Randomized, double-blind comparative trial of subunit and virosomal influenza vaccines for immunocompromised patients

BACKGROUND

To our knowledge, no study to date has compared the effects of a subunit influenza vaccine with those of a virosomal influenza vaccine on immunocompromised patients.

METHODS

A prospective, double-blind, randomized study was conducted to compare the immunogenicity and reactogenicity of subunit and virosomal influenza vaccines for adult patients who had an immunosuppressive disease or who were immunocompromised as a result of treatment.

RESULTS

There were 304 patients enrolled in our study: 131 with human immunodeficiency virus (HIV) infection, 47 with a chronic rheumatologic disease, 74 who underwent a renal transplant, 47 who received long-term hemodialysis, and 5 who had some other nephrologic disease. There were 151 patients who received the subunit vaccine and 153 patients who received the virosomal vaccine. A slightly higher percentage of patients from the subunit vaccine group were protected against all 3 influenza vaccine strains after being vaccinated, compared with patients from the virosomal vaccine group (41% vs. 30% of patients; P = .03). Among HIV-infected patients, the level of HIV RNA, but not the CD4 cell count, was an independent predictor of vaccine response. Among renal transplant patients, treatment with mycophenolate significantly reduced the immune response to vaccination. The 2 vaccines were comparable with regard to the frequency and severity of local and systemic reactions within 7 days after vaccination. Disease-specific scores for the activity of rheumatologic diseases did not indicate flare-ups 4-6 weeks after vaccination.

CONCLUSIONS

For immunosuppressed patients, the subunit vaccine was slightly more immunogenic than the virosomal vaccine. The 2 vaccines were comparable with regard to reactogenicity. Vaccine response decreased with increasing degree of immune suppression. Among HIV-infected patients, the viral load, rather than the CD4 cell count, predicted the protective immune response to the vaccine.

CLINICAL TRIALS REGISTRATION

NCT00783380 .

How reliable is an undetectable viral load?

OBJECTIVES

An article by the Swiss AIDS Commission states that patients with stably suppressed viraemia [i.e. several successive HIV-1 RNA plasma concentrations (viral loads, VL) below the limits of detection during 6 months or more of highly active antiretroviral therapy (HAART)] are unlikely to be infectious. Questions then arise: how reliable is the undetectability of the VL, given the history of measures? What factors determine reliability?

METHODS

We assessed the probability (henceforth termed reliability) that the n+1 VL would exceed 50 or 1000 HIV-1 RNA copies/mL when the nth one had been <50 copies/mL in 6168 patients of the Swiss HIV Cohort Study who were continuing to take HAART between 2003 and 2007. General estimating equations were used to analyse potential factors of reliability.

RESULTS

With a cut-off at 50 copies/mL, reliability was 84.5% (n=1), increasing to 94.5% (n=5). Compliance, the current type of HAART and the first antiretroviral therapy (ART) received (HAART or not) were predictive factors of reliability. With a cut-off at 1000 copies/mL, reliability was 97.5% (n=1), increasing to 99.1% (n=4). Chart review revealed that patients had stopped their treatment, admitted to major problems with compliance or were taking non-HAART ART in 72.2% of these cases. Viral escape caused by resistance was found in 5.6%. No explanation was found in the charts of 22.2% of cases.

CONCLUSIONS

After several successive VLs at <50 copies/mL, reliability reaches approximately 94% with a cut-off of 50 copies/mL and approximately 99% with a cut-off at 1000 copies/mL. Compliance is the most important factor predicting reliability.

Self-reported alcohol consumption and its association with adherence and outcome of antiretroviral therapy in the Swiss HIV Cohort Study

Background

Alcohol consumption leading to morbidity and mortality affects HIV-infected individuals. Here, we aimed to study self-reported alcohol consumption and to determine its association with adherence to antiretroviral therapy (ART) and HIV surrogate markers.

Methods

Cross-sectional data on daily alcohol consumption from August 2005 to August 2007 were analysed and categorized according to the World Health Organization definition (light, moderate or severe health risk). Multivariate logistic regression models and Pearson's χ2 statistics were used to test the influence of alcohol use on endpoints.

Results

Of 6,323 individuals, 52.3% consumed alcohol less than once a week in the past 6 months. Alcohol intake was deemed light in 39.9%, moderate in 5.0% and severe in 2.8%. Higher alcohol consumption was significantly associated with older age, less education, injection drug use, being in a drug maintenance programme, psychiatric treatment, hepatitis C virus coinfection and with a longer time since diagnosis of HIV. Lower alcohol consumption was found in males, non-Caucasians, individuals currently on ART and those with more ART experience. In patients on ART ( n=4,519), missed doses and alcohol consumption were positively correlated ( P<0.001). Severe alcohol consumers, who were pretreated with ART, were more often off treatment despite having CD4+ T-cell count <200 cells/μl; however, severe alcohol consumption per se did not delay starting ART. In treated individuals, alcohol consumption was not associated with worse HIV surrogate markers.

Conclusions

Higher alcohol consumption in HIV-infected individuals was associated with several psychosocial and demographic factors, non-adherence to ART and, in pre-treated individuals, being off treatment despite low CD4+ T-cell counts.

Hepatitis C virus drug resistance and immune-driven adaptations: relevance to new antiviral therapy

The efficacy of specifically targeted anti-viral therapy for hepatitis C virus (HCV) (STAT-C), including HCV protease and polymerase inhibitors, is limited by the presence of drug-specific viral resistance mutations within the targeted proteins. Genetic diversity within these viral proteins also evolves under selective pressures provided by host human leukocyte antigen (HLA)-restricted immune responses, which may therefore influence STAT-C treatment response. Here, the prevalence of drug resistance mutations relevant to 27 developmental STAT-C drugs, and the potential for drug and immune selective pressures to intersect at sites along the HCV genome, is explored. HCV nonstructural (NS) 3 protease or NS5B polymerase sequences and HLA assignment were obtained from study populations from Australia, Switzerland, and the United Kingdom. Four hundred five treatment-naïve individuals with chronic HCV infection were considered (259 genotype 1, 146 genotype 3), of which 38.5% were coinfected with human immunodeficiency virus (HIV). We identified preexisting STAT-C drug resistance mutations in sequences from this large cohort. The frequency of the variations varied according to individual STAT-C drug and HCV genotype/subtype. Of individuals infected with subtype 1a, 21.5% exhibited genetic variation at a known drug resistance site. Furthermore, we identified areas in HCV protease and polymerase that are under both potential HLA-driven pressure and therapy selection and identified six HLA-associated polymorphisms (P <or= 0.05) at known drug resistance sites.

CONCLUSION

Drug and host immune responses are likely to provide powerful selection forces that shape HCV genetic diversity and replication dynamics. Consideration of HCV viral adaptation in terms of drug resistance as well as host "immune resistance" in the STAT-C treatment era could provide important information toward an optimized and individualized therapy for chronic hepatitis C.

Specific immunotherapy in a pollen-allergic patient with human immunodeficiency virus infection

BACKGROUND

: According to the World Health Organization position paper, immunodeficiency such as human immunodeficiency virus (HIV) infection is a relative contraindication for specific immunotherapy (SIT). Since the introduction of highly active antiretroviral therapy, a significant reconstitution of immune competence in individuals with HIV is possible.

CASE REPORT

: In a 52-year-old man, HIV infection was diagnosed in 1987. Antiretroviral therapy was started in 1998. He presented himself in July 2001 because of an increasingly severe seasonal rhinoconjunctivitis. Symptoms were not sufficiently alleviated by various antiallergic drugs.

RESULTS

: The investigations showed a relevant sensitization to tree pollens. Specific immunotherapy with a tree pollen mix (hazel, birch, ash, and alder, 25% each) was started in November 2001. Viral load at this time was less than 50 copies/mL, the CD4 cell count was 307/μL. Therapy was given in monthly intervals until mid-April 2005 without any side effects. Viral load and CD4 cell counts did not change during SIT. Clinically, rhinoconjunctivitis was experienced only intermittently and symptom relief was almost 90%.

CONCLUSIONS

: This report indicates that in patients with well-controlled HIV infection on highly active antiretroviral therapy, SIT with pollen extracts is a potential and successful therapeutic option.

Immunogenicity and safety of yellow fever vaccination for 102 HIV-infected patients

BACKGROUND

Yellow fever vaccine (17DV) has been investigated incompletely in human immunodeficiency virus (HIV)-infected patients, and adequate immunogenicity and safety are of concern in this population.

METHODS

In the Swiss HIV Cohort Study, we identified 102 patients who received 17DV while they were HIV infected. We analyzed neutralization titers (NTs) after 17DV administration using the plaque reduction neutralization test. NTs of 1:>or=10 were defined as reactive, and those of 1:<10 were defined as nonreactive, which was considered to be nonprotective. The results were compared with data for HIV-uninfected individuals. Serious adverse events were defined as hospitalization or death within 6 weeks after receipt of 17DV.

