Characterizing treatment resistance in muscle invasive bladder cancer using the chicken egg chorioallantoic membrane patient-derived xenograft model

Background

Non-metastatic muscle invasive urothelial bladder cancer (MIBC) has a poor prognosis and standard of care (SOC) includes neoadjuvant cisplatin-based chemotherapy (NAC) combined with cystectomy. Patients receiving NAC have at best <10% improvement in five-year overall survival compared to cystectomy alone. This major clinical problem underscores gaps in our understanding of resistance mechanisms and a need for reliable pre-clinical models. The chicken embryo chorioallantoic membrane (CAM) represents a rapid, scalable, and cost-effective alternative to immunocompromised mice for establishing patient-derived xenografts (PDX) in vivo. CAM-PDX leverages an easily accessible engraftment scaffold and vascular-rich, immunosuppressed environment for the engraftment of PDX tumors and subsequent functional studies.

Methods

We optimized engraftment conditions for primary MIBC tumors using the CAM-PDX model and tested concordance between cisplatin-based chemotherapy response of patients to matching PDX tumors using tumor growth coupled with immunohistochemistry markers of proliferation and apoptosis. We also tested select kinase inhibitor response on chemotherapy-resistant bladder cancers on the CAM-PDX using tumor growth measurements and immuno-detection of proliferation marker, Ki-67.

Results

Our results show primary, NAC-resistant, MIBC tumors grown on the CAM share histological characteristics along with cisplatin-based chemotherapy resistance observed in the clinic for matched parent human tumor specimens. Patient tumor specimens acquired after chemotherapy treatment (post-NAC) and exhibiting NAC resistance were engrafted successfully on the CAM and displayed decreased tumor growth size and proliferation in response to treatment with a dual EGFR and HER2 inhibitor, but had no significant response to either CDK4/6 or FGFR inhibition.

Conclusions

Our data suggests concordance between cisplatin-based chemotherapy resistance phenotypes in primary patient tumors and CAM-PDX models. Further, proteogenomic informed kinase inhibitor use on MIBC CAM-PDX models suggests a benefit from integration of rapid in vivo testing of novel therapeutics to inform more complex, pre-clinical mouse PDX experiments for more effective clinical trial design aimed at achieving optimal precision medicine for patients with limited treatment options.

Protocol for the development of a CONSORT-equity guideline to improve reporting of health equity in randomized trials

BACKGROUND

Health equity concerns the absence of avoidable and unfair differences in health. Randomized controlled trials (RCTs) can provide evidence about the impact of an intervention on health equity for specific disadvantaged populations or in general populations; this is important for equity-focused decision-making. Previous work has identified a lack of adequate reporting guidelines for assessing health equity in RCTs. The objective of this study is to develop guidelines to improve the reporting of health equity considerations in RCTs, as an extension of the Consolidated Standards of Reporting Trials (CONSORT).

METHODS/DESIGN

A six-phase study using integrated knowledge translation governed by a study executive and advisory board will assemble empirical evidence to inform the CONSORT-equity extension. To create the guideline, the following steps are proposed: (1) develop a conceptual framework for identifying "equity-relevant trials," (2) assess empirical evidence regarding reporting of equity-relevant trials, (3) consult with global methods and content experts on how to improve reporting of health equity in RCTs, (4) collect broad feedback and prioritize items needed to improve reporting of health equity in RCTs, (5) establish consensus on the CONSORT-equity extension: the guideline for equity-relevant trials, and (6) broadly disseminate and implement the CONSORT-equity extension.

DISCUSSION

This work will be relevant to a broad range of RCTs addressing questions of effectiveness for strategies to improve practice and policy in the areas of social determinants of health, clinical care, health systems, public health, and international development, where health and/or access to health care is a primary outcome. The outcomes include a reporting guideline (CONSORT-equity extension) for equity-relevant RCTs and a knowledge translation strategy to broadly encourage its uptake and use by journal editors, authors, and funding agencies.

A prospective randomized evaluation of a pharmacogenomic approach to antiplatelet therapy among patients with ST-elevation myocardial infarction: the RAPID STEMI study

Treatment of carriers of the CYP2C19*2 allele and ABCB1 TT genotype with clopidogrel is associated with increased ischemic complications after percutaneous coronary intervention (PCI). We sought to evaluate a pharmacogenomic strategy among patients undergoing PCI for ST-elevation myocardial infarction (STEMI), by performing a randomized trial, enrolling 102 patients. Point-of-care genetic testing for CYP2C19*2, ABCB1 TT and CYP2C19*17 was performed with carriers of either the CYP2C19*2 allele or ABCB1 TT genotype randomly assigned to a strategy of prasugrel 10 mg daily or an augmented dosing strategy of clopidogrel (150 mg daily for 6 days then 75 mg daily). The primary end point was the proportion of at-risk carriers exhibiting high on-treatment platelet reactivity (HPR), a marker associated with increased adverse cardiovascular events, after 1 month. Fifty-nine subjects (57.8%) were identified as carriers of at least one at-risk variant. Treatment with prasugrel significantly reduced HPR compared with clopidogrel by P2Y12 reaction unit (PRU) thresholds of >234 (0 vs 24.1%, P=0.0046) and PRU>208 (3.3 vs 34.5%, P=0.0025). The sensitivity of point-of-care testing was 100% (95% CI 88.0-100), 100% (86.3-100) and 96.9% (82.0-99.8) and specificity was 97.0% (88.5-99.5), 97.1% (89.0-99.5) and 98.5% (90.9-99.9) for identifying CYP2C19*2, ABCB1 TT and CYP2C19*17, respectively. Logistic regression confirmed carriers as a strong predictor of HPR (OR=6.58, 95% CI 1.24-34.92; P=0.03). We confirmed that concurrent identification of three separate genetic variants in patients with STEMI receiving PCI is feasible at the bedside. Among carriers of at-risk genotypes, treatment with prasugrel was superior to an augmented dosing strategy of clopidogrel in reducing HPR.

Cost-effectiveness analysis of neoadjuvant pertuzumab and trastuzumab therapy for locally advanced, inflammatory, or early HER2-positive breast cancer in Canada

OBJECTIVE

The NeoSphere trial demonstrated that the addition of pertuzumab to trastuzumab and docetaxel for the neoadjuvant treatment of HER2-positive locally advanced, inflammatory, or early breast cancer (eBC) resulted in a significant improvement in pathological complete response (pCR). Furthermore, the TRYPHAENA trial supported the benefit of neoadjuvant dual anti-HER2 therapy. Survival data from these trials is not yet available; however, other studies have demonstrated a correlation between pCR and improved event-free survival (EFS) and overall survival (OS) in this patient population. This study represents the first Canadian cost-effectiveness analysis of pertuzumab in the neoadjuvant treatment of HER2-positive eBC.

METHODS

A cost-utility analysis (CUA) was conducted using a three health state Markov model ('event-free', 'relapsed', and 'dead'). Two separate analyses were conducted; the first considering total pCR (ypT0/is ypN0) data from NeoSphere, and the second from TRYPHAENA. Published EFS and OS data partitioned for patients achieving/not achieving pCR were used in combination with the percentage achieving pCR in the pertuzumab trials to estimate survival. This CUA included published utility values and direct medical costs including drugs, treatment administration, management of adverse events, supportive care, and subsequent therapy. To address uncertainty, a probabilistic sensitivity analysis (PSA) and alternative scenarios were explored.

RESULTS

Both analyses suggested that the addition of pertuzumab resulted in increased life-years and quality-adjusted life-years (QALYs). The incremental cost per QALY ranged from $25,388 (CAD; NeoSphere analysis) to $46,196 (TRYPHAENA analysis). Sensitivity analyses further support the use of pertuzumab, with cost-effectiveness ratios ranging from $9230-$64,421. At a threshold of $100,000, the addition of pertuzumab was cost-effective in nearly all scenarios (93% NeoSphere; 79% TRYPHAENA).

CONCLUSION

Given the improvement in clinical efficacy and a favorable cost per QALY, the addition of pertuzumab in the neoadjuvant setting represents an attractive treatment option for HER2-positive eBC patients.

Healthy Eating, Aerobic and Resistance Training in Youth (HEARTY): study rationale, design and methods

PURPOSE

The objective of the Healthy Eating Aerobic and Resistance Training in Youth (HEARTY) trial (ClinicalTrials.Gov # NCT00195858) was to examine the effects of resistance training, with and without aerobic training, on percent body fat in sedentary, post-pubertal overweight or obese adolescents aged 14-18 years. This paper describes the HEARTY study rationale, design and methods.

METHODS

After a 4-week supervised low-intensity exercise run-in period, 304 overweight or obese adolescents with a body mass index≥85th percentile for age and sex were randomized to 4 groups for 22 weeks (5 months): diet+aerobic exercise, diet+resistance exercise, diet+combined aerobic and resistance exercise, or a diet only waiting-list control. All participants received dietary counseling designed to promote healthy eating with a maximum daily energy deficit of -250 kcal.

OUTCOMES

The primary outcome is percent body fat measured by Magnetic Resonance Imaging. Secondary outcomes include changes in anthropometry, regional body composition, resting energy expenditure, cardiorespiratory fitness, musculoskeletal fitness, cardiometabolic risk markers, and psychological health.

SUMMARY

To our knowledge, HEARTY is the largest clinical trial examining effects of aerobic training, resistance training, and combined aerobic and resistance training on changes in adiposity and cardiometabolic risk markers in overweight and obese adolescents. The findings will have important clinical implications regarding the role that resistance training should play in the management of adolescent obesity and its co-morbidities.

Tuberculosis surveillance in Cape Town, South Africa: an evaluation

SETTING

Cape Town, South Africa.

OBJECTIVE

To evaluate the current system of tuberculosis surveillance in the Cape Metro region.

DESIGN

This evaluation was based on the 'Updated Guidelines for Evaluating Public Health Surveillance Systems' of the Centers for Disease Control and Prevention, modified to render the framework applicable to the context of tuberculosis (TB) surveillance. The evaluation incorporated qualitative exploration of perceptions and experiences of system users.

