Total hospitalizations after peripheral arterial revascularization in the VOYAGER trial

Background

In the VOYAGER PAD trial, rivaroxaban reduced first and total (first and subsequent) occurrences of major adverse limb and cardiovascular events in patients with peripheral artery disease (PAD) after lower extremity revascularization (LER), but also increased incident bleeding.

Purpose

Assessment of disease burden by the onset of a particular set of events does not necessarily capture all consequences of a disease process that negatively impact patients' quality of life, motivating the adoption of more patient-centered outcomes. The present analysis of VOYAGER PAD describes the total incidence and duration of hospitalizations reported during the study as a broader measure of total disease burden and net benefit of rivaroxaban therapy.

Methods

Patients were randomized 1:1 to rivaroxaban 2.5 mg twice daily plus aspirin (n=3286) or aspirin alone (n=3278). Investigators documented the primary reason and duration for each hospitalization occurring after randomization. Total hospitalization rates were estimated by events per 100 patient-years. Treatment group comparisons on total hospitalizations as a time-to-event outcome were by marginal proportional hazards models with death as a competing terminal event, while days in hospital were compared by zero-inflated Poisson regression. All analyses were intention-to-treat.

Results

A total of 7156 hospitalizations (3265 first, 3891 subsequent) occurred during a median 2.5 years of follow-up, with nearly 40% being hospitalizations for PAD and a small fraction attributed to bleeding events (Figure 1). The rivaroxaban rate was lower for PAD hospitalizations and higher for bleeding event hospitalizations, with more hospitalizations prevented than caused (Table 1). Mean days in hospital among patients hospitalized at least once was significantly lower in the rivaroxaban group for any reason, for PAD, and for bleeding, so that total days in hospital was numerically lower for rivaroxaban.

Conclusion

Patients with PAD undergoing LER have a high rate of subsequent hospitalizations after an index procedure, driven by re-hospitalizations for PAD. Rivaroxaban decreased both the incidence and duration of PAD hospitalizations. While rivaroxaban increased incident hospitalizations due to bleeding, the mean durations of these hospitalizations were lower relative to placebo, leading to fewer total days in hospital for bleeding (1252 vs. 1531 total days). These findings may be useful for clinicians and patients weighing the risks and benefits of rivaroxaban in PAD after revascularization.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): BayerJanssen

Parental and child genetic contributions to obesity traits in early life based on 83 loci validated in adults: the FAMILY study

BACKGROUND

The genetic influence on child obesity has not been fully elucidated.

OBJECTIVE

This study investigated the parental and child contributions of 83 adult body mass index (BMI)-associated single-nucleotide polymorphisms (SNPs) to obesity-related traits in children from birth to 5 years old.

METHODS

A total of 1402 individuals were genotyped for 83 SNPs. An unweighted genetic risk score (GRS) was generated by the sum of BMI-increasing alleles. Repeated weight and length/height were measured at birth, 1, 2, 3 and 5 years of age, and age-specific and sex-specific weight and BMI Z-scores were computed.

RESULTS

The GRS was significantly associated with birthweight Z-score (P = 0.03). It was also associated with weight/BMI Z-score gain between birth and 5 years old (P = 0.02 and 6.77 × 10^-3 , respectively). In longitudinal analyses, the GRS was associated with weight and BMI Z-score from birth to 5 years (P = 5.91 × 10^-3 and 5.08 × 10^-3 , respectively). The maternal effects of rs3736485 in DMXL2 on weight and BMI variation from birth to 5 years were significantly greater compared with the paternal effects by Z test (P = 1.53 × 10^-6 and 3.75 × 10^-5 , respectively).

CONCLUSIONS

SNPs contributing to adult BMI exert their effect at birth and in early childhood. Parent-of-origin effects may occur in a limited subset of obesity predisposing SNPs.

On Prognostic Models, Artificial Intelligence and Censored Observations

The development of prognostic models for assisting medical practitioners with decision making is not a trivial task. Models need to possess a number of desirable characteristics and few, if any, current modelling approaches based on statistical or artificial intelligence can produce models that display all these characteristics. The inability of modelling techniques to provide truly useful models has led to interest in these models being purely academic in nature. This in turn has resulted in only a very small percentage of models that have been developed being deployed in practice. On the other hand, new modelling paradigms are being proposed continuously within the machine learning and statistical community and claims, often based on inadequate evaluation, being made on their superiority over traditional modelling methods. We believe that for new modelling approaches to deliver true net benefits over traditional techniques, an evaluation centric approach to their development is essential. In this paper we present such an evaluation centric approach to developing extensions to the basic k-nearest neighbour (k-NN) paradigm. We use standard statistical techniques to enhance the distance metric used and a framework based on evidence theory to obtain a prediction for the target example from the outcome of the retrieved exemplars. We refer to this new k-NN algorithm as Censored k-NN (Ck-NN). This reflects the enhancements made to k-NN that are aimed at providing a means for handling censored observations within k-NN.

Empirical evaluation of the Q-Genie tool: a protocol for assessment of effectiveness

INTRODUCTION

Meta-analyses of genetic association studies are affected by biases and quality shortcomings of the individual studies. We previously developed and validated a risk of bias tool for use in systematic reviews of genetic association studies. The present study describes a larger empirical evaluation of the Q-Genie tool.