RESULTS

At the time of 17DV administration, the median CD4 cell count was 537 cells/mm(3) (range, 11-1730 cells/mm(3)), and the HIV RNA level was undetectable in 41 of 102 HIV-infected patients. During the first year after vaccination, fewer HIV-infected patients (65 [83%] of 78; P = .01) than HIV-uninfected patients revealed reactive NTs, and their NTs were significantly lower (P < .001) than in HIV-uninfected individuals. Eleven patients with initially reactive NTs lost these reactive NTs <or= 5 years after vaccination. Higher NTs during the first year after vaccination were associated with undetectable HIV RNA levels, increasing CD4 cell count, and female sex. We found no serious adverse events after 17DV administration among HIV-infected patients.

CONCLUSION

Compared with HIV-uninfected individuals, HIV-infected patients respond to 17DV with lower reactive NTs, more often demonstrate nonprotective NTs, and may experience a more rapid decline in NTs during follow-up. Vaccination with 17DV appears to be safe in HIV-infected individuals who have high CD4 cell counts, although rate of serious adverse events of up to 3% cannot be excluded.

Assessment of a real-time PCR test to diagnose syphilis from diverse biological samples

OBJECTIVES

To investigate the contribution of a real-time PCR assay for the detection of Treponema pallidum in various biological specimens with the secondary objective of comparing its value according to HIV status.

METHODS

Prospective cohort of incident syphilis cases from three Swiss hospitals (Geneva and Bern University Hospitals, Outpatient Clinic for Dermatology of Triemli, Zurich) diagnosed between January 2006 and September 2008. A case-control study was nested into the cohort. Biological specimens (blood, lesion swab or urine) were taken at diagnosis (as clinical information) and analysed by real-time PCR using the T pallidum 47 kDa gene.

RESULTS

126 specimens were collected from 74 patients with primary (n = 26), secondary (n = 40) and latent (n = 8) syphilis. Among primary syphilis, sensitivity was 80% in lesion swabs, 28% in whole blood, 55% in serum and 29% in urine, whereas among secondary syphilis, it was 20%, 36%, 47% and 44%, respectively. Among secondary syphilis, plasma and cerebrospinal fluid were also tested and provided a sensitivity of 100% and 50%, respectively. The global sensitivity of T pallidum by PCR (irrespective of the compartment tested) was 65% during primary, 53% during secondary and null during latent syphilis. No difference regarding serology or PCR results was observed among HIV-infected patients. Specificity was 100%.

CONCLUSIONS

Syphilis PCR provides better sensitivity in lesion swabs from primary syphilis and displays only moderate sensitivity in blood from primary and secondary syphilis. HIV status did not modify the internal validity of PCR for the diagnosis of primary or secondary syphilis.

Self-reported alcohol consumption and its association with adherence and outcome of antiretroviral therapy in the Swiss HIV Cohort Study

BACKGROUND

Alcohol consumption leading to morbidity and mortality affects HIV-infected individuals. Here, we aimed to study self-reported alcohol consumption and to determine its association with adherence to antiretroviral therapy (ART) and HIV surrogate markers.

METHODS

Cross-sectional data on daily alcohol consumption from August 2005 to August 2007 were analysed and categorized according to the World Health Organization definition (light, moderate or severe health risk). Multivariate logistic regression models and Pearson's chi(2) statistics were used to test the influence of alcohol use on endpoints.

RESULTS

Of 6,323 individuals, 52.3% consumed alcohol less than once a week in the past 6 months. Alcohol intake was deemed light in 39.9%, moderate in 5.0% and severe in 2.8%. Higher alcohol consumption was significantly associated with older age, less education, injection drug use, being in a drug maintenance programme, psychiatric treatment, hepatitis C virus coinfection and with a longer time since diagnosis of HIV. Lower alcohol consumption was found in males, non-Caucasians, individuals currently on ART and those with more ART experience. In patients on ART (n=4,519), missed doses and alcohol consumption were positively correlated (P<0.001). Severe alcohol consumers, who were pretreated with ART, were more often off treatment despite having CD4+ T-cell count <200 cells/microl; however, severe alcohol consumption per se did not delay starting ART. In treated individuals, alcohol consumption was not associated with worse HIV surrogate markers.

CONCLUSIONS

Higher alcohol consumption in HIV-infected individuals was associated with several psychosocial and demographic factors, non-adherence to ART and, in pretreated individuals, being off treatment despite low CD4+ T-cell counts.

Hierarchical modeling gave plausible estimates of associations between metabolic syndrome and components of antiretroviral therapy

OBJECTIVE

Hierarchical modeling has been proposed as a solution to the multiple exposure problem. We estimate associations between metabolic syndrome and different components of antiretroviral therapy using both conventional and hierarchical models.

STUDY DESIGN AND SETTING

We use discrete time survival analysis to estimate the association between metabolic syndrome and cumulative exposure to 16 antiretrovirals from four drug classes. We fit a hierarchical model where the drug class provides a prior model of the association between metabolic syndrome and exposure to each antiretroviral.

RESULTS

One thousand two hundred and eighteen patients were followed for a median of 27 months, with 242 cases of metabolic syndrome (20%) at a rate of 7.5 cases per 100 patient years. Metabolic syndrome was more likely to develop in patients exposed to stavudine, but was less likely to develop in those exposed to atazanavir. The estimate for exposure to atazanavir increased from hazard ratio of 0.06 per 6 months' use in the conventional model to 0.37 in the hierarchical model (or from 0.57 to 0.81 when using spline-based covariate adjustment).

CONCLUSION

These results are consistent with trials that show the disadvantage of stavudine and advantage of atazanavir relative to other drugs in their respective classes. The hierarchical model gave more plausible results than the equivalent conventional model.

The HCP5 single-nucleotide polymorphism: a simple screening tool for prediction of hypersensitivity reaction to abacavir

The HLA-B 5701 allele is predictive of hypersensitivity reaction to abacavir, a response herein termed "ABC-HSR." This study of 1,103 individuals infected with human immunodeficiency virus assessed the usefulness of genotyping a HCP5 single-nucleotide polymorphism (SNP), rs2395029, in relation to ABC-HSR. In populations with European ancestry, rs2395029 is in linkage disequilibrium with HLA-B 5701. The HCP5 SNP was present in all 98 HLA-B 5701-positive individuals and was absent in 999 of 1005 HLA-B 5701-negative individuals. rs2395029 was overrepresented in 25 individuals with clinically likely ABC-HSR, compared with its frequency in 175 ABC-tolerant individuals (80% vs. 2%, respectively; P < .0001). Therefore, HCP5 genotyping could serve as a simple screening tool for ABC-HSR, particularly in settings where sequence-based HLA typing is not available.

Tenofovir use is Associated with an Increase in Serum Alkaline Phosphatase in the Swiss HIV Cohort Study

Background

Tenofovir (TDF) use has been associated with proximal renal tubulopathy, reduced calculated glomerular filtration rates (cGFR) and losses in bone mineral density. Bone resorption could result in a compensatory osteoblast activation indicated by an increase in serum alkaline phosphatase (sAP). A few small studies have reported a positive correlation between renal phosphate losses, increased bone turnover and sAP.

Methods

We analysed sAP dynamics in patients initiating ( n=657), reinitiating ( n=361) and discontinuing ( n=73) combined antiretroviral therapy with and without TDF and assessed correlations with clinical and epidemiological parameters.

Results

TDF use was associated with a significant increase of sAP from a median of 74 U/l (interquartile range 60–98) to a plateau of 99 U/l (82–123) after 6 months ( P<0.0001), with a prompt return to baseline upon TDF discontinuation. No change occurred in TDF-sparing regimes. Univariable and multivariable linear regression analyses revealed a positive correlation between sAP and TDF use ( P≤0.003), but no correlation with baseline cGFR, TDF-related cGFR reduction, changes in serum alanine aminotransferase (sALT) or active hepatitis C.

Conclusions

We document a highly significant association between TDF use and increased sAP in a large observational cohort. The lack of correlation between TDF use and sALT suggests that the increase in sAP is because of the bone isoenzyme and indicates stimulated bone turnover. This finding, together with published data on TDF-related renal phosphate losses, this finding raises concerns that TDF use could result in osteomalacia with a loss in bone mineral density at least in a subset of patients. This potentially severe long-term toxicity should be addressed in future studies.

Refining Abacavir Hypersensitivity Diagnoses using a Structured Clinical Assessment and Genetic Testing in the Swiss HIV Cohort Study

Background

We aimed to assess the value of a structured clinical assessment and genetic testing for refining the diagnosis of abacavir hypersensitivity reactions (ABC-HSRs) in a routine clinical setting.