RESULTS

System users were very accepting of the system and were committed to seeing it achieve its purpose within public health. Some individuals expressed concerns about the rigidity of the Electronic TB Register software and its analysis capabilities. Dissemination of TB data and evidence-based action within the Cape Metro region are strong attributes of Cape Town's TB surveillance system. At the time of the evaluation, integration of TB and human immunodeficiency virus (HIV) data was weak, as was multidrug-resistant TB (MDR-TB) surveillance; the South African Tuberculosis Control Programme is developing initiatives to improve these areas.

CONCLUSIONS

Cape Metro's TB surveillance is strong, although it would be strengthened by increasing availability of data reflecting TB-HIV co-infection and MDR-TB. Systems operations could be improved by increasing software flexibility, and increased integration of electronic data across health regions would enhance the capacity and assessment of control efforts.

Finalisation and validation of the rheumatoid arthritis impact of disease score, a patient-derived composite measure of impact of rheumatoid arthritis: a EULAR initiative

OBJECTIVE

A patient-derived composite measure of the impact of rheumatoid arthritis (RA), the rheumatoid arthritis impact of disease (RAID) score, takes into account pain, functional capacity, fatigue, physical and emotional wellbeing, quality of sleep and coping. The objectives were to finalise the RAID and examine its psychometric properties.

METHODS

An international multicentre cross-sectional and longitudinal study of consecutive RA patients from 12 European countries was conducted to examine the psychometric properties of the different combinations of instruments that might be included within the RAID combinations scale (numeric rating scales (NRS) or various questionnaires). Construct validity was assessed cross-sectionally by Spearman correlation, reliability by intraclass correlation coefficient (ICC) in 50 stable patients, and sensitivity to change by standardised response means (SRM) in 88 patients whose treatment was intensified.

RESULTS

570 patients (79% women, mean ± SD age 56 ± 13 years, disease duration 12.5 ± 10.3 years, disease activity score (DAS28) 4.1 ± 1.6) participated in the validation study. NRS questions performed as well as longer combinations of questionnaires: the final RAID score is composed of seven NRS questions. The final RAID correlated strongly with patient global (R=0.76) and significantly also with other outcomes (DAS28 R=0.69, short form 36 physical -0.59 and mental -0.55, p<0.0001 for all). Reliability was high (ICC 0.90; 95% CI 0.84 to 0.94) and sensitivity to change was good (SRM 0.98 (0.96 to 1.00) compared with DAS28 SRM 1.06 (1.01 to 1.11)).

CONCLUSION

The RAID score is a patient-derived composite score assessing the seven most important domains of impact of RA. This score is now validated; sensitivity to change should be further examined in larger studies.

Effects of aerobic exercise, resistance exercise or both, on patient-reported health status and well-being in type 2 diabetes mellitus: a randomised trial

AIMS/HYPOTHESIS

The Diabetes Aerobic and Resistance Exercise (DARE) study showed that aerobic and resistance exercise training each improved glycaemic control and that a combination of both was superior to either type alone in patients with type 2 diabetes mellitus. Here we report effects on patient-reported health status and well-being in the DARE Trial.

METHODS

We randomised 218 inactive participants with type 2 diabetes mellitus in parallel to 22 weeks of aerobic exercise (n = 51), resistance exercise (n = 58), combined aerobic and resistance exercise (n = 57) or no exercise (control; n = 52). Intervention allocation was managed by a central office. Outcomes included health status as assessed by the physical and mental component scores of the Medical Outcomes Trust Short-Form 36-item version (SF-36) and well-being as measured by the Well-Being Questionnaire 12-item version (WBQ-12); these were measured at the Ottawa Hospital.

RESULTS

Using a p value of 0.0125 for statistical significance due to multiple comparisons, mixed model analyses indicated that resistance exercise led to clinically but not statistically significant improvements in the SF-36 physical component score compared with aerobic exercise (Delta = 2.7 points; p = 0.048) and control (i.e. no exercise; Delta = 3.3 points; p = 0.015). For mental component scores, there were clinically important improvements favouring no (control) compared with resistance (Delta = 7.6 points; p < 0.001) and combined (Delta = 7.2 points; p < 0.001) exercise. No effects on WBQ-12 scores were noted. Overall, 59/218 (27%) of participants included in this analysis sustained an adverse event during the course of the study, including 16 participants in the combined exercise group, 19 participants in the resistance exercise group, 16 participants in the aerobic exercise group, and eight participants in the control group. All participants were included in the intent-to-treat analyses. The trial is now closed to follow-up.

CONCLUSIONS/INTERPRETATION

Resistance exercise was better than aerobic or no exercise for improving physical health status in these patients. No exercise was superior to resistance or combined exercise for improving mental health status. Well-being was unchanged by intervention.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00195884

FUNDING

This study was funded by the Canadian Institutes of Health Research (grant MCT-44155) and the Canadian Diabetes Association (The Lillian Hollefriend Grant).

ST segment resolution in patients with tenecteplase-facilitated percutaneous coronary intervention versus tenecteplase alone: Insights from the Combined Angioplasty and Pharmacological Intervention versus Thrombolysis ALone in Acute Myocardial Infarction (CAPITAL AMI) trial

BACKGROUND

Compared with fibrinolysis alone, fibrinolysis followed by immediate percutaneous coronary intervention (PCI) reduced clinical events in the Combined Angioplasty and Pharmacological Intervention versus Thrombolysis ALone in Acute Myocardial Infarction (CAPITAL AMI) study. It is unclear whether the benefits go beyond achieving epicardial reperfusion.

OBJECTIVES

To determine the differences in ST segment resolution (STR) among patients treated with tenecteplase (TNK)-facilitated PCI compared with patients treated with TNK alone.

METHODS AND RESULTS

A formal ST segment analysis was conducted on the 170 patients with ST elevation myocardial infarction in the CAPITAL AMI trial: 86 patients treated with TNK-facilitated PCI were compared with 84 patients who were treated with TNK alone. Epicardial flow measured by percentage with Thrombolysis In Myocardial Infarction (TIMI) 3 flow improved from 52% (pre-PCI) to 89% (post-PCI) in those assigned to facilitated PCI. ST segment resolution was stratified by complete (70% or greater), partial (less than 70% to 30%) or no (less than 30% to 0%) resolution. The baseline mean ST segment elevation was 11.3+/-7.5 mm in the facilitated PCI patients and 11.8+/-7.1 mm in patients with TNK alone (P=0.66). Complete STR in the facilitated PCI patients versus the TNK-alone patients was present in 55.6% versus 54.6%, respectively (P=0.58) at 180 min and 62.0% versus 55.3% (P=0.64), respectively at day 1. The mean STR at 180 min and day 1 were similar in patients who experienced death, reinfarction, recurrent unstable ischemia or stroke at six months compared with patients who remained event free: 56.3% versus 64.6% at 180 min (P=0.40); and 67.7% versus 67.6% at day 1 (P=0.99), respectively.

CONCLUSIONS

TNK-facilitated PCI did not demonstrate differences in ST segment resolution compared with TNK alone, despite improvement in epicardial flow after PCI. Further studies are required to clarify these findings.

Antimalarial drug discovery: in silico structural biology and rational drug design

Malaria remains one of the most burdensome human infectious diseases, with a high rate of resistance outbreaks and a constant need for the discovery of novel antimalarials and drug targets. For several reasons, Plasmodial proteins are difficult to characterise structurally using traditional physical approaches. However, these problems can be partially overcome using a number of in silico approaches. This review describes the peculiarities of malaria proteins and then details various in silico strategies to select and allow descriptions of the molecular structures of drug target candidates as well as subsequent rational approaches for drug design. Chiefly, homology modelling with specific focus on unique aspects of malaria proteins including low homology, large protein size and the presence of parasite-specific inserts is addressed and alternative strategies including multiple sequence and structure-based prediction methods, sampling-based approaches that aim to reveal likely global or shared features of a Plasmodial structure and the value of molecular dynamics understanding of unique features of Plasmodial proteins are discussed. Once a detailed description of the drug target is available, in silico approaches to the specific design of an inhibitory drug thereof becomes invaluable as an economic and rational alternative to chemical library screening.

Ibandronate for the prevention of nonvertebral fractures: a pooled analysis of individual patient data

This analysis was conducted to assess the effect of high versus lower doses of ibandronate on nonvertebral fractures. The results were adjusted for clinical fracture, age, and bone density. The treatment effect was dose-dependent. Higher doses of ibandronate significantly reduced the risk of nonvertebral fractures more effectively compared with lower doses.

INTRODUCTION

The objective of this study was to assess the efficacy of different doses of ibandronate on nonvertebral fractures in a pooled analysis.

METHODS

Eight randomized trials of ibandronate were reviewed for inclusion. Alternative definitions of high versus low doses based on annual cumulative exposure (ACE) were explored. A time-to-event analysis was conducted using Kaplan-Meier methodology. Hazard ratios (HR) were derived using Cox regression and adjusted for covariates.

RESULTS

Combining higher ACE doses of > or = 10.8 mg (150 mg once monthly, 3 mg i.v. quarterly, and 2 mg i.v. every 2 months) versus ACE doses of 5.5 mg, from two trials, resulted in an HR 0.62 (95% CI 0.396-0.974, p = 0.038). There was a dose-response trend with increasing ACE doses (7.2-12 mg) versus ACE of 5.5 mg.

CONCLUSIONS

A dose-response effect on nonvertebral fractures was observed when comparing high with low ACE doses. A significant reduction in nonvertebral fractures was noted when pooling data from trials using ACE doses of > or = 10.8 mg versus ACE < or = 7.2 mg; and with ACE > or = 10.8 mg versus ACE of 5.5 mg (38% reduction). Higher ibandronate dose levels (150 mg monthly or 3 mg i.v. quarterly) significantly reduced nonvertebral fracture risk in postmenopausal women.

Elaboration of the preliminary Rheumatoid Arthritis Impact of Disease (RAID) score: a EULAR initiative

BACKGROUND

Current response criteria in rheumatoid arthritis (RA) usually assess only three patient-reported outcomes (PROs): pain, functional disability and patient global assessment. Other important PROs such as fatigue are not included.

OBJECTIVE

To elaborate a patient-derived composite response index for use in clinical trials in RA, the RA Impact of Disease (RAID) score.

METHODS

Ten patients identified 17 domains or areas of health relevant for inclusion in the score, then 96 patients (10 per country in 10 European countries) ranked these domains in order of decreasing importance. The seven most important domains were selected. Instruments were chosen for each domain after extensive literature research of psychometric properties and expert opinion. The relative weight of each of the domains was obtained from 505 patients who were asked to "distribute 100 points" among the seven domains. The average ranks of importance of these domains were then computed.

