High specificity of line-immunoassay based algorithms for recent HIV-1 infection independent of viral subtype and stage of disease

Background

Serologic testing algorithms for recent HIV seroconversion (STARHS) provide important information for HIV surveillance. We have shown that a patient's antibody reaction in a confirmatory line immunoassay (INNO-LIA^TM HIV I/II Score, Innogenetics) provides information on the duration of infection. Here, we sought to further investigate the diagnostic specificity of various Inno-Lia algorithms and to identify factors affecting it.

Methods

Plasma samples of 714 selected patients of the Swiss HIV Cohort Study infected for longer than 12 months and representing all viral clades and stages of chronic HIV-1 infection were tested blindly by Inno-Lia and classified as either incident (up to 12 m) or older infection by 24 different algorithms. Of the total, 524 patients received HAART, 308 had HIV-1 RNA below 50 copies/mL, and 620 were infected by a HIV-1 non-B clade. Using logistic regression analysis we evaluated factors that might affect the specificity of these algorithms.

Results

HIV-1 RNA <50 copies/mL was associated with significantly lower reactivity to all five HIV-1 antigens of the Inno-Lia and impaired specificity of most algorithms. Among 412 patients either untreated or with HIV-1 RNA ≥50 copies/mL despite HAART, the median specificity of the algorithms was 96.5% (range 92.0-100%). The only factor that significantly promoted false-incident results in this group was age, with false-incident results increasing by a few percent per additional year. HIV-1 clade, HIV-1 RNA, CD4 percentage, sex, disease stage, and testing modalities exhibited no significance. Results were similar among 190 untreated patients.

Conclusions

The specificity of most Inno-Lia algorithms was high and not affected by HIV-1 variability, advanced disease and other factors promoting false-recent results in other STARHS. Specificity should be good in any group of untreated HIV-1 patients.

Evaluation of three chromogenic media (MRSA-ID, MRSA-Select and CHROMagar MRSA) and ORSAB for surveillance cultures of methicillin-resistant Staphylococcus aureus

Screening specimens were homogenised in saline 0.9% w/v before either direct inoculation or following enrichment in broth on three chromogenic media (MRSA-ID, CHROMagar MRSA and MRSA Select) and ORSAB medium for the detection of methicillin-resistant Staphylococcus aureus (MRSA). In total, 102 of 466 specimens yielded MRSA on at least one medium. After incubation for 16-18 h, the sensitivity was 51%, 59%, 47% and 65% on MRSA-ID, CHROMagar MRSA, ORSAB and MRSA Select, respectively, compared with 82%, 75%, 67% and 80%, respectively, after 42 h, and 93%, 95%, 79% and not tested, respectively, following broth enrichment. There were significantly more MRSA colonies on MRSA-Select after 16-18 h than on ORSAB or MRSA ID (p 0.001 and 0.0022, respectively), whereas there were more MRSA colonies after 42 h on MRSA-ID and MRSA-Select than on ORSAB (p 0.0004 and 0.012, respectively). The specificity of the media for identifying MRSA based on the colour of colonies after incubation for 16-18 h was 100%, 99%, 99% and 100%, respectively, compared with 98%, 97%, 98% and 98%, respectively, after 42 h, and 100%, 99%, 100% and not tested, respectively, following broth enrichment. The speed of detection (mean time to report a positive result) was 1.65, 1.72, 2.31 and 1.35 days, respectively. For each of the three media tested following enrichment, the use of an enrichment broth increased the detection rate of MRSA by 16-24%.

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.

Molecular Epidemiology of Pseudomonas aeruginosa in the Intensive Care Units - A Review

Pseudomonas aeruginosa is one of the leading nosocomial pathogens in intensive care units (ICU). This opportunist pathogen is commonly recovered from moist environments, and is also found colonizing 2.6 to 24% of hospitalized patients. We reviewed the recent literature that used highly discriminatory typing methods to precisely identify the reservoirs and modes of transmission of this microorganism in the ICU setting. In most ICUs, the endogenous flora was suspected to be the main source of infection compared to exogenous sources (other patients, the contaminated environment such as sinks or taps). However, the percentage of endogenous versus exogenous sources might vary considerably from one setting to another. Reasons for this include the compliance of health care workers to infection control measures, the contamination of the environment, and probably also the biology of the pathogen (intrinsic fitness factors). As P. aerugi-nosa is ubiquitous in the environment and colonizes up to 15% of hospitalized patients, eradication of the reservoir is difficult, if not impossible. Therefore, efforts should primarily focus on reinforcement of infection control measures to limit its transmission.

Changing molecular epidemiology of methicillin-resistant Staphylococcus aureus in a small geographic area over an eight-year period

The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) at an international level shows that most MRSA strains belong to a few pandemic clones. At the local level, a predominance of one or two clones was generally reported. However, the situation is evolving and new clones are emerging worldwide, some of them with specific biological characteristics, such as the presence of Panton-Valentine leucocidin (PVL). Understanding these changes at the local and international levels is of great importance. Our objective was to analyze the evolution of MRSA epidemiology at multiple sites on a local level (Western Switzerland) over a period of 8 years. Data were based on MRSA reports from seven sentinel laboratories and infection control programs covering different areas. Pulsed-field gel electrophoresis was used to type MRSA isolates. From 1997 to 2004, a total of 2,256 patients with MRSA were reported. Results showed the presence of four predominant clones (accounting for 86% of patients), which could be related to known international clones (Berlin, New York/Japan, Southern Germany, and Iberian clones). Within the small geographic region, the 8-year follow-up period in the different areas showed spacio-temporal differences in the relative proportions of the four clones. Other international MRSA clones, as well as clones showing genetic characteristics identical to those of community-acquired MRSA (SCCmec type IV and the presence of PVL genes), were also identified but presumably did not disseminate. Despite the worldwide predominance of a few MRSA clones, our data showed that at a local level, the epidemiology of MRSA might be different from one hospital to another. Moreover, MRSA clones were replaced by other emerging clones, suggesting a rapid change.

