Retraction speed and chronic poststernotomy pain: A randomized controlled trial

OBJECTIVES

Approximately 30% of patients develop chronic poststernotomy pain (CPSP) following cardiac surgery with sternal retraction. Risk factors have been described but no causal determinants identified. Investigators hypothesized that opening the sternum slowly would impart less force (and thereby less nerve/tissue damage) and translate to a reduced incidence of CPSP. The main objectives were to determine whether or not slower sternal retraction would reduce the incidence of CPSP and improve health-related quality of life.

METHODS

Patients undergoing coronary artery bypass graft surgery were recruited to this randomized controlled trial. Patients were randomized to slow or standard retraction (ie, sternum opened over 15 minutes vs 30 seconds, respectively). Although the anesthesiologist and surgeon were aware of the randomization, the patients, assessors, and postoperative nursing staff remained blinded. Sternotomy pain and analgesics were measured in hospital. At 3, 6, and 12 months postoperatively, all patients completed the Medical Outcomes Survey Short Form and reported on CPSP and complications requiring rehospitalization. Thirty-day rehospitalizations and mortality were recorded.

RESULTS

In total, 326 patients consented to participate and 313 were randomized to slow (n = 159) versus standard retraction (n = 154). No clinically relevant differences were detected in acute pain, analgesic consumption, or the incidence of CPSP or health-related quality of life. Although the slow group had significantly more hospitalizations at 3 and 12 months postoperatively, the reasons were unrelated to retraction speed. No differences were observed in 30-day rehospitalizations or mortality.

CONCLUSIONS

All outcomes were consistent with previous reports, but no clinically significant differences were observed with retraction speed.

Postpartum reverse-Takotsubo from pheochromocytoma diagnosed by bedside point-of-care ultrasound: A case report

Point-of-care ultrasound is invaluable in the setting of obstetric anesthesia, where the differential diagnosis for dyspnea, hypoxemia and/or hemodynamic abnormalities is broad. This report describes a previously apparently healthy parturient with an uncomplicated pregnancy at 35-weeks gestation who underwent an emergency cesarean section under general anesthesia due to severe acute abdominal pain and fetal bradycardia. Intraoperatively, she presented with severe hypertension and tachycardia that were difficult to control and associated with ischemic ECG changes. In the immediate postoperative period, she developed retrosternal tightness and dyspnea, and a bedside point-of-care ultrasound scan revealed a grossly dilated and hypokinetic left ventricle, as well as diffuse B-lines throughout all lung fields - consistent with cardiogenic pulmonary edema. She was admitted to the intensive care unit, where she recovered over several days. Pheochromocytoma was subsequently diagnosed, and she eventually underwent uneventful elective adrenalectomy after appropriate endocrine and hemodynamic optimization.

Potential effect of habitat disturbance on reproduction of the critically endangered harlequin frog Atelopus varius in Las Tablas, Costa Rica

We studied a population of Atelopus varius in Las Tablas Protected Zone in southwest Costa Rica, where we estimated occupancy rates of tadpoles along the Cotón River. In addition, we report the first tadpoles observed in the wild in 20 years. Tadpole rate of occupancy was greater in habitat containing native forest than in disturbed areas bordering cattle pasture. This same pattern was also reflected in adult hotspots, where encounter rates were higher for adults in habitat surrounded by forest versus pasture. We present evidence for the potential effect of habitat modification on the presence and reproduction of A. varius and suspect that over time this modification impacts the species’ demography. However, further study is necessary before we can confirm that habitat change alone was the key factor involved in patterns of decline for the species.

Interscalene Block in an Anesthetized Adult with Hypertrophic Obstructive Cardiomyopathy Undergoing Clavicle Fracture Reduction

Whether regional anesthesia procedures should be performed in heavily sedated/anesthetized adults remains controversial. One of the purported advantages of performing regional nerve blocks in conversant patients is early warning against major nerve injury and, arguably, early detection of local anesthetic systemic toxicity. A 60-year-old man with hypertrophic obstructive cardiomyopathy (HOCM) underwent a clavicle fracture repair under general anesthesia. Intraoperative transesophageal echocardiography revealed dynamic left ventricular outflow track obstruction and systolic anterior motion of the posterior mitral valve leaflet. In part based on such echo findings, he received an ultrasound-guided interscalene plus a superficial cervical plexus block for postoperative analgesia prior to emergence from general anesthesia. Given the lack of robust data on the safety of ultrasound-guided regional techniques in heavily sedated/anesthetized adults, we use the example of echographic evidence of significant HOCM to argue for a pragmatic and individualized approach when faced with unusual situations in which the pros of such an approach may outweigh the cons - in this case for performing an interscalene block on an anesthetized adult.