RESULTS

The RAID score includes seven domains with the following relative weights: pain (21%), functional disability (16%), fatigue (15%), emotional well-being (12%), sleep (12%), coping (12%) and physical well-being (12%). Weights were similar across countries and across patient and disease characteristics. Proposed instruments include the Health Assessment Questionnaire and numerical ratings scales.

CONCLUSION

The preliminary RAID score is a patient-derived weighted score to assess the impact of RA. An ongoing study will allow the final choice of questionnaires and assessment of validity. This score can be used in clinical trials as a new composite index that captures information relevant to patients.

Socioeconomic status influences bystander CPR and survival rates for out-of-hospital cardiac arrest victims

OBJECTIVES

While lower socioeconomic status is associated with lower level of education and increased incidence of cardiovascular diseases, the impact of socioeconomic status on out-of-hospital cardiac arrest outcomes is unclear. We used residential property values as a proxy for socioeconomic status to determine if there was an association with: (1) bystander CPR rates and (2) survival to hospital discharge for out-of-hospital cardiac arrest.

METHODS

We performed a secondary data analysis of cardiac arrest cases prospectively collected as part of the Ontario Prehospital Advanced Life Support study, conducted in 20 cities with ALS and BLS-D paramedics. We measured patient and system characteristics for cardiac arrests of cardiac origin, not witnessed by EMS, occurring in a single residential dwelling. We obtained property values from the Municipal Property Assessment Corporation. Analyses included descriptive statistics with 95% CIs and stepwise logistic regression.

RESULTS

Three thousand six hundred cardiac arrest cases met our inclusion criteria between 1 January 1995 and 31 December 1999. Patient characteristics were: mean age 69.2, male 67.8%, witnessed 44.7%, bystander CPR 13.2%, VF/VT 33.8%, time to vehicle stop 5:36min:s, return of spontaneous circulation 12.7%, and survival 2.7%. Median property value was $184,000 (range $25,500-2,494,000). For each $100,000 increment in property value, the likelihood of receiving bystander CPR increased (OR=1.07; 95% CI 1.01-1.14; p=0.03) and survival decreased (OR=0.77; 95% CI 0.61-0.97; p=0.03).

CONCLUSIONS

This is the largest study showing an association between socioeconomic status and survival, and the first study showing an association with bystander CPR. Our findings suggest targeting CPR training among lower socioeconomic groups.

Alendronate for the primary and secondary prevention of osteoporotic fractures in postmenopausal women

BACKGROUND

Osteoporosis is an abnormal reduction in bone mass and bone deterioration leading to increased fracture risk. Alendronate belongs to the bisphosphonate class of drugs, which act to inhibit bone resorption by interfering with the activity of osteoclasts.

OBJECTIVES

To assess the efficacy of alendronate in the primary and secondary prevention of osteoporotic fractures in postmenopausal women.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE and EMBASE for relevant randomized controlled trials published between 1966 to 2007.

SELECTION CRITERIA

Women receiving at least one year of alendronate, for postmenopausal osteoporosis, were compared to those receiving placebo and/or concurrent calcium/vitamin D. The outcome was fracture incidence.

DATA COLLECTION AND ANALYSIS

We undertook study selection and data abstraction in duplicate. We performed meta-analysis of fracture outcomes using relative risks and a > 15% relative change was considered clinically important. We assessed study quality through reporting of allocation concealment, blinding and withdrawals.

MAIN RESULTS

Eleven trials representing 12,068 women were included in the review. Relative (RRR) and absolute (ARR) risk reductions for the 10 mg dose were as follows. For vertebral fractures, a significant 45% RRR was found (RR 0.55, 95% CI 0.45 to 0.67). This was significant for both primary prevention, with 45% RRR (RR 0.55, 95% CI 0.38 to 0.80) and 2% ARR, and secondary prevention with 45% RRR (RR 0.55, 95% CI 0.43 to 0.69) and 6% ARR. For non-vertebral fractures, a significant 16% RRR was found (RR 0.84, 95% CI 0.74 to 0.94). This was significant for secondary prevention, with 23% RRR (RR 0.77, 95% CI 0.64 to 0.92) and 2% ARR, but not for primary prevention (RR 0.89, 95% CI 0.76 to 1.04). There was a significant 40% RRR in hip fractures (RR 0.60, 95% CI 0.40 to 0.92), but only secondary prevention was significant with 53% RRR (RR 0.47, 95% CI 0.26 to 0.85) and 1% ARR. The only significance found for wrist was in secondary prevention, with a 50% RRR (RR 0.50 95% CI 0.34 to 0.73) and 2% ARR. For adverse events, we found no statistically significant differences in any included study. However, observational data raise concerns regarding potential risk for upper gastrointestinal injury and, less commonly, osteonecrosis of the jaw.

AUTHORS' CONCLUSIONS

At 10 mg per day, both clinically important and statistically significant reductions in vertebral, non-vertebral, hip and wrist fractures were observed for secondary prevention ('gold' level evidence, www.cochranemsk.org). We found no statistically significant results for primary prevention, with the exception of vertebral fractures, for which the reduction was clinically important ('gold' level evidence).

Alendronate for the primary and secondary prevention of osteoporotic fractures in postmenopausal women

BACKGROUND

Osteoporosis is an abnormal reduction in bone mass and bone deterioration leading to increased fracture risk. Alendronate belongs to the bisphosphonate class of drugs, which act to inhibit bone resorption by interfering with the activity of osteoclasts.

OBJECTIVES

To assess the efficacy of alendronate in the primary and secondary prevention of osteoporotic fractures in postmenopausal women.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE and EMBASE for relevant randomized controlled trials published between 1966 to 2007.

SELECTION CRITERIA

Women receiving at least one year of alendronate, for postmenopausal osteoporosis, were compared to those receiving placebo and/or concurrent calcium/vitamin D. The outcome was fracture incidence.

DATA COLLECTION AND ANALYSIS

We undertook study selection and data abstraction in duplicate. We performed meta-analysis of fracture outcomes using relative risks and a > 15% relative change was considered clinically important. We assessed study quality through reporting of allocation concealment, blinding and withdrawals.

MAIN RESULTS

Eleven trials representing 12,068 women were included in the review. Relative (RRR) and absolute (ARR) risk reductions for the 10 mg dose were as follows. For vertebral fractures, a significant 45% RRR was found (RR 0.55, 95% CI 0.45 to 0.67). This was significant for both primary prevention, with 45% RRR (RR 0.55, 95% CI 0.38 to 0.80) and 2% ARR, and secondary prevention with 45% RRR (RR 0.55, 95% CI 0.43 to 0.69) and 6% ARR. For non-vertebral fractures, a significant 16% RRR was found (RR 0.84, 95% CI 0.74 to 0.94). This was significant for secondary prevention, with 23% RRR (RR 0.77, 95% CI 0.64 to 0.92) and 2% ARR, but not for primary prevention (RR 0.89, 95% CI 0.76 to 1.04). There was a significant 40% RRR in hip fractures (RR 0.60, 95% CI 0.40 to 0.92), but only secondary prevention was significant with 53% RRR (RR 0.47, 95% CI 0.26 to 0.85) and 1% ARR. The only significance found for wrist was in secondary prevention, with a 50% RRR (RR 0.50 95% CI 0.34 to 0.73) and 2% ARR. For adverse events, we found no statistically significant differences in any included study. However, observational data raise concerns regarding potential risk for upper gastrointestinal injury and, less commonly, osteonecrosis of the jaw.

AUTHORS' CONCLUSIONS

At 10 mg per day, both clinically important and statistically significant reductions in vertebral, non-vertebral, hip and wrist fractures were observed for secondary prevention ('gold' level evidence, www.cochranemsk.org). We found no statistically significant results for primary prevention, with the exception of vertebral fractures, for which the reduction was clinically important ('gold' level evidence).

Etidronate for the primary and secondary prevention of osteoporotic fractures in postmenopausal women

BACKGROUND

Osteoporosis is an abnormal reduction in bone mass and bone deterioration leading to increased fracture risk. Etidronate belongs to the bisphosphonate class of drugs which act to inhibit bone resorption by interfering with the activity of osteoclasts.

OBJECTIVES

To assess the efficacy of etidronate in the primary and secondary prevention of osteoporotic fractures in postmenopausal women.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE and EMBASE for relevant randomized controlled trials published between 1966 to 2007.

SELECTION CRITERIA

Women receiving at least one year of etidronate for postmenopausal osteoporosis were compared to those receiving placebo and/or concurrent calcium/vitamin D. The outcome was fracture incidence.

DATA COLLECTION AND ANALYSIS

Study selection and data abstraction was done in duplicate. Meta-analysis of fracture outcomes was performed with data presented as relative risks and a relative change greater than 15% was considered clinically important. Study quality was assessed through the reporting of allocation concealment, blinding and withdrawals.

MAIN RESULTS

Eleven studies representing a total of 1248 patients were included in the review.A significant 41% relative risk reduction (RRR) in vertebral fractures across eight studies (RR 0.59, 95% CI 0.36 to 0.96) was found. The six secondary prevention trials demonstrated a significant RRR of 47% in vertebral fractures (RR 0.53, 95% CI 0.32 to 0.87) and a 5% absolute risk reduction (ARR); compared with the pooled result for the two primary prevention trials (RR 3.03, 95% CI 0.32 to 28.44), which was not significant. There were no statistically significant risk reductions for non-vertebral (RR 0.98, 95% CI 0.68 to 1.42), hip (RR 1.20, 95% CI 0.37 to 3.88) or wrist fractures (RR 0.87, 95% CI: 0.32 to 2.36). For adverse events, no statistically significant differences were found in the included studies. However, observational data has led to concerns regarding potential risk for upper gastrointestinal injury.

AUTHORS' CONCLUSIONS

Etidronate, at 400 mg per day, demonstrated a statistically significant and clinically important benefit in the secondary prevention of vertebral fractures. No statistically significant reductions in vertebral fractures were observed when it was used for primary prevention. In addition, no statistically significant reductions in non-vertebral, hip, or wrist fractures were found, regardless of whether etidronate was used for primary or secondary prevention. The level of evidence for all outcomes is Silver (www.cochranemsk.org.).