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.

Blood samples drawn for culture as a surrogate marker for case-mix adjustment of hospital antibiotic use

Hospital antibiotic consumption is generally adjusted to occupancy. This study hypothesised that the number of blood culture samples could be a surrogate marker for case-mix adjustment. Antibiotic consumption was compared over 16 consecutive trimesters in one medical ward in terms of patient-days or blood culture samples. Compared with patient-days, measurement adjusted to blood culture samples detected three trimesters with an unusually high consumption, and one trimester with consumption falsely classified as high because of a high incidence of infections. Blood culture numbers enabled easy and accurate identification of periods with a drift in antibiotic consumption ina medical ward.

Double-locus sequence typing using clfB and spa, a fast and simple method for epidemiological typing of methicillin-resistant Staphylococcus aureus

Sequence-based epidemiological typing of methicillin-resistant Staphylococcus aureus (MRSA) has recently been promoted because it results in unambiguous data sets that can be organized in local and global databases. The replacement of previous typing methods, such as the highly discriminatory pulsed-field gel electrophoresis (PFGE), has been attempted with various markers and typing schemes, including spa typing and multilocus sequence typing. However, despite a number of advantages, none of these methods showed convincing evidence for performance in epidemiological typing comparable to that of PFGE. By using three sets of 48 MRSA strains comprising isolates that were (i) genetically highly diverse, (ii) genetically related, and (iii) obtained from long-term carriers, we analyzed the performance of the four highly polymorphic S. aureus markers: clfA, clfB, fnbA, and spa. Typeability, discriminatory power, in vivo stability, and evolution of these markers were compared to those of PFGE. Clearly, none of the markers alone could match the discriminatory power of PFGE (63 genotypes; index of discrimination of 0.96). Instead, this could be achieved by combining markers in pairs. We showed that by using only 3' partial sequences of approximately 500 bp, the majority of each marker's discriminatory power was displayed, and using the partial sequences, the best performance was obtained with the combination of clfB and spa (57 genotypes; index of discrimination of 0.94). Genetic changes were not observed for any of the sequence markers over a period of 3 years and in the case of partial sequences for a period of more than 4 years. This is in contrast to PFGE where changes occurred after several months. The genetic differences found between isolate pairs of long-term carriers and among highly related isolates indicated clonal evolution. A typing scheme based on 500-bp 3' partial sequences of clfB and spa is proposed.

A Smoking Cessation Programme in HIV-Infected Individuals: A Pilot Study

Background

Antiretroviral therapy (ART) is a risk factor for cardiovascular disease (CVD) and smoking the most important modifiable cardiovascular risk factor.

Methods

We prospectively evaluated a smoking cessation programme (SCP) in HIV-infected individuals (intervention: counselling and nicotine replacement therapy). Primary endpoint was the smoking cessation rate at 12 months; secondary endpoints were CVD morbidity and mortality. Controls were a not randomized control group of smokers not participating in the SCP.

Results

Four-hundred and seventeen of 680 (61%) patients were smokers, and 34 of these participated in the SCP. Of these 34 individuals, 82% were male, the median age was 43 years, prior AIDS was recorded in 29%, and depressive disorder was recorded in 18%. Twenty-five (74%) patients were receiving ART. Additional risk factors were dyslipidaemia (68%), a prior cardiovascular event (24%), hypertension (15%), and a family history of CVD in 2/34 (6%) individuals. According to the Framingham equation, the 10-year risk of CVD was higher in SCP participants than in controls (11.2% versus 8.5%, P=0.06). At termination of the SCP, 17/34 (50%) individuals had stopped smoking compared with 57/383 (15%) controls. Self-reported smoking abstinence for ≥12 months was 13/34 (38%) in the intervention group and 27/383 (7%) in the control group (odds ration 6.2, 95% confidence interval 2.8–14.3). During the follow-up, two SCP participants and 4 controls experienced a myocardial infarction. One patient in the control group died of CVD.

Conclusions

SCP in HIV-infected individuals is feasible and should be encouraged. The long-term impact of smoking cessation on CVD morbidity and mortality should be evaluated in comparative trials.

[Infective endocarditis and outpatient practice]

The incidence of infectious endocarditis is fairly stable over the past decades. It is estimated at roughly 3-4 case per patient-year. However, as a consequence of medical progress, Staphylococcus aureus endocarditis has become more prevalent. This is particularly true for health-care associated endocarditis, especially in iv-drug abusers or hemodialysis patients. Mortality (15-20% of patients in the last series) remains high. About 50% of patients undergo surgical treatment, whereas outpatient therapy is more and more frequent for highly selected subgroups of patients without complications and infected with low-risk organims. The present paper reviews in detail the epidemiology of infective endocarditis and discuss in detail the different out-patients therapies.

A Longitudinal Analysis of Healthcare Costs after Treatment Optimization following Genotypic Antiretroviral Resistance Testing: Does Resistance Testing pay off?

Objective

To assess the impact of antiretroviral therapy optimized by genotypic antiretroviral resistance testing (GRT) on healthcare costs over a 2-year period in patients after antiretroviral treatment failure.

Study design

Non-randomized, prospective, tertiary care, clinic-based study.

Patients

One-hundred and forty-two HIV patients enrolled in the ‘ZIEL’ study and the Swiss HIV Cohort Study who experienced virological treatment failure.

Methods

For all patients GRT was used to optimize the antiretroviral treatment regimen. All healthcare costs during 2 years following GRT were assessed using micro-costing. Costs were separated into ART medication costs and healthcare costs other than ART medication (that is, non-ART medication costs, in-patient costs and ambulatory [out-patient] costs). These cost estimates were then split into four consecutive 6-month periods (period 1–4) and the accumulated cost for each period was calculated. Univariate and multivariate regression modelling techniques for repeated measurements were applied to assess the changes of healthcare costs over time and factors associated with healthcare costs following GRT.

