Lipid and Lipoprotein Profile in HIV-Infected Patients Treated with Lopinavir/Ritonavir as a Component of the First Combination Antiretroviral Therapy

Abstract

We characterized lipid and lipoprotein changes associated with a lopinavir/ritonavir-containing regimen. We enrolled previously antiretroviral-naive patients participating in the Swiss HIV Cohort Study. Fasting blood samples (baseline) were retrieved retrospectively from stored frozen plasma and posttreatment (follow-up) samples were collected prospectively at two separate visits. Lipids and lipoproteins were analyzed at a single reference laboratory. Sixty-five patients had two posttreatment lipid profile measurements and nine had only one. Most of the measured lipids and lipoprotein plasma concentrations increased on lopinavir/ritonavir-based treatment. The percentage of patients with hypertriglyceridemia (TG >150 mg/dl) increased from 28/74 (38%) at baseline to 37/65 (57%) at the second follow-up. We did not find any correlation between lopinavir plasma levels and the concentration of triglycerides. There was weak evidence of an increase in small dense LDL-apoB during the first year of treatment but not beyond 1 year (odds ratio 4.5, 90% CI 0.7 to 29 and 0.9, 90% CI 0.5 to 1.5, respectively). However, 69% of our patients still had undetectable small dense LDL-apoB levels while on treatment. LDL-cholesterol increased by a mean of 17 mg/dl (90% CI −3 to 37) during the first year of treatment, but mean values remained below the cut-off for therapeutic intervention. Despite an increase in the majority of measured lipids and lipoproteins particularly in the first year after initiation, we could not detect an obvious increase of cardiovascular risk resulting from the observed lipid changes.

Introduction

L opinavir/ritonavir (LPV/r) is a boosted protease inhibitor (PI) widely used at each stage of HIV disease due to its antiviral activity, very low selection rate of resistant mutants, and good tolerance.¹ However, several studies have shown a significant increase in triglycerides (TG) and total cholesterol (TC) on LPV/r-based therapy.^2

–5 In general, combination antiretroviral treatments (cART), in particular PI-containing regimens, are thought to be involved in the genesis of lipid abnormalities, especially hypertriglyceridemia.^6
–8 Yet it is not clear whether changes in lipids and lipoproteins are a direct effect of cART or the result of a more complex scenario also involving genetic, virologic, immunologic, and inflammatory factors.^9
–11 Independent from their origin, lipid changes have led to concern about increased cardiovascular risk in HIV-infected patients.^12
–14 In addition to well-established coronary heart disease (CHD) lipid risk factors, such as increased low-density lipoprotein (LDL) and reduced high-density lipoprotein (HDL), the U.S. National Cholesterol Education Program (NCEP) states that certain hypertriglyceridemic lipid disorders are strong risk factors for CHD. In particular, slightly triglyceride-enriched very-low-density lipoprotein (VLDL) and small dense LDL-apolipoprotein B-100 (sdLDL-apoB) are regarded as emerging CHD lipid risk factors associated with hypertriglyceridemia.¹⁵

Most previous studies of lipid abnormalities in patients treated with a LPV/r-based cART have some limitations: either cART-experienced patients were also recruited,^{4,16

–21} measurements were made irrespective of fasting status,² or not all relevant lipid and lipoproteins were measured.^3,22
–24

The aim of our study was a detailed assessment of lipids and lipoproteins in fasting cART-naive patients before and twice during an LPV/r-based therapy. In particular, we investigated risk factors associated with development of hypertriglyceridemia and the possible association between TG and slightly triglyceride-enriched VLDL, sdLDL, and LPV plasma levels.

Materials and Methods

Study design and population

The Swiss HIV Cohort Study (SHCS) is a prospective multicentric cohort study that enrolled more than 15,600 HIV-infected persons aged 16 years or older at seven outpatient clinics or specialized private practices (http://www.shcs.ch). Each SHCS patient undergoes a clinical visit every 6 months with collection of clinical data and storage of plasma and cells. In our study we included all the white SHCS patients, previously antiretroviral naive, who started an LPV/r-based cART between March 2001 and January 2006. Only patients in a fasting state (defined as ≥8 h without caloric intake) were included in the study. Patients were taking LPV/r at the standard daily dose (800/200 mg) together with two or three nucleoside reverse transcriptase inhibitors (NRTIs) for more than 3 months. The exclusion criteria were previous antiretroviral therapy, use of lipid-lowering drugs, TG >500 mg/dl, and no familial combined hyperlipidemia. To characterize the lipid and lipoprotein profile of patients we collected blood samples before initiation of treatment (baseline) and twice during an LPV/r-based therapy (follow-up 1 and 2). The baseline lipid profile was assessed retrospectively using retrieved frozen plasma samples from the SHCS collection, whereas follow-up samples were prospectively collected at two consecutive SHCS visits.