Strontium ranelate for preventing and treating postmenopausal osteoporosis

BACKGROUND

Strontium ranelate is a new treatment for osteoporosis therefore, its benefits and harms need to be known.

OBJECTIVES

To determine the efficacy and safety of strontium ranelate for the treatment and prevention of postmenopausal osteoporosis.

SEARCH STRATEGY

We searched MEDLINE (1996 to March 2005), EMBASE (1996 to week 9 2005), the Cochrane Library (1996 to Issue 1 2005), reference lists of relevant articles and conference proceedings from the last two years. Additional data was sought from authors.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) of at least one year duration comparing strontium ranelate versus placebo reporting fracture incidence, bone mineral density (BMD), health related quality of life or safety in postmenopausal women. Treatment (versus prevention) population was defined as women with prevalent vertebral fractures and/or lumbar spine BMD T score < -2.5 SD.

DATA COLLECTION AND ANALYSIS

Two reviewers independently determined study eligibility, assessed trial quality and extracted the relevant data. Disagreements were resolved by consensus. RCTs were grouped by dose of strontium ranelate and treatment duration. Where possible, meta-analysis was conducted using the random effects model.

MAIN RESULTS

Four trials met the inclusion criteria. Three included a treatment population (0.5 to 2 g of strontium ranelate daily) and one a prevention population (0.125 g, 0.5 g and 1 g daily). A 37% reduction in vertebral fractures (RR 0.63, 95% CI 0.56, 0.71) and a 14% reduction in non-vertebral fractures (RR 0.86, 95% CI 0.75, 0.98) were demonstrated over three years with 2 g of strontium ranelate daily in a treatment population. An increase in BMD was shown at all BMD sites after two to three years in both populations. Lower doses of strontium ranelate were superior to placebo and the highest dose demonstrated the greatest reduction in vertebral fractures and increase in BMD. An increased risk of diarrhea with 2 g of strontium ranelate was found; however, adverse events did not affect the risk of discontinuing treatment nor did it increase the risk of serious side effects, gastritis or death. Additional data suggests that the risk of vascular and nervous system side-effects is slightly increased with taking 2 g of strontium ranelate daily over three to four years.

AUTHORS' CONCLUSIONS

There is silver level evidence (www.cochranemsk.org) to support the efficacy of strontium ranelate for the reduction of fractures (vertebral and to a lesser extent non-vertebral) in postmenopausal osteoporotic women and an increase in BMD in postmenopausal women with/without osteoporosis. Diarrhea may occur however, adverse events leading to study withdrawal were not significantly increased with taking 2 g of strontium ranelate daily. Potential vascular and neurological side-effects need to be further explored.

Strontium ranelate for preventing and treating postmenopausal osteoporosis

BACKGROUND

Strontium ranelate is a new anti-osteoporosis therapy therefore, its benefits and harms need to be known.

OBJECTIVES

To determine the efficacy and safety of strontium ranelate for the treatment and prevention of postmenopausal osteoporosis.

SEARCH STRATEGY

We searched MEDLINE (1996 to March 2005), EMBASE (1996 to week 9 2005), the Cochrane Library (1996 to Issue 1 2005), reference lists of relevant articles and conference proceedings from the last two years. Additional data was sought from authors and industry sponsors.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) of at least one year duration comparing strontium ranelate versus placebo reporting fracture incidence, bone mineral density (BMD), health related quality of life and/or safety outcomes in postmenopausal women. Treatment (versus prevention) population was defined as women with prevalent vertebral fractures and/or lumbar spine BMD T score < -2.5 SD.

DATA COLLECTION AND ANALYSIS

Two reviewers independently determined study eligibility, assessed trial quality and extracted the relevant data. Disagreements were resolved by consensus. RCTs were grouped by dose of strontium ranelate and treatment duration. Where possible, meta-analysis was conducted using the random effects model.

MAIN RESULTS

A total of four trials met our inclusion criteria, three of which investigated the effects of strontium ranelate compared to placebo in a treatment population (doses ranged from 0.5 to 2 g daily) and one, in a prevention population (doses 0.125, 0.5 and 1 g daily). In osteoporotic, postmenopausal women a 37% reduction in vertebral fractures (two trials, n = 5082, RR 0.63, 95% CI 0.56 to 0.71) and a 14% reduction in non-vertebral fractures (two trials, n = 6572, RR 0.86, 95% CI 0.75 to 0.98) was demonstrated over a three year period with 2 g of strontium ranelate daily. An increase in BMD at all sites was shown with the same dose: lumbar spine BMD (two trials, n = 1614, WMD adjusted for strontium content 5.44, 95% CI 3.41 to 7.46 and WMD not adjusted 11.29, 95% CI 10.22 to 12.37 over two years), femoral neck and total hip (two trials, n = 4230, WMD 8.25, 95% CI 7.84 to 8.66 and WMD 9.83, 95% CI 9.39 to 10.26 respectively over three years). One gram of strontium ranelate daily in postmenopausal women without osteoporosis increased BMD at all sites over a two year period: lumbar spine (one trial, n = 59, WMD adjusted for strontium content 2.39, 95% CI 0.15 to 4.63 and WMD not adjusted 6.68, 95% CI 5.16 to 8.20), femoral neck (one trial, n= 60, WMD 2.52, 95%CI 0.96 to 4.09) and total hip (one trial, n = 60, WMD 1.02, 95% CI 0.48 to 1.56). In both the treatment and prevention populations, lower doses of strontium ranelate were superior to placebo with the highest dose of strontium ranelate demonstrating the greatest reduction in vertebral fractures and increase in BMD. There is some evidence to suggest that 2 g of strontium ranelate daily compared to placebo may have a beneficial effect on health related quality of life in postmenopausal women after three years of treatment. Two grams of strontium ranelate daily increased the risk of diarrhea (RR 1.38%, 95% CI 1.02 to 1.87); however, adverse events did not affect the risk of discontinuing strontium ranelate nor did it increase the risk of serious side effects, gastritis or death. Additional data obtained suggests that the risk of vascular system disorders including venous thromboembolism (two trials, n = 6669, 2.2% versus 1.5%, OR 1.5, 95% CI 1.1 to 2.1) and pulmonary embolism (two trials, n = 6669, 0.8% versus 0.4%, OR 1.7, 95% CI 1.0 to 3.1) as well as nervous system disorders such as headaches (3.9% versus 2.9%), seizures (0.3% versus 0.1%), memory loss (2.4% versus 1.9%) and disturbance in consciousness (2.5% versus 2.0%) is slightly increased with taking 2 g of strontium ranelate daily over a 3 to 4 year period.

AUTHORS' CONCLUSIONS

There is silver level evidence to support the efficacy of strontium ranelate for the reduction of vertebral fractures (and to a lesser extent non-vertebral fractures) in postmenopausal osteoporotic women and an increase in BMD (all sites) in postmenopausal women with and without osteoporosis. Diarrhea may occur however, adverse events leading to study withdrawal were not significantly increased in the strontium ranelate group. Potential risks to the vascular and neurological system associated with taking 2 g of strontium ranelate daily need to be further explored and quantified.

Prophylactic Antibiotics for Abdominal Hysterectomy: Indication for Low-Risk Canadian Women

OBJECTIVE

To determine whether prophylactic antibiotics decrease the risk of infectious morbidity after total abdominal hysterectomy (TAH) in women at low risk for infection.

METHODS

An analysis of data from 1570 women undergoing planned TAH at 15 secondary and tertiary hospitals in Nova Scotia, Ontario, and Quebec, who agreed to participate in a centrally randomized controlled trial of vaginal antisepsis with povidone-iodine gel compared to no gel after the standard preoperative vaginal preparation with povidone-iodine solution.

RESULTS

Prophylactic antibiotics were used in 993 of 1570 women (63%). Appropriately timed prophylactic antibiotics decreased infectious morbidity (odds ratio [OR], 0.65; 95% confidence interval [CI], 0.50-0.85; P < .002). After controlling for risk factors for infection and study centre, the protective effect was even more pronounced (adjusted OR, 0.51; 95% CI, 0.36-0.73). Prophylactic antibiotics were associated with decreases in abdominal wound infection (OR, 0.45; 95% CI, 0.30-0.66) and pelvic infection (OR, 0.49; 95% CI, 0.26-0.92).

CONCLUSION

Women who did not receive prophylactic antibiotics had a higher surgical infection rate. Prophylactic antibiotics should be recommended for all women undergoing TAH.

Cost effectiveness of defibrillation by targeted responders in public settings

BACKGROUND

Out-of-hospital cardiac arrest is frequent and has poor outcomes. Defibrillation by trained targeted nontraditional responders improves survival versus historical controls, but it is unclear whether such defibrillation is a good value for the money. Therefore, this study estimated the incremental cost effectiveness of defibrillation by targeted nontraditional responders in public settings by using decision analysis.

METHODS AND RESULTS

A Markov model evaluated the potential cost effectiveness of standard emergency medical services (EMS) versus targeted nontraditional responders. Standard EMS included first-responder defibrillation followed by advanced life support. Targeted nontraditional responders included standard EMS supplemented by defibrillation by trained lay responders. The analysis adopted a US societal perspective. Input data were derived from published or publicly available data. Future costs and effects were discounted at 3%. Monte Carlo simulation and sensitivity analyses assessed the robustness of results. Standard EMS had a median of 0.47 (interquartile range [IQR]=0.32 to 0.69) quality-adjusted life years and a median of 14 100 dollars (IQR=8600 dollars to 21 900 dollars) costs per arrest. Targeted nontraditional responders in casinos had an incremental cost of a median 56 700 dollars (IQR=44 100 dollars to 77 200 dollars) per additional quality-adjusted life year. The results were sensitive to changes in time to defibrillation, incidence of arrest, and number of devices required to implement rapid defibrillation.

CONCLUSIONS

Where cardiac arrest is frequent and response time intervals are short, rapid defibrillation by targeted nontraditional responders may be a good value for the money compared with standard EMS. The incidence of arrest should be considered when choosing locations to implement public access defibrillation.

Meta-analysis of the effect of structured exercise training on cardiorespiratory fitness in Type 2 diabetes mellitus

AIMS/HYPOTHESIS

Low cardiorespiratory fitness is a powerful and independent predictor of mortality in people with diabetes. Several studies have examined the effects of exercise on cardiorespiratory fitness in Type 2 diabetic individuals. However, these studies had relatively small sample sizes and highly variable results. Therefore the aim of this study was to systematically review and quantify the effects of exercise on cardiorespiratory fitness in Type 2 diabetic individuals.