Results

Overall healthcare costs after GRT decreased over time and were significantly higher in period 1 (32%; 95% confidence interval [CI]: 18–47) compared with period 4. ART medication costs significantly increased by 1,017 (95% CI: 22–2,014) Swiss francs (CHF) from period 1–4, whereas healthcare costs other than ART medication costs decreased substantially by a factor of 3.1 (95% CI: 2.6–3.7) from period 1 to period 4. Factors mostly influencing healthcare costs following GRT were AIDS status, costs being 15% (95% CI: 6–24) higher in patients with AIDS compared with patients without AIDS, and baseline viral load, costs being 12% (95% CI: 6–17) higher in patients with each log increase in plasma RNA.

Conclusions

Optimized antiretroviral treatment regimens following GRT lead to a reduction of healthcare costs in patients with treatment failure over 2 years. Patients in a worse health state (that is, a positive AIDS status and high baseline viral load) will experience higher overall costs.

Evidence for clonal evolution among highly polymorphic genes in methicillin-resistant Staphylococcus aureus

The evolution of Staphylococcus aureus has been described as predominantly clonal, based on evidence from seven housekeeping genes. We aimed to test if this was also true for more polymorphic genes. In a collection of 60 isolates including major European epidemic methicillin-resistant S. aureus (MRSA) and sporadic MRSA strains, we compared the partial gene sequences of seven housekeeping genes (arcC, aroE, glpF, gmk, pta, tpi, and yqiL), six core adhesion genes (present in all strains) (clfA, clfB, fnbA, map, sdrC, and spa), and four accessory adhesion genes (not present in all strains) (ebpS, fnbB, sdrD, and sdrE). Nucleotide diversity of adhesion genes was 2- to 10-fold higher than genes used for multilocus sequence typing. All genes showed evidence for purifying selection with a weakly reduced level among accessory adhesion genes. Among these highly variable genes, there was no evidence for a difference in molecular evolution between epidemic and sporadic strains. Gene trees constructed from concatenated sequences of housekeeping, core adhesion, and accessory adhesion genes were highly congruent, indicating clonality, despite some evidence for homologous exchange. Further evidence for clonality was found with an overall positive correlation of allelic and nucleotidic divergence for both seven housekeeping genes and six core adhesion genes. However, for small allelic differences that fit the demarcations of clonal complexes (CCs) there was no such correlation, suggesting that recombination occurred. Therefore, despite an overall clonal population structure, recombination between related isolates within CCs might have contributed to S. aureus evolution.

[Respiratory syncytial virus infections: measures in immunocompromised patients]

RSV infections are an annually recurring problem of significant morbiditiy and mortality in the immunocompromised host, especially after lung and stem cell transplantation. The effectiveness of hygienic (isolation) and therapeutic (ribavirin, immunoglobulin, pavilizumab) measures depends of high index of suspicion and rapid diagnostic confirmation by the antigen test, PCR and/or culture. Allocation of resources require stratification of measures according to the known or estimated risk for complications.

Are Specific Antiretrovirals associated with an Increased Risk of Discontinuation due to Toxicities or Patient/Physician Choice in patients with Hepatitis C Virus Coinfection?

Background

Liver damage associated with hepatitis C (HCV) may influence the likelihood of experiencing discontinuation due to toxicities or patient/physician choice (TOXPC) in patients taking combination antiretroviral therapy (cART). Little information to address this concern is available from clinical trials as patients with HCV are often excluded.

Aims

To compare incidence rates of discontinuation due to TOXPC associated with specific antiretrovial drugs in patients with or without HCV.

Patients/methods

A total of 4929 patients from EuroSIDA under follow-up from January 1999 on a specific nucleoside pair (zidovudine/lamivudine, didanosine/stavudine, stavudine/lamivudine, or other) with a third drug (abacavir, nelfinavir, indinavir, nevirapine, efavirenz, lopinavir/ ritonavir or other boosted-protease inhibitor (PI)-containing regimen) and with known HCV serostatus were studied for the incidence of discontinuation of any nucleoside pair or third drug due to TOXPC. Incidence rate ratios were derived from Poisson regression models.

Results

In total 1358 patients had HCV (27.5%). During 12 799 person-years of follow-up there were 2141 discontinuations due to TOXPC for nucleoside pairs and 2501 for third drugs. The incidence of discontinuation due to TOXPC was consistently higher in patients with HCV after stratification by nucleoside pair or third drug. After adjustment for CD4+ count, gender, exposure group, time on HAART, region and treatment regimen, there were few differences in the rate of discontinuation due to TOXPC in those with HCV compared with those without for any nucleoside pairs or third drugs. Similar results were seen when concentrating on discontinuation due to toxicities alone.

Conclusions

Although patients with HCV generally had higher rates of discontinuation due to TOXPC compared with patients without HCV, there was little evidence to suggest that this was associated with any specific nucleoside pair or third drug used as part of cART. Our results do not suggest that any specific component of cART is more poorly tolerated in patients with HCV or that the presence of HCV should influence the choice between antiretrovirals used as part of a cART regimen.

Thymidine Analogue Mutation Profiles: Factors Associated with Acquiring Specific Profiles and their Impact on the Virological Response to Therapy

Background

Studies have suggested that HIV-1 may develop thymidine analogue mutations (TAMs) by one of two distinct pathways – the TAM1 pathway (including mutations 41L, 210W and 215Y) or the TAM2 pathway (including mutations 67N, 70R and 219E/Q) – under the pressure of a not fully suppressive thymidine-analogue-containing regimen.

Methods

Frozen plasma samples stored in the EuroSIDA repository were selected and sent to two central laboratories for genotypic analysis. We considered 733 patients with at least one genotypic test showing ≥1 TAMs (the first of these tests in chronological order was used). TAM1 and TAM2 genotypic profiles were defined in accordance with previous literature. Statistical modelling involved logistic regression and linear regression analysis for censored data.

