OBJECTIVE: To identify the optimal CD4 cell count at which cART should be initiated.
DESIGN: Prospective observational data from the HIV-CAUSAL Collaboration and dynamic marginal structural models were used to compare cART initiation strategies for CD4 thresholds between 0.200 and 0.500 × 10(9) cells/L.
SETTING: HIV clinics in Europe and the Veterans Health Administration system in the United States.
PATIENTS: 20, 971 HIV-infected, therapy-naive persons with baseline CD4 cell counts at or above 0.500 × 10(9) cells/L and no previous AIDS-defining illnesses, of whom 8392 had a CD4 cell count that decreased into the range of 0.200 to 0.499 × 10(9) cells/L and were included in the analysis.
MEASUREMENTS: Hazard ratios and survival proportions for all-cause mortality and a combined end point of AIDS-defining illness or death.
RESULTS: Compared with initiating cART at the CD4 cell count threshold of 0.500 × 10(9) cells/L, the mortality hazard ratio was 1.01 (95% CI, 0.84 to 1.22) for the 0.350 threshold and 1.20 (CI, 0.97 to 1.48) for the 0.200 threshold. The corresponding hazard ratios were 1.38 (CI, 1.23 to 1.56) and 1.90 (CI, 1.67 to 2.15), respectively, for the combined end point of AIDS-defining illness or death.
LIMITATIONS: CD4 cell count at cART initiation was not randomized. Residual confounding may exist.
CONCLUSION: Initiation of cART at a threshold CD4 count of 0.500 × 10(9) cells/L increases AIDS-free survival. However, mortality did not vary substantially with the use of CD4 thresholds between 0.300 and 0.500 × 10(9) cells/L.
METHODOLOGY: Cord blood samples from a pilot screening programme for congenital hypothyroidism in 1995 at Ipoh city and surrounding district hospitals were screened anonymously for HIV 1 and 2. HIV status was determined using chemiluminescent technology. Positive samples were retested using the Genelavia Mixt assay.
RESULTS: A total of 4927 samples were tested. The ethnic breakdown included 51.7% Malays, 18.9% Chinese, 14.3% Indian, 2.3% Others and 12.9% unknown. The geographical distribution of samples was 73.9% urban, 24.2% rural and 1.9% unknown. The seroprevalence of HIV positivity was 3.25 per 1000 deliveries (95% CI: 1.92-5.16). Seroprevalence was higher for samples from rural and Malay mothers.
CONCLUSION: The high seroprevalence in this study suggests that the spread of HIV is far wider than that anticipated by mandatory national reporting. It also supports antenatal screening and the use of antiretroviral therapy as an important strategy to reduce perinatal transmission.