METHODS

MEDLINE, EMBASE, and four other databases were searched up to March 2002 for randomized, controlled trials evaluating effects of structured aerobic exercise interventions of 8 weeks or more on cardiorespiratory fitness in adults with Type 2 diabetes. Cardiorespiratory fitness was defined as maximal oxygen uptake (VO(2max)) during a maximal exercise test.

RESULTS

Seven studies, presenting data for nine randomized trials comparing exercise and control groups (overall n=266), met the inclusion criteria. Mean exercise characteristics were as follows: 3.4 sessions per week, 49 min per session for 20 weeks. Exercise intensity ranged from 50% to 75% of VO(2max). There was an 11.8% increase in VO(2max) in the exercise group and a 1.0% decrease in the control group (post intervention standardized mean difference =0.53, p<0.003). Studies with higher exercise intensities tended to produce larger improvements in VO(2max). Exercise intensity predicted post-intervention weighted mean difference in HbA(1c) (r=-0.91, p=0.002) to a larger extent than did exercise volume (r=-0.46, p=0.26).

CONCLUSIONS/INTERPRETATION

Regular exercise has a statistically and clinically significant effect on VO(2max) in Type 2 diabetic individuals. Higher intensity exercise could have additional benefits on cardiorespiratory fitness and HbA(1c).

Number needed to treat (NNT): implication in rheumatology clinical practice

OBJECTIVE

To calculate the number needed to treat (NNT) and number needed to harm (NNH) from the data in rheumatology clinical trials and systematic reviews.

METHODS

The NNTs for the clinically important outcome measures in the rheumatology systematic reviews from the Cochrane Library, issue 2, 2000 and in the original randomised, double blind, controlled trials were calculated. The measure used for calculating the NNT in rheumatoid arthritis (RA) interventions was the American College of Rheumatology 20% improvement or Paulus criteria; in osteoarthritis (OA) interventions, the improvement of pain; and in systemic sclerosis (SSc) interventions, the improvement of Raynaud's phenomenon. The NNH was calculated from the rate of withdrawals due to adverse events from the treatment.

RESULTS

The data required for the calculation of the NNT were available in 15 systematic reviews and 11 original articles. For RA interventions, etanercept treatment for six months had the smallest NNT (1.6; 95% confidence interval (CI) 1.4 to 2.0), whereas leflunomide had the largest NNH (9.6; 95% CI 6.8 to 16.7). For OA treatment options, only etodolac and tenoxicam produced significant pain relief compared with placebo (NNT=4.4; 95% CI 2.4 to 24.4 and 3.8; 95% CI 2.5 to 7.3, respectively). For SSc interventions, none were shown to be efficacious in improving Raynaud's phenomenon because the 95% CI of the NNT was infinite.

CONCLUSIONS

The NNT and NNH are helpful for clinicians, enabling them to translate the results from clinical trials and systematic reviews to use in routine clinical practice. Both NNT and NNH should be accompanied by a limited 95% CI and adjusted for the individual subject's baseline risk.

Rapid test for the preclinical postmortem diagnosis of BSE in central nervous system tissue

The efficacy of a rapid test for detecting PrP(Sc) in central nervous system tissue was evaluated for the postmortem diagnosis of BSE at different times during the course of the disease. One hundred and six samples of brain, at the level of the medulla oblongata, and spinal cord, derived from the experimental study of the pathogenesis of BSE carried out in Great Britain between 1991 and 1995, were examined. PrP(Sc) was detected in the samples from most of the exposed animals killed 32 months or more after they had been exposed to the agent, and before the onset of clinical signs which were first recorded at 35 months. Comparisons with the results of histology, fibril detection, PrP immunohistochemistry and mouse bioassay indicated that the rapid test is at least as sensitive as these conventional confirmatory diagnostic methods and its result can be obtained more quickly.

The effect of low dose methotrexate on bone density

OBJECTIVE

High dose methotrexate (MTX) has been linked with bone loss in oncology patients. However, it is unclear whether longterm low dose MTX used in the treatment of inflammatory arthritis is associated with bone loss. We compared the effect of low dose MTX on bone density in prospectively recruited patients with rheumatoid arthritis (RA) and psoriasis/psoriatic arthritis (Ps/PsA).

METHODS

Thirty RA patients and 30 Ps/PsA patients taking MTX were compared to controls not taking MTX (30 with RA, 27 Ps/PsA). Bone mineral density (BMD) of the radius, lumbar spine, trochanter, and femoral neck was measured using Lunar dual energy x-ray absorptiometry. Student t tests were used to detect differences in bone density (using Z scores) of the MTX group versus controls for both the RA and Ps/PsA groups. Analysis of covariance was used to examine for confounders including disease duration, disease activity, age, and sex.

RESULTS

BMD of the radius/femoral neck/trochanter did not differ significantly between the MTX treated groups and controls when analyzed by Z scores. The mean difference between the MTX group and controls of the femoral neck was 0.040 (95% CI -0.40, 0.12) and 0.060 (95% CI -0.30, 0.15) for the RA and Ps/PsA groups, respectively. The absolute BMD of the lumbar spine (L2-L4) was higher in the RA MTX group than in controls. Analysis of covariance did not reveal an effect of study group on bone density.

CONCLUSION

This study suggests that low dose MTX does not have a negative effect on bone density, at either cortical or trabecular sites.

The Canadian C-spine rule for radiography in alert and stable trauma patients

CONTEXT

High levels of variation and inefficiency exist in current clinical practice regarding use of cervical spine (C-spine) radiography in alert and stable trauma patients.

OBJECTIVE

To derive a clinical decision rule that is highly sensitive for detecting acute C-spine injury and will allow emergency department (ED) physicians to be more selective in use of radiography in alert and stable trauma patients.

DESIGN

Prospective cohort study conducted from October 1996 to April 1999, in which physicians evaluated patients for 20 standardized clinical findings prior to radiography. In some cases, a second physician performed independent interobserver assessments.

SETTING

Ten EDs in large Canadian community and university hospitals.

PATIENTS

Convenience sample of 8924 adults (mean age, 37 years) who presented to the ED with blunt trauma to the head/neck, stable vital signs, and a Glasgow Coma Scale score of 15.

MAIN OUTCOME MEASURE

Clinically important C-spine injury, evaluated by plain radiography, computed tomography, and a structured follow-up telephone interview. The clinical decision rule was derived using the kappa coefficient, logistic regression analysis, and chi(2) recursive partitioning techniques.

RESULTS

Among the study sample, 151 (1.7%) had important C-spine injury. The resultant model and final Canadian C-Spine Rule comprises 3 main questions: (1) is there any high-risk factor present that mandates radiography (ie, age >/=65 years, dangerous mechanism, or paresthesias in extremities)? (2) is there any low-risk factor present that allows safe assessment of range of motion (ie, simple rear-end motor vehicle collision, sitting position in ED, ambulatory at any time since injury, delayed onset of neck pain, or absence of midline C-spine tenderness)? and (3) is the patient able to actively rotate neck 45 degrees to the left and right? By cross-validation, this rule had 100% sensitivity (95% confidence interval [CI], 98%-100%) and 42.5% specificity (95% CI, 40%-44%) for identifying 151 clinically important C-spine injuries. The potential radiography ordering rate would be 58.2%.

CONCLUSION

We have derived the Canadian C-Spine Rule, a highly sensitive decision rule for use of C-spine radiography in alert and stable trauma patients. If prospectively validated in other cohorts, this rule has the potential to significantly reduce practice variation and inefficiency in ED use of C-spine radiography.

Neuroprotective effect of mild hypothermia in patients undergoing coronary artery surgery with cardiopulmonary bypass: a randomized trial

BACKGROUND

Neuropsychological deficits occur in 30% to 80% of patients undergoing heart surgery and are due in part to ischemic cerebral injury during cardiopulmonary bypass. We tested whether mild hypothermia, the most efficacious neuroprotective strategy found in laboratory studies, improved cognitive outcome in patients undergoing coronary artery surgery.

METHODS AND RESULTS

Patients 60 years or older scheduled for coronary artery surgery were enrolled. During cardiopulmonary bypass, patients were initially cooled to 32 degrees C then randomly assigned to rewarming to 37 degrees C (control) or 34 degrees C (hypothermic), with no further intraoperative warming. Testing was scheduled preoperatively and 1 week and 3 months postoperatively. Eleven tests were combined into 3 cognitive domains: memory, attention, and psychomotor speed and dexterity. A patient was classified as having a cognitive deficit if a decrease of >/=0.50 SD was realized in 1 or more domains. The incidence of cognitive deficits 1 week after surgery, which was the primary outcome, was 62% () in the control group and 48% () in the hypothermic group (relative risk 0.77, P=0.048). In the hypothermic group, the magnitude of deterioration in attention and in speed and dexterity was reduced by 55.6% (P=0.038) and 41.3% (P=0.042), respectively. At 3 months, the hypothermic group still performed better on one test of speed and dexterity (grooved pegboard). There was no difference in morbidity or mortality.

CONCLUSIONS

Our findings support a neuroprotective effect of mild hypothermia in patients undergoing coronary artery surgery and should encourage physicians and perfusionists to pay careful attention to brain temperature during cardiopulmonary bypass.

Effects of exercise on glycemic control and body mass in type 2 diabetes mellitus: a meta-analysis of controlled clinical trials

CONTEXT

Exercise is widely perceived to be beneficial for glycemic control and weight loss in patients with type 2 diabetes. However, clinical trials on the effects of exercise in patients with type 2 diabetes have had small sample sizes and conflicting results.

OBJECTIVE

To systematically review and quantify the effect of exercise on glycosylated hemoglobin (HbA(1c)) and body mass in patients with type 2 diabetes.

DATA SOURCES

Database searches of MEDLINE, EMBASE, Sport Discuss, Health Star, Dissertation Abstracts, and the Cochrane Controlled Trials Register for the period up to and including December 2000. Additional data sources included bibliographies of textbooks and articles identified by the database searches.

