Connick_edit01.qxp 6/8/08 12:02 pm Page 44
HIV and AIDS
Figure 1: Worldwide Distribution of Hormonal Contraceptive Use
1
subsequently adjusted for demographic factors and presence of
syphilis, found no association between OCPs and HIV-1 acquisition.
15
35 To collate the overall strength of the published data, Wang et al.
100
Oral contraceptive
30
performed a meta-analysis of 28 studies and found small but
Depot progesterone
significant associations between OCP use and incident HIV-1 infection
80 25
(OR 1.32, 95% CI 1.12–1.57).
16
However, others have argued that
60
20
such meta-analyses of the effects of OCPs on HIV-1 transmission are
15
inappropriate because of the substantial methodological differences
40
c
eption (in millions)
c
eption (in millions)
among the studies.
17
10
Number using hormonal
c
ontra
20
Number using hormonal
c
ontra
5
Major limitations of these studies, which have been well summarised
0
0
elsewhere,
18
include their observational nature, small size and
World
a
Asia
c
a
c c
a
Afri
Europe
O
c
eania
consequent lack of statistical power, failure to include rigorous
North Ameri
Latin Ameri measures of adherence, variability in duration of hormonal
One limitation of OCPs is that there are a variety of drug interactions contraceptive use and variability in duration of follow-up. Another
that can decrease ethinyl oestradiol levels, potentially leading to limitation of these older studies is the lack of documentation of the
decreased effectiveness. Limited data suggest that the type of OCPs used, which can vary widely in terms of both the dose of
pharmacokinetics of a single dose of OCP may be altered by various ethinyl oestradiol and the type and dose of progestin. Thus, multiple
antiretroviral therapies, including a number of HIV-1 protease factors may account for the inconsistency in results on the risk of HIV-
inhibitors (nelfinavir, ritonavir, lopinavir/ ritonavir, atazanavir, 1 acquisition in OCP users.
amprenavir, indinavir and saquinavir) and non-nucleoside reverse
transcriptase inhibitors (efavirenz, nevirapine, and delavirdine).
9
The
Hormonal contraception plays an
clinical significance of most of these changes is unknown and, notably,
the World Health Organization (WHO) considers the health benefits of
important role in HIV-1 prevention by
initiation of OCPs in the setting of antiretroviral therapy to generally
averting unwanted pregnancies in HIV-1-
outweigh the risks.
9
infected women and, consequently,
Limited data suggest that progestin-only contraceptive levels are not
decreasing vertical transmission of
altered by antiretroviral medications.
10
Historically, IUDs have not been
recommended in HIV-1-infected women due to theoretical concerns
HIV-1 from mothers to children.
over possible increased rates of pelvic inflammatory disease.
5
Thus, at
least until recently, hormonal contraception in combination with Variable results also exist regarding the role of DMPA in HIV-1
condoms has been the preferred method of reversible contraception in transmission. Prospective studies of commercial sex workers in
HIV-1-infected women, based on efficacy and perceived safety.
2,5
Thailand
15
and Kenya
14
suggest that women who use DMPA have a
two- to three-fold increased risk of HIV-1 acquisition compared with
Evidence that Hormonal Contraception Alters the those who do not use it. However, other prospective studies – one in
Susceptibility of Women to HIV-1 Infection Rwanda that recruited women from a lower-risk antenatal clinic,
3
and
Epidemiological studies have yielded variable results regarding the another in Thailand that evaluated commercial sex workers
19
– have
effect of OCPs on HIV-1 transmission. Two prospective studies of not observed an increased risk of HIV-1 acquisition associated with
female partners of HIV-1-seropositive men from multiple sites in Italy
11
DMPA use. Animal studies support an increased risk of retroviral
and Europe
12
showed no increased risk of HIV-1 seroconversion with infection in the context of DMPA use. Both simian immunodeficiency
administration of OCPs. Nevertheless, there were small numbers of virus (SIV) and simian–human immunodeficiency virus (SHIV) are more
women using OCPs and low rates of HIV-1 seroconversion in these readily transmitted to macaques that are treated with supra-
cohorts, and therefore these studies could have detected only large physiological doses of progesterone, which are comparable to serum
differences. In a cohort of 124 commercial sex workers in Mombasa, levels in the setting of DMPA.
20–22
Kenya with extremely high HIV-1 incidence (two-thirds seroconverted,
47/100 person-years), it was observed that women using OCPs had an Interestingly, the results of more recent prospective studies,
4,18,23–25
increased risk of HIV-1 acquisition compared with non-OCP users (odds which were much larger and specifically designed to evaluate the risk
ratio [OR] 4.5, 95% confidence interval [CI] 1.4–13.8) after adjustment factors associated with HIV-1 transmission, remain mixed concerning
for genital ulcer disease, Chlamydia infection and condom use.
13
the impact of hormonal contraception on HIV-1 transmission. In rural
Rakai, Uganda, 5,117 women were followed prospectively from 1994.
Another study in Mombasa, Kenya prospectively enrolled 779 female No increased risk of HIV-1 transmission was demonstrated in women
sex workers from 1993 and 1997, and found a non-statistically using OCPs (adjusted incidence rate ratio [IRR] 1.12, 95% CI
significant association between high-dose OCPs (50µg ethinyl 0.48–2.56) or protestin-based contraception (adjusted IRR 0.84, 95%
oestradiol and either 250µg levonorgestrel or 500µg norgestrel) and CI 0.41–1.72) compared with women not using hormonal
increased HIV-1 seroconversion (hazard ratio [HR] 2.6, 95% CI contraception after adjusting for age and sexual behaviour. However,
0.8–8.5).
14
However, a study of commercial sex workers in Thailand, in overall HIV-1 incidence in this population was low – 1.5/100 person-
which 6% of women seroconverted (9.2/100 person years), years – thereby limiting the statistical power of the study.
24
A cohort
44 EUROPEAN INFECTIOUS DISEASE
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