Predictors of CD4 cell count response to first-line combination antiretroviral treatment among HIV-positive adult patients from the Asia-Pacific region

Abstract

The introduction of combination antiretroviral treatment (ART) has had substantial impact on the human immunodeficiency virus (HIV) epidemic [1, 2]. Patients responding to ART have reduced HIV viral replication and lower rates of HIV-associated morbidity, mortality and AIDS-related events [3-5]. Recommendations on when to initiate ART is largely based upon the CD4 T lymphocyte cell count [6-10]. The CD4 T lymphocyte cell is generally regarded as an indicator of immune deficiency and used as a prognostic marker of HIV disease progression [11-13]. Early World Health Organisation (WHO) guidelines recommended ART initiation when patients were at an advanced stage of HIV or in asymptomatic stages of HIV with a CD4 cell count below 200cells/μL [6]. However, recent research has suggested that initiating ART at higher CD4 cell count levels has greater benefits in preventing further disease progression, further HIV transmission and reduced occurrence of opportunistic infections [14-17]. Although ideal, earlier ART initiation has been difficult to implement, particularly in low-income or resource-limited countries, as it requires patients to access health care facilities to receive HIV testing and diagnosis at early stages of disease progression [18, 19]. The Asia Pacific region retains a heavy burden of the HIV epidemic, with close to 5 million people living with HIV in 2013 [20, 21]. Despite an increasing push towards earlier initiation of ART, barriers to receiving care have contributed to the inability of many HIV-positive patients, within the Asia-Pacific region, to be diagnosed and initiate ART at higher CD4 cell count levels [22, 23]. In 2012, UNAIDS estimates for the Asia-Pacific region indicated that the number of people accessing ART has increased yet, the treatment coverage rate remains lower than the global average at 51% and a majority of people living with HIV are not diagnosed [21]. Patients presenting with CD4 cell counts <200 cells/μL require longer periods of time to fully restore CD4 cell count levels which increases there susceptibility to treatment failure and death [23]. Other factors, such as previous exposure to mono/duo therapy and older age, are also known to hinder CD4 restoration [24, 25]. The study objective is to examine the CD4 cell count response to first-line ART among HIV-positive patients from the TREAT Asia HIV Observational database low intensity transfer (TAHOD-LITE). Factors associated with mean CD4 cell count at 12 months will also be evaluated. Study findings will be useful for guiding decision making in future programs addressing the HIV-epidemic in the Asia-Pacific region.