700 
A Comparison of the Association on Current CD4 Cell Count with Short-term Risk of AIDS of Death in HIV-infected Children and Adults
David Dunn*1, P Woodburn2, T Duong1, A Phillips3, D Gibb1, K Porter1, and HIV Paediatric Prognostic Markers Collaborative Study (HPPMCS) and The CASCADE Collaboration
1Med Res Council Clin Trials Unit, London, UK; 2Med Res Council/Uganda Virus Res Inst, Entebbe; and 3Royal Free and Univ Coll London Med Sch, UK
Background: Analyses of the association of CD4 count with
short-term risk of disease progression in HIV-infected adolescents/adults aged
15 years or above (CASCADE) and perinatally infected children from birth to 14
years (HPPMCS) have informed guidelines on when to start ART. We analyzed data from both studies using a common
methodology to give a more complete picture of how disease progression rates
varied by age and to assess whether there is an age threshold in children where
the association CD4 with the rate of progression approximates that observed in
adults.
Methods: Follow-up for each individual was censored at
date last known to be alive or the last clinical visit or December 31, 1995,
prior to widespread use of dual ART. AIDS and death incidence rates (expressed
as per 100 person-years) were tabulated by CD4 count (per mm3) and
age, spanning from birth to ≥60 years.
Results: We included 6741 patients (3224 HPPMCS, 3497
CASCADE) among whom we observed 1260 deaths and 1894 initial AIDS events over
20,500 and 17,200 person-years of observation. Young children (age <5 years)
experienced much higher mortality rates than older children and adults. Among children ≥5 yrs, the
effect of age (1.7% mortality decrease per year; 95%CI –6.5 to 9.9%) was not
statistically significant. By contrast, in adults, mortality increased by an
estimated 3.1% (95%CI 2.4 to 3.8%) per year. Mortality rates were comparable in
children aged ≥5 years and adults aged ~20 years;
at CD4 200 to 350 it was 0.9 in children vs 0.7 and 1.1 in adults aged 15 to 24
and 25 to 34 years, respectively. For children ≥5 years and adults at all ages, mortality increased sharply
at CD4 <150 to 200, with 71% deaths occurring at CD4 <50. AIDS incidence in children ≥5 years and adults aged 25 to 34 years was very similar at
CD4 200 to 350 (both 6.1), but increased to 7.7 and 10.0 in adults 45 to 55 and
>55 years, respectively. AIDS incidence was lower in children ≥5 years than adults 25 to 34 years when CD4 <100 (eg, at
CD4 50 to 100, 19.6 vs 57.6, respectively), but higher at CD4 350 to 500 (4.4 vs 2.3) and at CD4 >500 (3.5 vs 1.1).
Conclusions: The short-term risk of death in children 5 to 14
years is similar to that of young adults and lower than older adults,
controlling for current CD4 count. The short-term risk of AIDS in children 5 to
14 years is also similar to that of young adults for CD4 200 to 350. These
findings suggest that the same CD4 count criteria for starting ART can be
applied to adults and children ≥5 yrs.
|