Methods

We performed a diagnostic reassessment using a structured patient chart review in individuals who had stopped ABC because of suspected HSR. Two HIV physicians blinded to the human leukocyte antigen (HLA) typing results independently classified these individuals on a scale between 3 (ABC-HSR highly likely) and -3 (ABC-HSR highly unlikely). Scoring was based on symptoms, onset of symptoms and comedication use. Patients were classified as clinically likely (mean score ≥2), uncertain (mean score ≥-1 and ≤1) and unlikely (mean score ≤-2). HLA typing was performed using sequence-based methods.

Results

From 131 reassessed individuals, 27 (21%) were classified as likely, 43 (33%) as unlikely and 61 (47%) as uncertain ABC-HSR. Of the 131 individuals with suspected ABC-HSR, 31% were HLA-B*5701-positive compared with 1% of 140 ABC-tolerant controls ( P<0.001). HLA-B*5701 carriage rate was higher in individuals with likely ABC-HSR compared with those with uncertain or unlikely ABC-HSR (78%, 30% and 5%, respectively, P<0.001). Only six (7%) HLA-B*5701-negative individuals were classified as likely HSR after reassessment.

Conclusions

HLA-B*5701 carriage is highly predictive of clinically diagnosed ABC-HSR. The high proportion of HLA-B*5701-negative individuals with minor symptoms among individuals with suspected HSR indicates overdiagnosis of ABC-HSR in the era preceding genetic screening. A structured clinical assessment and genetic testing could reduce the rate of inappropriate ABC discontinuation and identify individuals at high risk for ABC-HSR.

Factors associated with the emergence of K65R in patients with HIV-1 infection treated with combination antiretroviral therapy containing tenofovir

BACKGROUND

The human immunodeficiency virus type 1 reverse-transcriptase mutation K65R is a single-point mutation that has become more frequent after increased use of tenofovir disoproxil fumarate (TDF). We aimed to identify predictors for the emergence of K65R, using clinical data and genotypic resistance tests from the Swiss HIV Cohort Study.

METHODS

A total of 222 patients with genotypic resistance tests performed while receiving treatment with TDF-containing regimens were stratified by detectability of K65R (K65R group, 42 patients; undetected K65R group, 180 patients). Patient characteristics at start of that treatment were analyzed.

RESULTS

In an adjusted logistic regression, TDF treatment with nonnucleoside reverse-transcriptase inhibitors and/or didanosine was associated with the emergence of K65R, whereas the presence of any of the thymidine analogue mutations D67N, K70R, T215F, or K219E/Q was protective. The previously undescribed mutational pattern K65R/G190S/Y181C was observed in 6 of 21 patients treated with efavirenz and TDF. Salvage therapy after TDF treatment was started for 36 patients with K65R and for 118 patients from the wild-type group. Proportions of patients attaining human immunodeficiency virus type 1 loads <50 copies/mL after 24 weeks of continuous treatment were similar for the K65R group (44.1%; 95% confidence interval, 27.2%-62.1%) and the wild-type group (51.9%; 95% confidence interval, 42.0%-61.6%).

CONCLUSIONS

In settings where thymidine analogue mutations are less likely to be present, such as at start of first-line therapy or after extended treatment interruptions, combinations of TDF with other K65R-inducing components or with efavirenz or nevirapine may carry an enhanced risk of the emergence of K65R. The finding of a distinct mutational pattern selected by treatment with TDF and efavirenz suggests a potential fitness interaction between K65R and nonnucleoside reverse-transcriptase inhibitor-induced mutations.

Durability and outcome of initial antiretroviral treatments received during 2000--2005 by patients in the Swiss HIV Cohort Study

BACKGROUND

Little is known about time trends, predictors, and consequences of changes made to antiretroviral therapy (ART) regimens early after patients initially start treatment.

METHODS

We compared the incidence of, reasons for, and predictors of treatment change within 1 year after starting combination ART (cART), as well as virological and immunological outcomes at 1 year, among 1866 patients from the Swiss HIV Cohort Study who initiated cART during 2000--2001, 2002--2003, or 2004--2005.

RESULTS

The durability of initial regimens did not improve over time (P = .15): 48.8% of 625 patients during 2000--2001, 43.8% of 607 during 2002--2003, and 44.3% of 634 during 2004--2005 changed cART within 1 year; reasons for change included intolerance (51.1% of all patients), patient wish (15.4%), physician decision (14.8%), and virological failure (7.1%). An increased probability of treatment change was associated with larger CD4+ cell counts, larger human immunodeficiency virus type 1 (HIV-1) RNA loads, and receipt of regimens that contained stavudine or indinavir/ritonavir, but a decreased probability was associated with receipt of regimens that contained tenofovir. Treatment discontinuation was associated with larger CD4+ cell counts, current use of injection drugs, and receipt of regimens that contained nevirapine. One-year outcomes improved between 2000--2001 and 2004--2005: 84.5% and 92.7% of patients, respectively, reached HIV-1 RNA loads of <50 copies/mL and achieved median increases in CD4+ cell counts of 157.5 and 197.5 cells/microL, respectively (P < .001 for all comparisons).

CONCLUSIONS

Virological and immunological outcomes of initial treatments improved between 2000--2001 and 2004--2005, irrespective of uniformly high rates of early changes in treatment across the 3 study intervals.

Public-health and individual approaches to antiretroviral therapy: township South Africa and Switzerland compared

BACKGROUND

The provision of highly active antiretroviral therapy (HAART) in resource-limited settings follows a public health approach, which is characterised by a limited number of regimens and the standardisation of clinical and laboratory monitoring. In industrialized countries doctors prescribe from the full range of available antiretroviral drugs, supported by resistance testing and frequent laboratory monitoring. We compared virologic response, changes to first-line regimens, and mortality in HIV-infected patients starting HAART in South Africa and Switzerland.

METHODS AND FINDINGS

We analysed data from the Swiss HIV Cohort Study and two HAART programmes in townships of Cape Town, South Africa. We included treatment-naïve patients aged 16 y or older who had started treatment with at least three drugs since 2001, and excluded intravenous drug users. Data from a total of 2,348 patients from South Africa and 1,016 patients from the Swiss HIV Cohort Study were analysed. Median baseline CD4+ T cell counts were 80 cells/mul in South Africa and 204 cells/mul in Switzerland. In South Africa, patients started with one of four first-line regimens, which was subsequently changed in 514 patients (22%). In Switzerland, 36 first-line regimens were used initially, and these were changed in 539 patients (53%). In most patients HIV-1 RNA was suppressed to 500 copies/ml or less within one year: 96% (95% confidence interval [CI] 95%-97%) in South Africa and 96% (94%-97%) in Switzerland, and 26% (22%-29%) and 27% (24%-31%), respectively, developed viral rebound within two years. Mortality was higher in South Africa than in Switzerland during the first months of HAART: adjusted hazard ratios were 5.90 (95% CI 1.81-19.2) during months 1-3 and 1.77 (0.90-3.50) during months 4-24.

CONCLUSIONS

Compared to the highly individualised approach in Switzerland, programmatic HAART in South Africa resulted in similar virologic outcomes, with relatively few changes to initial regimens. Further innovation and resources are required in South Africa to both achieve more timely access to HAART and improve the prognosis of patients who start HAART with advanced disease.

Delayed diagnosis of HIV infection and late initiation of antiretroviral therapy in the Swiss HIV Cohort Study

OBJECTIVES

To investigate delayed HIV diagnosis and late initiation of antiretroviral therapy (ART) in the Swiss HIV Cohort Study.

METHODS

Two sub-populations were included: 1915 patients with HIV diagnosis from 1998 to 2007 and within 3 months of cohort registration (group A), and 1730 treatment-naïve patients with CD4>or=200 cells/microL before their second cohort visit (group B). In group A, predictors for low initial CD4 cell counts were examined with a median regression. In group B, we studied predictors for CD4<200 cells/microL without ART despite cohort follow-up.

RESULTS

Median initial CD4 cell count in group A was 331 cells/microL; 31% and 10% were <200 and <50 cells/microL, respectively. Risk factors for low CD4 count were age and non-White race. Homosexual transmission, intravenous drug use and living alone were protective. In group B, 30% initiated ART with CD4>or=200 cells/microL; 18% and 2% dropped to CD4 <200 and <50 cells/microL without ART, respectively. Sub-Saharan origin was associated with lower probability of CD4 <200 cells/microL without ART during follow-up. Median CD4 count at ART initiation was 207 and 253 cells/microL in groups A and B, respectively.

CONCLUSIONS

CD4<200 cells/microL and, particularly, CD4<50 cells/microL before starting ART are predominantly caused by late presentation. Earlier HIV diagnosis is paramount.