STUDY SELECTION

We selected studies that evaluated the effects of exercise interventions (duration >/=8 weeks) in adults with type 2 diabetes. Fourteen (11 randomized and 3 nonrandomized) controlled trials were included. Studies that included drug cointerventions were excluded.

DATA EXTRACTION

Two reviewers independently extracted baseline and postintervention means and SDs for the intervention and control groups. The characteristics of the exercise interventions and the methodological quality of the trials were also extracted.

DATA SYNTHESIS

Twelve aerobic training studies (mean [SD], 3.4 [0.9] times/week for 18 [15] weeks) and 2 resistance training studies (mean [SD], 10 [0.7] exercises, 2.5 [0.7] sets, 13 [0.7] repetitions, 2.5 [0.4] times/week for 15 [10] weeks) were included in the analyses. The weighted mean postintervention HbA(1c) was lower in the exercise groups compared with the control groups (7.65% vs 8.31%; weighted mean difference, -0.66%; P<.001). The difference in postintervention body mass between exercise groups and control groups was not significant (83.02 kg vs 82.48 kg; weighted mean difference, 0.54; P =.76).

CONCLUSION

Exercise training reduces HbA(1c) by an amount that should decrease the risk of diabetic complications, but no significantly greater change in body mass was found when exercise groups were compared with control groups.

Canadian CT head rule study for patients with minor head injury: methodology for phase II (validation and economic analysis)

Prospective validation on a new set of patients is an essential test of a new decision rule. However, many clinical decision rules are not prospectively assessed to determine their accuracy, reliability, clinical sensibility, or potential impact on practice. This validation process is important because many statistically derived rules or guidelines do not perform well when tested in a new population. The methodologic standards for a validation study are similar to those described in the article on phase I for derivation studies in the August 2001 issue of Annals of Emergency Medicine. The goal of phase II is to prospectively assess the accuracy, reliability, and acceptability of the decision rule in a new set of patients with minor head injury. This will determine the clinical utility of the rule and is essential if such a rule is to be widely adopted into clinical practice.

Physicians' accuracy and interrator reliability for the diagnosis of unstable meniscal tears in patients having osteoarthritis of the knee

OBJECTIVE

To determine clinicians' accuracy and reliability for the clinical diagnosis of unstable meniscus tears in patients with symptomatic osteoarthritis of the knee.

DESIGN

A prospective cohort study.

SETTING

A single tertiary care centre.

PATIENTS

One hundred and fifty-two patients with symptomatic osteoarthritis of the knee refractory to conservative medical treatment were selected for prospective evaluation of arthroscopic debridement.

INTERVENTION

Arthroscopic debridement of the knee, including meniscal tear and chondral flap resection, without abrasion arthroplasty.

OUTCOME MEASURES

A standardized assessment protocol was administered to each patient by 2 independent observers. Arthroscopic determination of unstable meniscal tears was recorded by 1 observer who reviewed a video recording and was blinded to preoperative data. Those variables that had the highest interobserver agreement and the strongest association with meniscal tear by univariate methods were entered into logistic regression to model the best prediction of resectable tears.

RESULTS

There were 92 meniscal tears (77 medial, 15 lateral). Interobserver agreement between clinical fellows and treating surgeons was poor to fair (kappa < 0.4) for all clinical variables except radiographic measures, which were good. Fellows and surgeons predicted unstable meniscal tear preoperatively with equivalent accuracy of 60%. Logistic regression modelling revealed that a history of swelling and a ballottable effusion were negative predictors. A positive McMurray test was the only positive predictor of unstable meniscal tear. "Mechanical" symptoms were not reliable predictors in this prospective study. The model was 69% accurate for all patients and 76% for those with advanced medial compartment osteoarthritis defined by a joint space height of 2 mm or less.

CONCLUSIONS

This study underscored the difficulty in using clinical variables to predict unstable medial meniscal tears in patients with pre-existing osteoarthritis of the knee. The lack of interobserver agreement must be overcome to ensure that the findings can be generalized to other physician observers.

The Canadian CT Head Rule Study for patients with minor head injury: rationale, objectives, and methodology for phase I (derivation)

Head injuries are among the most common types of trauma seen in North American emergency departments, with an estimated 1 million cases seen annually. "Minor" head injury (sometimes known as "mild") is defined by a history of loss of consciousness, amnesia, or disorientation in a patient who is conscious and talking, that is, with a Glasgow Coma Scale score of 13 to 15. Although most patients with minor head injury can be discharged without sequelae after a period of observation, in a small proportion, their neurologic condition deteriorates and requires neurosurgical intervention for intracranial hematoma. The objective of the Canadian CT Head Rule Study is to develop an accurate and reliable decision rule for the use of computed tomography (CT) in patients with minor head injury. Such a decision rule would allow physicians to be more selective in their use of CT without compromising care of patients with minor head injury. This paper describes in detail the rationale, objectives, and methodology for Phase I of the study in which the decision rule was derived. [Stiell IG, Lesiuk H, Wells GA, McKnight RD, Brison R, Clement C, Eisenhauer MA, Greenberg GH, MacPhail I, Reardon M, Worthington J, Verbeek R, Rowe B, Cass D, Dreyer J, Holroyd B, Morrison L, Schull M, Laupacis A, for the Canadian CT Head and C-Spine Study Group. The Canadian CT Head Rule Study for patients with minor head injury: rationale, objectives, and methodology for phase I (derivation). Ann Emerg Med. August 2001;38:160-169.]

Vasopressin versus epinephrine for inhospital cardiac arrest: a randomised controlled trial

BACKGROUND

Survival rates for cardiac arrest patients, both in and out of hospital, are poor. Results of a previous study suggest better outcomes for patients treated with vasopressin than for those given epinephrine, in the out-of-hospital setting. Our aim was to compare the effectiveness and safety of these drugs for the treatment of in-patient cardiac arrest.

METHODS

We did a triple-blind randomised trial in the emergency departments, critical care units, and wards of three Canadian teaching hospitals. We assigned adults who had cardiac arrest and required drug therapy to receive one dose of vasopressin 40 U or epinephrine 1 mg intravenously, as the initial vasopressor. Patients who failed to respond to the study intervention were given epinephrine as a rescue medication. The primary outcomes were survival to hospital discharge, survival to 1 h, and neurological function. Preplanned subgroup assessments included patients with myocardial ischaemia or infarction, initial cardiac rhythm, and age.

FINDINGS

We assigned 104 patients to vasopressin and 96 to epinephrine. For patients receiving vasopressin or epinephrine survival did not differ for hospital discharge (12 [12%] vs 13 [14%], respectively; p50.67; 95% CI for absolute increase in survival 211.8% to 7.8%) or for 1 h survival (40 [39%] vs 34 [35%]; p50.66; 210.9% to 17.0%); survivors had closely similar median mini-mental state examination scores (36 [range 19-38] vs 35 [20-40]; p50.75) and median cerebral performance category scores (1 vs 1).

INTERPRETATION

We failed to detect any survival advantage for vasopressin over epinephrine. We cannot recommend the routine use of vasopressin for inhospital cardiac arrest patients, and disagree with American Heart Association guidelines, which recommend vasopressin as alternative therapy for cardiac arrest.

Tolterodine versus oxybutynin in the treatment of urge urinary incontinence: a meta-analysis

OBJECTIVE

To compare tolterodine with oxybutynin in treatment of urge incontinence.

STUDY DESIGN

A systematic review, following Cochrane methods, was performed to retrieve results of randomized trials that compared tolterodine with oxybutynin in adults with urge incontinence. Composite point estimates of efficacy (episodes of incontinence per 24-hour period, frequency, and voided volume) and safety (dry mouth, withdrawal, and dose modification) were calculated.

RESULTS

Four studies were included. Both drugs similarly decreased the number of micturitions in a 24-hour period. Oxybutynin was marginally superior to tolterodine in decreasing the number of incontinent episodes in a 24-hour period (weighted mean difference, 0.41; 95% confidence interval [CI], 0.04 to 0.77) and increasing the mean voided volume per micturition (8.24 mL; 95% CI, 14.19 to 3.38). Fewer patients had dry mouth (relative risk, 0.54; 95% CI, 0.48 to 0.61) and withdrew from the study because of side effects (relative risk, 0.63; 95% CI, 0.46 to 0.88) with tolterodine.

CONCLUSIONS

Oxybutynin and tolterodine share a clinically similar efficacy profile (although oxybutynin is statistically superior), but tolterodine is better tolerated and leads to fewer withdrawals as a result of adverse events.

CPR-only survivors of out-of-hospital cardiac arrest: implications for out-of-hospital care and cardiac arrest research methodology

STUDY OBJECTIVE

There is little evidence that cardiopulmonary resuscitation (CPR) alone may lead to the resuscitation of cardiac arrest victims with other than respiratory causes (eg, pediatric arrest, drowning, drug overdose). The objective of this study was to identify out-of-hospital cardiac arrest survivors resuscitated without defibrillation or advanced cardiac life support.

METHODS

This observational cohort included all adult survivors of out-of-hospital cardiac arrest of a cardiac cause from phases I and II of the Ontario Prehospital Advanced Life Support Study. During the study period, the system provided a basic life support/defibrillation level of care but no advanced life support. CPR-only patients were patients determined to be without vital signs by EMS personnel who regained a palpable pulse in the field with precordial thump or CPR only and then were admitted alive to the hospital. Six members of a 7-member expert review panel had to rate the patient as either probably or definitely having an out-of-hospital cardiac arrest, and a rhythm strip consistent with a cardiac arrest rhythm had to be present to be considered a patient. Criteria considered were witness status, citizen or first responder CPR, CPR duration, arrest rhythm and rate, and performance of precordial thump.

RESULTS

From January 1, 1991, to June 30, 1997, 9,667 patients with out-of-hospital cardiac arrest were treated. The overall survival rate to hospital discharge was 4.6%. There were 97 apparent CPR-only patients admitted to the hospital. Application of the inclusion criteria yielded 24 CPR-only patients who had true out-of-hospital cardiac arrest and 73 patients judged not to have cardiac arrest. Of the 24 true CPR-only patients admitted to the hospital, 15 patients were discharged alive, 10 patients were witnessed by bystanders, and 7 patients were witnessed by EMS personnel. The initial arrest rhythm was pulseless electrical activity in 9 patients, asystole in 12 patients, and ventricular tachycardia in 3 patients. One patient with ventricular tachycardia converted to sinus tachycardia with a single precordial thump.