METHODS AND ANALYSIS

MEDLINE, Embase, Global Health and the Human Genome Epidemiology Network will be searched for published meta-analyses of genetic association studies. Twelve reviewers in pairs will apply the Q-Genie tool to all studies in included meta-analyses. The Q-Genie will then be evaluated on its ability to (i) increase precision after exclusion of low quality studies, (ii) decrease heterogeneity after exclusion of low quality studies and (iii) good agreement with experts on quality rating by Q-Genie. A qualitative assessment of the tool will also be conducted using structured questionnaires.

DISCUSSION

This systematic review will quantitatively and qualitatively assess the Q-Genie's ability to identify poor quality genetic association studies. This information will inform the selection of studies for inclusion in meta-analyses, conduct sensitivity analyses and perform metaregression. Results of this study will strengthen our confidence in estimates of the effect of a gene on an outcome from meta-analyses, ultimately bringing us closer to deliver on the promise of personalised medicine.

ETHICS AND DISSEMINATION

An updated Q-Genie tool will be made available from the Population Genomics Program website and the results will be submitted for a peer-reviewed publication.

Impact of rosiglitazone on body composition, hepatic fat, fatty acids, adipokines and glucose in persons with impaired fasting glucose or impaired glucose tolerance: a sub-study of the DREAM trial

AIMS

Thiazolidinediones reduce ectopic fat, increase adiponectin and reduce inflammatory adipokines, fatty acids and glucose in people with Type 2 diabetes. We aimed to measure these effects in people with impaired fasting glucose and/or impaired glucose tolerance.

METHODS

After approximately 3.5 years of exposure to rosiglitazone 8 mg (n = 88) or placebo (n = 102), 190 DREAM trial participants underwent abdominal computed tomography and dual-energy X-ray absorptiometry scans. Visceral and subcutaneous adipose tissue areas, estimated hepatic fat content, total fat and lean mass were calculated and changes in levels of fasting adipokines, free fatty acids, glucose and post-load glucose were assessed.

RESULTS

Compared with the placebo, participants on rosiglitazone had no difference in lean mass, had 4.1 kg more body fat (P < 0.0001) and 31 cm(2) more subcutaneous abdominal adipose tissue area (P = 0.007). Only after adjusting for total fat, participants on rosiglitazone had 23 cm² less visceral adipose tissue area (P = 0.01) and an 0.08-unit higher liver:spleen attenuation ratio (i.e. less hepatic fat; P = 0.02) than those on the placebo. Adiponectin increased by 15.0 μg/ml with rosiglitazone and by 0.4 μg/ml with placebo (P < 0.0001). Rosiglitazone's effect on fat distribution was not independent of changes in adiponectin. Rosiglitazone's effects on fasting (-0.36 mmol/l; P = 0.0004) and 2-h post-load glucose (-1.21 mmol/l; P = 0.0008) were not affected by adjustment for fat distribution or changes in adiponectin or free fatty acids.

CONCLUSIONS

In people with impaired fasting glucose/impaired glucose tolerance, rosiglitazone is associated with relatively less hepatic and visceral fat, increased subcutaneous fat and increased adiponectin levels. These effects do not appear to explain the glucose-lowering effect of rosiglitazone.

An emerging double burden of disease: the prevalence of individuals with cardiovascular disease and cancer

OBJECTIVE

Cardiovascular disease (CVD) and cancer are the two leading causes of death in the United States; at the same time, the number of survivors is increasing as therapies continue to improve. The primary objective of this study is to determine the prevalence and characteristics of individuals affected by both CVD and cancer.

DESIGN AND SETTING

We conducted a prevalence study using the 2009 and 2010 national Behavioural Risk Factor Surveillance System population survey. Data from a random sample of individuals (aged 25-99 years) from all states were collected. All participants provided information regarding their CVD and cancer status. Multivariable regression identified associations between participants' characteristics and the prevalence of double disease burden.

RESULTS

Amongst 442,964 study participants, the overall prevalence rates were 11% for CVD and 15% for cancer; 3% of participants reported being survivors of both CVD and cancer. The prevalence of CVD+cancer increased twofold by 65 years of age (odds ratio [OR] 2.4, 95% confidence interval [CI] 2.3-2.5) and doubled again at ≥75 years (OR 4.9, 95% CI 4.6-5.1) and was higher amongst men (OR 1.6, 95% CI 1.6-1.7), multiracial individuals (OR 1.8, 95% CI 1.5-2.0) and those without a high school diploma (OR 1.3, 95% CI 1.2-1.4). Amongst individuals with CVD, 25% also reported having cancer, whilst 19% of all cancer survivors reported having CVD.

CONCLUSIONS

The prevalence of the double burden of disease increased with age; this is particularly important as the 'baby boomers' reach this high-risk age group. Future studies should explore potential common upstream or downstream mechanisms of CVD and cancer as well as public health strategies to cope with the double burden of disease.

Measures of body fat in South Asian adults

BACKGROUND

South Asian people who originate from the Indian subcontinent have greater percent body fat (%BF) for the same body mass index (BMI) compared with white Caucasians. This has been implicated in their increased risk of type 2 diabetes and cardiovascular disease. There is limited information comparing different measures of body fat in this ethnic group.

OBJECTIVES

The objectives of this study were: (1) to investigate the correlation of %BF measured by a foot-to-foot bioelectrical impedance analysis (FF-BIA) against the BOD POD, a method of air-displacement plethysmography, and (2) to determine the correlations of simple anthropometric measures, (that is, BMI, body adiposity index (BAI), waist circumference (WC), hip circumference (HC) and waist-to-hip ratio (WHR)) against the BOD POD measure of body fat.

METHODS

Eighty apparently healthy South Asian men and women were recruited from the community, and measurements of height, weight, WC, HC and body composition using Tanita FF-BIA and BOD POD were taken.