Low Current and Nadir CD4+ T-Cell Counts are Associated with Higher Hepatitis C virus RNA Levels in the Swiss HIV Cohort Study

Background

The aim of this study was to evaluate the effect of CD4+ T-cell counts and other characteristics of HIV-infected individuals on hepatitis C virus (HCV) RNA levels.

Methods

All HIV–HCV-coinfected Swiss HIV Cohort Study participants with available HCV RNA levels and concurrent CD4+ T-cell counts before starting HCV therapy were included. Potential predictors of HCV RNA levels were assessed by multivariate censored linear regression models that adjust for censored values.

Results

The study included 1,031 individuals. Low current and nadir CD4+ T-cell counts were significantly associated with higher HCV RNA levels ( P=0.004 and 0.001, respectively). In individuals with current CD4+ T-cell counts <200/μl, median HCV RNA levels (6.22 log10 IU/ml) were +0.14 and +0.24 log10 IU/ml higher than those with CD4+ T-cell counts of 200-500/μ l and >500/μl. Based on nadir CD4+ T-cell counts, median HCV RNA levels (6.12 log10 IU/ml) in individuals with <200/μl CD4+ T-cells were +0.06 and +0.44 log10 IU/ml higher than those with nadir T-cell counts of 200-500/μ l and >500/μ l. Median HCV RNA levels were also significantly associated with HCV genotype: lower values were associated with genotype 4 and higher values with genotype 2, as compared with genotype 1. Additional significant predictors of lower HCV RNA levels were female gender and HIV transmission through male homosexual contacts. In multivariate analyses, only CD4+ T-cell counts and HCV genotype remained significant predictors of HCV RNA levels.

Conclusions

Higher HCV RNA levels were associated with CD4+ T-cell depletion. This finding is in line with the crucial role of CD4+ T-cells in the control of HCV infection.

Tenofovir use is associated with an increase in serum alkaline phosphatase in the Swiss HIV Cohort Study

BACKGROUND

Tenofovir (TDF) use has been associated with proximal renal tubulopathy, reduced calculated glomerular filtration rates (cGFR) and losses in bone mineral density. Bone resorption could result in a compensatory osteoblast activation indicated by an increase in serum alkaline phosphatase (sAP). A few small studies have reported a positive correlation between renal phosphate losses, increased bone turnover and sAP.

METHODS

We analysed sAP dynamics in patients initiating (n = 657), reinitiating (n = 361) and discontinuing (n = 73) combined antiretroviral therapy with and without TDF and assessed correlations with clinical and epidemiological parameters.

RESULTS

TDF use was associated with a significant increase of sAP from a median of 74 U/I (interquartile range 60-98) to a plateau of 99 U/I (82-123) after 6 months (P < 0.0001), with a prompt return to baseline upon TDF discontinuation. No change occurred in TDF-sparing regimes. Univariable and multivariable linear regression analyses revealed a positive correlation between sAP and TDF use (P < or = 0.003), but no correlation with baseline cGFR, TDF-related cGFR reduction, changes in serum alanine aminotransferase (sALT) or active hepatitis C.

CONCLUSIONS

We document a highly significant association between TDF use and increased sAP in a large observational cohort. The lack of correlation between TDF use and sALT suggests that the increase in sAP is because of the bone isoenzyme and indicates stimulated bone turnover. This finding, together with published data on TDF-related renal phosphate losses, this finding raises concerns that TDF use could result in osteomalacia with a loss in bone mineral density at least in a subset of patients. This potentially severe long-term toxicity should be addressed in future studies.

Refining abacavir hypersensitivity diagnoses using a structured clinical assessment and genetic testing in the Swiss HIV Cohort Study

BACKGROUND

We aimed to assess the value of a structured clinical assessment and genetic testing for refining the diagnosis of abacavir hypersensitivity reactions (ABC-HSRs) in a routine clinical setting.

METHODS

We performed a diagnostic reassessment using a structured patient chart review in individuals who had stopped ABC because of suspected HSR. Two HIV physicians blinded to the human leukocyte antigen (HLA) typing results independently classified these individuals on a scale between 3 (ABC-HSR highly likely) and -3 (ABC-HSR highly unlikely). Scoring was based on symptoms, onset of symptoms and comedication use. Patients were classified as clinically likely (mean score > or =2), uncertain (mean score > or = -1 and < or = 1) and unlikely (mean score < or = -2). HLA typing was performed using sequence-based methods.

RESULTS

From 131 reassessed individuals, 27 (21%) were classified as likely, 43 (33%) as unlikely and 61 (47%) as uncertain ABC-HSR. Of the 131 individuals with suspected ABC-HSR, 31% were HLA-B*5701-positive compared with 1% of 140 ABC-tolerant controls (P < 0.001). HLA-B*5701 carriage rate was higher in individuals with likely ABC-HSR compared with those with uncertain or unlikely ABC-HSR (78%, 30% and 5%, respectively, P < 0.001). Only six (7%) HLA-B*5701-negative individuals were classified as likely HSR after reassessment.

CONCLUSIONS

HLA-B*5701 carriage is highly predictive of clinically diagnosed ABC-HSR. The high proportion of HLA-B*5701-negative individuals with minor symptoms among individuals with suspected HSR indicates overdiagnosis of ABC-HSR in the era preceding genetic screening. A structured clinical assessment and genetic testing could reduce the rate of inappropriate ABC discontinuation and identify individuals at high risk for ABC-HSR.

Self-Reported Non-Adherence to Antiretroviral Therapy Repeatedly assessed by Two Questions Predicts Treatment Failure in Virologically Suppressed Patients

Background

The aim of this study was to explore the predictive value of longitudinal self-reported adherence data on viral rebound.

Methods

Individuals in the Swiss HIV Cohort Study on combined antiretroviral therapy (cART) with RNA <50 copies/ml over the previous 3 months and who were interviewed about adherence at least once prior to 1 March 2007 were eligible. Adherence was defined in terms of missed doses of cART (0, 1, 2 or >2) in the previous 28 days. Viral rebound was defined as RNA >500 copies/ml. Cox regression models with time-independent and -dependent covariates were used to evaluate time to viral rebound.

Results

A total of 2,664 individuals and 15,530 visits were included. Across all visits, missing doses were reported as follows: 1 dose 14.7%, 2 doses 5.1%, >2 doses 3.8%, taking <95% of doses 4.5% and missing ≥2 consecutive doses 3.2%. In total, 308 (11.6%) patients experienced viral rebound. After controlling for confounding variables, self-reported non-adherence remained significantly associated with the rate of occurrence of viral rebound (compared with zero missed doses: 1 dose, hazard ratio [HR] 1.03, 95% confidence interval [CI] 0.72–1.48; 2 doses, HR 2.17, 95% CI 1.46–3.25; >2 doses, HR 3.66, 95% CI 2.50–5.34). Several variables significantly associated with an increased risk of viral rebound irrespective of adherence were identified: being on a protease inhibitor or triple nucleoside regimen (compared with a non-nucleoside reverse transcriptase inhibitor), >5 previous cART regimens, seeing a less-experienced physician, taking co-medication, and a shorter time virally suppressed.

Conclusions

A simple self-report adherence questionnaire repeatedly administered provides a sensitive measure of non-adherence that predicts viral rebound.

Self-reported non-adherence to antiretroviral therapy repeatedly assessed by two questions predicts treatment failure in virologically suppressed patients

BACKGROUND

The aim of this study was to explore the predictive value of longitudinal self-reported adherence data on viral rebound.

METHODS

Individuals in the Swiss HIV Cohort Study on combined antiretroviral therapy (cART) with RNA <50 copies/ml over the previous 3 months and who were interviewed about adherence at least once prior to 1 March 2007 were eligible. Adherence was defined in terms of missed doses of cART (0, 1, 2 or >2) in the previous 28 days. Viral rebound was defined as RNA >500 copies/ml. Cox regression models with time-independent and -dependent covariates were used to evaluate time to viral rebound.

RESULTS

A total of 2,664 individuals and 15,530 visits were included. Across all visits, missing doses were reported as follows: 1 dose 14.7%, 2 doses 5.1%, >2 doses 3.8% taking <95% of doses 4.5% and missing > or =2 consecutive doses 3.2%. In total, 308 (11.6%) patients experienced viral rebound. After controlling for confounding variables, self-reported non-adherence remained significantly associated with the rate of occurrence of viral rebound (compared with zero missed doses: 1 dose, hazard ratio [HR] 1.03, 95% confidence interval [CI] 0.72-1.48; 2 doses, HR 2.17, 95% CI 1.46-3.25; >2 doses, HR 3.66, 95% CI 2.50-5.34). Several variables significantly associated with an increased risk of viral rebound irrespective of adherence were identified: being on a protease inhibitor or triple nucleoside regimen (compared with a non-nucleoside reverse transcriptase inhibitor), >5 previous cART regimens, seeing a less-experienced physician, taking co-medication, and a shorter time virally suppressed.