Laboratory parameters

Citrate plasma was obtained by centrifugation of blood for 20 min at 1500 × g and deep-frozen at −80°C until analysis. VLDL were separated by ultracentrifugation (Airfuge, Beckman Coulter, Krefeld, Germany) at a density of 1.006 g/ml (4 h, 20°C, 95,000 rpm) using an A-95 rotor with 8 × 20-mm Ultra-Clear tubes. LDL-cholesterol (LDL-C) was determined after removal of VLDL in the resulting infranatant by subtracting HDL-cholesterol (HDL-C) from TC concentration. TC, HDL-C, and TG in plasma and lipoprotein fractions were determined with commercially available enzymatic assays (Synchron CX5, Beckman Coulter, Krefeld, Germany), apolipoprotein B (apoB) and lipoprotein (a) [Lp(a)] by turbimetry using the same equipment. The antibody against Lp(a) used for the assay was purchased from Technoclone, Vienna, Austria, and antibodies against apoB from Beckman Coulter, Krefeld, Germany. sdLDL-apoB was determined after ultracentrifugation at a density >1.044 g/ml in the resulting infranatant. All procedures and methods were checked for their compatibility with citrate plasma. The obtained values were corrected according to the dilution of blood with sodium citrate. All determinations were performed in a central laboratory. The presence of slightly triglyceride-enriched VLDL was detected by a VLDL-triglyceride/VLDL-apoB ratio between 6 and 8. A ratio below 6 defined normally composed VLDL, while a ratio >8.0 defined triglyceride-rich VLDL. A concentration >13.5 mg/dl of sdLDL-apoB was regarded as abnormally high, while the detection limit was 5.3 mg/dl. Lipid and lipoprotein values were defined according to the thresholds established by the U.S. NCEP. CD4 T lymphocytes were quantified by flow cytometry. The plasma HIV-1 RNA level was measured by a PCR assay (Amplicor HIV monitor; Roche Diagnostic System; limit of detection <50 copies/ml). LPV concentrations were measured in plasma extracted before the morning dose (C through), using a validated high-performance liquid chromatography (HPLC) method.

Statistical analysis

A paired t-test is appropriate if there is a constant difference between baseline and follow-up measurements on the same patient. We fit models that assume that this difference (between baseline and follow-up) was not constant but varied with time on LPV/r. In our models, time on LPV/r was represented by a linear spline²⁵ and this allows us to estimate the rate of change (per year) during the first year after starting and beyond 1 year. We give 90% confidence intervals for these estimates in order to focus on the clinical implications of the range of values in the interval.²⁶ Because most patients contributed two sets of data to each model (most have two follow-up measurements), we estimated intervals using robust standard errors calculated using generalized estimating equations (and assuming an independent working correlation²⁷). We also adjusted estimates for a set of prespecified covariates (gender, smoking status, and baseline age, BMI, CD4 counts per 100, and log₁₀ viral RNA) in order to estimate the rate of change for a “reference patient”—a male smoker with other covariates set at typical values (40 years, 25 kg/m², 200 cells/μl, 5 log₁₀ copies/ml; see Table 1).

Table 1.

Baseline Characteristics of 74 Antiretroviral-Naive Patients Initiating an LPV/r-Based cART

Characteristic	n (%)
Age [mean (SD)]	40 (10)
Male gender	65 (88%)
Route of HIV transmission
Intravenous drug user	11 (15%)
Homosexual	31 (42%)
Heterosexual	29 (39%)
Other	3 (4%)
Baseline BMI (kg/m²) [mean (SD)]	23 (4)
Current or ex-smokers	48 (65%)
HCV coinfected	11 (15%)
Concurrent NRTI backbone
ABC/3TC	3 (4%)
AZT/3TC	60 (81%)
AZT/ABC/3TC	1 (1%)
DDI/D4T	1 (1%)
TNV/3TC	4 (5%)
TNV/AZT/3TC	1 (1%)
TNV/DDI	2 (3%)
TNV/ETC	2 (3%)
Nadir CD4⁺; <200 cells/μl	50 (68%)
HIV-1 RNA (log₁₀ copies/ml) [mean (SD)]	5.2 (0.82)
CD4⁺ (cells/μl) [median (range)]	179 (2–675)

For most lipid parameters, the outcome was the difference between baseline and follow-up measurements with models fit by linear regression. However, for two parameters, models were fit using logistic regression. For sdLDL-apoB, more than half of the values were below the limit of detection; therefore the response for this parameter was whether the follow-up measurement was known to be higher than at baseline. For the ratio of VLDL-TG to VLDL-apoB, the response was whether the follow-up measurement was more atherogenic than at baseline, with the absolute difference between the observed ratio and 7.0 used as a measure of atherogenic risk. We also tested a limited number of prespecified hypotheses about associations between increases in TG and changes in other parameters. These were tested by replacing time on LPV/r in our models with the level of another parameter and we illustrate these associations using graphs. We used Intercooled Stata Version 9.2 for analyses and R 2.5.1 for graphics.