RESULTS

The mean±s.d. age of participants was 27.78±10.49 years, 42.5% were women, and the mean BMI was 22.68±3.51 kg m(-2). The mean body fat (%BF) calculated by FF-BIA and BOD POD was 21.94±7.88% and 26.20±8.47%, respectively. The %BF calculated by FF-BIA was highly correlated with the BOD POD (Pearson's r=0.83, P<0.001), however, FF-BIA underestimated %BF by 4.3%. When anthropometric measures were compared with % BF by BOD POD, the BAI showed the strongest correlation (r=0.74) and the WHR showed the weakest (r=0.33). BAI generally underestimated %BF by 2.6% in comparison with %BF by BOD POD. The correlations of BOD POD with other measures of %BF were much stronger in subjects with a BMI >21 kg m(-2) than those with a BMI 21 kg m(-2).

CONCLUSION

The FF-BIA and BAI estimates of %BF are highly correlated with that of BOD POD among people of South Asian origin, although both methods somewhat underestimate % BF. Furthermore, their correlations with % BF from BOD POD are significantly weakened among men and women with a BMI 21 kg m(-2).

Increased cardiovascular risk after pre-eclampsia in women with dysglycaemia

AIMS

Compared with women with uncomplicated pregnancies, women with a history of pre-eclampsia have two to five times the risk of cardiovascular disease. It is not known whether this risk is related to albuminuria, a known cardiovascular risk factor that is part of the definition of pre-eclampsia and that often persists after delivery. Our objective was to determine if the high risk of cardiovascular disease in women with pre-eclampsia is accounted for by known cardiovascular risk factors including albuminuria.

METHODS

We performed a cross-sectional analysis of 4080 dysglycaemic women enrolled in a large randomized controlled trial who provided an obstetric history and had at least one delivery. Blood pressure, height, weight, waist circumference and hip circumference were measured. An oral glucose tolerance test, lipids, an electrocardiogram and an albumin/creatinine ratio from a first morning urine sample were obtained.

RESULTS

There were 3613 women with no history of pre-eclampsia during their pregnancies, 108 with severe pre-eclampsia and 359 with non-severe pre-eclampsia. Women with a history of severe pre-eclampsia had higher rates of previous cardiovascular disease than women with non-severe pre-eclampsia or women without pre-eclampsia (87, 72 and 72%, P = 0.0019). The high risk of previous cardiovascular disease in women with a history of severe pre-eclampsia (odds ratio 2.67, 95% CI 1.52-4.70) persisted after adjustment for albuminuria (odds ratio 2.74, 95% CI 1.55-4.83) and also after adjusting for other covariates including albuminuria (odds ratio 3.03, 95% CI 1.69-5.44).

CONCLUSION

Even after accounting for cardiovascular risk factors including albuminuria, a history of severe pre-eclampsia is independently associated with a threefold higher risk of cardiovascular disease.

Clinical Applications of PET and PET-CT

Positron emission tomography (PET) and PET/ computed tomography (CT) are emerging as important imaging techniques and their popularity is growing within the medical fraternity. Though PET has been a useful research tool for many decades its real growth into clinical applications has occurred in the last one decade or so. Currently its major use is in oncologic imaging. However it has a multitude of clinical applications in cardiology, neurology and psychiatry as well. In oncologic imaging, a major advantage of PET is that a single whole-body examination can provide accurate assessment of disease activity and spread. PET/CT amalgamates the functional information of PET with the structural details of the CT scan, thus greatly aiding in accurate staging, therapy response assessment and early detection of recurrent disease.

Anthropometric measures and glucose levels in a large multi-ethnic cohort of individuals at risk of developing type 2 diabetes

AIMS/HYPOTHESES

We determined: (1) which of BMI, waist circumference, hip circumference and WHR has the strongest association and explanatory power for newly diagnosed type 2 diabetes and glucose status; and (2) the impact of considering two measures simultaneously. We also explored variation in anthropometric associations by sex and ethnicity.

METHODS

We performed cross-sectional analysis of 22,293 men and women who were from five ethnic groups and 21 countries, and at risk of developing type 2 diabetes. Standardised anthropometric associations with type 2 diabetes and AUC of glucose status from OGTT (AUC(OGTT)) were determined using multiple regression. Explanatory power was assessed using the c-statistic and adjusted r (2).

RESULTS

An increase in BMI, waist circumference or WHR had similar positive associations with type 2 diabetes, AUC(OGTT) and explanatory power after adjustment for age, sex, smoking and ethnicity (p < 0.01). However, using BMI and WHR together resulted in greater explanatory power than with other models (p < 0.01). Associations were strongest when waist circumference and hip circumference were used together, a combination that had greater explanatory power than other models except for BMI and WHR together (p < 0.01). Results were directionally similar according to sex and ethnicity; however, significant variations in associations were observed among these subgroups.

CONCLUSIONS/INTERPRETATION

The combination of BMI and WHR, or of waist circumference and hip circumference has the best explanatory power for type 2 diabetes and glucose status compared with a single anthropometric measure. Measurement of waist circumference and hip circumference is required to optimally identify people at risk of type 2 diabetes and people with elevated glucose levels.

Identifying women with severe angiographic coronary disease

OBJECTIVES

To determine sex/gender differences in the distribution of risk factors according to age and identify factors associated with the presence of severe coronary artery disease (CAD).

DESIGN

We analysed 23,771 consecutive patients referred for coronary angiography from 2000 to 2006.