CONCLUSIONS

A simple self-report adherence questionnaire repeatedly administered provides a sensitive measure of non-adherence that predicts viral rebound.

Low current and nadir CD4+ T-cell counts are associated with higher hepatitis C virus RNA levels in the Swiss HIV cohort study

BACKGROUND

The aim of this study was to evaluate the effect of CD4+ T-cell counts and other characteristics of HIV-infected individuals on hepatitis C virus (HCV) RNA levels.

METHODS

All HIV-HCV-coinfected Swiss HIV Cohort Study participants with available HCV RNA levels and concurrent CD4+ T-cell counts before starting HCV therapy were included. Potential predictors of HCV RNA levels were assessed by multivariate censored linear regression models that adjust for censored values.

RESULTS

The study included 1,031 individuals. Low current and nadir CD4+ T-cell counts were significantly associated with higher HCV RNA levels (P = 0.004 and 0.001, respectively). In individuals with current CD4+ T-cell counts < 200/microl, median HCV RNA levels (6.22 log10 IU/ml) were +0.14 and +0.24 log10 IU/ml higher than those with CD4+ T-cell counts of 200-500/microl and > 500/microl. Based on nadir CD4+ T-cell counts, median HCV RNA levels (6.12 log10 IU/ml) in individuals with < 200/microl CD4+ T-cells were +0.06 and +0.44 log10 IU/ml higher than those with nadir T-cell counts of 200-500/microl and > 500/microl. Median HCV RNA levels were also significantly associated with HCV genotype: lower values were associated with genotype 4 and higher values with genotype 2, as compared with genotype 1. Additional significant predictors of lower HCV RNA levels were female gender and HIV transmission through male homosexual contacts. In multivariate analyses, only CD4+ T-cell counts and HCV genotype remained significant predictors of HCV RNA levels.

CONCLUSIONS

Higher HCV RNA levels were associated with CD4+ T-cell depletion. This finding is in line with the crucial role of CD4+ T-cells in the control of HCV infection.

Contribution of 20 single nucleotide polymorphisms of 13 genes to dyslipidemia associated with antiretroviral therapy

BACKGROUND

HIV-1 infected individuals have an increased cardiovascular risk which is partially mediated by dyslipidemia. Single nucleotide polymorphisms in multiple genes involved in lipid transport and metabolism are presumed to modulate the risk of dyslipidemia in response to antiretroviral therapy.

METHODS

The contribution to dyslipidemia of 20 selected single nucleotide polymorphisms of 13 genes reported in the literature to be associated with plasma lipid levels (ABCA1, ADRB2, APOA5, APOC3, APOE, CETP, LIPC, LIPG, LPL, MDR1, MTP, SCARB1, and TNF) was assessed by longitudinally modeling more than 4400 plasma lipid determinations in 438 antiretroviral therapy-treated participants during a median period of 4.8 years. An exploratory genetic score was tested that takes into account the cumulative contribution of multiple gene variants to plasma lipids.

RESULTS

Variants of ABCA1, APOA5, APOC3, APOE, and CETP contributed to plasma triglyceride levels, particularly in the setting of ritonavir-containing antiretroviral therapy. Variants of APOA5 and CETP contributed to high-density lipoprotein-cholesterol levels. Variants of CETP and LIPG contributed to non-high-density lipoprotein-cholesterol levels, a finding not reported previously. Sustained hypertriglyceridemia and low high-density lipoprotein-cholesterol during the study period was significantly associated with the genetic score.

CONCLUSIONS

Single nucleotide polymorphisms of ABCA1, APOA5, APOC3, APOE, and CETP contribute to plasma triglyceride and high-density lipoprotein-cholesterol levels during antiretroviral therapy exposure. Genetic profiling may contribute to the identification of patients at risk for antiretroviral therapy-related dyslipidemia.

Tenofovir Use is associated with a Reduction in Calculated Glomerular Filtration Rates in the Swiss HIV Cohort Study

Background

A growing number of case reports have described tenofovir (TDF)-related proximal renal tubulopathy and impaired calculated glomerular filtration rates (cGFR). We assessed TDF-associated changes in cGFR in a large observational HIV cohort.

Methods

We compared treatment-naive patients or patients with treatment interruptions ≥12 months starting either a TDF-based combination antiretroviral therapy (cART) ( n=363) or a TDF-sparing regime ( n=715). The predefined primary endpoint was the time to a 10 ml/min reduction in cGFR, based on the Cockcroft-Gault equation, confirmed by a follow-up measurement at least 1 month later. In sensitivity analyses, secondary endpoints including calculations based on the modified diet in renal disease (MDRD) formula were considered. Endpoints were modelled using pre-specified covariates in a multiple Cox proportional hazards model.

Results

Two-year event-free probabilities were 0.65 (95% confidence interval [CI] 0.58–0.72) and 0.80 (95% CI 0.76–0.83) for patients starting TDF-containing or TDF-sparing cART, respectively. In the multiple Cox model, diabetes mellitus (hazard ratio [HR]=2.34 [95% CI 1.24–4.42]), higher baseline cGFR (HR=1.03 [95% CI 1.02–1.04] by 10 ml/min), TDF use (HR=1.84 [95% CI 1.35–2.51]) and boosted protease inhibitor use (HR=1.71 [95% CI 1.30–2.24]) significantly increased the risk for reaching the primary endpoint. Sensitivity analyses showed high consistency.

Conclusion

There is consistent evidence for a significant reduction in cGFR associated with TDF use in HIV-infected patients. Our findings call for a strict monitoring of renal function in long-term TDF users with tests that distinguish between glomerular dysfunction and proximal renal tubulopathy, a known adverse effect of TDF.

Adverse Events to Antiretrovirals in the Swiss HIV Cohort Study: Effect on Mortality and Treatment Modification

Background

Antiretroviral therapy (ART) decreases morbidity and mortality in HIV-infected patients but is associated with considerable adverse events (AEs).

Methods

We examined the effect of AEs to ART on mortality, treatment modifications and drop-out in the Swiss HIV Cohort Study. A cross-sectional evaluation of prevalence of 13 clinical and 11 laboratory parameters was performed in 1999 in 1,078 patients on ART. AEs were defined as abnormalities probably or certainly related to ART. A score including the number and severity of AEs was defined. The subsequent progression to death, drop-out and treatment modification due to intolerance were evaluated according to the baseline AE score and characteristics of individual AEs.

Results

Of the 1,078 patients, laboratory AEs were reported in 23% and clinical AEs in 45%. During a median follow up of 5.9 years, laboratory AEs were associated with higher mortality with an adjusted hazard ratio (HR) of 1.3 (95% confidence interval [CI] 1.2–1.5; P<0.001) per score point. For clinical AEs no significant association with increased mortality was found. In contrast, an increasing score for clinical AEs (HR 1.11, 95% CI 1.04–1.18; P=0.002), but not for laboratory AEs (HR 1.07, 95% CI 0.97–1.17; P=0.17), was associated with antiretroviral treatment modification. AEs were not associated with a higher drop-out rate.

Conclusions

The burden of laboratory AEs to antiretroviral drugs is associated with a higher mortality. Physicians seem to change treatments to relieve clinical symptoms, while accepting laboratory AEs. Minimizing laboratory drug toxicity seems warranted and its influence on survival should be further evaluated.

Emergence of HIV-1 drug resistance in previously untreated patients initiating combination antiretroviral treatment: a comparison of different regimen types

BACKGROUND

Standard first-line combination antiretroviral treatment (cART) against human immunodeficiency virus 1 (HIV-1) contains either a nonnucleoside reverse transcriptase inhibitor (NNRTI) or a ritonavir-boosted protease inhibitor (PI/r). Differences between these regimen types in the extent of the emergence of drug resistance on virological failure and the implications for further treatment options have rarely been assessed.

METHODS

We investigated virological outcomes in patients from the Swiss HIV Cohort Study initiating cART between January 1, 1999, and December 31, 2005, with an unboosted PI, a PI/r, or an NNRTI and compared genotypic drug resistance patterns among these groups at treatment failure.

RESULTS

A total of 489 patients started cART with a PI, 518 with a PI/r, and 805 with an NNRTI. A total of 177 virological failures were observed (108 [22%] PI failures, 24 [5%] PI/r failures, and 45 [6%] NNRTI failures). The failure rate was highest in the PI group (10.3 per 100 person-years; 95% confidence interval [CI], 8.5-12.4). No difference was seen between patients taking a PI/r (2.7; 95% CI, 1.8-4.0) and those taking an NNRTI (2.4; 95% CI, 1.8-3.3). Genotypic test results were available for 142 (80%) of the patients with a virological treatment failure. Resistance mutations were found in 84% (95% CI, 75%-92%) of patients taking a PI, 30% (95% CI, 12%-54%) of patients taking a PI/r, and 66% (95% CI, 49%-80%) of patients taking an NNRTI (P < .001). Multidrug resistance occurred almost exclusively as resistance against lamivudine-emtricitabine and the group-specific third drug and was observed in 17% (95% CI, 9%-26%) of patients taking a PI, 10% (95% CI, 0.1%-32%) of patients taking a PI/r, and 50% (95% CI, 33%-67%) of patients taking an NNRTI (P < .001).

