Frequent testing for HIV is associated with improved
outcomes after diagnosis, Dutch investigators report in the online edition of AIDS. People who tested regularly for HIV but subsequently contracted the infection had half the risk of death when compared to people diagnosed at their first HIV test, the researchers found.
Patients who tested for HIV at least annually had higher CD4
cell counts at the time HIV therapy was started and lower mortality rates compared
to individuals who tested for HIV less frequently. The worst outcomes were seen
in patients who were diagnosed at their first HIV test, and a high
proportion of these individuals already had a CD4 cell count below 200 cells/mm3
at the time of diagnosis.
“Patients repeatedly tested for HIV antibodies…had higher
CD4 cell counts at cART [combination antiretroviral therapy] initiation and a
lower rate compared to those initially tested positive,” comment the authors.
Thanks to antiretroviral therapy, many HIV-positive
individuals can look forward to a long and healthy life.
However, even with HIV therapy mortality rates are still
higher among HIV-positive individuals than the general population, and this is largely
because many people have their HIV diagnosed late.
Guidelines in the Netherlands and many other countries
recommend that individuals at high risk of HIV, such as gay men, should test
for HIV at least annually.
“Although seemingly obvious, it has never before been
demonstrated that patients who were repeatedly tested for HIV before testing
positive have a better clinical prognosis than patients who initially tested
positive,” write the investigators.
They therefore designed a study involving 5494 patients who
were newly diagnosed with HIV in the Netherlands between 2004 and 2008.
On the basis of their HIV testing history prior to
diagnosis, these patients were divided into three groups:
Never previously tested – HIV-positive at first
Infrequently tested – last negative test between
twelve and 24 months before positive result.
Frequently tested – tested HIV-negative less
than a year before repeat tests and positive diagnosis.
The investigators then conducted analyses to see if
frequency of testing was associated with two outcomes:
The vast majority of patients were diagnosed with HIV at their
first HIV test (4067 individuals vs 561 infrequent testers vs 866 frequent
There were important demographic differences between these
three groups, most notably, 23% of individuals diagnosed at their first test
were sub-Saharan Africans, but just 4% of those diagnosed with HIV after
frequent screening came from this group.
The median CD4 cell count at the time of diagnosis was
associated with testing history, and was lowest for those whose HIV was
diagnosed at a first test (350 cells/mm3 vs 470 cells/mm3
for infrequent testers, and 550 cells/mm3 for patients who tested
Frequency of testing was also associated with the presence
of an AIDS diagnosis at the time of diagnosis (16% first test vs 2% infrequent
testing vs 3% frequent testing).
Overall, 186 patients died. The mortality rate was highest
for patients diagnosed at a first HIV test (1.33 per 100 person years), and
was significantly lower for individuals who had tested previously (infrequent
test = 0.58 per 100 person years, p = 0.02; frequent testing = 0.54 per 100 person
years, p = 0.003).
After taking into consideration differences in baseline
characteristics, the investigators calculated that individuals with a history
of HIV testing had a 50% reduction in their risk of death compared to patients
whose HIV was detected the first time they had an HIV test.
Median CD4 cell count at the time HIV therapy was started
was 190 cells/mm3 among patients diagnosed the first time they had an HIV test, compared
to 250 cells/mm3 (difference, p < 0.0007) for patients with a
history of infrequent testing, and 260 cells/mm3 (difference, p <
0.0007) for patients who tested for HIV at least once a year.
Patients diagnosed the first time they had an HIV test were also the group
most likely to have an AIDS diagnosis and CD4 cell count below 200 cells/mm3
at the time antiretroviral therapy was initiated.
“Our findings illustrate the benefit of repeated testing for
HIV,” write the investigators, “it shortens the time between infection and
diagnosis and improves the likelihood of timely treatment, with the prevention
of clinical progression to AIDS and death.”
The researchers also believe that “increasing testing to
annually may greatly impact on transmission rates at a population level.” They
quote a modelling study that suggested that transmission rates in the
Netherlands could be reduced by 40% over a decade “if the average time between
infection and diagnosis was reduced to 1 year.”