Results

Population and treatment outcome

We identified 84 patients initiating an LPV/r-based therapy. Ten of these patients were excluded due to previous use of NRTIs or NNRTIs. Sixty-five (88%) patients had their lipid profiles measured prospectively at two consecutive SHCS visits, while nine (12%) had only one follow-up measurement (due to a change of antiretroviral therapy). The median time between start of LPV/r and the first follow-up was 15 months (range 1–51 months), while the median time between the first and the second follow-up was 6 months (range 1–13 months), resulting in a median time between start of LPV/r and the second follow-up of 22 months (range 5–58 months). Baseline characteristics of patients are shown in Table 1.

LPV/r-based therapy led to a reduction of median viral load from 5.1 (range 1.7–7.8) to 1.7 (range 1.7–3.3) log₁₀ copies/ml at follow-up 1 and 2. Of note, 66 (89%) patients at follow-up 1 and 62 (95%) at follow-up 2 had an undetectable HIV-1 RNA (<50 copies/ml). Meanwhile, median CD4 cell count increased from 179 (range 2–675) at baseline to 363 (range 51–915) and 411 (range 32–827) at follow-up 1 and 2, respectively (Table 2).

Table 2.

CD4 ⁺ Cell Count, HIV1-RNA, and Body Mass Index at Baseline and After the Initiation of an LPV/r-Based cART ^a

Variable	Baseline (n = 74)	Follow-up 1 (n = 74)	Follow-up 2 (n = 65)
CD4⁺ cells	179 (2–675)	363 (51–915)	411 (32–827)
HIV-1 RNA (log₁₀ copies/ml)	5.1 (1.7–7.8)	1.7 (1.7–3.3)	1.7 (1.7–3.3)
BMI (kg/m²)	22.4 (14.4–37.8)	24.0 (15.7–37.9)	24.2 (15.7–39.4)

All values are given as median and range.

Lipids and lipoproteins

Lipid and lipoprotein values before and changes after the initiation of an LPV/r-based cART are summarized in Table 3.

Table 3.

Mean (SD) Lipid and Lipoprotein Levels at Baseline and Estimated Mean Change Per Year (90% CI) After the Initiation of an LPV/r-Based cART ^a,b

		Mean change per year (90% CI)
Variable	Baseline level mean (SD)	During first year	Beyond first year
HDL-cholesterol	28 (8)	6.7 (0.3, 13)	−0.7 (−2.9, 1.5)
Apolipoprotein A-I	94 (22)	24 (6, 42)	3.9 (−1.2, 8.9)
Apolipoprotein A-II	22 (4)	3.0 (0.1, 5.8)	0.6 (−0.2, 1.4)
Total cholesterol	113 (30)	45 (20, 71)	−3.1 (−10, 4.3)
LDL-cholesterol	61 (21)	17 (−3, 37)	0.3 (−5.1, 5.6)
LDL apolipoprotein B	37 (12)	12 (2, 23)	1.2 (−1.7, 4.2)
Apolipoprotein B	50 (15)	17 (4.7, 29)	0.4 (−3.2, 4.0)
Small dense LDL-apolipoprotein B^c	8/74 (11%)	4.5 (0.7, 29)	0.9 (0.5, 1.5)
Lipoprotein (a)	14 (21)	3.2 (−5.7, 12)	−0.7 (−2.4, 1.0)
Triglycerides	141 (74)	110 (15, 210)	−7 (−42, 28)
VLDL-cholesterol	24 (9)	22 (10, 34)	−2.7 (−7.0, 1.6)
VLDL-triglycerides	75 (50)	110 (21, 190)	0 (−33, 32)
VLDL apolipoprotein B	12 (5)	4.2 (0.7, 7.7)	−1.6 (−2.7, −0.5)
VLDL-triglycerides/VLDL-apoB ratio^d	13/74 (18%)	0.6 (0.2, 2.6)	1.1 (0.7, 1.8)
Apolipoprotein CII	2.7 (0.8)	1.1 (0.1, 2.2)	−0.1 (−0.4, 0.2)
Apolipoprotein CIII	7 (3)	7.5 (4.1, 11)	−0.2 (−1.4, 1.0)
Apolipoprotein CII/CIII ratio	0.5 (0.4)	−0.22 (−0.39, −0.05)	−0.03 (−0.07, 0.01)
Glucose	86 (21)	3.5 (−8.7, 16)	6.1 (−1.1, 13)

Change was modeled as two slopes, during the first year and beyond the first year, and estimates were adjusted for six covariates (gender, smoking status, and baseline age, body mass index (BMI), CD4 counts per 100, and log₁₀ HIV-1 RNA).

All values are mg/dl (except ratios and proportions).

Since most patients were below the detection limit, we report the percentage of patients with a detectable level at baseline and adjusted odds ratio for whether follow-up measurements were known to be higher than at baseline.

Here we report the percentage of patients with an atherogenic VLDL-triglycerides/VLDL-apoB ratio at baseline and estimate the adjusted odds ratio of having a more atherogenic ratio over time on treatment, with the absolute difference between the observed ratio and 7.0 used as a measure of atherogenic risk.