Results

The observed frequencies of patterns classifiable as TAM1 or TAM2 profiles were markedly higher than the probabilities of falling into these classifications by chance alone. The chance of detecting a TAM2 profile increased by 25% per additional year of exposure to zidovudine. We found that mutations 67N and 184V were not associated with a particular TAM profile. In the presence of TAM2 profiles, the adjusted mean difference in the 6-month viral reduction was 0.96 log10 copies/ml (95% confidence interval: 0.20; 1.73) higher in patients who started stavudine-containing regimens instead of zidovudine-containing regimens.

Conclusions

This study provides evidence that the suggested TAM clustering is a real phenomenon and that it may be driven by which thymidine analogue the patients has used. In patients with TAM2-resistant viruses, stavudine appears to retain greater viral activity than zidovudine.

Lipid Profiles for Antiretroviral-Naive Patients Starting Pi- and Nnrti-Based Therapy in the Swiss HIV Cohort Study

Background

Blood lipid abnormalities in patients on highly active antiretroviral therapy (HAART) have been associated with exposure to protease inhibitors (PIs), particularly ritonavir. First therapy with a non-nucleoside reverse transcriptase inhibitor (NNRTI) leads to relatively favourable lipid profiles. We report on medium-term lipid profiles (up to 5 years) for antiretroviral-naive patients starting NNRTI- and PI-based HAART in the Swiss HIV Cohort Study.

Methods

Since April 2000, blood samples taken at visits scheduled every 6 months have been analysed for cholesterol and triglyceride concentrations. For 1065 antiretroviral-naive patients starting HAART after April 2000, we estimated changes in concentration over time using multivariate linear regression with adjustment for baseline covariates, use of lipid-lowering drugs and whether the sample was taken in a fasting state.

Results

Non-high density lipoprotein (HDL) cholesterol levels increase with increasing exposure to either PI- or NNRTI-based therapy, HDL cholesterol levels increase and triglyceride levels decrease with increasing exposure to NNRTI-based therapy, whereas triglyceride levels increase with increasing exposure to PI-based therapy. Between NNRTI-based therapies, there is a slight difference in triglyceride levels, which tend to increase with increasing exposure to efavirenz and to decrease with increasing exposure to nevirapine. Of the three common PI-based therapies, nelfinavir appears to have a relatively favourable lipid profile, with little change with increasing exposure. Of the other two PI therapies, lopinavir with ritonavir has a more favourable profile than indinavir with ritonavir, with smaller increases in both non-HDL cholesterol and triglycerides and an increase in HDL cholesterol. Increasing exposure to abacavir is associated with a decrease in the level of triglycerides.

Conclusion

In general, NNRTI-based therapy is associated with a more favourable lipid profile than PI-based therapy, but different PI-based therapies are associated with very different lipid profiles. Nelfinavir appears to have a relatively favourable lipid profile. Of the two boosted PI therapies, lopinavir appears to have a more favourable lipid profile than indinavir.

Water disinfection with ozone, copper and silver ions, and temperature increase to control Legionella: seven years of experience in a university teaching hospital

The efficacy of ozonation, copper-silver ionization and increased temperature in controlling Legionella spp. in the hot water distribution networks of a university hospital was evaluated. Two separate water distribution networks were studied; network 1 which supplies the surgical intensive care units, and network 2 which supplies the medical intensive care units and the emergency room. Network 1 has been disinfected by ozonation since 1995, and network 2 has been disinfected by ionisation since 1999. The hot water temperature was increased from 50 to 65 degrees C in 1998 and 2000 in networks 1 and 2, respectively. Water samples and swabs of the water outlets were cultured for Legionella spp. between four and six times each year, providing data before and after implementation of the disinfection procedures. There was no significant difference in the proportion of samples positive for Legionella spp. after ozonation in network 1 or after ionization in network 2. In both networks, there was a significant reduction in legionella isolates after increasing the hot water temperature to 65 degrees C. Maintaining the hot water temperature above 50 degrees C throughout both networks proved to be the most effective control measure in our hospital.

Influence of Bacille Calmette-Guerin Vaccination on Size of Tuberculin Skin Test Reaction: To What Size?

BACKGROUND

Previous bacillus Calmette-Guerin (BCG) vaccination can confound the results of a tuberculin skin test (TST). We sought to determine a cutoff diameter of TST induration beyond which the influence of BCG vaccination was negligible in evaluating potential Mycobacterium tuberculosis infection in a population of health care workers with a high vaccination rate and low incidence of tuberculosis.

METHODS

From 1991 through 1998, all new employees at the University Hospital of Lausanne, Switzerland, underwent a 2-step TST at entry visit. We also gathered information on demographic characteristics, along with factors commonly associated with tuberculin positivity, including previous BCG vaccination, history of latent M. tuberculosis infection, and predictors for M. tuberculosis infection.

RESULTS

Among the 5117 investigated subjects, we found that influence of BCG vaccination on TST results varied across categories of age (likelihood ratio test, 0.0001). Prior BCG vaccination had a strong influence on skin test results of <or=18 mm in diameter among persons <40 years old, compared with the influence of factors predictive of M. tuberculosis infection. Prior latent M. tuberculosis infection and travel or employment in a country in which tuberculosis is endemic also had significant influences.

CONCLUSIONS

Interpretation of TST reactions of <or=18 mm among BCG-vaccinated persons <40 years of age must be done with caution in areas with a low incidence of tuberculosis. In such a population, except for persons who have never been vaccinated, TST reactions of <or=18 mm are more likely to be the result of prior vaccination than infection and should not systematically lead to preventive treatment.