Perioperative Aspirin for Prevention of Venous Thromboembolism: The PeriOperative ISchemia Evaluation-2 Trial and a Pooled Analysis of the Randomized Trials

BACKGROUND

The PeriOperative ISchemia Evaluation-2 (POISE-2) trial compared aspirin with placebo after noncardiac surgery.

METHODS

The authors randomly assigned 10,010 patients undergoing noncardiac surgery to receive 200 mg aspirin or placebo 2 to 4 h before surgery and then 100 mg aspirin daily or placebo daily for up to 30 days after surgery. Herein, the authors report the effect of aspirin on venous thromboembolism (VTE), including deep vein thrombosis and pulmonary embolism, as well as an updated pooled analysis of randomized trials of antiplatelet therapy for VTE prevention in noncardiac surgery patients.

RESULTS

Six thousand five hundred forty-eight patients (65.4%) received anticoagulant prophylaxis. VTE occurred in 53 patients (1.1%) allocated to aspirin and in 60 patients (1.2%) allocated to placebo (hazard ratio, 0.89; 95% CI, 0.61 to 1.28). Major or life-threatening bleeding occurred in 312 patients (6.3%) allocated to aspirin and in 256 patients (5.1%) allocated to placebo (hazard ratio, 1.22; 95% CI, 1.04 to 1.44). Concomitant use of anticoagulant prophylaxis did not modify the effect of aspirin on VTE or bleeding. Pooled analysis of the POISE-2 and Pulmonary Embolism Prevention trials demonstrated that symptomatic VTE occurred in 173 (1.3%) of 13,724 patients allocated to aspirin and in 246 (1.8%) of 13,730 patients allocated to placebo (odds ratio, 0.71; 95% CI, 0.56 to 0.89; heterogeneity P = 0.27; I = 17%); the impact of aspirin was very similar in those who did and did not receive pharmacologic prophylaxis. Pooled estimates for symptomatic VTE were similar to the pooled estimates for any deep vein thrombosis and pulmonary embolism from the POISE-2 trial, Pulmonary Embolism Prevention trial, and the Antiplatelet Trialists' Collaboration meta-analysis.

CONCLUSIONS

Aspirin in the POISE-2 trial did not reduce VTE, but two thirds of patients received anticoagulant prophylaxis, there were few VTE events, and results were consistent with a wide range of aspirin effects. A pooled analysis of the randomized trials demonstrates evidence for the efficacy of aspirin for VTE prevention in hospitalized surgical patients.

Adverse event assessment and reporting in trials of newer treatments for post-operative pain

BACKGROUND

Assessment and reporting of adverse events (AEs) in studies of perioperative interventions is critical given the potential for unintended and preventable iatrogenic morbidity and mortality. This focused review evaluated the quality of AE assessment and reporting in acute post-operative pain treatment trials. Since older analgesics (e.g., opioids, NSAIDs) already have a well-characterized safety profile, we concentrated on trials of pregabalin and gabapentin as a representative sample of studies where the perioperative safety profile was relatively unknown.

METHODS

We reviewed primary reports of trials of pregabalin and gabapentin for treatment of acute post-operative pain for: (1) adherence to the 10 recommendations from the 'CONSORT Extension for Harms,' (2) AE assessment method, (3) timing of AE assessment and reporting, and (4) assessment and reporting of AE severity.

RESULTS

We identified 31 trials of pregabalin and 59 of gabapentin. The median number of CONSORT harms recommendations that were satisfied was 7 of 10. The most common (41%) method of AE assessment was direct questioning about specific AEs by investigators. However, AE assessment method was not described in 18% of trials. AE assessments were reported for specified perioperative time points in only 24% of trials. Of greatest concern, no AE data were reported whatsoever in 8 of the included publications.

CONCLUSIONS

Considerable widespread improvements are needed in AE reporting for post-operative pain treatment trials. In addition to heightened awareness among clinical investigators, mandatory journal editorial policies may further facilitate improvements in safety assessment and reporting.

Management of a hospital outbreak of extensively drug-resistant Acinetobacter baumannii using a multimodal intervention including daily chlorhexidine baths

BACKGROUND

Extensively drug-resistant Acinetobacter baumannii (XDR-Ab) is an increasingly important cause of healthcare-associated infection. Uncertainties remain concerning optimal control measures for healthcare-associated outbreaks.

