Thrombofilia, inflammation and markers of cardiovascular disease in HIV-1 infected patients

Mortality of HIV and HIV-related diseases has changed since the introduction of
combined antiretroviral therapy (cART) in 1996. Although AIDS related deaths
and unknown deaths decreased both over time when receiving cART, an increasing
proportion of HIV-infected patients died of non-AIDS deaths [1]. The most
frequently reported causes of death in the cART era are cardiovascular,
pulmonary, hepatic disease and non-AIDS malignancies [1]. Thus, either through
this prolonged survival or by the introduction of antiretroviral therapy, other
underlying diseases or risks for such diseases could become clinically
relevant.
Before highly active antiretroviral therapy was introduced in 1996, a
few reports indicated that HIV-infected patients were at increased risk of
venous and arterial thrombosis [2]. Moreover, patients with AIDS have an almost
30-fold increased risk of venous thrombosis compared to patients without
AIDS-defining illness [3]. In 1992, Bissuel et al [4] found free protein S
levels were significantly lower in patients with full-blown AIDS (37.6% +/-
12.3) than in patients without AIDS (69.8% +/- 19.9, P<0.001). Low plasma free
protein S levels correlated with low CD4+ T-cell counts (P<0.001). Similar
results were found in a study of Stahl et al in 1993 [5]. Feffer et al [6]
showed that protein C levels are also decreased in HIV-infected patients
(n=52), while D-dimer and VWF levels were increased. Moreover, abnormal results
correlated significantly with lower CD4+ cell counts. Recently, 109 consecutive
HIV-infected patients in our university hospital were tested twice for
currently known thrombophilic abnormalities at an interval of at least 3 months
[7]. Repeated measurements established protein C deficiency in 9% of the
patients, increased factor VIII levels in 41%, high fibrinogen levels in 22%,
and free protein S deficiency in 60%. These frequencies are much higher than in
the general population [8]. Median factor VIII levels were higher in patients
with AIDS than in patients with a non-AIDS-defining illness (226% vs. 149%;
P<0.001), whereas median free protein S levels were lower (45% vs. 58%;
P<0.001). Developing AIDS was associated with increasing factor VIII levels and
decreasing free protein S levels. Increasing factor VIII levels were correlated
with increasing fibrinogen levels and decreasing free protein S levels. These
findings all provide further evidence that HIV-infection itself contributes to
the high prevalence of venous and arterial thrombosis in HIV-infected patients.
However, there is little research available focusing on all thrombophilic
markers in patients with HIV-infection but who are not on cART.
After the introduction of cART in the therapeutic regimen for HIV due their
highly significant contribution to HIV suppression and reducing mortality [9],
a new phenomenon was observed in which patients on protease inhibitors
developed a syndrome of peripheral lipodystrophy, hyperlipidemia and insulin
resistance [10]. These findings were confirmed by others [11-13]. Wolf et al
[14] found significantly higher levels of von Willebrand factor (VWF) in
HIV-infected patients before they started with ART compared with healthy
control subjects. After five months of treatment with ART, the levels of these
markers decreased significantly. Also, there are large epidemiological studies
suggesting a relationship between ART and increased risk of arterial and venous
thrombosis [15-19], but not all [20, 21]. However, there are very few studies
reporting on a cause by which this increased risk could be explained. Also, the
effect of cART, especially non-nucleoside reverse transcriptase inhibitors
(nNRTI*s), on the coagulation system has not been investigated systematically.
This problem could be solved with the use of a randomized clinical trial, but
would not be ethical to perform as ART is very effective in reducing mortality
and morbidity in HIV-infected patients [1, 22]. Thus, in this study we want to
determine the effect of starting cART in HIV-infected patients on the
coagulation system, measuring all known thrombophilic factors and
cardiovascular markers as well as inflammatory markers like (hs)C-reactive
protein. This will provide us data about the status of the coagulation system
in HIV-infected patients who are not on cART yet, and about the changes in
those markers after starting cART till one year of treatment.

2.1 Primary Objective
• Evaluation of the levels of thrombophilic factors in the blood of
HIV-infected patients before starting with cART and the changes of these levels
when on cART for the time of one year.

2.2 Secondary Objective
• Evaluation of the levels of hs-CRP in the blood of HIV-infected patients
before starting with cART, and of the changes of these levels when on cART for
one year.
• Evaluation of the levels of total cholesterol, HDL cholesterol, LDL
cholesterol and trigiclerids in the blood of HIV-infected patients before
starting with cART, and of the changes of these levels when on cART for one
year.

Longitudinal, prospective, observational case series.

After giving informed consent, blood samples will be taken from patients when
visiting the hospital for a regular visit including regular blood sampling as
determined by their primary HIV-treatment doctor, for a total of five times.
Also, at start and after one year, a questionnaire will be needed to answer,
taking 10 minutes of time. There are no direct benefits for patients, neither
are there any risks. However, when the investigators detect clinical relevant
findings, the primary doctor (infectiologist) will discuss these with the
patient. Patients are informed about this and have to agree with it. Overall
the burden is low for patients and adverse events are not expected.