CONCLUSIONS

Regimens that contained a PI/r or an NNRTI exhibited similar potency as first-line regimens. However, the use of a PI/r led to less resistance in case of virological failure, preserving more drug options for the future.

Mycobacterium avium subspecies paratuberculosis and Crohn's disease: a systematic review and meta-analysis

This systematic review assesses the evidence for an association between Mycobacterium avium subspecies paratuberculosis (MAP) and Crohn's disease. We analysed 28 case-control studies comparing MAP in patients with Crohn's disease with individuals free of inflammatory bowel disease (IBD) or patients with ulcerative colitis. Compared with individuals free of IBD, the pooled odds ratio (OR) from studies using PCR in tissue samples was 7.01 (95% CI 3.95-12.4) and was 1.72 (1.02-2.90) in studies using ELISA in serum. ORs were similar for comparisons with ulcerative colitis patients (PCR, 4.13 [1.57-10.9]; ELISA, 1.88 [1.26-2.81]). The association of MAP with Crohn's disease seems to be specific, but its role in the aetiology of Crohn's disease remains to be defined.

Late Presentation of HIV-Infected Individuals

Late presentation remains a major concern despite the dramatically improved prognosis realized by ART. We define a first presentation for HIV care during the course of HIV infection as ‘late’ if an AIDS-defining opportunistic disease is apparent, or if CD4+ T-cells are <200/μl. In the Western world, approximately 10 and 30% of HIV-infected individuals still present with CD4+ T-cells <50 and <200/μl, respectively; estimates are substantially higher for developing countries. Diagnosis and treatment of opportunistic diseases and intense supportive in-hospital care take precedence over ART. Benefits of starting ART without delay, that is, when opportunistic diseases are still active, include faster resolution of opportunistic diseases and a decreased risk of recurrence. The downside of starting ART without delay could include toxicity, drug interactions and immune reconstitution inflammatory syndrome (IRIS). Among asymptomatic or oligosymptomatic individuals presenting late, where ART and primary prophylaxis are initiated, ∼10–20% will become symptomatic from drug toxicity or undiagnosed opportunistic complications, including IRIS, which require appropriate therapies. In this review we describe late presentation to HIV care, the scale of the problem, the evaluation of a late-presenting patient and challenges associated with initiation of potent anti-retroviral therapy (ART) in the setting of acute opportunistic infections and other comorbidities.

Treatment and Prognosis of AIDS-Related Lymphoma in the Era of Highly Active Antiretroviral Therapy: Findings from the Swiss HIV Cohort Study

Objective

To assess the characteristics of combination antiretroviral therapy (cART) administered concomitantly with chemotherapy and to establish prognostic determinants of patients with AIDS-related non-Hodgkin's lymphoma.

Methods

The study included 91 patients with AIDS-related non-Hodgkin's lymphoma from the Swiss HIV Cohort Study enrolled between January 1997 and October 2003, excluding lymphomas of the brain. We extracted AIDS-related non-Hodgkin's lymphoma- and HIV-specific variables at the time of lymphoma diagnosis as well as treatment changes over time from charts and from the Swiss HIV Cohort Study database. Cox regression analyses were performed to study predictors of overall and progression-free survival.

Results

During a median follow up of 1.6 years, 57 patients died or progressed. Thirty-five patients stopped chemotherapy prematurely (before the sixth cycle) usually due to disease progression; these patients had a shorter median survival than those who completed six or more cycles (14 versus 28 months). Interruptions of cART decreased from 35% before chemotherapy to 5% during chemotherapy. Factors associated with overall survival were CD4+ T-cell count (<100 cells/μl) (hazard ratio [HR] 2.95 [95% confidence interval (CI) 1.53–5.67], hepatitis C seropositivity (HR 2.39 [95% CI 1.01–5.67]), the international prognostic index score (HR 1.98–3.62 across categories) and Burkitt histological subtypes (HR 2.56 [95% CI 1.13–5.78]).

Conclusions

Interruptions of cART were usually not induced by chemotherapy. The effect of cART interruptions on AIDS-related non-Hodgkin's lymphoma prognosis remains unclear, however, hepatitis C seropositivity emerged as a predictor of death beyond the well-known international prognostic index score and CD4+ T-cell count.

CD4+ T-Cell Count Increase in HIV-1-Infected Patients with Suppressed Viral Load Within 1 year after start of antiretroviral therapy

Background

CD4+ T-cell recovery in patients with continuous suppression of plasma HIV-1 viral load (VL) is highly variable. This study aimed to identify predictive factors for long-term CD4+ T-cell increase in treatment-naive patients starting combination antiretroviral therapy (cART).

Methods

Treatment-naive patients in the Swiss HIV Cohort Study reaching two VL measurements <50 copies/ml >3 months apart during the 1st year of cART were included ( n=1,816 patients). We studied CD4+ T-cell dynamics until the end of suppression or up to 5 years, subdivided into three periods: 1st year, years 2–3 and years 4–5 of suppression. Multiple median regression adjusted for repeated CD4+T-cell measurements was used to study the dependence of CD4+ T-cell slopes on clinical covariates and drug classes.

Results

Median CD4+ T-cell increases following VL suppression were 87, 52 and 19 cells/μl per year in the three periods. In the multiple regression model, median CD4+ T-cell increases over all three periods were significantly higher for female gender, lower age, higher VL at cART start, CD4+ T-cell <650 cells/μ l at start of the period and low CD4+ T-cell increase in the previous period. Patients on tenofovir showed significantly lower CD4+T-cell increases compared with stavudine.

Conclusions

In our observational study, long-term CD4+ T-cell increase in drug-naive patients with suppressed VL was higher in regimens without tenofovir. The clinical relevance of these findings must be confirmed in, ideally, clinical trials or large, collaborative cohort projects but could influence treatment of older patients and those starting cART at low CD4+ T-cell levels.

Effect of tenofovir on renal glomerular and tubular function

To evaluate tenofovir-related nephropathy, we quantified calculated glomerular filtration rates (GFR) and renal tubular function in 46 tenofovir-treated patients and 25 without tenofovir. We also analysed patients who stopped tenofovir for drug-related nephrotoxicity at our clinic. Tenofovir use combined with non-nucleoside reverse transcriptase inhibitors, but not with protease inhibitors, resulted in a significant increase in calculated GFR. Tenofovir use was associated with significantly lower phosphatemia and a marginally increased fractional excretion of uric acid, but no other signs of tubulopathy.

Influence of inhibitory killer immunoglobulin-like receptors and their HLA-C ligands on resolving hepatitis C virus infection

An estimated 2%-3% of the world's population is chronically infected with hepatitis C virus (HCV) and this is a major cause of liver disease worldwide. Following acute infection, outcome is variable with acute HCV successfully resolved in some individuals (20%-30%), but in the majority of cases the virus is able to persist. Co-infection with human immunodeficiency virus has been associated with a negative impact on the course of HCV infection. The host's immune response is an important correlate of HCV infection outcome and disease progression. Natural killer (NK) cells provide a major component of the antiviral immune response by recognising and killing virally infected cells. NK cells modulate their activity through a combination of inhibitory and activatory receptors such as the killer immunoglobulin-like receptors (KIRs) that bind to human leukocyte antigen (HLA) Class I molecules. In this workshop component, we addressed the influence of KIR genotypes and their HLA ligands on resolving HCV infection and we discuss the implications of the results of the study of Lopez-Vazquez et al. on KIR and HCV disease progression.

Factors associated with the incidence of type 2 diabetes mellitus in HIV-infected participants in the Swiss HIV Cohort Study

BACKGROUND

Human immunodeficiency virus (HIV)-infected persons may be at increased risk for developing type 2 diabetes mellitus because of viral coinfection and adverse effects of treatment.

METHODS

We studied associations of new-onset diabetes mellitus with hepatitis B virus and hepatitis C virus coinfections and antiretroviral therapy in participants in the Swiss HIV Cohort Study, using Poisson regression.