AIM

To describe the epidemiology and control of an XDR-Ab outbreak that involved multiple units of a large hospital from March 2012 to January 2014.

METHODS

Case-finding included screening of rectum, groin, throat, nose, wounds, iatrogenic portals of entry, and catheterized sites. Antimicrobial susceptibility was evaluated by disc diffusion and E-test. Resistance genes were detected by polymerase chain reaction. Clonality was assessed by pulsed-field gel electrophoresis. Charts of cases were reviewed to identify risk factors for invasive infection. Control measures included isolation and cohorting of cases, hand hygiene reinforcement, environmental decontamination, and source control with daily baths using wipes pre-impregnated with chlorhexidine gluconate.

FINDINGS

A single clonal strain of XDR-Ab colonized or infected 29 patients. Five patients died of XDR-Ab bacteraemia. Transmission occurred primarily on two wards. Colonization was detected at all anatomical screening sites; only 57% (16/28) of cases were rectal carriers. Advanced malignancy was a risk factor for bacteraemia (relative risk: 5.8; 95% confidence interval: 1.2-27.0). Transmission ended following implementation of the multimodal control strategy. No additional nosocomial cases occurred during the following 20 months.

CONCLUSION

Our study highlights the need to screen multiple anatomic sites to diagnose carriage and identifies risk factors for XDR-Ab bacteraemia. A multimodal intervention that included daily chlorhexidine baths for cases was rapidly followed by the termination of the outbreak. Hospitals should consider similar interventions when managing future XDR-Ab outbreaks.

A signature for immune response correlates with HCV treatment outcome in Caucasian subjects

This data article contains Supplementary material for a published research article describing a whole-blood proteomic signature that predicts treatment outcome for subjects infected with hepatitis C virus (HCV) [1]. The proteomic signature is derived from whole-blood samples from subjects infected with HCV. The article includes detailed experimental and computational methods used in the analysis. The article also includes tables of demographic and other information about the subjects. Finally, the article includes several figures and tables showing detailed results of the analyses (e.g. lists of identified proteins and coefficients/ROC curves for the regression models).

Neuraxial block and postoperative epidural analgesia: effects on outcomes in the POISE-2 trial†

BACKGROUND

We assessed associations between intraoperative neuraxial block and postoperative epidural analgesia, and a composite primary outcome of death or non-fatal myocardial infarction, at 30 days post-randomization in POISE-2 Trial subjects.

METHODS

10 010 high-risk noncardiac surgical patients were randomized aspirin or placebo and clonidine or placebo. Neuraxial block was defined as intraoperative spinal anaesthesia, or thoracic or lumbar epidural anaesthesia. Postoperative epidural analgesia was defined as postoperative epidural local anaesthetic and/or opioid administration. We used logistic regression with weighting using estimated propensity scores.

RESULTS

Neuraxial block was not associated with the primary outcome [7.5% vs 6.5%; odds ratio (OR), 0.89; 95% CI (confidence interval), 0.73-1.08; P=0.24], death (1.0% vs 1.4%; OR, 0.84; 95% CI, 0.53-1.35; P=0.48), myocardial infarction (6.9% vs 5.5%; OR, 0.91; 95% CI, 0.74-1.12; P=0.36) or stroke (0.3% vs 0.4%; OR, 1.05; 95% CI, 0.44-2.49; P=0.91). Neuraxial block was associated with less clinically important hypotension (39% vs 46%; OR, 0.90; 95% CI, 0.81-1.00; P=0.04). Postoperative epidural analgesia was not associated with the primary outcome (11.8% vs 6.2%; OR, 1.48; 95% CI, 0.89-2.48; P=0.13), death (1.3% vs 0.8%; OR, 0.84; 95% CI, 0.35-1.99; P=0.68], myocardial infarction (11.0% vs 5.7%; OR, 1.53; 95% CI, 0.90-2.61; P=0.11], stroke (0.4% vs 0.4%; OR, 0.65; 95% CI, 0.18-2.32; P=0.50] or clinically important hypotension (63% vs 36%; OR, 1.40; 95% CI, 0.95-2.09; P=0.09).

CONCLUSIONS

Neuraxial block and postoperative epidural analgesia were not associated with adverse cardiovascular outcomes among POISE-2 subjects.