CONCLUSION

CPR-only survivors of true out-of-hospital cardiac arrest do exist; some victims of out-of-hospital cardiac arrest of primary cardiac cause can survive after provision of out-of-hospital basic life support care only. However, many patients found to be pulseless by means of out-of-hospital evaluation likely did not have a true cardiac arrest. This has implications for the survival rates of most, if not all, previous cardiac arrest reports. Survival rates from cardiac arrest may actually be lower if one excludes survivors who never had a true arrest. The absence of vital signs by out-of-hospital assessment alone is not adequate to include patients in research reports or quality evaluations for cardiac arrest.

The Canadian CT Head Rule for patients with minor head injury

BACKGROUND

There is much controversy about the use of computed tomography (CT) for patients with minor head injury. We aimed to develop a highly sensitive clinical decision rule for use of CT in patients with minor head injuries.

METHODS

We carried out this prospective cohort study in the emergency departments of ten large Canadian hospitals and included consecutive adults who presented with a Glasgow Coma Scale (GCS) score of 13-15 after head injury. We did standardised clinical assessments before the CT scan. The main outcome measures were need for neurological intervention and clinically important brain injury on CT.

FINDINGS

The 3121 patients had the following characteristics: mean age 38.7 years); GCS scores of 13 (3.5%), 14 (16.7%), 15 (79.8%); 8% had clinically important brain injury; and 1% required neurological intervention. We derived a CT head rule which consists of five high-risk factors (failure to reach GCS of 15 within 2 h, suspected open skull fracture, any sign of basal skull fracture, vomiting >2 episodes, or age >65 years) and two additional medium-risk factors (amnesia before impact >30 min and dangerous mechanism of injury). The high-risk factors were 100% sensitive (95% CI 92-100%) for predicting need for neurological intervention, and would require only 32% of patients to undergo CT. The medium-risk factors were 98.4% sensitive (95% CI 96-99%) and 49.6% specific for predicting clinically important brain injury, and would require only 54% of patients to undergo CT.

INTERPRETATION

We have developed the Canadian CT Head Rule, a highly sensitive decision rule for use of CT. This rule has the potential to significantly standardise and improve the emergency management of patients with minor head injury.

Inconsistent detection of PrP in extraneural tissues of cats with feline spongiform encephalopathy

Feline spongiform encephalopathy (FSE), a transmissible spongiform encephalopathy or prion disease of cats, first reported in Great Britain in 1990, is believed to result from the consumption of food contaminated by the agent of bovine spongiform encephalopathy (BSE). The accumulation of PrP in non-neural tissues of cats diagnosed as suffering from FSE was investigated by immunohistochemistry. In the majority of the cats no disease-specific PrP was detected in lymphoid tissues. Small amounts of PrP were detected in the spleen of only two of 13 samples examined, in Peyer's patches of one of the two cases for which suitable material was available, but in the myenteric plexus of all four cats in which sections of intestine were examined. In addition PrP immunostaining was found in the kidney of all the cats with FSE whose kidneys were examined.

Cardiac troponin T predicts long-term outcomes in hemodialysis patients

BACKGROUND

Increased plasma troponin T (cTnT), but not troponin I (cTnI), is frequently observed in end-stage renal failure patients. Although generally considered spurious, we previously reported an associated increased mortality at 12 months.

METHODS

We studied long-term outcomes in 244 patients on chronic hemodialysis for up to 34 months, correlating the outcomes to plasma cTnT in routine predialysis samples. In addition, subsequent plasma samples at least 1 year later and within 6 months of data analysis were available in 97 patients and were used to identify patients with increasing plasma cTnT. The endpoints used were death and new or worsening coronary, cerebro-, and peripheral vascular disease and neuropathy.

RESULTS

Transplantation occurred more frequently in patients with low initial cTnT: 31%, 13%, and 3% in the groups with cTnT < 0.010, 0.010-0.099, and > or = 0.100 microg/L, respectively. In the same groups, total deaths occurred in 6%, 43%, and 59% and cardiac deaths in 0%, 14%, and 24% of patients. In patients with follow-up samples, the group with increasing cTnT had a significantly increased death (relative risk, 2.0; P = 0.028). The increase was mainly in cardiac and sudden deaths.

CONCLUSIONS

Higher plasma cTnT predicts long-term all-cause mortality in hemodialysis patients, even at concentrations < 0.100 microg/L, as does an increasing cTnT concentration over time.

Histological observations on the brains of symptomless 7-year-old cattle

The histological changes in the brains of 506 clinically normal 7-year-old cattle, which were part of a cohort study on maternal transmission of bovine spongiform encephalopathy, are described. Vacuolation of the white matter, of unknown aetiology, located particularly in the substantia nigra, was a frequent finding. Vacuolated neurons were commonly observed in the red nucleus (64.3% of the animals) and in the habenular nucleus (50.1%). Spheroids were found in 10.8% of the brains, most frequently in the vestibular nuclei. Cellular inflammatory infiltrates in association with blood vessels occurred in 30% of the animals at various locations in the brain; their aetiology remains uncertain, but they may have reflected subclinical or latent infections. Mineralization of the wall of blood vessels, with proliferation of the intima, was observed frequently in vessels of the internal capsule and was probably associated with ageing. The description of histological findings in the brain of symptomless adult cattle in the present study provides a useful background for diagnostic bovine neuropathology.

Neonatal and fetal methylenetetrahydrofolate reductase genetic polymorphisms: an examination of C677T and A1298C mutations

Methylenetetrahydrofolate reductase (MTHFR) mutations are commonly associated with hyperhomocysteinemia, and, through their defects in homocysteine metabolism, they have been implicated as risk factors for neural tube defects and unexplained, recurrent embryo losses in early pregnancy. Folate sufficiency is thought to play an integral role in the phenotypic expression of MTHFR mutations. Samples of neonatal cord blood (n=119) and fetal tissue (n=161) were analyzed for MTHFR C677T and A1298C mutations to determine whether certain MTHFR genotype combinations were associated with decreased in utero viability. Mutation analysis revealed that all possible MTHFR genotype combinations were represented in the fetal group, demonstrating that 677T and 1298C alleles could occur in both cis and trans configurations. Combined 677CT/1298CC and 677TT/1298CC genotypes, which contain three and four mutant alleles, respectively, were not observed in the neonatal group (P=.0402). This suggests decreased viability among fetuses carrying these mutations and a possible selection disadvantage among fetuses with increased numbers of mutant MTHFR alleles. This is the first report that describes the existence of human MTHFR 677CT/1298CC and 677TT/1298CC genotypes and demonstrates their potential role in compromised fetal viability.

Adverse outcomes and opioid analgesic administration in acute abdominal pain

To the authors' knowledge, no outcome-based, randomized clinical trial of the safety of opioid analgesics in acute abdominal pain exists.

OBJECTIVES

1) To assess the feasibility of a randomized clinical trial of opioid safety by estimating the adverse outcome rate among patients with abdominal pain severe enough to necessitate opioid analgesics. 2) To explore the association of opioid administration with adverse outcomes in acute abdominal pain.

METHODS

The authors conducted a prospective observational study of emergency department (ED) abdominal pain patients, and followed them by telephone at three weeks to determine whether an adverse outcome occurred (defined as obstruction, perforation, ischemia, hemorrhage, peritonitis, sepsis, or death). A logistic regression of factors predicting adverse outcome was performed.

RESULTS

Adverse outcomes occurred in 67 of 860 abdominal pain patients (7.8%, 95% CI = 6.1% to 9.8%), and 252 of 860 (29%) received opioids. The adverse outcome rate was 12.7% (95% CI = 9.0% to 17.0%) among patients who received opioids. Variables predictive of adverse outcome in logistic regression included: ED diagnosis of adverse outcome (OR 12.4), age (OR 1.6 per decade), fever (OR 4.6), received opioids (OR 2.1), pain duration (OR 1.5 per day), and leukocytosis (OR 2.0).

CONCLUSIONS

A clinical trial would need to randomize more than 1,500 patients to establish the equivalent adverse outcome rates of opioids and placebo: the sample size of all existing studies combined is insufficient to make such a conclusion. Although opioids were associated with a higher adverse outcome rate in this logistic regression, the authors believe this may be due to confounding by pain severity. They emphasize that the study's design precludes conclusion of a causal link. No change in clinical practice is warranted. A randomized clinical trial of sufficient size to definitively resolve this issue is needed.

Preclinical diagnosis of scrapie by immunohistochemistry of third eyelid lymphoid tissue

Ovine scrapie is a member of the transmissible spongiform encephalopathies (TSEs), a heterogeneous family of fatal neurologic disorders characterized by deposition of an abnormal isoform (prion protein [PrP] PrP-Sc) of a cellular sialoglycoprotein in neural tissue. PrP-Sc is detectable in some lymphoid tissues of infected sheep months or years before development of clinical disease. Detection of PrP-Sc in these tissues is the basis for live-animal testing. In this study, we characterize the performance of a preclinical diagnostic test for ovine scrapie based on a monoclonal antibody (MAb)-based immunohistochemistry assay of nictitating membrane ("third eyelid")-associated lymphoid tissue. The results of third eyelid immunohistochemistry assay agreed with the scrapie status of the sheep for 41 of 42 clinical suspects with confirmed scrapie and 174 of 175 sheep without scrapie. Third eyelid sampling agreed with the scrapie status for 36 of 41 clinically normal sheep positive for PrP-Sc immunostaining of brain tissue, including 27 sheep with positive biopsy specimens that progressed to clinical disease with confirmed scrapie 3 to 20 months after biopsy. The assay used MAb F89/160.1.5, which binds to residues 142 to 145 of ovine PrP. This antibody can be used in combination with MAb F99/97. 6.1, which binds to residues 220 to 225. One or both MAbs in this cocktail recognize PrP sequences conserved in most mammalian species in which natural TSEs have been reported. Immunohistochemistry assay of routinely formalin-fixed lymphoid tissues with a cocktail of pan-specific MAbs is a practical, readily standardized live-animal and preclinical test for ovine scrapie.

Effect of hemoglobin levels in hemodialysis patients with asymptomatic cardiomyopathy

BACKGROUND

Hemoglobin levels below 10 g/dL lead to left ventricular (LV) hypertrophy, LV dilation, a lower quality of life, higher cardiac morbidity, and a higher mortality rate in end-stage renal disease. The benefits and risks of normalizing hemoglobin levels in hemodialysis patients without symptomatic cardiac disease are unknown.