At baseline the mean values of TC, HDL-C, LDL-C, and TG were 113 (SD 30) mg/dl, 28 (SD 8) mg/dl, 61 (SD 21) mg/dl, and 141 (SD 74) mg/dl, respectively. LDL-C ≥130 mg/dl (a threshold regarded as significantly atherogenic according to U.S. NCEP guidelines) was present in 1/74 patients (1%). Low HDL-C levels (<40 mg/dl) were found in 69/74 patients (93%). Moreover, 28/74 patients (38%) had TG >150 mg/dl. Atherogenic slightly triglyceride-enriched VLDLs (defined by a VLDL-TG to VLDL-apoB ratio between 6 and 8) were present in 13/74 patients (18%). sdLDL-apoB values were below the detection limit in 66/74 patients (89%) and 1/74 patients (1%) had elevated concentrations (>13.5 mg/dl). Elevated levels of Lp(a) (>30 mg/dl) were present in 11/74 patients (15%).

After initiation of LPV/r-based cART, TG had a mean increase of 110 mg/dl (90% CI 15–210) during the first year of treatment followed by little change beyond 1 year of treatment (a decrease of 7 mg/dl, 90% CI −42 to 28, Fig. 1A). The percentage of patients with hypertriglyceridemia (TG >150 mg/dl) increased from 28/74 (38%) at baseline to 38/74 (51%) and 37/65 (57%) at follow-up 1 and 2, respectively. We also tested a prespecified hypothesis that hypertriglyceridemia on treatment represents a worsening of a preexisting condition by adding an interaction term to our model between TG at baseline and time on treatment. This interaction term was estimated to be negative implying that higher baseline values of TG show smaller increases over time than lower baseline values of TG (Fig. 1B). Moreover, we found a small decrease in TG for patients with higher HDL-C levels (−5.5 mg/dl in TG, 90% CI −8.8 to −2.1, for each mg/dl increase in HDL-C, see also Fig. 2A). There was no obvious increase in the atherogenicity of the VLDL-TG to VLDL-apoB ratio in either the first or subsequent years (odds ratio 0.6, 90% CI 0.2 to 2.6, and 1.1, 90% CI 0.7 to 1.8, respectively). Consistent with these estimates, the percentage of patients with an atherogenic ratio of VLDL-TG to VLDL-apoB was relatively constant with 13/74 (18%) patients at baseline and 14/74 (19%) and 13/65 (20%) patients at follow-up 1 and 2, respectively. Moreover, we observed a roughly linear relationship between the TG and VLDL-TG/VLDL-apoB ratio (Fig. 2B).

FIG. 1.

Triglyceride levels over time for 74 patients treated with an LPV/r-containing regimen. (A) A nonparametric average response curve (calculated using the default LOESS function in R 2.5.1) and individual response profiles for a random sample of 19 (25%) patients. (B) Nonparametric average response curves for patients with baseline triglycerides ≤150 mg/dl (+, − − −) and for patients with baseline triglycerides >150 mg/dl (o, …).

FIG. 2.

Triglyceride versus other lipid levels for 74 patients on an LPV/r-containing regimen. (A–D) Nonparametric average response curves are shown (calculated using the default LOESS function in R 2.5.1) and the two values per patient are connected for each patient. (B) The atherogenic range of the VLDL triglyceride to VLDL apolipoprotein B ratio is indicated by vertical lines (between 6 and 8).

The apoCII to apoCIII ratio declined by a mean 0.22 (90% CI −0.39 to −0.05) during the first year of treatment and remained stable thereafter. The decline of this ratio was driven by a sizable increase in apoCIII during the first year of treatment (7.5 mg/dl, 90% CI 4.1 to 11). There was weak evidence of a small decrease in TG for patients with higher apoCII to apoCIII ratios (−25 mg/dl, 90% CI −62 to 12 change in TG per unit change in the apoCII to apoCIII ratio; see also Fig. 2C). There was weak evidence of an increase in sdLDL-apoB during the first year of treatment but not beyond 1 year (odds ratios 4.5, 90% CI 0.7 to 29, and 0.9, 90% CI 0.5 to 1.5). Consistent with these estimates, 66/74 patients (89%) had a concentration of sdLDL-apoB below the detection limit at baseline compared with 51/74 (69%) patients and 45/65 (69%) patients at follow-up 1 and 2, respectively. Accordingly, few follow-up measurements (40/139) showed an increase in the level of sdLDL-apoB; most of them (99/139) showed no discernible change or a decrease. However, in patients with detectable sdLDL-apoB at follow-up, we found a higher increase in TG from baseline to follow-up compared to patients with sdLDL-apoB below the detection limit at follow-up (by 144 mg/dl 90% CI 83 to 205, see also Fig. 2D). Highly atherogenic concentrations of sdLDL-apoB (>13.5 mg/dl) were found in 2/74 (3%) and 0/65 patients at follow-up 1 and 2, respectively, compared to 1/74 (1%) at baseline.

TC had a mean increase of 45 mg/dl (90% CI 20 to 71) during the first year of treatment followed by little change beyond 1 year of treatment (a mean decrease of 3.1 mg/dl, 90% CI −10 to 4.3).