Development and evaluation of a multiplexed mass spectrometry based assay for measuring candidate peptide biomarkers in Alzheimer's Disease Neuroimaging Initiative (ADNI) CSF

PURPOSE

We describe the outcome of the Biomarkers Consortium CSF Proteomics Project (where CSF is cerebral spinal fluid), a public-private partnership of government, academia, nonprofit, and industry. The goal of this study was to evaluate a multiplexed MS-based approach for the qualification of candidate Alzheimer's disease (AD) biomarkers using CSF samples from the AD Neuroimaging Initiative.

EXPERIMENTAL DESIGN

Reproducibility of sample processing, analytic variability, and ability to detect a variety of analytes of interest were thoroughly investigated. Multiple approaches to statistical analyses assessed whether panel analytes were associated with baseline pathology (mild cognitive impairment (MCI), AD) versus healthy controls or associated with progression for MCI patients, and included (i) univariate association analyses, (ii) univariate prediction models, (iii) exploratory multivariate analyses, and (iv) supervised multivariate analysis.

RESULTS

A robust targeted MS-based approach for the qualification of candidate AD biomarkers was developed. The results identified several peptides with potential diagnostic or predictive utility, with the most significant differences observed for the following peptides for differentiating (including peptides from hemoglobin A, hemoglobin B, and superoxide dismutase) or predicting (including peptides from neuronal pentraxin-2, neurosecretory protein VGF (VGF), and secretogranin-2) progression versus nonprogression from MCI to AD.

CONCLUSIONS AND CLINICAL RELEVANCE

These data provide potential insights into the biology of CSF in AD and MCI progression and provide a novel tool for AD researchers and clinicians working to improve diagnostic accuracy, evaluation of treatment efficacy, and early diagnosis.

A signature for immune response correlates with HCV treatment outcome in Caucasian subjects

Broad proteomic profiling was performed on serum samples of phase 2 studies (PROVE1, PROVE2, and PROVE3) of the direct-acting antiviral drug telaprevir in combination with peg-interferon and ribavirin in subjects with HCV. Using only profiling data from subjects treated with peg-interferon and ribavirin, a signature composed of pretreatment levels of 13 components was identified that correlated well (R(2)=0.68) with subjects' underlying immune response as measured by week 4 viral decline and was highly predictive of sustained virologic response in non-African American subjects (AUC=0.99). The signature was validated by predicting in an independent cohort of non-African American subjects treated with telaprevir, peg-interferon and ribavirin (AUC=0.854). Samples from extreme responders were over-represented in these analyses. Proteins identified as differentially-expressed between responders and non-responders to HCV treatment were quantified using multiple reaction monitoring in samples from all Caucasian subjects in the peg-interferon and ribavirin arms of PROVE1 and PROVE2, revealing 15 proteins that were significantly differentially expressed between treatment responders and non-responders. Seven of the proteins are part of focal adhesions or other macromolecular assemblies that form structural links between integrins and the actin cytoskeleton and are involved in antiviral response.

BIOLOGICAL SIGNIFICANCE

HCV is a significant health problem. We describe a novel approach for identifying markers that predicts HCV treatment response different treatment regimens and use this approach to identify a novel HCV treatment response signature. The signature has potential to guide optimization of HCV treatment regimens.

A blood-based proteomic classifier for the molecular characterization of pulmonary nodules

Each year, millions of pulmonary nodules are discovered by computed tomography and subsequently biopsied. Because most of these nodules are benign, many patients undergo unnecessary and costly invasive procedures. We present a 13-protein blood-based classifier that differentiates malignant and benign nodules with high confidence, thereby providing a diagnostic tool to avoid invasive biopsy on benign nodules. Using a systems biology strategy, we identified 371 protein candidates and developed a multiple reaction monitoring (MRM) assay for each. The MRM assays were applied in a three-site discovery study (n = 143) on plasma samples from patients with benign and stage IA lung cancer matched for nodule size, age, gender, and clinical site, producing a 13-protein classifier. The classifier was validated on an independent set of plasma samples (n = 104), exhibiting a negative predictive value (NPV) of 90%. Validation performance on samples from a nondiscovery clinical site showed an NPV of 94%, indicating the general effectiveness of the classifier. A pathway analysis demonstrated that the classifier proteins are likely modulated by a few transcription regulators (NF2L2, AHR, MYC, and FOS) that are associated with lung cancer, lung inflammation, and oxidative stress networks. The classifier score was independent of patient nodule size, smoking history, and age, which are risk factors used for clinical management of pulmonary nodules. Thus, this molecular test provides a potential complementary tool to help physicians in lung cancer diagnosis.