METHODS

One hundred forty-six hemodialysis patients with either concentric LV hypertrophy or LV dilation were randomly assigned to receive doses of epoetin alpha designed to achieve hemoglobin levels of 10 or 13.5 g/dL. The study duration was 48 weeks. The primary outcomes were the change in LV mass index in those with concentric LV hypertrophy and the change in cavity volume index in those with LV dilation.

RESULTS

In patients with concentric LV hypertrophy, the changes in LV mass index were similar in the normal and low target hemoglobin groups. The changes in cavity volume index were similar in both targets in the LV dilation group. Treatment-received analysis of the concentric LV hypertrophy group showed no correlation between the change in mass index and a correlation between the change in LV volume index and mean hemoglobin level achieved (8 mL/m2 per 1 g/dL hemoglobin decrement, P = 0.009). Mean hemoglobin levels and the changes in LV mass and cavity volume index were not correlated in patients with LV dilation. Normalization of hemoglobin led to improvements in fatigue (P = 0.009), depression (P = 0.02), and relationships (P = 0.004).

CONCLUSIONS

Normalization of hemoglobin does not lead to regression of established concentric LV hypertrophy or LV dilation. It may, however, prevent the development of LV dilation, and it leads to improved quality of life.

Randomized trial of high-flux vs low-flux haemodialysis: effects on homocysteine and lipids

BACKGROUND

Uncontrolled studies have found that high-flux haemodialysis favourably modifies homocysteine and lipid profiles. We sought to confirm these findings by carrying out a randomized prospective comparison of high-flux and low-flux polysulphone in chronic, stable dialysis patients.

METHODS

Forty-eight patients were randomly assigned to either high or low-flux dialysis for 3 months. Serum levels of homocysteine, lipoprotein (a), and lipids were compared between the treatment groups at monthly intervals.

RESULTS

All patient characteristics and laboratory variables were equally distributed between the groups at baseline. Over the study duration, we observed no differences between high- and low-flux treatment groups for the following outcomes: pre-dialysis homocysteine, lipoprotein (a), total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides (all P>0.05). Geometric mean (interquartile range) homocysteine at baseline was 20.0 (16.8-24.5) and 19.5 (15.3-22.0) micromol/l for the high-and low-flux groups respectively (P=0.80), and levels did not change significantly during the study. We did demonstrate a more pronounced intradialytic effect of high-flux dialysis on homocysteine levels, which fell during dialysis by 42%, compared to 32% with low-flux dialysis (P<0. 001).

CONCLUSIONS

In this randomized controlled trial, the effects of high-flux and low-flux haemodialysis on homocysteine and lipid profiles were comparable. The greater intradialytic effect of high-flux dialysis on homocysteine did not translate into a significant difference in pre-dialysis levels after 3 months of study.

Scrapie surveillance in Great Britain: results of an abattoir survey, 1997/98

A randomised sample of 2,809 apparently healthy sheep, 55 per cent of them less than 15 months of age, which were slaughtered for human consumption at abattoirs in Great Britain in 1997/98, was taken to establish the prevalence of scrapie infection. The medulla oblongata of each sheep was examined histopathologically at the level of the obex, and fresh brain tissue was examined for scrapie-associated fibrils (SAF) to establish whether there was evidence of scrapie. In addition, histological sections of the medulla from 500 of the sheep were immunostained with an antiserum to PrP, and the same technique was also applied to any animal found positive or inconclusive by the histological or SAF examinations. Any sheep which was positive by any of these diagnostic methods was also examined by Western immunoblotting, for the detection of the disease-specific protein PrP(Sc). A total of 2,798 sheep (99.6 per cent) were negative by all the methods applied. Ten animals were SAF-positive but negative by all the other methods, and in one animal there was immunohistochemical staining which could not be interpreted unequivocally as disease-specific. A mathematical model was used to estimate the prevalence of scrapie infection in the national slaughtered sheep population which would be consistent with these results. By this model, the absence of unequivocally substantiated cases of scrapie in the sample was consistent with a prevalence of infection in the slaughter population of up to 11 per cent.

Cardiac arrest witnessed by emergency medical services personnel: descriptive epidemiology, prodromal symptoms, and predictors of survival. OPALS study group

STUDY OBJECTIVE

The Utstein guidelines recommend that emergency medical services (EMS)-witnessed cardiac arrests be considered separately from other out-of-hospital cardiac arrest cases. The objective of this study was to assess EMS-witnessed cardiac arrest and to determine predictors of survival in this group.

METHODS

This prospective cohort included all adults with an EMS-witnessed cardiac arrest in the 21 communities of the Ontario Prehospital Advanced Life Support (OPALS) study. Systems provided a basic life support with defibrillation (BLS-D) level of care. Case and survival definitions followed the Utstein style. Descriptive and univariate methods (chi(2) and t test) were used to characterize EMS-witnessed cardiac arrest. Multivariate logistic regression was undertaken to assess predictors of survival to hospital discharge.

RESULTS

From January 1, 1991, to December 31, 1996, there were 9,072 cardiac arrest cases in the study communities. Of these, 610 (6.7%) were EMS-witnessed. The majority had preexisting cardiac or respiratory disease (81.5%) and experienced prodromal symptoms before EMS personnel arrived (91.4%). An initial rhythm of pulseless electrical activity was present in 50.1% of the patients, ventricular fibrillation/ventricular tachycardia in 34.2%, and asystole in 15.7%. Survival to discharge was 12.6%. Multivariate analysis identified the following as independent predictors of survival (odds ratio with 95% confidence intervals [CIs]): nitroglycerin use before EMS arrival: 2.3 (95% CI 1.2 to 4.5), prodromal symptoms of chest pain: 2.5 (95% CI 1.4 to 4.5) or dyspnea: 0.5 (95% CI 0.3 to 1.0), and unconsciousness on EMS arrival: 0.5 (95% CI 0.2 to 0.9). Patients with chest pain were more likely than dyspneic patients to experience ventricular fibrillation/ventricular tachycardia (62% versus 17%, P<.0001), and were 5 times more likely to survive (30.6% versus 6.3%, P<.0001).

CONCLUSION

EMS-witnessed cases are clearly an important subset of out-of-hospital cardiac arrest and are characterized by 2 distinct symptom groups: chest pain and dyspnea. These symptoms are important predictors of survival and may also help determine underlying mechanisms before patient collapse. A later phase of the OPALS study will prospectively evaluate the impact of out-of-hospital advanced life support on the survival of victims of EMS-witnessed cardiac arrest.

The neuropathology of experimental bovine spongiform encephalopathy in the pig

In an experimental study of the transmissibility of BSE to the pig, seven of 10 pigs, infected at 1-2 weeks of age by multiple-route parenteral inoculation with a homogenate of bovine brain from natural BSE cases developed lesions typical of spongiform encephalopathy. The lesions consisted principally of severe neuropil vacuolation affecting most areas of the brain, but mainly the forebrain. In addition, some vacuolar change was identified in the rostral colliculi and hypothalamic areas of normal control pigs. PrP accumulations were detected immunocytochemically in the brains of BSE-infected animals. PrP accumulation was sparse in many areas and its density was not obviously related to the degree of vacuolation. The patterns of PrP immunolabelling in control pigs differed strikingly from those in the infected animals.

An assessment of methods to combine published survival curves

PURPOSE

To assess the accuracies of different techniques for combining published survival curves, for use in disease modeling applications.

METHODS

Five methods were identified: 1) iterative generalized least-squares (IGLS), 2) meta-analysis of failure-time data with adjustment for covariates (MFD), 3) nonlinear regression (NLR), 4) log relative risk (LRR), and 5) weighted LRR (w-LRR). Each method was used to combine the survival curves from eight single-arm Phase II trials of chemotherapy in 918 patients with advanced non-small-cell lung cancer (NSCLC). The resulting summary curves were compared with the curve calculated from the corresponding individual patient data (IPD).

RESULTS

All methods were able to produce accurate summary survival curves statistically similar to the IPD-derived curve. Maximum discrepancies ranged from 1.8% to 4.7%. MFD appeared to be the most accurate when censoring information was complete. Characteristics of the component trials that adversely affected the accuracies of the different techniques were 1) a high proportion of censored observations (MFD); 2) variability in the length of follow-up (IGLS, NLR, LRR, w-LRR); and 3) the heterogeneity of the treatment results (NLR, w-LRR).

CONCLUSIONS

All methods were able to accurately reproduce summary survival curves from the published literature. The best method depends on characteristics of the data and the purpose of the analysis.

Increased mortality in hemodialyzed patients with elevated serum troponin T: a one-year outcome study

OBJECTIVES

To determine the significance of elevated serum troponin T (cTnT) occurring in hemodialysis patients in the absence of clinical evidence of acute coronary ischemia.

DESIGN AND METHODS

Twelve-month follow-up of cohort of 172 hemodialyzed patients with known serum cTnT concentration. The cohort consisted of patients undergoing hemodialysis in a hospital unit over a 5-month period, with one to four measurements of cTnT. The main outcome measure was death. Cause of death was determined by autopsy in six patients.

RESULTS

Of the 31 deaths, 12 were due to acute coronary disease, 14 were noncoronary, and 5 were undefined. Death rates of patients with cTnT <0.1, 0.1-0.2, and >0.2 microg/L were 9.9% (11/111), 32.4% (12/37), and 33.3% (8/24), respectively. The increase in death rate with cTnT > or =0.1 microg/L was significant (p<0.001) for noncoronary deaths, but not for acute coronary deaths. The risk ratios for noncoronary deaths in the subgroups were: nondiabetics 6.6 (95% CI 1.9-23.6), patients with no coronary artery disease 7.3 (1.6-32.4), patients with no peripheral vascular disease 8.9 (2.0-39.7), and hypertensives 9.0 (1.1-76.5). Significant increase in coronary deaths was seen only in patients without hypertension and those aged > or =50 years. The risk ratios for these groups were 9.3 (1.2-74.3) and 3.3 (1.0-10.6), respectively.

CONCLUSIONS

Serum cTnT is a potential prognostic marker of mortality in hemodialyzed patient, with increase in death from coronary and noncoronary causes.