Risk of Borrelia burgdorferi infection in western Switzerland following a tick bite

The aim of this study was to define the risk of developing Lyme borreliosis after a tick bite. A survey was conducted from 1993 to 1995 in the western part of Switzerland in a group of patients who presented for treatment of a recent tick bite. Only patients with negative serological tests (enzyme-linked fluorescent assay screening test, and IgG and IgM immunoblots) at the first consultation and for whom a second blood sample was available 2 months later were included in the study. Of the 376 patients included, 266 had no clinical manifestation (group 1) and 110 had a small local cutaneous reaction (<2 cm) (group 2). The tick was available for 160 patients. Seroconversion was observed in 4.5% of 376 patients, 3.4% in group 1 and 7.2% in group 2. Typical erythema migrans, confirmed by seroconversion, was observed in three of 376 (0.8%) patients, while five of 376 (1.3%) patients developed a skin lesion without seroconversion. No other clinical manifestation of Lyme borreliosis was observed among these 376 patients. Borrelia detection in ticks did not correlate significantly with the risk of Lyme borreliosis. In conclusion, the risk of developing Lyme borreliosis in western Switzerland after a tick bite is low, and therefore, prophylactic antibiotics are not required.

Faucets as a reservoir of endemic Pseudomonas aeruginosa colonization/infections in intensive care units

OBJECTIVE

To evaluate the role of faucets as a reservoir for Pseudomonas aeruginosa colonization/infection of patients hospitalized in intensive care units (ICUs).

DESIGN

Prospective epidemiological investigation performed during a nonepidemic period of 1 year. The inner part of the ICU faucets were swabbed for P. aeruginosa. Data were recorded on all patients with at least one culture of a clinical specimens positive for P. aeruginosa. Pulsed-field gel electrophoresis was used to characterize the strains.

SETTING

Five ICUs of a university hospital which are supplied by two separate water distribution networks.

PATIENTS

During a 1-year period 132 cases were investigated.

RESULTS

In 42% of cases (56/132) there were isolates identical to those found in the faucets, with a total of nine different genotypes. Among the nine genotypes isolated from both patients and faucets one of them, the most prevalent, was isolated in the two networks and in 30 cases. The other eight genotypes were recovered almost exclusively from either one (three genotypes in 12 cases) or the other (five genotypes in 12 cases) network and from the patients in the corresponding ICUs.

CONCLUSIONS

These results suggest that the water system of the ICUs was the primary reservoir of patient's colonization/infection with P. aeruginosa in a substantial proportion of patients, although the exact mode of acquisition could not be determined.

Baseline Resistance and Virological Outcome in Patients with Virological Failure who Start a Regimen Containing Abacavir: Eurosida Study

Objectives

To investigate the ability of several HIV-1 drug-resistance interpretation systems, as well as the number of pre-specified combinations of abacavir-related mutations, to predict virological response to abacavir-containing regimens in antiretroviral therapy-experienced, abacavir-naive patients starting an abacavir-containing regimen in the EuroSIDA cohort.

Patients and methods

A total of 100 HIV-infected patients with viral load (VL) >500 copies/ml who had a plasma sample available at the time of starting abacavir (baseline) were included. Resistance to abacavir was interpreted by using eight different commonly used systems that consisted of rules-based algorithms or tables of mutations. Correlation between baseline abacavir-resistance mutations and month 6 virological response was performed on this population using a multivariable linear regression model accounting for censored data.

Results

The baseline VL was 4.36 log10 RNA copies/ml [interquartile range (IQR): 3.65–4.99 log10 RNA copies/ml] and the median CD4 cell count was 210 cells/μl (IQR: 67–305 cells/μl). Our patients were pre-exposed to a median of seven antiretrovirals (2–12) before starting abacavir therapy. The median (range) number of abacavir mutations (according to the International AIDS Society-USA) detected at baseline was 3.5 (0–8). Overall, the Kaplan–Meier estimate of the median month 6 VL decline was 0.86 log10 RNA copies/ml [95% confidence intervals (95% CI): 0.45–1.24]. The VL in those patients ( n=31) who intensified treatment by adding only abacavir decreased by a median 0.20 log10 RNA copies/ml (95% CI: -0.18; +0.94). The proportion of patients who harboured viruses fully resistant to abacavir among the eight genotypic resistance interpretation algorithms ranged from 12% [Agence Nationale de Recherches sur le SIDA (ANRS)] to 79% [Stanford HIV RT and PR Sequence Database (HIVdb)]. Some interpretation systems showed statistically significant associations between the predicted resistance status and the virological response while others showed no consistent association. The number of active drugs in the regimen was associated with greater virological suppression (additional month 6 VL reduction per additional sensitive drug=0.51, 95% CI: 0.15–0.88, P=0.006); baseline VL was also weakly associated (additional month 6 VL reduction per log10 higher=0.30, 95% CI: -0.02; +0.62, P=0.06). In contrast, the number of drugs previously received was associated with diminished viral reduction (additional month 6 VL reduction per additional drug=-0.14, 95% CI: -0.28; 0.00, P=0.05).

Conclusions

Our results revealed a high degree of variability among several genotypic resistance interpretation algorithms currently in use for abacavir. Therefore, the interpretation of genotypic resistance for predicting response to regimens containing abacavir remains a major challenge.

Long-Term Virological Response to Multiple Sequential Regimens of Highly Active Antiretroviral Therapy for HIV Infection

Objective

Information about the virological response to sequential highly active antiretroviral therapy (HAART) for HIV infection is limited. The virological response to four consecutive therapies was evaluated in the Swiss HIV Cohort.

Design

Retrospective analysis in an observational cohort.

Methods

1140 individuals receiving uninterrupted HAART for 4.8 ±0.6 years were included. The virological response was classified as success (<400 copies/ml), low-level (LF: 400–5000 copies/ml) or high-level failure (HF: >5000 copies/ml). Potential determinants of the virological response, including patient demographics, treatment history and virological response to previous HAART regimens were analysed using survival and logistic regression analyses.