Visually induced postural reactivity is velocity-dependent at low temporal frequencies and frequency-dependent at high temporal frequencies

Visual stimulation alone is sufficient to produce visually induced postural reactivity (VIPR). While some studies have shown that VIPR increases with the velocity of a moving visual stimulus, others have shown that it decreases with the temporal frequency of an oscillating visual stimulus. These results seem contradictory given that these two variables co-vary in the same direction. The purpose of this study is to determine whether the VIPR can be different depending on the frequency range being considered. Twelve subjects were placed standing up in a virtual reality environment that simulated a black and white checkerboard at floor level. This checkerboard oscillated at seven frequencies (0.03–2.0 Hz) and three amplitudes (2, 4, and 8°), corresponding to nine velocities (0.125–32°/s). The virtual floor oscillated from left to right (mediolateral) or from front to back (anteroposterior). We calculated the subjects’ mean velocity (Ω) based on data from electromagnetic sensors positioned on the head and lower back. Our experiment shows that for temporal frequencies below 0.12 Hz, VIPR is visually dependent and increases with stimulus velocity. When stimulus velocity becomes too high, the body becomes incapable of following, and the VIPR saturates between 0.12 and 0.25 Hz. In this frequency range, maximal postural oscillation seems to depend on biomechanical constraints imposed by the positioning of the feet. For frequencies above 0.5 Hz, the body can no longer maintain the same oscillation state. This saturation may be linked to proprioceptive feedback mechanisms in the postural system.

Invasive bacterial infections following influenza: a time-series analysis in Montréal, Canada, 1996-2008

BACKGROUND

Shared seasonal patterns, such as between influenza and some respiratory bacterial infections, can create associations between phenomena not causally related.

OBJECTIVES

To estimate the association of influenza with subsequent bacterial infections after full adjustment for confounding by seasonal and long-term trends.

METHODS

Time series of weekly counts of notified cases of invasive infections with Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae and Streptococcus pyogenes, in Montréal, Canada, 1996-2008, were modelled by negative binomial regression, with terms representing seasonal and long-term trends and terms for numbers of positive laboratory tests for influenza A and B.

RESULTS

The associations of S. pneumoniae, H. influenzae and N. meningitidis with influenza disappeared after seasonal terms were added to the model. However, the influenza B count remained associated with the S. pyogenes counts for the same week and the following week: S. pyogenes incidence rate ratios were 1.0376 (95% CI: 1.0009-1.0757) and 1.0354 (0.9958-1.0766), respectively, for each increase of 1 in the influenza count.

CONCLUSIONS

Influenza B accounts for about 8 percnt; of the incidence of invasive S. pyogenes infections, over and above any effect associated with modellable seasonal and long-term trends. This association of influenza B with S. pyogenes infections can be attributed largely to the years 1997, 2001, 2007 and 2008, when late peaks in influenza B counts were followed by peaks in S. pyogenes notifications. This finding reinforces the case for universal immunization against influenza, as partial protection against the 'flesh eating disease'.

Characteristics and survival of HIV-infected patients not screened for hepatitis C virus infection in a hospital-based cohort

The rate of human immunodeficiency virus (HIV) disease progression or death of individuals coinfected with hepatitis C virus (HCV) is conflicting. The complete-case analysis systematically used, excludes patients unscreened for HCV. Our objective was to assess if rate of survival differed between HIV-infected patients screened and unscreened for HCV in a hospital-based prospective cohort study. Patients were enrolled in the Lyon section of the French Hospital Database on HIV between 1 July 1992 and 31 May 2005. A multivariate Cox regression model was used to analyse the association of HCV screening with survival. Of 3244 patients, 299 (9.2%) were not screened for HCV. The populations screened and unscreened differed by the proportion of acquired immune deficiency syndrome at baseline, presumed route of infection, CD4 cell count category at baseline, mean duration of follow-up, mean number of visits per year, type of antiretroviral therapy and survival. The rate of progression to death was higher for non-HCV-screened vs HCV-screened patients: the incidence rate among HCV-screened patients was 22.9/1000 patient-years; the incidence rate among HCV-unscreened patients was 52.4/1000 patient-years. The adjusted hazards ratio of death was 2.48 [95% confidence interval (1.83-3.35); P < 0.001] for patients with unknown HCV status compared with others. In conclusion, unscreened or unknown HCV status was associated with an increased risk of death in our hospital cohort. Important prognostic factors are related to, or confounded by the practice of HCV screening.

