Of 4871 patients with a confirmed low CD4 cell count, 436 (8.9%) remained untreated. In multivariable analyses, those starting HAART were older [adjusted relative hazard (aRH)/10 years 1.15], were more likely to be female heterosexual (aRH 1.13), were more likely to have had AIDS (aRH 1.14), had a greater number of CD4 measurements < 350 cells/μL (aRH/additional count 1.18), had a lower CD4 count over follow-up (aRH/50 cells/μL higher 0.57), had a lower CD4 percentage (aRH/5% higher 0.90) and had a higher viral load (aRH/log10HIV-1 RNA copies/ml higher 1.06). Injecting drug users (aRH 0.53), women

Inhibitor Library infected with HIV via nonsexual or injecting drug HDAC inhibitor review use routes (aRH 0.75) and those of unknown ethnicity (aRH 0.69) were less likely to commence HAART. A substantial minority of patients with a CD4 count < 350 cells/μL remain untreated despite its indication. Since the introduction of highly active antiretroviral therapy (HAART), treatment guidelines have evolved in terms of the CD4 cell count at which antiretroviral therapy (ART) should be initiated. British HIV Association

(BHIVA) guidelines published from 2003 to 2006 advised initiation of ART in patients whose CD4 count was in the range 200-350 cells/μL. Although the exact timing of ART was dependent on other factors, it was expected that all patients should have initiated

Etomidate ART before their CD4 count dropped below the lower limit of 200 cells/μL [1-3]. Following more recent evidence of a higher rate of AIDS and death among patients initiating ART at a CD4 count of 251–350 cells/μL compared with those starting at higher counts [4], the most recent BHIVA guidelines (2008) [5] now recommend treatment at a CD4 count < 350 cells/μL. The UK Collaborative HIV Cohort (UK CHIC) Study [6] collates data on around one-third of patients diagnosed with HIV infection in the UK. In a previous analysis based on data collected to the end of 2003, only 50–60% of patients with a CD4 count < 200 cells/μL and 10–15% of patients with a CD4 count between 200 and 350 cells/μL initiated HAART in the following 6 months [7]. A BHIVA national audit carried out in 2006 also highlighted significant deviation from guidelines, with 59.7% of patients starting HAART at a CD4 count < 200 cells/μL [8]. The aim of this project was therefore to describe the proportion of patients initiating treatment at a CD4 count < 350 cells/μL following alterations to treatment guidelines, and to identify risk factors for delayed initiation of ART in this group. The UK CHIC Study currently involves 12 of the largest HIV clinical centres in the UK [6].