Results

40.1% failed virologically on the first (22.0% LF; 18.1% HF), 35.1% on the second (14.2% LF; 20.9% HF), 34.2% on the third (9.9% LF; 24.3% HF) and 32.7% on the fourth HAART regimen (9% LF; 23.7% HF). Nucleoside pre-treatment (OR: 2.34; 95% CI: 1.67–3.29) and low baseline CD4 T-cell count (OR: 0.79/100 cells rise; 95% CI: 0.72–0.88) increased the risk of HF on the first HAART. Virological failure on HAART with HIV-1 RNA levels exceeding 1000 copies/ml predicted a poor virological response to subsequent HAART regimens. A switch from a protease inhibitor- to a non-nucleoside reverse transcriptase inhibitor-containing regimen significantly reduced the risk of HF. Multiple switches of HAART did not affect the recovery of CD4 T lymphocytes.

Conclusion

Multiple sequential HAART regimens do not per se reduce the likelihood of long-term virological suppression and immunological recovery. However, early virological failure increases significantly the risk of subsequent unfavourable virological responses. The choice of a potent initial antiretroviral drug regimen is therefore critical. This study has been presented in part at the 10th Conference on Retroviruses & Opportunistic Infections. Boston, Mass., USA, 2003. Abstract #571.

Effect of Individual Cognitive Behaviour Intervention on Adherence to Antiretroviral Therapy: Prospective Randomized Trial

Objective

A high level of adherence to antiretroviral therapy is required for complete suppression of HIV replication, immunological and clinical effectiveness. We investigated whether cognitive behaviour therapy can improve medication adherence.

Design

Prospective randomized 1-year trial.

Setting

Collaboration of HIV university outpatient clinic and psychotherapists in private practice.

Participants

60 HIV-infected persons on stable anti-retroviral combination therapy and viral load below 50 copies/ml.

Intervention

Cognitive behaviour intervention in individual patients, in addition to standard of care.

Main outcome measures

Feasibility and acceptance of intervention; adherence to therapy assessed using medication event monitoring system (MEMS) and self-report questionnaire; virological failure; psychosocial measures.

Results

The median number of sessions for cognitive behaviour intervention per patient during the 1-year trial was 11 (range 2–25). At months 10–12, mean adherence to therapy as assessed using MEMS was 92.8% in the intervention and 88.9% in the control group ( P=0.2); the proportion of patients with adherence ≥95% was 70 and 50.0% ( P=0.014), respectively. While there was no significant deterioration of adherence during the study in the intervention arm, adherence decreased by 8.7% per year ( P=0.006) in the control arm. No differences between the intervention group and standard of care group were found regarding virological outcome. Compared with the control group, participants in the intervention group perceived a significant improvement of their mental health during the study period.

Conclusions

Cognitive behavioural support in addition to standard of care of HIV-infected persons is feasible in routine practice, and can improve medication adherence and mental health.

Impact of Genotypic Resistance Testing on Selection of Salvage Regimen in Clinical Practice

Objective

To determine whether genotypic resistance testing leads to selection of more potent drug regimens when compared to regimens based on treatment history only.

Design

Prospective, tertiary care centre-based study. Patients: One-hundred-and-forty-five HIV-infected adults on stable antiretroviral therapy (ART) for >6 months experiencing virological failure.

Methods

The physicians’ decision-making process when choosing a salvage regimen was prospectively documented: at time of virological failure, on ‘failing ART’, genotyping was performed and a hypothetical ‘clinical expert ART’ based upon patient's drug history was documented. Subsequently, data on resistance mutations, rating by a decision support software and drug history were used to define ‘genotyping ART’. After discussion with the patient, final treatment, ‘new personalized ART’ was chosen and prescribed. To compare the relative potency of the four ART regimens in a standardized manner, a resistance score ranging from 1 (best) to 8 (worst) based on drug ranking by decision support software was attributed to each ART regimen. Virological and immunological outcomes were analysed based on the magnitude of the resistance score.

Results

Median follow-up was 1.5 years. In all 145 patients, median resistance scores for the stepwise selected ART regimens were: ‘failing ART’: 4.5, ‘clinical expert ART’: 1.8, ‘genotyping ART’: 1.5 and ‘new personalized ART’: 2. The latter was 1.5 in patients who effectively switched to ‘new personalized ART’ ( n=89). Lower resistance scores translated into significantly improved virological response after initiation of ‘new personalized ART’. In multivariable analysis, lower resistance scores, lower baseline HIV RNA levels and use of novel antiretroviral drugs were associated with the probability of reducing plasma viraemia to <50 copies/ml. Conclusions: This study suggests that treatment choices including genotype and decision support software were virologically superior to those based on drug history only.

Poor value of pulsed-field gel electrophoresis to investigate long-term scale epidemiology of methicillin-resistant Staphylococcus aureus

Pulsed-field gel electrophoresis (PFGE) is widely used for epidemic investigations of methicillin-resistant Staphylococcus aureus (MRSA). In the present study, we evaluated its use in a long-term epidemiological setting (years to few decades, country to continent level). The clustering obtained from PFGE patterns after SmaI digestion of the DNA of 20 strains was compared to that obtained using a phylogenetic typing method (multiprimer RAPD). The results showed that the analysis of small PFGE bands (10-85kb) correlates better with multiprimer RAPD than the analysis of large PFGE bands (>85-700kb), suggesting that the analysis of small bands would be more suitable for the investigation of long-term epidemiological setting. However, given the technical difficulties to obtain a good resolution of these bands and the putative presence of plasmids among them, PFGE does not appear to be a method of choice for the long-term epidemiology analysis of MRSA.