The use of environmental factors as adjuncts to traditional tuberculosis contact investigation

SETTING

A 25-year-old university student was diagnosed with cavitary pulmonary and laryngeal tuberculosis following symptoms of underlying cough of 6 months' duration.

OBJECTIVES

To estimate the hourly risk of infection (HRI) and examine the role of environmental factors, including room size and ventilation, in modulating this risk.

METHODS

Contact investigation.

RESULTS

Of 1100 contacts identified, 78.3% (n = 896) received a tuberculin skin test (TST), of whom 27.5% had a positive result. Among 634 Canadian-born contacts tested, 22.7% had a positive TST. The independent risk factors for a positive TST among Canadian-born university students were: > 35 h spent with the index case (adjusted OR 6.6, 95% CI 1.0-44.9) and smaller classroom size (aOR 5.0, 95% CI 1.4-10.0). In the first school term, the HRI among Canadian-born student contacts was 0.9%; in the second term, it was 1.6%.

CONCLUSION

There are inherent limitations in generalising findings from an outbreak investigation, due to the considerable variation in the infectiousness of cases. Nevertheless, in situations where the index case has a high degree of infectiousness, and there are numerous contacts with low expected prevalence of infection, the HRI can, together with ventilation measurements, be useful in guiding the extent of contact investigation needed.

Prevalence and sexual risk of hepatitis C virus infection when human immunodeficiency virus was acquired through sexual intercourse among patients of the Lyon University Hospitals, France, 1992-2002

To report the prevalence and the risk factors for hepatitis C virus (HCV) infection in a hospital cohort of 2691 sexually human immunodeficiency virus (HIV)-infected patients. The patients were enrolled in the Lyon section of the French Hospital Database on HIV between 1992 and 2002. Baseline characteristics were analysed. The detection of HCV-antibodies (Ab) was used for diagnosis. The HCV-Ab prevalence rate was 5.7 and 12.89% for individuals infected by HIV after homosexual intercourse or heterosexual intercourse, respectively. HCV-Ab was three times more frequently found among patients infected with HIV after heterosexual intercourse compared with patients infected with HIV after homosexual intercourse (adjusted OR: 3.2, 95% CI: 2.28-4.62, multiple logistic regression). The risk of HCV infection among HIV-infected individuals differed according to sexual behaviour. The determinants associated with HCV transmission through the sexual route needs to be explored further.

HIV status of sexual partners is more important than antiretroviral treatment related perceptions for risk taking by HIV positive MSM in Montreal, Canada

OBJECTIVE

To examine the role of antiretroviral treatment related perceptions relative to other clinical and psychosocial factors associated with sexual risk taking in HIV positive men who have sex with men (MSM).

METHODS

Participants were recruited from ambulatory HIV clinics in Montreal. Information on sociodemographic factors, health status, antiretroviral treatment related perceptions, and sexual behaviours was collected using a self administered questionnaire. At-risk sexual behaviour was defined as at least one occurrence of unprotected insertive or receptive anal intercourse in the past 6 months. Multivariate logistic regression was performed to evaluate the associations between at-risk sexual behaviour and covariates.

RESULTS

346 subjects participated in the study. Overall, 34% of subjects were considered at risk; 43% of sexually active subjects (n=274). At-risk sexual behaviour was associated with two antiretroviral treatment related perceptions: (1) taking antiretroviral treatment reduces the risk of transmitting HIV (adjusted odds ratio (OR), 2.10; 95% confidence interval (CI), 1.16 to 3.80); and (2) there is less safer sex practised by MSM because of HIV treatment advances (OR, 1.82; CI, 1.14 to 2.90). Other factors, however, were more strongly associated with risk. These were: (1) safer sex fatigue (OR, 3.23; CI, 1.81 to 5.78); (2) use of "poppers" during sexual intercourse (OR, 6.28; CI, 2.43 to 16.21); and (3) reporting a greater proportion of HIV positive anal sex partners, compared with reporting no HIV positive anal sex partners: (a) <50% HIV positive (OR, 16.79; CI, 4.70 to 59.98); (b) > or =50% HIV positive (OR, 67.67; CI, 15.43 to 296.90).

CONCLUSION

Despite much emphasis on HIV treatment related beliefs as an explanation for sexual risk taking in MSM, this concern may play a relatively minor part in the negotiation of risk by HIV positive MSM. Serosorting, safer sex fatigue, and the use of poppers appear to be more important considerations in understanding the sexual risk behaviours of HIV positive MSM.