LDL-C had a mean increase of 17 mg/dl (90% CI −3 to 37) during the first year of treatment followed by little change beyond 1 year of treatment (a mean increase of 0.3 mg/dl, 90% CI −5.1 to 5.6). LDL-C ≥130 mg/dl was found in 2/74 (3%) and 1/65 patients (2%) at follow-up 1 and 2, respectively, compared with 1/74 (1%) at baseline.

HDL-C had a mean increase of 6.7 mg/dl (90% CI 0.3 to 13) during the first year of treatment followed by little change beyond 1 year of treatment (a mean decrease of 0.7 mg/dl, 95% CI −2.9 to 1.5). The number of patients with HDL-C >40 mg/dl increased from 5/74 (7%) at baseline to 9/74 (12%) and 7/65 (11%) at follow-up 1 and 2, respectively.

Lp(a) had a mean increase of 3.2 mg/dl (95% CI −5.7 to 12) during the first year of treatment followed by little change beyond 1 year of treatment (a mean decrease of 0.7 mg/dl, 90% CI −2.4 to 1.0). Elevated plasma levels of Lp(a) (>30 mg/dl) were found in 13/74 (18%) and 11/65 patients (17%) at follow-up 1 and 2, respectively, compared to 11/74 patients (15%) at baseline.

Lopinavir plasma level and triglycerides

During the study period nine patients had only one measurement of LPV through plasma concentration, while 65 had two. The mean through plasma concentrations of LPV were 5.9 (SD 3) μg/ml and 6.2 (SD 4) μg/ml at the first and the second follow-up, respectively. We did not observe any obvious increase in TG with increasing plasma levels of LPV (0.1 mg/dl increase in TG, 90% CI −7.7 to 7.9, Fig. 3).

FIG. 3.

Lopinavir plasma levels and triglyceride for 74 patients treated with an LPV/r-containing regimen. A nonparametric average response curve is shown (calculated using the default LOESS function in R 2.5.1) and the two values per patient are connected for each patient.

Discussion

HIV infection has itself a profound impact on lipid and lipoprotein metabolism that is further influenced by antiretroviral drugs. In a population of 74 previously treatment-naive HIV-infected patients we found that most of the lipid and lipoprotein plasma levels increased after initiation of an LPV/r-based cART. When time on treatment was considered most of these increases tended to occur during the first year of cART and reached a plateau in the following years, as in previous reports.^3,5,19

As expected in a fairly advanced and untreated HIV population,^10,28 TGs were already elevated at baseline in more than one-third of our patients, with a further increase of the percentage of patients with hypertriglyceridemia (TG >150 mg/dl) at follow-up. Triglycerides markedly increased only during the first year of an LPV/r-based cART. However, higher baseline values of TG were followed by a lower increase over time. In other words the odds of having elevated triglycerides on LPV/r therapy was lower in those patients who already had elevated triglycerides at baseline. This result is in contrast with data from other publications,^3
–5,19 but is consistent with the results of a previous SHCS study involving patients on a PI other than LPV/r.⁷

We could not confirm a correlation between increase in TG and higher LPV plasma concentration as reported in some,^18,24,29 but not all studies.^21,30

Hypertriglyceridemia is characterized either by a normal number of large, triglyceride-rich VLDLs or an increased number of small VLDLs that are relatively poor in TG and rich in cholesterol (slightly triglyceride-enriched VLDL). The latter particles carry a strongly increased risk of coronary heart disease as shown in patients with familial combined hyperlipidemia. As one VLDL contains one molecule of apoB, the ratio of VLDL-TG to VLDL-apoB can be used to determine VLDL composition^31
–33 and to better estimate atherogenicity in patients with hypertriglyceridemia. In this study, there was no obvious increase in the atherogenicity of the VLDL-TG to VLDL-apoB ratio in either the first or subsequent years of treatment. The percentage of patients with atherogenic slightly triglyceride-enriched VLDL did not change appreciably after initiation of LPV/r-based cART. Moreover, we found a positive correlation between the increase in TG and a higher VLDL-TG to VLDL-apoB ratio. This suggests that in HIV-positive patients treated with antiretroviral therapy there is a predominance of large, triglyceride-rich VLDL, similarly to the VLDL pattern seen in familial hypertriglyceridemia associated with a low cardiovascular risk.³¹