RESULTS

A total of 123 of 6513 persons experienced diabetes mellitus during 27,798 person-years of follow-up (PYFU), resulting in an incidence of 4.4 cases per 1000 PYFU (95% confidence interval [CI], 3.7-5.3 cases per 1000 PYFU). An increased incidence rate ratio (IRR) was found for male subjects (IRR, 2.5; 95% CI, 1.5-4.2), older age (IRR for subjects >60 years old, 4.3; 95% CI, 2.3-8.2), black (IRR, 2.1; 95% CI, 1.1-4.0) and Asian (IRR, 4.9; 95% CI, 2.2-10.9) ethnicity, Centers for Disease Control and Prevention disease stage C (IRR, 1.6; 95% CI, 1.04-2.4), and obesity (IRR, 4.7; 95% CI, 3.1-7.0), but results for hepatitis C virus infection or active hepatitis B virus infection were inconclusive. Strong associations were found for current treatment with nucleoside reverse-transcriptase inhibitors (IRR, 2.22; 95% CI, 1.11-4.45), nucleoside reverse-transcriptase inhibitors plus protease inhibitors (IRR, 2.48; 95% CI, 1.42-4.31), and nucleoside reverse-transcriptase inhibitors plus protease inhibitors and nonnucleoside reverse-transcriptase inhibitors (IRR, 3.25; 95% CI, 1.59-6.67) but were not found for treatment with nucleoside reverse-transcriptase inhibitors plus nonnucleoside reverse-transcriptase inhibitors (IRR, 1.47; 95% CI, 0.77-2.82).

CONCLUSIONS

In addition to traditional risk factors, current treatment with protease inhibitor- and nucleoside reverse-transcriptase inhibitor-containing regimens was associated with the risk of developing type 2 diabetes mellitus. Our study did not find a significant association between viral hepatitis infection and risk of incident diabetes.

HAART and the heart: changes in coronary risk factors and implications for coronary risk in men starting antiretroviral therapy

OBJECTIVES

To estimate changes in coronary risk factors and their implications for coronary heart disease (CHD) rates in men starting highly active antiretroviral therapy (HAART).

METHODS

Men participating in the Swiss HIV Cohort Study with measurements of coronary risk factors both before and up to 3 years after starting HAART were identified. Fractional polynomial regression was used to graph associations between risk factors and time on HAART. Mean risk factor changes associated with starting HAART were estimated using multilevel models. A prognostic model was used to predict corresponding CHD rate ratios.

RESULTS

Of 556 eligible men, 259 (47%) started a nonnucleoside reverse transcriptase inhibitor (NNRTI) and 297 a protease inhibitor (PI) based regimen. Levels of most risk factors increased sharply during the first 3 months on HAART, then more slowly. Increases were greater with PI- than NNRTI-based HAART for total cholesterol (1.18 vs. 0.98 mmol L(-1)), systolic blood pressure (3.6 vs. 0 mmHg) and BMI (1.04 vs. 0.55 kg m(2)) but not HDL cholesterol (0.24 vs. 0.32 mmol L(-1)) or glucose (1.02 vs. 1.03 mmol L(-1)). Predicted CHD rate ratios were 1.40 (95% CI 1.13-1.75) and 1.17 (0.95-1.47) for PI- and NNRTI-based HAART respectively.

CONCLUSIONS

Coronary heart disease rates will increase in a majority of patients starting HAART: however the increases corresponding to typical changes in risk factors are relatively modest and could be offset by lifestyle changes.

Hypogonadism in HIV-1-Infected Men is common and does not resolve during antiretroviral therapy

Objectives

To assess the prevalence of abnormal testosterone and gonadotropin values in HIV-infected men before and after 2 years of combination antiretroviral therapy (cART).

Design

Multicentre cohort of HIV-infected adults.

Methods

We identified 139 Caucasian antiretroviral-naive male patients who started zidovudine/ lamivudine-based cART that was virologically successful over a 2 year period. Ninety-seven were randomly chosen and plasma hormone determinations of free testosterone (fT) and luteinizing hormone (LH) at baseline and after 2 years of cART were evaluated.

Results

At baseline 68 patients (70%) had subnormal fT levels. In these, LH levels were low in 44%, normal in 47% and high in 9%. There was a trend for an association between lower CD4+ T-cell counts and hypogonadism. Most participants had normal FSH levels. No significant changes of fT, LH and FSH levels were observed after 2 years of cART.

Conclusions

Low fT levels, mainly with normal or low LH levels and thus indicating secondary hypogonadism, are found in the majority of HIV-infected men and do not resolve during 2 years of successful cART.

Predictive value of known and novel alleles of CYP2B6 for efavirenz plasma concentrations in HIV-infected individuals

To assess the association of CYP2B6 allelic diversity with efavirenz (EFV) pharmacokinetics, we performed extensive genotyping of 15 relevant single nucleotide polymorphism in 169 study participants, and full resequencing of CYP2B6 in individuals with abnormal EFV plasma levels. Seventy-seven (45.5%) individuals carried a known (CYP2B6*6, *11, *15, or *18) or new loss/diminished-function alleles. Resequencing defined two new loss-of-function alleles: allele *27 (marked by 593T>C [M198T]), that results in 85% decrease in enzyme activity and allele *28 (marked by 1132C>T), that results in protein truncation at arginine 378. Median AUC levels were 188.5 microg h/ml for individuals homozygous for a loss/diminished-function allele, 58.6 microg h/ml for carriers, and 43.7 microg h/ml for noncarriers (P<0.0001). Individuals with a poor metabolizer genotype had a likelihood ratio of 35 (95% CI, 11-110) of presenting very high EFV plasma levels. CYP2B6 poor metabolizer genotypes explain to a large extent EFV pharmacokinetics and identify individuals at risk of extremely elevated EFV plasma levels.

CD4+ T-cell count increase in HIV-1-infected patients with suppressed viral load within 1 year after start of antiretroviral therapy

BACKGROUND

CD4+ T-cell recovery in patients with continuous suppression of plasma HIV-1 viral load (VL) is highly variable. This study aimed to identify predictive factors for long-term CD4+ T-cell increase in treatment-naive patients starting combination antiretroviral therapy (cART).

METHODS

Treatment-naive patients in the Swiss HIV Cohort Study reaching two VL measurements <50 copies/ml >3 months apart during the 1st year of cART were included (n=1816 patients). We studied CD4+ T-cell dynamics until the end of suppression or up to 5 years, subdivided into three periods: 1st year, years 2-3 and years 4-5 of suppression. Multiple median regression adjusted for repeated CD4+ T-cell measurements was used to study the dependence of CD4+ T-cell slopes on clinical covariates and drug classes.

RESULTS

Median CD4+ T-cell increases following VL suppression were 87, 52 and 19 cells/microl per year in the three periods. In the multiple regression model, median CD4+ T-cell increases over all three periods were significantly higher for female gender, lower age, higher VL at cART start, CD4+ T-cell <650 cells/microl at start of the period and low CD4+ T-cell increase in the previous period. Patients on tenofovir showed significantly lower CD4+ T-cell increases compared with stavudine.

CONCLUSIONS

In our observational study, long-term CD4+ T-cell increase in drug-naive patients with suppressed VL was higher in regimens without tenofovir. The clinical relevance of these findings must be confirmed in, ideally, clinical trials or large, collaborative cohort projects but could influence treatment of older patients and those starting cART at low CD4+ T-cell levels.

Tenofovir use is associated with a reduction in calculated glomerular filtration rates in the Swiss HIV Cohort Study

BACKGROUND

A growing number of case reports have described tenofovir (TDF)-related proximal renal tubulopathy and impaired calculated glomerular filtration rates (cGFR). We assessed TDF-associated changes in cGFR in a large observational HIV cohort.

METHODS

We compared treatment-naive patients or patients with treatment interruptions > or = 12 months starting either a TDF-based combination antiretroviral therapy (cART) (n = 363) or a TDF-sparing regime (n = 715). The predefined primary endpoint was the time to a 10 ml/min reduction in cGFR, based on the Cockcroft-Gault equation, confirmed by a follow-up measurement at least 1 month later. In sensitivity analyses, secondary endpoints including calculations based on the modified diet in renal disease (MDRD) formula were considered. Endpoints were modelled using pre-specified covariates in a multiple Cox proportional hazards model.

RESULTS

Two-year event-free probabilities were 0.65 (95% confidence interval [CI] 0.58-0.72) and 0.80 (95% CI 0.76-0.83) for patients starting TDF-containing or TDF-sparing cART, respectively. In the multiple Cox model, diabetes mellitus (hazard ratio [HR] = 2.34 [95% CI 1.24-4.42]), higher baseline cGFR (HR = 1.03 [95% CI 1.02-1.04] by 10 ml/min), TDF use (HR = 1.84 [95% CI 1.35-2.51]) and boosted protease inhibitor use (HR = 1.71 [95% CI 1.30-2.24]) significantly increased the risk for reaching the primary endpoint. Sensitivity analyses showed high consistency.

