The relationship, in 539 individuals infected with the human
immunodeficiency virus (HIV),
between two prognostic markers, the CD4 count and beta-2-microglobulin
(B2M), and the
development of the acquired immunodeficiency syndrome (AIDS) and death
was investigated.
Cox proportional hazards models were used to determine the risk of AIDS
or death. In a
multivariate model which adjusted for demographic factors and treatment,
the most recent
measurements of B2M (relative hazard (RH) 1·37 per g/l higher)
and CD4 count (RH 2·17 per
log-unit lower) were both significantly associated with the development
of AIDS. Similarly, in
a multivariate model which additionally adjusted for the development of
AIDS as a time
dependant covariate, there was a strong relationship with risk of death
for the most recent
measurements of B2M (RH 1·34 per g/l higher), and CD4
lymphocyte count (RH 1·91 per log-unit lower). A difference in
the level of B2M could be used among patients with similar CD4
counts as an indicator of increased risk of progression to AIDS or death.
Using the most
recent values of these markers provides a better estimate of the risk
of AIDS or death,
compared to the more common method of analysis, where baseline
values of the markers are used.