We observed an important increase in apoC3 concentration and a concomitant decrease of the apoC2 to apoC3 ratio after the initiation of a LPV/r-based cART, in agreement with previous studies.^16,17,34 Since apoC2 stimulates the catabolism of VLDL via lipoprotein lipase, while apoC3 inhibits this pathway, our data support the hypothesis of a decreased activation of lipoprotein lipase as a key factor in the observed increase of TG.^16,17,35 Moreover, genetic variants of apoC3 have been found to be associated with extreme hypertriglyceridemia in patients treated with ritonavir-boosted PIs, introducing genetic variability as an additional factor in the pathogenesis of cART-associated hypertriglyceridemia.¹¹

sdLDL-apoB, an emerging atherogenetic risk factor,¹⁵ is thought to mediate the cardiovascular risk of certain hypertriglyceridemias.^36,37 Atherogenicity of sdLDL-apoB is due to a great capacity to infiltrate the arterial wall, a reduced affinity for the LDL receptors, and an increased susceptibility to ex vivo oxidation.³⁸ Although most of our population had undetectable values of sdLDL-apoB (below 5.3 mg/dl) before and after initiation of an LPV/r-based cART, patients with detectable sdLDL-apoB had, on average, a higher increase in TG from baseline to follow-up. Yet highly atherogenic concentrations of sdLDL-apoB were found only in a small proportion of subjects before and after an LPV/r-based cART.^39,40 Other studies reporting on elevated sdLDL-apoB before and after starting a cART with LPV/r may be influenced by a previous treatment, since they were conducted on patients who switched to a new regimen because of virologic failure or drug intolerance.^16,17

The majority of our study population had low TC and LDL-C mean values before starting antiretroviral treatment. Although both TC and LDL-C increased in the first year after the initiation of LPV/r, the mean follow-up values remained far below the recommended therapeutic goal for LDL-C according to the U.S. NCEP guidelines. Moreover, after the initiation of an LPV/r-based cART only <3% of our population had LDL-C values regarded as significantly atherogenic (≥130 mg/dl).

We found a minimal increase of HDL-C in the first year after initiation of an LPV/r-based cART. Nevertheless, the percentage of patients with protective HDL-C values (>40 mg/dl) increased from 7% at baseline to 12% on cART.

Lp(a), another emerging atherogenetic risk factor,¹⁵ tended to increase in the first year after the initiation of LPV/r. However, the percentage of patients with elevated values associated with premature development of atherosclerosis (>30 mg/dl) did not increase on LPV/r-based cART.

The well-characterized population of cART-naive HIV-infected patients enabled us to obtain an extensive assessment of lipids and lipoproteins before and after the initiation of an LPV/r-based cART. Laboratory samples were collected in a fasting status and analyzed in a single reference laboratory. However, the size of our population was relatively small, although larger than the majority of previous studies that have reported on this topic. The different NRTIs used in combination with LPV/r could have influenced the lipid profile, as it has been shown for zidovudine and stavudine.⁴¹ Finally, the use of frozen plasma samples prevented standardization of the intervals between baseline and follow-up assessment of lipid and lipoproteins. However, our models allowed for variation in the timing of assessments. Similarly, we were not able to measure additional laboratory parameters, i.e., lipoprotein lipase and hepatic lipase, that could have been valuable to clarify some of the pathogenic pathways.

In conclusion, the majority of the measured lipids and lipoproteins were shown to increase on an LPV/r-based cART. We could not demonstrate a significant change in the percentage of patients with atherogenic plasma levels of lipoproteins commonly associated with hypertriglyceridemia, such as slightly triglyceride-enriched VLDL and sdLDL-apoB. However, the risk of cardiovascular events in our population remains a concern mainly due to the high percentage of patients with low HDL,⁴² frequent smoking,⁴³ and inflammatory factors associated with HIV infection.⁴⁴

Footnotes

Acknowledgments

We thank all involved physicians, study nurses, and most importantly participants of the SHCS. This study has been financed in the framework of the Swiss HIV Cohort Study, supported by the Swiss National Science Foundation, and by an unrestricted grant from Abbott Laboratories.

The members of the Swiss HIV Cohort Study are Barth J, Battegay M, Bernasconi E, Böni J, Bucher HC, Bürgisser P, Burton- Jeangros C, CalmyA, Cavassini M, Dubs R, Egger M, Elzi L, Fehr J, Fischer M, Flepp M, Francioli P (President of the SHCS), Furrer H (Chairman of the Clinical and Laboratory Committee), Fux CA, Gorgievski M, Günthard H (Chairman of the Scientific Board), Hasse B, Hirsch HH, Hirschel B, Hösli I, Kahlert C, Kaiser L, Keiser O, Kind C, Klimkait T, Kovari H, Ledergerger B, Marinetti G, Martinez de Tejada B, Müller N, Nadal D, Pantalco G, Rauch A, Regenass S, Richenbach M (Head of Data Center), Rudin C (Chairman of the Mother & Child Substudy), Schmid P, Schultze D, Schöni-Affolter F, Schüpbach J, Speck R, Taffé P, Tolenti A, Trkola A, Vernazza P, von Wyl V, Weber R, Yerly S.

Author Disclosure Statement

No competing financial interests exist.

References

Panel on Antiretroviral Guidelines for Adult and Adolescents: Guidelines for the use of antiretroviral agents in HIV-infected adults and adolescents. Department of Health and Human Services(Updated 3 November 2008.)http//www.aidsinfo.nih.gov/ContentFiles/AdultandAdolescentGL.pdf.

Walmsley

, Bernstein

, King

et al. Lopinavir-ritonavir versus nelfinavir for the initial treatment of HIV infection. N Engl J Med, 2002; 346:2039–2046.

