights a discrepancy between viral load suppression and rising HIV diagnoses/incidence in Australia.
- Further research is needed to understand the factors contributing to increased HIV incidence despite cART advancements.
Background:
Recent papers have suggested that expanded combination antiretroviral treatment (cART) through lower viral load may be a strategy to reduce HIV transmission at a population level. We assessed calendar trends in detectable viral load in patients recruited to the Australian HIV Observational Database who were receiving cART.
Methods:
Patients were included in analyses if they had started cART (defined as three or more antiretrovirals) and had at least one viral load assessment after 1 January 1997. We analyzed detectable viral load (>400 copies/ml) in the first and second six months of each calendar year while receiving cART. Repeated measures logistic regression methods were used to account for within and between patient variability. Rates of detectable viral load were predicted allowing for patients lost to follow up.
Results:
Analyses were based on 2439 patients and 31,339 viral load assessments between 1 January 1997 and 31 March 2009. Observed detectable viral load in patients receiving cART declined to 5.3% in the first half of 2009. Predicted detectable viral load based on multivariate models, allowing for patient loss to follow up, also declined over time, but at higher levels, to 13.8% in 2009.
Conclusions:
Predicted detectable viral load in Australian HIV Observational Database patients receiving cART declined over calendar time, albeit at higher levels than observed. However, over this period, HIV diagnoses and estimated HIV incidence increased in Australia.