SUBJECTS

Patients did not have previously diagnosed CAD and were referred for first diagnostic angiography.

OUTCOME MEASURES

Patients were classified according to angiographic disease severity. Severe CAD was defined as left main stenosis > or = 50%, three-vessel disease with > or = 70% stenosis or two-vessel disease including proximal left anterior descending stenosis of > or = 70%. Univariate and multivariate logistic regression was used to assess the association between risk factors and angina symptoms with severe CAD.

RESULTS

Women were less likely to have severe CAD (22.3% vs. 36.5%) compared with men. Women were also significantly older (69.8 +/- 10.6 vs. 66.3 +/- 10.7 years), had higher rates of diabetes (35.0% vs. 26.6%), hypertension (74.8% vs. 63.3%) and Canadian Cardiovascular Society (CCS) class IV angina symptoms (56.7% vs. 47.8%). Men were more likely to be smokers (56.9% vs. 37.9%). Factors independently associated with severe CAD included age (OR = 1.05; 95% CI 1.05-1.05, P < 0.01), male sex (OR = 2.43; CI 2.26-2.62, P < 0.01), diabetes (OR = 2.00; CI 1.86-2.18, P < 0.01), hyperlipidaemia (OR = 1.50; CI 1.39-1.61, P < 0.01), smoking (OR = 1.10; CI 1.03-1.18, P = 0.06) and CCS class IV symptoms (OR = 1.43; CI 1.34-1.53, P < 0.01). CCS Class IV angina was a stronger predictor of severe CAD amongst women compared with men (women OR = 1.82; CI 1.61-2.04 vs. men OR = 1.28; CI 1.18-1.39, P < 0.01).

CONCLUSIONS

Women referred for first diagnostic angiography have lower rates of severe CAD compared with men across all ages. Whilst conventional risk factors, age, sex, diabetes, smoking and hyperlipidaemia are primary determinants of CAD amongst women and men, CCS Class IV angina is more likely to be associated with severe CAD in women than men.

Hepato-biliary Scintigraphy in diagnosis of Biliary Atresia

BACKGROUND

Biliary Atresia and Neonatal Hepatitis are the two major causes of Persistent Neonatal Jaundice. Differentiation is done by biochemical and radiological tests. Radiological investigations use intra-or extra-hepatic biliary dilation for diagnosing biliary atresia but this is not always reliable.

METHODS

14 neonates with persistent conjugated hyperbilirubinemia who had undergone hepato-biliary scintigraphy were retrospectively evaluated and those having Extrahepatic Biliary Atresia were analyzed with reference to operative findings.

RESULTS

11 out of 14 had Extrahepatic Biliary Atresia during operation whereas 3 proved to be false positive.

CONCLUSION

Mebrofenin hepato - biliary scintigraphy is a simple, safe, accurate and cost effective investigation for diagnosis of biliary atresia.

Thyroid dyshormonogenesis

Dyshormonogenesis is an uncommon cause of congenital hypothyroidism. The most common abnormality is absent or insufficient thyroid peroxidase enzyme. Perchlorate discharge test can be used to diagnose thyroid peroxidase deficiency. We report three siblings with hypothyroidism due to thyroid dyshormonogenesis. Early institution of therapy in these patients can prevent mental retardation and other features of hypothyroidism.

Dose-dependent liver regeneration in chloroform, trichloroethylene and allyl alcohol ternary mixture hepatotoxicity in rats

The present study was designed to examine the hypothesis that liver tissue repair induced after exposure to chloroform (CF) + trichloroethylene (TCE) + allyl alcohol (AA) ternary mixture (TM) is dose-dependent similar to that elicited by exposure to these compounds individually. Male Sprague Dawley (S-D) rats (250-300 g) were administered with fivefold dose range of CF (74-370 mg/kg, ip), and TCE (250-1250 mg/kg, ip) in corn oil and sevenfold dose range of AA (5-35 mg/kg, ip) in distilled water. Liver injury was assessed by plasma alanine amino transferase (ALT) activity and liver tissue repair was measured by (3) H-thymidine incorporation into hepatonuclear DNA. Blood and liver levels of parent compounds and two major metabolites of TCE [trichloroacetic acid (TCA) and trichloroethanol (TCOH)] were quantified by gas chromatography. Blood and liver CF and AA levels after TM were similar to CF alone or AA alone, respectively. However, the TCE levels in blood and liver were substantially decreased after TM in a dose-dependent fashion compared to TCE alone. Decreased plasma and liver TCE levels were consistent with decreased production of metabolites and elevated urinary excretion of TCE. The antagonistic interaction resulted in lower liver injury than the summation of injury caused by the individual components at all three-dose levels. On the other hand, tissue repair showed a dose-response leading to regression of injury. Although the liver injury was lower and progression was contained by timely tissue repair, 50% mortality occurred only with the high dose combination, which is several fold higher than environmental levels. The mortality could be due to the central nervous system toxicity. These findings suggest that exposure to TM results in lower initial liver injury owing to higher elimination of TCE, and the compensatory liver tissue repair stimulated in a dose-dependent manner mitigates progression of injury after exposure to TM.

Comparison of 3 and 6 months of oral anticoagulant therapy after a first episode of proximal deep vein thrombosis or pulmonary embolism and comparison of 6 and 12 weeks of therapy after isolated calf deep vein thrombosis. Pinede L, Ninet J, Duhaut P et al for the Investigators of the 'Durée Optimale du Traitement Antivitamines K' (DOTAVK) study. Circulation 2001; 103: 2453-60

QUESTION

Is anticoagulant treatment for calf vein thrombosis for 6 weeks duration associated with acceptable recurrence and safety outcomes? Is anticoagulant therapy for 3 months duration for proximal deep vein thrombosis (DVT) or pulmonary embolism (PE) associated with acceptable recurrence and safety outcomes?