Regional and temporal changes in AIDS in Europe before HAART

In a prospective observational study 4,485 patients from 46 clinical centres in 17 European countries were followed between April 1994 and November 1996. Information on AIDS-defining events (ADEs) were collected together with basic demographic data, treatment history and laboratory results. The centres were divided into four geographical regions (north, central, south-west and south-east) so that it was possible to identify any existing regional differences in ADEs. The regional differences that we observed included a higher risk of all forms of Mycobacterium tuberculosis infections (Tb) and wasting disease in the south-west and an increased risk of infections with the Mycobacterium avium complex (MAC) in the north. In Cox multivariable analyses, where north was used as the reference group, we observed hazard ratios of 6.87, 7.77, 2.29 and 0.16 (P < 0.05 in all cases) for pulmonary Tb, extrapulmonary Tb, wasting disease and MAC respectively in the south-west. Pneumocystis carinii pneumonia (PCP) was less commonly diagnosed in the central region (RH = 0.51, 95% CI 0 32-0.79, P = 0.003) and most common in the south-east (RH = 1.04, 95% CI 0.71-1.51, P = 0.85). Comparisons with a similar 'AIDS in Europe' study that concentrated on the early phase of the epidemic reveal that most of the regional differences that were observed in the 1980s still persist in the mid-1990s.

Changes in the cause of death among HIV positive subjects across Europe: results from the EuroSIDA study

OBJECTIVES

The causes of death among HIV-positive patients may have changed since the introduction of highly active antiretroviral therapy (HAART). We investigated these changes, patients who died without an AIDS diagnosis and factors relating to pre-AIDS deaths.

METHODS

Analyses of 1826 deaths among EuroSIDA patients, an observational study of 8556 patients. Incidence rates of pre-AIDS deaths were compared to overall rates. Factors relating to pre-AIDS deaths were identified using Cox regression.

RESULTS

Death rates declined from 15.6 to 2.7 per 100 person-years of follow-up (PYFU) between 1994 and 2001. Pre-AIDS incidence declined from 2.4 to 1.1 per 100 PYFU. The ratio of overall to pre-AIDS deaths peaked in 1996 at 8.4 and dropped to < 3 after 1998. The adjusted odds of dying following one AIDS defining event (ADE) increased yearly (odds ratio, 1.53; P < 0.001), conversely the odds of dying following three or more ADE decreased yearly (odds ratio, 0.79; P < 0.001). The proportion of deaths that followed an HIV-related disease decreased by 23% annually; in contrast there was a 32% yearly increase in the proportion of deaths due to known causes other than HIV-related or suicides. Injecting drug users (IDU) were significantly more likely to die before an ADE than homosexuals (relative hazard, 2.97; P < 0.0001) and patients from northern/eastern Europe (relative hazard, 2.01; P < 0.0001) were more likely to die pre-AIDS than southern patients.

CONCLUSIONS

The proportion of pre-AIDS deaths increased from 1994 to 2001; however, the incidence of pre-AIDS deaths and deaths overall declined. IDU and subjects from northern/eastern Europe had an increased risk of pre-AIDS death. HIV-positive patients live longer therefore it is essential to continue to monitor all causes of mortality to identify changes.

Molecular epidemiology of predominant clones and sporadic strains of methicillin resistant Staphylococcus aureus in Switzerland and comparison with European epidemic clones

OBJECTIVE

To assess the molecular epidemiology and risk factors of predominant clones and sporadic strains of methicillin-resistant Staphylococcus aureus (MRSA) in Swiss hospitals and to compare them with European strains of epidemic clones.

MATERIAL AND METHODS

One-year national survey of MRSA cases. Analysis of epidemiological and molecular typing data (PFGE) of MRSA strains.

RESULTS

In 1997, 385 cases of MRSA were recorded in the five Swiss university hospitals and in 47 community hospitals. Half of the cases were found in Geneva hospitals where MRSA was already known to be endemic. Molecular typing of 288 isolates (one per case) showed that 186 (65%) belong to four predominant clones, three of which were mostly present in Geneva hospitals. In contrast, the fourth clone (85 cases) was found in 23 hospitals (in one to 16 cases per hospital). The remaining 35% of the strains were clustered into 62 pulsed field gel electrophoresis types. They accounted for one to five patients per hospital and were defined as sporadic. Multivariate analysis revealed no independent risk factors for harboring a predominant versus a sporadic strain, except that transfer from a foreign hospital increases the risk of harboring a sporadic strain (OR, 42; 95% CI, 5-360).

CONCLUSION

While cases with predominant clones were due to the local spread of these clones, most sporadic cases appear to be due to the continuous introduction of new strains into the country. With the exception of a transfer from a hospital outside Switzerland, no difference in the clinical or epidemiological characteristics was observed between patients harboring a predominant clone and those with a sporadic strain.

Response to Antiretroviral Therapy among Patients Exposed to Three Classes of Antiretrovirals: Results from the Eurosida Study

There is an increasing proportion of HIV-positive patients exposed to all licensed classes of antiretrovirals, and the response to salvage regimens may be poor. Among over 8500 patients in EuroSIDA, the proportion of treated patients exposed to nucleosides, protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitor (NNRTI) increased from 0% in 1996 to 47% in 2001. Four-hundred-and-thirteen patients, who had failed virologically two highly active antiretroviral therapy (HAART) regimens and experienced all three main drug classes, started a salvage regimen of at least three drugs, in which at least one new PI or NNRTI was included. Median viral load was 4.7 log copies/ml [Interquartile range (IQR) 4.2–5.2], CD4 lymphocyte count 150/mm3 (IQR 60–274/mm3) and follow-up 14 months. Of these patients, 283 (69%) subsequently experienced at least a 1 log decline in viral load and 202 (49%) achieved a viral load <500 copies/ml. Conversely, the CD4 count halved from the baseline value in 88 (21%), and 45 (11%) experienced a new AIDS-defining disease. In multivariable analyses, a 1 log viral load reduction was related to baseline viral load [relative hazard (RH) 1.27 per 1 log higher; P=0.008], a previous viral load of less than 500 copies/ml (RH 1.69; P=0.002), more recent initiation of the regimen (RH 1.36 per year more recent; P=0.02), number of new drugs in the regimen (RH 1.20 per drug; P=0.02), time since start of antiretroviral therapy (RH 0.94 per extra year; P=0.035) and time spent on HAART with viral load >1000 copies/ml (RH 0.96 per extra month; P=0.0001). Analysis of factors associated with CD4 count decline and new AIDS disease also indicated improved outcomes in more recent times and a tendency for a better response in those starting more new drugs, but no relationship with the total number of drugs. Outcomes in people starting salvage regimens appear to depend on the number of new drugs started but not on the total number of drugs being used.

