Until recently, BHIVA recommended that individuals with chronic HIV infection should start ART before the CD4 count fell to below 350 cells.
Results of the START study have now been presented and published . This study enrolled 4685 adults with CD4 cell counts above 500 cells/µL (median CD4 cell count 651 cells/µL) in 35 countries, and randomised them to start ART immediately or to defer ART until the CD4 count fell below 350 cells/µL. The risk of developing AIDS, a serious non-AIDS event or of death (combined as the primary endpoint) was reduced by 57% in those who were randomised to start earlier, after a median follow-up period of 3 years. The results were similar in high-income when compared to low- and middle-income countries and driven mainly by a difference in rates of AIDS events, particularly TB and cancers .

It is important to recognise that despite the significant reduction in relative risk of disease progression associated with early ART, the absolute risk of deferring ART was small in this study, around 4.1% of individuals in the deferred arm vs. 1.8% in the immediate treatment arm experienced a serious illness over 3 years of follow-up, while immediate ART was not associated with higher risk of grade 4 events or unscheduled hospital admissions. The absolute risk of deferring therapy should be considered when making individual decisions.