POPULATION

Men and women with a first episode of symptomatic calf vein thrombosis or proximal DVT confirmed by ultrasound or venography, or PE confirmed by lung scan or angiography. Patients with pregnancy, thrombophilia, severe PE, and cancer were excluded.

DESIGN AND METHODS

After treatment with heparin and oral anticoagulants targeting an INR of 2-3, patients with calf DVT were randomized to 6 weeks (n = 105) versus 3 months (n = 92) of treatment, and patients with proximal DVT and/or PE were randomized to 3 months (n = 270) versus 6 months (n = 269) of treatment. The outcome events were recurrences and major, minor, or fatal bleeding complications. The mean follow-up time was 12 months.

RESULTS

A total of 736 patients were enrolled. For calf vein thrombosis the recurrence of DVT or PE after 6 weeks of therapy was 2/105 (2.0%) versus 3/92 (3.4%) with 3 months of therapy, relative risk of 0.58 (95% CI: 0.10-3.36). The rates of major bleeding were 1/105 (1.0%) and 3/92 (3.4%) respectively, relative risk of 0.29 (95% CI: 0.03-2.72). For proximal DVT or PE, the recurrence rate after 3 months of therapy was 21/270 (8.1%) versus 23/269 (8.7%) after 6 months of treatment, relative risk of 0.93 (95% CI: 0.53-1.65). The rates of major bleeding were 5/270 (1.9%) versus 7/269 (2.6%) respectively, relative risk of 0.73 (95% CI: 0.24-2.27).

CONCLUSION

After isolated calf vein DVT, 6 weeks of oral anticoagulation is sufficient. For proximal DVT or PE, 3 and 6 months of anticoagulant therapy is equivalent. For patients with temporary risk factors who have a low risk of recurrence, 3 months of treatment seems to be sufficient.

Risk factors, atherosclerosis, and cardiovascular disease among Aboriginal people in Canada: the Study of Health Assessment and Risk Evaluation in Aboriginal Peoples (SHARE-AP)

BACKGROUND

Little is known about the rates of cardiovascular disease (CVD), atherosclerosis, and their risk factors among Canada's Aboriginal people. To establish the relative prevalence of risk factors, atherosclerosis, and CVD, we undertook a population-based study among people of Aboriginal and European ancestry in Canada.

METHODS

We randomly recruited 301 Aboriginal people from the Six Nations Reservation, and 326 people of European origin from Hamilton, Toronto, and Edmonton, Canada. Clinical CVD was defined by history or electrocardiographic findings, atherosclerosis was measured by B-mode carotid ultrasonography, and conventional and new CVD risk factors were measured using standardised methods.

FINDINGS

Aboriginal people had significantly more carotid atherosclerosis (mean of the maximum intimal-medial thickness 0.82 (SD 0.20) mm vs 0.78 (0.20) mm, p=0.027), and had a higher frequency of CVD (18.5% vs 7.6%, p=0.00002) compared with Europeans. Aboriginal people had significantly higher rates of smoking, glucose intolerance, obesity, abdominal obesity, and substantially higher concentrations of fibrinogen, and plasminogen activator inhibitor-1. Aboriginal people had significantly higher rates of unemployment and a lower annual household income. For any given income level, Aboriginal people had higher rates of risk factors and CVD compared with the Europeans.

INTERPRETATION

A significant proportion of Aboriginal people live in poverty which is associated with high rates of CVD and CVD risk factors. Improvement of the socioeconomic status of Aboriginal people might be a key to reduce CVD in this group.

Guidelines as rationing tools: a qualitative analysis of psychosocial patient selection criteria for cardiac procedures

BACKGROUND

Cardiac procedure guidelines often include psychosocial criteria for selecting patients that potentially introduce social value judgements into clinical decisions and decisions about the rationing of care. The aim of this study was to investigate the terms and justifications for and the meanings of psychosocial patient characteristics used in cardiac procedure guidelines.

METHODS

We selected English-language guidelines published since 1990 and chapters in textbooks published since 1989. These guidelines amalgamated multiple sources of evidence and expertise and made recommendations regarding patient selection for specific procedures. A multidisciplinary team of physicians and social scientists extracted passages regarding psychosocial criteria and developed categories and conceptual relationships to describe and interpret their content.

RESULTS

Sixty-five papers met the criteria for inclusion in the study. Forty-five (69%) mentioned psychosocial criteria as procedure indications or contraindications. The latter fell into several categories, including behavioural and psychological issues, relationships with significant others, financial resources, social roles and environmental circumstances.

INTERPRETATION

Psychosocial characteristics are portrayed as having 2 roles in patient selection: as risk factors intrinsic to the candidate or as indicators of need for special intervention. Guidelines typically simply list psychosocial contraindications without clarifying their specific nature or providing any justification for their use. Psychosocial considerations can help in the evaluation of patients for cardiac procedures, but they become ethically controversial when used to restrict access. The use of psychosocial indications and contraindications could be improved by more precise descriptions of the psychosocial problem at issue, explanations regarding why the criterion matters and justification of the characteristic using a biological rationale or research evidence.

