Mortality rates in certain groups of HIV positive people on
treatment are similar to those in the general population
A study by COHERE in EuroCoord has shown that mortality
patterns in treated HIV positive people with a high CD4 count who
are not injecting drug users are similar to those in the general
population.
Since the introduction of effective treatment
in the late 1990s, HIV positive people have benefitted from a
dramatic improvement in survival. This has encouraged researchers
to investigate whether mortality rates have reached levels that are
comparable to those in the general population.
This study by Lewden et al, analysed data from
over 80,000 HIV positive people from 31 different European
countries to identify the circumstances in which those on treatment
will experience similar mortality rates to the general
population.
In particular, the authors wished to explore
the impact on the mortality rate of attaining and maintaining over
a long period, a CD4 count (measure of how healthy the immune
system is) of 500/mm3 or more in different
subgroups.
Standardised mortality ratios (SMR) were used
to compare mortality between treated HIV positive people and the
general population. The SMR is the ratio of the number of observed
deaths to the number of expected deaths. Expected deaths were
obtained by applying country-, calendar year-, gender- and
age-specific mortality rates for the general population to the
number of years of follow-up in the HIV cohort.
The authors found that among the subgroup of
non-injecting drug users (non-IDUs) with a CD4 count of
500/mm3 or more, males immediately on achieving this CD4
threshold, and females after 3 years, had similar mortality rates
to those in the general population.
In contrast, for male and female IDUs,
mortality remained high even after five consecutive years of
maintaining a CD4 count of 500/mm3 or more. This finding
supports observations from other studies that IDUs have a poor
prognosis due to factors such as higher incidence of hepatitis C
coinfection, poorer adherence to treatment, and more risk
behaviours.
An AIDS diagnosis at treatment initiation was
associated with higher mortality in all groups even when the
current CD4 count was 500/mm3 or more. This finding
highlights the importance of earlier diagnosis and entry into
care.
The strength of this study lies in the large
amount of data that was analysed, a particular advantage of
EuroCoord, which has the biggest dataset of HIV positive people in
the World, as the author emphasises:
“Given this large number of patients, as well
as the inclusion of patients from 31 different European countries,
and the fact that many of the participating cohorts are based
within health-care delivery systems in these countries, the results
presented may be considered to provide a fair representation of the
wider situation of HIV-infected individuals in Europe over the
first 10 years of widespread cART [combination antiretroviral]
use.”
The authors conclude that further studies are
needed to confirm this trend in mortality across several decades of
treatment.
The Collaboration of Observational HIV
Epidemiological Research Europe (COHERE)* in EuroCoord. All-cause
mortality in treated HIV-infected adults with CD4 ≥500 /mm3
compared to the general population: evidence from a large European
observational cohort collaboration. Int. J. Epidemiol. 2012 Avr 41
(2): 433-445.
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