Montes

, Pulido

, Barros

et al. Lipid disorders in antiretroviral-naive patients treated with lopinavir/ritonavir-based HAART: Frequency, characterization and risk factors. J Antimicrob Chemother, 2005; 55:800–804.

Martinez

, Domingo

, Galindo

et al. Risk of metabolic abnormalities in patients infected with HIV receiving antiretroviral therapy that contains lopinavir-ritonavir. Clin Infect Dis, 2004; 38:1017–1023.

Kaplan

, Hicks

. Safety and antiviral activity of lopinavir/ritonavir-based therapy in human immunodeficiency virus type 1 (HIV-1) infection. J Antimicrob Chemother, 2005; 56:273–6.

Fontas

, van Leth

, Sabin

et al.

Lipid profiles in HIV-infected patients receiving combination antiretroviral therapy: Are different antiretroviral drugs associated with different lipid profiles?

J Infect Dis, 2004; 189:1056–1074.

Periard

, Telenti

, Sudre

et al. Atherogenic dyslipidemia in HIV-infected individuals treated with protease inhibitors. The Swiss HIV Cohort Study. Circulation, 1999; 100:700–705.

Young

, Weber

, Rickenbach

et al. Lipid profiles for antiretroviral-naive patients starting PI- and NNRTI-based therapy in the Swiss HIV cohort study. Antivir Ther, 2005; 10:585–591.

Feingold

, Krauss

, Pang

, Doerrler

, Jensen

, Grunfeld

. The hypertriglyceridemia of acquired immunodeficiency syndrome is associated with an increased prevalence of low density lipoprotein subclass pattern B. J Clin Endocrinol Metab, 1993; 76:1423–1427.

10.

Grunfeld

, Pang

, Doerrler

, Shigenaga

, Jensen

, Feingold

. Lipids, lipoproteins, triglyceride clearance, and cytokines in human immunodeficiency virus infection and the acquired immunodeficiency syndrome. J Clin Endocrinol Metab, 1992; 74:1045–1052.

11.

Tarr

, Taffe

, Bleiber

et al. Modeling the influence of APOC3, APOE, and TNF polymorphisms on the risk of antiretroviral therapy-associated lipid disorders. J Infect Dis, 2005; 191:1419–1426.

12.

Currier

, Lundgren

, Carr

et al. Epidemiological evidence for cardiovascular disease in HIV-infected patients and relationship to highly active antiretroviral therapy. Circulation, 2008; 118:e29–e35.

13.

Friis-Moller

, Reiss

, Sabin

et al. Class of antiretroviral drugs and the risk of myocardial infarction. N Engl J Med, 2007; 356:1723–1735.

14.

Mary-Krause

, Cotte

, Simon

, Partisani

, Costagliola

. Increased risk of myocardial infarction with duration of protease inhibitor therapy in HIV-infected men. AIDS, 2003; 17:2479–2486.

15.

Executive Summary of The Third Report of The National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III)

JAMA, 2001; 285:2486–2497.

16.

Badiou

, Merle De

, Dupuy

, Baillat

, Cristol

, Reynes

. Decrease in LDL size in HIV-positive adults before and after lopinavir/ritonavir-containing regimen: An index of atherogenicity? Atherosclerosis, 2003; 168:107–113.

17.

Badiou

, De Boever

, Dupuy

, Baillat

, Cristol

, Reynes

. Small dense LDL and atherogenic lipid profile in HIV-positive adults: Influence of lopinavir/ritonavir-containing regimen. AIDS, 2003; 17:772–774.

18.

Gutierrez

, Padilla

, Navarro

et al. Lopinavir plasma concentrations and changes in lipid levels during salvage therapy with lopinavir/ritonavir-containing regimens. J Acquir Immune Defic Syndr, 2003; 33:594–600.

19.

Lafeuillade

, Hittinger

, Philip

, Lambry

, Jolly

, Poggi

. Metabolic evaluation of HIV-infected patients receiving a regimen containing lopinavir/ritonavir (Kaletra) HIV Clin Trials, 2004; 5:392–398.

20.

Meynard

, Lacombe

, Poirier

et al. Sustained increase of HDL cholesterol over a 72-week period in HIV-infected patients exposed to an antiretroviral regimen including lopinavir/ritonavir. J Int Assoc Physicians AIDS Care, 2008; 7:311–316.

21.

Torti

, Quiros-Roldan

, Regazzi-Bonora

et al. Lipid abnormalities in HIV-infected patients are not correlated with lopinavir plasma concentrations. J Acquir Immune Defic Syndr, 2004; 35:324–326.

22.

Antoniou

, Park-Wyllie

, Boyle

. A comparison of dyslipidemias associated with either lopinavir/ritonavir- or indinavir/ritonavir-based antiretroviral therapy. J Acquir Immune Defic Syndr, 2004; 37:1666–1667.

23.

Galindo

, Verdejo

, Gonzalez-Munoz

, Ferrer

, Polo

. Metabolic changes in protease inhibitor-naive patients treated for 1 year with lopinavir/ritonavir. J Acquir Immune Defic Syndr, 2008; 48:628–629.

