Trends in human immunodeficiency virus type 1 (HIV-1) load among HIV-1-infected children with hemophilia

Pediatric HIV-1 in Kenya: pattern and correlates of viral load and association with mortality

BACKGROUND

There is limited information regarding the pattern and correlates of viral replication in vertically HIV-1-infected children and its role on their outcomes in resource-limited settings.

METHODS

HIV-1-infected infants were followed from birth to 24 months. Serial HIV-1 RNA levels were compared in infants infected in utero (<48 hours), peripartum (48 hours-1 month), and late postnatal (after 1 month). Cofactors for viral peak [highest viral load (VL) within 6 months of infection] and set point and mortality were determined.

RESULTS

Among 85 HIV-1-infected infants, 24 were infected in utero, 41 peripartum, 13 late postnatal; 7 had no 48-hour assay. HIV-1 VL set point was significantly lower in infants infected >1 month vs. < or = 1 month (5.59 vs. 6.24 log10 copies per milliliter, P = 0.01). Maternal VL correlated with peak infant VL (P < 0.001). Univariately, infant peak and set point VL and 6-month CD4% <15% predicted mortality; and 6-month CD4% <15% remained independently predictive in multivariate analyses (hazard ratio = 4.85, 95% confidence interval: 1.90 to 12.36).

CONCLUSIONS

Infants infected after the age of 1 month contained virus better than infants infected before 1 month of age. Maternal VL predicted infant VL, which, in turn was associated with early mortality.

Assessing uncertainty in reference intervals via tolerance intervals: application to a mixed model describing HIV infection

We define the reference interval as the range between the 2.5th and 97.5th percentiles of a random variable. We use reference intervals to compare characteristics of a marker of disease progression between affected populations. We use a tolerance interval to assess uncertainty in the reference interval. Unlike the tolerance interval, the estimated reference interval does not contains the true reference interval with specified confidence (or credibility). The tolerance interval is easy to understand, communicate and visualize. We derive estimates of the reference interval and its tolerance interval for markers defined by features of a linear mixed model. Examples considered are reference intervals for time trends in HIV viral load, and CD4 per cent, in HIV-infected haemophiliac children and homosexual men. We estimate the intervals with likelihood methods and also develop a Bayesian model in which the parameters are estimated via Markov-chain Monte Carlo. The Bayesian formulation naturally overcomes some important limitations of the likelihood model.

Maternal viral load and rate of disease progression among vertically HIV-1-infected children: an international meta-analysis

OBJECTIVE

To evaluate whether maternal human immunodeficiency virus type 1 (HIV-1) RNA levels in the serum/plasma of mothers at or close to the time of delivery affects the rate of disease progression among vertically HIV-1-infected children and whether it correlates with other parameters affecting infant disease progression.

METHODS

International meta-analysis of eight studies with 574 HIV-1 infected infants with available maternal HIV-1 RNA measurements at or close to delivery and clinical follow-up. The primary outcome was disease progression (stage C disease or death, n = 178). Cohort-stratified Cox models were used.

RESULTS

Higher maternal HIV-1 RNA level at or close to delivery significantly increased disease progression risk [hazard ratio (HR), 1.25; 95% confidence interval (CI), 1.04-1.52 per 1 log10 increase; P = 0.02) with a borderline effect on mortality (HR, 1.26; 95% CI, 0.96-1.65; P = 0.10]. The association with disease progression risk was strong in the first 6 months of life (HR, 1.77; 95% CI, 1.28-2.45; P = 0.001), but not subsequently (HR, 1.03; 95% CI, 0.81-1.30). Maternal HIV-1 RNA, early infant HIV-1 RNA (at 30-200 days after birth) and infant CD4 were independent predictors of disease progression in the first 6 months. Maternal HIV-1 RNA at or close to delivery correlated with early infant HIV-1 RNA (r = 0.26, P < 0.001). Effects were independent of maternal and infant treatment.

CONCLUSIONS

Higher maternal HIV-1 RNA at or close to delivery strongly predicts disease progression for HIV-1-infected infants, especially in their first 6 months of life and correlates with the early peak of viremia in the infected child.