Spare post-exposure prophylaxis with round-the-clock HIV testing of the source patient

After occupational exposures, immediate HIV testing of source patients may avoid the unnecessary use of post-exposure prophylaxis (PEP). Two time periods were compared. Before the availability of 24 h a day immediate testing, PEP was initiated after 12.6% of exposures, compared with 3.7% during the second period. The adjusted relative odds ratio of PEP during the second compared with the first period, was 0.23. The availability of immediate HIV testing limits unnecessary occupational PEP.

Hyperlactatemia and antiretroviral therapy: the Swiss HIV Cohort Study

The prevalence, clinical presentation, and risk factors for hyperlactatemia among patients receiving antiretroviral therapy was determined during a 1-month period for patients in the Swiss HIV Cohort Study. Overall, 73 (8.3%) of 880 patients presented an increase in serum lactate of >1.1 times the upper normal limit (UNL). For 9 patients (1%), lactate elevation was moderate or severe (>2.2 times the UNL). Patients who presented with hyperlactatemia were more likely to be receiving stavudine with or without didanosine (odds ratio, 2.7; 95% confidence interval, 1.5-4.8), as compared with patients who received zidovudine-based regimens. The risk increased with increasing time receiving stavudine with or without didanosine. The association between hyperlactatemia and stavudine with or without didanosine was not biased by these medications being more recently available and, therefore, being given preferentially to patients who had prolonged use of nucleoside analog reverse-transcriptase inhibitors. Hyperlactatemia was associated with lipoatrophy, hyperlipidemia, and hyperglycemia. Age, sex, or stage of infection with human immunodeficiency virus were not predictive of hyperlactatemia. Determination of lactate levels may prove useful in the screening for mitochondrial toxicity.

HIV viral load response to antiretroviral therapy according to the baseline CD4 cell count and viral load

CONTEXT

It is unclear whether delay in initiation of antiretroviral therapy (ART) may lead to a poorer viral load response for patients with human immunodeficiency virus (HIV).

OBJECTIVE

To characterize the relationship of viral load response to ART with baseline CD4 cell count and baseline viral load.

DESIGN

Inception cohort of 3430 therapy-naive patients with HIV, of whom 3226 patients had at least 1 viral load count after the start of ART.

SETTING

Three cohort studies of patients cared for in HIV clinics in Europe between 1996 and 2000.

PATIENTS

All patients initiating ART consisting of at least 3 drugs initiated in or after 1996 and for whom CD4 cell count and viral load were available in the prior 6 months (at most).

MAIN OUTCOME MEASURES

Viral load decrease to below 500 copies/mL; viral load rebound to above 500 copies/mL (2 consecutive values).

RESULTS

Of 3226 patients during the median follow-up of 119 weeks, 2741 (85%) experienced viral suppression to less than 500 copies/mL by 32 weeks. Relative hazards (RHs) of achieving this were 1.08 (95% confidence interval [CI], 0.98-1.21) and 0.94 (95% CI, 0.84-1.04) for baseline CD4 cell counts between 200 and 349 x 10(6)/L and baseline CD4 cell counts lower than 200 x 10(6)/L, respectively, compared with baseline CD4 cell counts of 350 x 10(6)/L or higher, after adjustment for several factors including baseline viral load. For baseline viral load, the RHs were 0.95 (95% CI, 0.84-1.07) and 0.65 (95% CI, 0.58-0.74), for 10 000 to 99 999 and 100 000 copies/mL or greater, respectively, compared with less than 10 000 copies/mL, but the probability of viral load lower than 500 copies/mL at week 32 was similar in all 3 groups. Subsequent rebound above 500 copies/mL was no more likely with a lower baseline CD4 cell count or higher viral load.

CONCLUSION

In this study, lower CD4 cell counts and higher viral loads at baseline were not associated with poorer virological outcome of ART. Those with baseline viral loads of greater than 100 000 copies/mL had a slower rate of achieving viral suppression.

Prevalence of adverse events associated with potent antiretroviral treatment: Swiss HIV Cohort Study

BACKGROUND

Data on adverse events to antiretroviral treatment have been recorded in clinical trials, post-marketing analyses, and anecdotal reports. Such data might not be an up-to-date or comprehensive assessment of all possible treatment combinations defined as potent antiretroviral treatment.

METHODS

Using a standard clinical and laboratory method, we assessed prevalence of adverse events in 1160 patients who were receiving antiretroviral treatment. We measured the toxic effects associated with the drug regimen (protease inhibitor [PI], non-nucleoside and nucleoside analogue reverse transcriptase inhibitor) and specific compounds using multivariate analyses.

FINDINGS

47% (545 of 1160) of patients presented with clinical and 27% (194 of 712) with laboratory adverse events probably or definitely attributed to antiretroviral treatment. Among these, 9% (47 of 545) and 16% (30 of 194), respectively, were graded as serious or severe. Single-PI and PI-sparing-antiretroviral treatment were associated with a comparable prevalence of adverse events. Compared with single-PI treatment, use of dual-PI-antiretroviral treatment and three-class-antiretroviral treatment was associated with higher prevalence of adverse events (odds ratio [OR] 2.0 [95% CI 1.0-4.0], and 3.9 [1.2-12.9], respectively). Compound specific associations were identified for zidovudine, lamivudine, stavudine, didanosine, abacavir, ritonavir, saquinavir, indinavir, nelfinavir, efavirenz, and nevirapine.

INTERPRETATION

We recorded a high prevalence of toxic effects attributed to antiretroviral treatment for HIV-1. Such data provides a reference for regimen-specific and compound-specific adverse events and could be useful in postmarketing analyses of toxic effects.