CONCLUSION

There is consistent evidence for a significant reduction in cGFR associated with TDF use in HIV-infected patients. Our findings call for a strict monitoring of renal function in long-term TDF users with tests that distinguish between glomerular dysfunction and proximal renal tubulopathy, a known adverse effect of TDF.

Late presentation of HIV-infected individuals

Late presentation remains a major concern despite the dramatically improved prognosis realized by ART. We define a first presentation for HIV care during the course of HIV infection as 'late' if an AIDS-defining opportunistic disease is apparent, or if CD4+ T-cells are <200/microl. In the Western world, approximately 10 and 30% of HIV-infected individuals still present with CD4+ T-cells <50 and <200/microl, respectively; estimates are substantially higher for developing countries. Diagnosis and treatment of opportunistic diseases and intense supportive in-hospital care take precedence over ART. Benefits of starting ART without delay, that is, when opportunistic diseases are still active, include faster resolution of opportunistic diseases and a decreased risk of recurrence. The downside of starting ART without delay could include toxicity, drug interactions and immune reconstitution inflammatory syndrome (IRIS). Among asymptomatic or oligosymptomatic individuals presenting late, where ART and primary prophylaxis are initiated, approximately 10-20% will become symptomatic from drug toxicity or undiagnosed opportunistic complications, including IRIS, which require appropriate therapies. In this review we describe late presentation to HIV care, the scale of the problem, the evaluation of a late-presenting patient and challenges associated with initiation of potent antiretroviral therapy (ART) in the setting of acute opportunistic infections and other comorbidities.

Does Tenofovir Influence Efavirenz Pharmacokinetics?

Introduction

A recent report described a possible interaction between tenofovir (TFV) and efavirenz (EFV). Patients developed neuropsychiatric manifestations upon introduction of TFV on a stable EFV-containing regimen. We evaluated the possibility of a pharmacokinetic interaction between TFV and EFV by assessing cross-sectional and longitudinal data in 169 individuals receiving EFV.

Results

EFV plasma area-under-the-curve (AUC) levels were comparable among individuals receiving ( n=18) or not receiving TFV ( n=151); 57,962 versus 52,293 ng*h/ml. However, under conditions of limited EFV metabolism, that is, the group of 23 individuals carrying two copies of CYP2B6 loss/diminished-function alleles, plasma AUC values were highest among individuals receiving TFV ( n=5, 353,031 ng*h/ml), compared with those not receiving TFV ( n=18, 180,689 ng*h/ml). Statistical analysis identified both a global, sixfold effect of CYP2B6 loss/diminished function ( P<0.0001) and a significant interaction between the number of loss/diminished-function alleles and the co-medication with TFV ( P=0.009).

Conclusion

Although there is no clear evidence for a pharmacokinetic interaction between TFV and EFV, we cannot rule out an interaction between these drugs restricted to individuals who are slow EFV metabolizers.

Hypogonadism in HIV-1-infected men is common and does not resolve during antiretroviral therapy

OBJECTIVES

To assess the prevalence of abnormal testosterone and gonadotropin values in HIV-infected men before and after 2 years of combination antiretroviral therapy (cART).

DESIGN

Multicentre cohort of HIV-infected adults.

METHODS

We identified 139 Caucasian antiretroviral-naive male patients who started zidovudine/ lamivudine-based cART that was virologically successful over a 2 year period. Ninety-seven were randomly chosen and plasma hormone determinations of free testosterone (fT) and luteinizing hormone (LH) at baseline and after 2 years of cART were evaluated.

RESULTS

At baseline 68 patients (70%) had subnormal fT levels. In these, LH levels were low in 44%, normal in 47% and high in 9%. There was a trend for an association between lower CD4+ T-cell counts and hypogonadism. Most participants had normal FSH levels. No significant changes of fT, LH and FSH levels were observed after 2 years of cART.

CONCLUSIONS

Low fT levels, mainly with normal or low LH levels and thus indicating secondary hypogonadism, are found in the majority of HIV-infected men and do not resolve during 2 years of successful cART.

Does tenofovir influence efavirenz pharmacokinetics?

INTRODUCTION

A recent report described a possible interaction between tenofovir (TFV) and efavirenz (EFV). Patients developed neuropsychiatric manifestations upon introduction of TFV on a stable EFV-containing regimen. We evaluated the possibility of a pharmacokinetic interaction between TFV and EFV by assessing cross-sectional and longitudinal data in 169 individuals receiving EFV.

RESULTS

EFV plasma area-under-the-curve (AUC) levels were comparable among individuals receiving (n=18) or not receiving TFV (n=151); 57,962 versus 52,293 ng*h/ml. However, under conditions of limited EFV metabolism, that is, the group of 23 individuals carrying two copies of CYP2B6 loss/diminished-function alleles, plasma AUC values were highest among individuals receiving TFV (n=5, 353,031 ng*h/ml), compared with those not receiving TFV (n=18, 180,689 ng*h/ml). Statistical analysis identified both a global, sixfold effect of CYP2B6 loss/diminished function (P < 0.0001) and a significant interaction between the number of loss/diminished-function alleles and the co-medication with TFV (P = 0.009).

CONCLUSION

Although there is no clear evidence for a pharmacokinetic interaction between TFV and EFV, we cannot rule out an interaction between these drugs restricted to individuals who are slow EFV metabolizers.

Treatment and prognosis of AIDS-related lymphoma in the era of highly active antiretroviral therapy: findings from the Swiss HIV Cohort Study

OBJECTIVE

To assess the characteristics of combination antiretroviral therapy (cART) administered concomitantly with chemotherapy and to establish prognostic determinants of patients with AIDS-related non-Hodgkin's lymphoma.

METHODS

The study included 91 patients with AIDS-related non-Hodgkin's lymphoma from the Swiss HIV Cohort Study enrolled between January 1997 and October 2003, excluding lymphomas of the brain. We extracted AIDS-related non-Hodgkin's lymphoma- and HIV-specific variables at the time of lymphoma diagnosis as well as treatment changes over time from charts and from the Swiss HIV Cohort Study database. Cox regression analyses were performed to study predictors of overall and progression-free survival.

RESULTS

During a median follow up of 1.6 years, 57 patients died or progressed. Thirty-five patients stopped chemotherapy prematurely (before the sixth cycle) usually due to disease progression; these patients had a shorter median survival than those who completed six or more cycles (14 versus 28 months). Interruptions of cART decreased from 35% before chemotherapy to 5% during chemotherapy. Factors associated with overall survival were CD4+ T-cell count (<100 cells/microl) (hazard ratio [HR] 2.95 [95% confidence interval (CI) 1.53-5.67], hepatitis C seropositivity (HR 2.39 [95% CI 1.01-5.67]), the international prognostic index score (HR 1.98-3.62 across categories) and Burkitt histological subtypes (HR 2.56 [95% CI 1.13-5.78]).

CONCLUSIONS

Interruptions of cART were usually not induced by chemotherapy. The effect of cART interruptions on AIDS-related non-Hodgkin's lymphoma prognosis remains unclear, however, hepatitis C seropositivity emerged-as a predictor of death beyond the well-known international prognostic index score and CD4+ T-cell count.

Adverse events to antiretrovirals in the Swiss HIV Cohort Study: effect on mortality and treatment modification

BACKGROUND

Antiretroviral therapy (ART) decreases morbidity and mortality in HIV-infected patients but is associated with considerable adverse events (AEs).

METHODS

We examined the effect of AEs to ART on mortality, treatment modifications and drop-out in the Swiss HIV Cohort Study. A cross-sectional evaluation of prevalence of 13 clinical and 11 laboratory parameters was performed in 1999 in 1,078 patients on ART. AEs were defined as abnormalities probably or certainly related to ART. A score including the number and severity of AEs was defined. The subsequent progression to death, drop-out and treatment modification due to intolerance were evaluated according to the baseline AE score and characteristics of individual AEs.

RESULTS

Of the 1,078 patients, laboratory AEs were reported in 23% and clinical AEs in 45%. During a median follow up of 5.9 years, laboratory AEs were associated with higher mortality with an adjusted hazard ratio (HR) of 1.3 (95% confidence interval [CI] 1.2-1.5; P < 0.001) per score point. For clinical AEs no significant association with increased mortality was found. In contrast, an increasing score for clinical AEs (HR 1.11,95% CI 1.04-1.18; P = 0.002), but not for laboratory AEs (HR 1.07, 95% CI 0.97-1.17; P = 0.17), was associated with antiretroviral treatment modification. AEs were not associated with a higher drop-out rate.

CONCLUSIONS

The burden of laboratory AEs to antiretroviral drugs is associated with a higher mortality. Physicians seem to change treatments to relieve clinical symptoms, while accepting laboratory AEs. Minimizing laboratory drug toxicity seems warranted and its influence on survival should be further evaluated.