24.

Valerio

, Fontas

, Pradier

et al. Lopinavir/ritonavir combination and total/HDL cholesterol ratio. J Infect, 2005; 50:229–235.

25.

Greenland

. Dose-response and trend analysis in epidemiology: Alternatives to categorical analysis. Epidemiology, 1995; 6:356–365.

26.

Sterne

, Davey

. Sifting the evidence-what's wrong with significance tests? BMJ, 2001; 322:226–231.

27.

Pan

, Louis

, Connett

. A note on marginal linear regression with correlated response data. Am Stat, 2000; 54:191–195.

28.

Grunfeld

, Kotler

, Hamadeh

, Tierney

, Wang

, Pierson

. Hypertriglyceridemia in the acquired immunodeficiency syndrome. Am J Med, 1989; 86:27–31.

29.

Gonzalez de

, Blanco

, Garcia-Benayas

, Jimenez-Nacher

, Gonzalez-Lahoz

, Soriano

. Correlation between lopinavir plasma levels and lipid abnormalities in patients taking lopinavir/ritonavir. AIDS Patient Care STDS, 2003; 17:443–445.

30.

Leon

, Martinez

, Sarasa

et al. Impact of steady-state lopinavir plasma levels on plasma lipids and body composition after 24 weeks of lopinavir/ritonavir-containing therapy free of thymidine analogues. J Antimicrob Chemother, 2007; 60:824–830.

31.

Mauss

, Stechel

, Willers

, Schmutz

, Berger

, Richter

. Differentiating hyperlipidaemia associated with antiretroviral therapy. AIDS, 2003; 17:189–194.

32.

Brunzell

, Albers

, Chait

, Grundy

, Groszek

, McDonald

. Plasma lipoproteins in familial combined hyperlipidemia and monogenic familial hypertriglyceridemia. J Lipid Res, 1983; 24:147–155.

33.

van Barlingen

, Kock

, de Man

, Erkelens

, De Bruin

. In vitro lipolysis of human VLDL: Effect of different VLDL compositions in normolipidemia, familial combined hyperlipidemia and familial hypertriglyceridemia. Atherosclerosis, 1996; 121:75–84.

34.

Bonnet

, Ruidavets

, Tuech

et al. Apoprotein c-III and E-containing lipoparticles are markedly increased in HIV-infected patients treated with protease inhibitors: Association with the development of lipodystrophy. J Clin Endocrinol Metab, 2001; 86:296–302.

35.

Baril

, Beucler

, Valantin

et al. Low lipolytic enzyme activity in patients with severe hypertriglyceridemia on highly active antiretroviral therapy. AIDS, 2001; 15:415–47.

36.

Ayyobi

, McGladdery

, McNeely

, Austin

, Motulsky

, Brunzell

. Small, dense LDL and elevated apolipoprotein B are the common characteristics for the three major lipid phenotypes of familial combined hyperlipidemia. Arterioscler Thromb Vasc Biol, 2003; 23:1289–1294.

37.

Georgieva

, Van Greevenbroek

, Krauss

et al. Subclasses of low-density lipoprotein and very low-density lipoprotein in familial combined hyperlipidemia: Relationship to multiple lipoprotein phenotype. Arterioscler Thromb Vasc Biol, 2004; 24:744–749.

38.

Chapman

, Guerin

, Bruckert

. Atherogenic, dense low-density lipoproteins. Pathophysiology and new therapeutic approaches. Eur Heart J, 1998; 19:A24–A30.

39.

Riddler

, Li

, Otvos

et al. Antiretroviral therapy is associated with an atherogenic lipoprotein phenotype among HIV-1-infected men in the Multicenter AIDS Cohort Study. J Acquir Immune Defic Syndr, 2008; 48:281–288.

40.

Trein

, Schnaitmann

, Richter

. Lower prevalence of small, dense low-density lipoprotein (sd-LDL) in hyper triglyceridemic HIV-infected patients than in non-HIV-infected subjects. 4th IAS Conference on HIV Pathogenesis, Treatment and Prevention, July 22–25, 2007, Sydney, AustraliaAbstract TUPEB074.

41.

Madruga

, Cassetti

, Suleiman

et al. The safety and efficacy of switching stavudine to tenofovir df in combination with lamivudine and efavirenz in HIV-1-infected patients: Three-year follow-up after switching therapy. HIV Clin Trials, 2007; 8:381–390.

42.

Duprez

, Kuller

, Tracy

et al. Lipoprotein particle subclasses, cardiovascular disease and HIV infection. Atherosclerosis, 2009; 207:524–529.

43.

Glass

, Ungsedhapand

, Wolbers

et al. Prevalence of risk factors for cardiovascular disease in HIV-infected patients over time: The Swiss HIV Cohort Study. HIV Med, 2006; 7:404–410.

44.

El-Sadr

, Lundgren

, Neaton

et al. CD4+ count-guided interruption of antiretroviral treatment. N Engl J Med, 2006; 355:2283–2296.