Using practice guidelines to allocate medical technologies. An ethics framework

Clinical practice guidelines are expanding their scope of authority from clinical decision making to collective policy making, and promise to gain ground as resource allocation tools in coming years. A close examination of how guidelines approach patient selection criteria offers insight into their ethical implications when used as resource allocation or rationing instruments. The purposes of this paper are: a) to examine the structure of allocative reasoning found in clinical guidelines; b) to identify the ethical principles implied and compare how guidelines enact these principles with how explicit systems-level rationing exercises and health policy analyses have approached them; and c) to offer some preliminary suggestions for how these ethical issues might be addressed in the process of guideline development. The resulting framework can be used by guideline developers and users to understand and address some of the ethical issues raised by guidelines for the use of scarce technologies.

On prognostic models, artificial intelligence and censored observations

The development of prognostic models for assisting medical practitioners with decision making is not a trivial task. Models need to possess a number of desirable characteristics and few, if any, current modelling approaches based on statistical or artificial intelligence can produce models that display all these characteristics. The inability of modelling techniques to provide truly useful models has led to interest in these models being purely academic in nature. This in turn has resulted in only a very small percentage of models that have been developed being deployed in practice. On the other hand, new modelling paradigms are being proposed continuously within the machine learning and statistical community and claims, often based on inadequate evaluation, being made on their superiority over traditional modelling methods. We believe that for new modelling approaches to deliver true net benefits over traditional techniques, an evaluation centric approach to their development is essential. In this paper we present such an evaluation centric approach to developing extensions to the basic k-nearest neighbour (k-NN) paradigm. We use standard statistical techniques to enhance the distance metric used and a framework based on evidence theory to obtain a prediction for the target example from the outcome of the retrieved exemplars. We refer to this new k-NN algorithm as Censored k-NN (Ck-NN). This reflects the enhancements made to k-NN that are aimed at providing a means for handling censored observations within k-NN.

Prognostic significance of thrombocytopenia during hirudin and heparin therapy in acute coronary syndrome without ST elevation: Organization to Assess Strategies for Ischemic Syndromes (OASIS-2)study

BACKGROUND

The development of thrombocytopenia in acute coronary syndromes (ACS) appears to be associated with adverse clinical outcomes. Unfractionated heparin is a recognized cause of thrombocytopenia, but the incidence, predictors, and prognostic significance of thrombocytopenia during hirudin therapy in ACS have not been reported.

METHODS AND RESULTS

Patients with ACS without ST elevation were randomized in a double-blind manner to receive a 72-hour intravenous infusion of unfractionated heparin or hirudin. Platelet counts were measured at baseline and within 24 hours of completion of study drug. The overall incidence of thrombocytopenia (<100x10(9)/L) was 1% and was similar in unfractionated heparin- and hirudin-treated patients (P:=0.42). Thrombocytopenia during study drug infusion was an independent predictor of 7-day outcomes, including death (OR, 6.7; 95% CI, 1.9 to 25); the composite of death, myocardial infarction, and recurrent ischemia (OR, 2.0; 95% CI, 1.0 to 1.5); revascularization (OR, 4.0; 95% CI, 2.2 to 7.1); and major bleeding (OR, 8.3; 95% CI, 3.4 to 17.7). Among patients who developed thrombocytopenia, hirudin (OR, 5.4; 95% CI, 2.6 to 11.3) but not unfractionated heparin (OR, 2.0; 95% CI, 0.3 to 14.4) therapy was associated with a significantly increased risk of major bleeding.

CONCLUSIONS

Early-onset thrombocytopenia in patients with ACS without ST elevation is strongly associated with adverse clinical outcomes, including death, ischemic events, and bleeding. The excess of major bleeding in hirudin-treated patients who develop thrombocytopenia suggests that thrombocytopenia may contribute to the increased risk of bleeding observed with hirudin.

Differences in risk factors, atherosclerosis and cardiovascular disease between ethnic groups in Canada: the study of health assessment and risk in ethnic groups (SHARE)

Cardiovascular disease rates vary greatly between ethnic groups in Canada. To establish whether this variation can be explained by differences in disease risk factors and subclinical atherosclerosis, we undertook a population-based study of three ethnic groups in Canada: South Asians, Chinese and Europeans. A total of 985 participants were recruited from three cities (Hamilton, Toronto and Edmonton) by stratified random sampling. Clinical cardiovascular disease was defined by history or electrocardiographic findings. Carotid atherosclerosis was measured with B-mode ultrasonography. Conventional (smoking, hypertension, diabetes, raised cholesterol) and novel risk factors (markers of a prothrombotic state) were measured. Within each ethnic group and overall, the degree of carotid atherosclerosis was associated with a higher prevalence of cardiovascular disease. South Asians had the highest prevalence of this condition compared with Europeans and Chinese (11%, 5% and 2%, respectively; p=0.0004). Despite this finding, Europeans had more atherosclerosis (mean of the maximum intimal medial thickness 0.75 [0.16] mm) than South Asians (0.72 [0.15] mm) and Chinese (0.69 [0.16] mm). South Asians had an increased prevalence of glucose intolerance, higher total and low-density lipoprotein cholesterol, higher triglycerides and lower high-density lipoprotein cholesterol, and much greater abnormalities in novel risk factors including higher concentrations of fibrinogen, homocysteine, lipoprotein(a), and plasminogen activator inhibitor-1. Although there are differences in conventional and novel risk factors between ethnic groups, this variation and the degree of atherosclerosis only partly explains the higher rates of cardiovascular disease among South Asians compared with Europeans and Chinese. The increased risk of cardiovascular events could be due to factors affecting plaque rupture, the interaction between prothrombotic factors and atherosclerosis, or as yet undiscovered risk factors.

Differences in risk factors, atherosclerosis, and cardiovascular disease between ethnic groups in Canada: the Study of Health Assessment and Risk in Ethnic groups (SHARE)

BACKGROUND

Cardiovascular disease rates vary greatly between ethnic groups in Canada. To establish whether this variation can be explained by differences in disease risk factors and subclinical atherosclerosis, we undertook a population-based study of three ethnic groups in Canada: South Asians, Chinese, and Europeans.

METHODS

985 participants were recruited from three cities (Hamilton, Toronto, and Edmonton) by stratified random sampling. Clinical cardiovascular disease was defined by history or electrocardiographic findings. Carotid atherosclerosis was measured with B-mode ultrasonography. Conventional (smoking, hypertension, diabetes, raised cholesterol) and novel risk factors (markers of a prothrombotic state) were measured.

FINDINGS

Within each ethnic group and overall, the degree of carotid atherosclerosis was associated with a higher prevalence of cardiovascular disease. South Asians had the highest prevalence of this condition compared with Europeans and Chinese (11%, 5%, and 2%, respectively, p=0.0004). Despite this finding, Europeans had more atherosclerosis (mean of the maximum intimal medial thickness 0.75 [0.16] mm) than South Asians (0.72 [0.15] mm), and Chinese (0.69 [0.16] mm). South Asians had an increased prevalence of glucose intolerance, higher total and LDL cholesterol, higher triglycerides, and lower HDL cholesterol, and much greater abnormalities in novel risk factors including higher concentrations of fibrinogen, homocysteine, lipoprotein (a), and plasminogen activator inhibitor-1.

INTERPRETATION

Although there are differences in conventional and novel risk factors between ethnic groups, this variation and the degree of atherosclerosis only partly explains the higher rates of cardiovascular disease among South Asians compared with Europeans and Chinese. The increased risk of cardiovascular events could be due to factors affecting plaque rupture, the interaction between prothrombotic factors and atherosclerosis, or as yet undiscovered risk factors.

Unfractionated heparin and low-molecular-weight heparin in acute coronary syndrome without ST elevation: a meta-analysis

BACKGROUND

In acute coronary syndrome without ST elevation, the role of unfractionated and low-molecular-weight heparin in aspirin-treated patients remains unclear, and there is conflicting evidence regarding the efficacy and safety of low-molecular-weight heparin (LMWH) relative to unfractionated heparin. We did a systematic overview of the randomised trials to assess the effect of unfractionated heparin and LMWH on death, myocardial infarction, and major bleeding.

METHODS

Randomised trials comparing unfractionated heparin or LMWH with placebo or untreated control, or comparing unfractionated heparin with LMWH, for the short-term and long-term management of patients with acute coronary syndrome without ST elevation, were identified by electronic and manual searches and through contact with experts and industry representatives. Odds ratios for death, myocardial infarction, and major bleeding were calculated for each trial, and results for the individual trials were combined by a modification of the Mantel-Haenszel method.

FINDINGS

12 trials, involving a total of 17157 patients, were included. The summary odds ratio (OR) for myocardial infarction or death during short-term (up to 7 days) unfractionated heparin or LMWH compared with placebo or untreated control was 0.53 (95% CI 0.38-0.73; p=0.0001) or 29 events prevented per 1000 patients treated; during short-term LMWH compared with unfractionated heparin was 0.88 (0.69-1.12; p=0.34); and during long-term LMWH (up to 3 months) compared with placebo or untreated control was 0.98 (0.81-1.17; p=0.80). Long-term LMWH was associated with a significantly increased risk of major bleeding (OR 2.26, [95% CI 1.63-3.14], p<0.0001), which is equivalent to 12 major bleeds per 1000 patients treated.

INTERPRETATION

In aspirin-treated patients with acute coronary syndrome without ST elevation, short-term unfractionated heparin or LMWH halves the risk of myocardial infarction or death. There is no convincing difference in efficacy or safety between LMWH and unfractionated heparin. Long-term LMWH has not been proven to confer benefit additional to aspirin and there is no evidence to support its use after the first 7 days.

Association between high homocyst(e)ine and ischemic stroke due to large- and small-artery disease but not other etiologic subtypes of ischemic stroke

BACKGROUND AND PURPOSE

Elevated plasma homocyst(e)ine may be a causal and modifiable risk factor for ischemic stroke, but the results of previous studies have been conflicting. One possible explanation is that homocyst(e)ine may only be associated with certain pathophysiological subtypes of ischemic stroke.

METHODS

We conducted a case-control study of 219 hospital cases with a first-ever ischemic stroke and 205 randomly selected community control subjects stratified by age, sex, and postal code. With the use of established criteria, cases of stroke were classified by etiologic subtype in a blinded fashion. The prevalence of conventional vascular risk factors, fasting plasma homocyst(e)ine levels, vitamin levels, and nucleotide 677 methylene tetrahydrofolate reductase (MTHFR) genotypes were determined in cases and controls.

RESULTS

Increasing homocyst(e)ine was a strong and independent risk factor for ischemic stroke (adjusted OR 2.7, 95% CI 1.4 to 5.1 for a 5-micromol/L increase in fasting plasma homocyst(e)ine from 10 to 15 micromol/L). Compared with the lowest quartile, the highest quartile of homocyst(e)ine was associated with an adjusted OR of ischemic stroke of 2.2 (95% CI 1.1 to 4.2). Mean plasma homocyst(e)ine was significantly higher in cases of ischemic stroke due to large-artery disease (14.1 micromol/L, 95% CI 12.5 to 15.9, P<0.001) and small-artery disease (12.7 micromol/L, 95% CI 11. 4 to 14.1, P=0.004) compared with control subjects (10.5 micromol/L; 95% CI 10.0 to 11.0) but not in cardioembolic or other etiologic subtypes of ischemic stroke. Compared with the lowest quartile of homocyst(e)ine, the upper 3 quartiles were associated with an adjusted OR of ischemic stroke due to large-artery disease of 3.0 (95% CI 0.8 to 10.8) for the second quartile, 5.6 (95% CI 1.6 to 20) for the third quartile, and 8.7 (95% CI 2.4 to 32) for the fourth quartile (P for trend=0.0005). However, despite a clear association between the TT MTHFR genotype and elevated fasting plasma homocyst(e)ine, there was no association between MTHFR genotype and ischemic stroke or subtype of ischemic stroke.

CONCLUSIONS

There is a strong, graded association between increasing plasma homocyst(e)ine and ischemic stroke caused by large-artery atherosclerosis and, to a much lesser extent, small-artery disease, but not cardioembolic or other etiologic subtypes of ischemic stroke. Our results are consistent with the hypothesis that the deleterious effect of high homocyst(e)ine is mediated primarily via a proatherogenic effect.

Oral anticoagulant therapy in patients with coronary artery disease: a meta-analysis

CONTEXT

Despite years of use in coronary artery disease (CAD) and several studies of its effectiveness, the role of oral anticoagulants (OAs) remains controversial.

OBJECTIVE

To determine the effects of long-term OA therapy, stratified by the intensities of anticoagulation and aspirin therapy, on outcomes in patients with CAD.

DATA SOURCES

Studies were identified by MEDLINE, EMBASE, and CURRENT CONTENTS searches (1960-July 1999) and by reviewing reference lists and inquiring with experts and pharmaceutical companies.

STUDY SELECTION

Studies were included if they were published between 1960 and July 1999, were randomized, had recruited patients with CAD, who had used OA therapy for at least 3 months. Of 43 articles identified, 30 articles (31 trials) were analyzed.

DATA EXTRACTION

Information on type, duration, and method of monitoring OA therapy, as well as rates of death, myocardial infarction (MI), thromboembolic complications, stroke, and bleeding were abstracted by 2 independent observers.

DATA SYNTHESIS

With high-intensity (international normalized ratio [INR], 2.8-4.8) OAs vs control (16 trials, 10056 patients), clear reductions in mortality (odds reduction [ORed], 22%; 95% confidence interval [CI], 13%-31%), MIs (ORed, 42%; 95% CI, 34%-48%), and thromboembolic complications including stroke (ORed, 63%; 95% CI, 53-71%) were observed, but were associated with a 6.0-fold (95% CI, 4.4- to 8.2-fold) increase in major bleeding. For moderate OAs (INR, 2-3) vs control (4 trials, 1365 patients) the ORed for death was 18% (95% CI, -6% to 37%); for MI, 52% (95% CI, 37%-64%); and for stroke, 53% (95% CI, 19%-73%), but it increased bleeding by 7.7-fold (95% CI, 3.3- to 18-fold). For moderate- to high-intensity OAs (INR, > or =2) vs aspirin (7 trials, 3457 patients), no reduction in death, MI, or stroke was observed, and it was associated with a 2.4-fold (95% CI, 1.6- to 3.6-fold) increase in major bleeding. For moderate- to high-intensity OAs and aspirin vs aspirin alone (3 trials, 480 patients), the ORed for death, MI, or stroke was 56% (95% CI, 17%-77%) and major bleeding increased by 1.9-fold (0.6- to 6.0-fold). For low-intensity OAs (INR, <2.0) and aspirin vs aspirin alone (3 trials, 8435 patients), no significant reduction in death, MI, or stroke was observed, and major bleeding increased by 1.3-fold (95% CI, 1.0- to 1.8-fold).

CONCLUSIONS

Among patients with CAD, high-intensity and moderate-intensity OA are effective in reducing MI and stroke but increase the risk of bleeding. In the presence of aspirin, low-intensity OA does not appear to be superior to aspirin alone, while moderate- to high-intensity OA and aspirin vs aspirin alone appears promising and the bleeding risk is modest, but this requires confirmation from ongoing trials.

Low rates of preventive practices in patients with peripheral vascular disease

BACKGROUND

Patients with peripheral vascular disease (PVD) have a three-fold increased risk of myocardial infarction, stroke and death. Recently, a number of therapies have been demonstrated to prevent morbidity or mortality in patients with PVD or other arterial disease. Given the scarcity of data on the preventive practice patterns of this high risk patient group, the in-hospital management of patients admitted to hospital for a peripheral vascular intervention was reviewed.

PATIENTS AND METHODS

Charts of 195 patients with a diagnosis of peripheral arteriosclerotic disease (International Classification of Diseases, 9th revision, code 440.2) who were hospitalized at a tertiary care hospital in Ontario between June 1996 and June 1998 were reviewed.

RESULTS

The average age of patients admitted was 70.6 years, and 39% of patients were women. The main reason for admission was peripheral artery bypass graft surgery in 88% (172 of 195). Fifty-four per cent (106 of 195) of patients had clinically apparent coronary or cerebrovascular disease, and 92% (180 of 195) of patients had at least one cardiovascular disease risk factor. Fewer than half of all patients (49%) were discharged on any antithrombotic therapy (antiplatelet agent or anticoagulant), and a small proportion of patients were treated with a beta-blocker (20%) and cholesterol-lowering medications (16%).

CONCLUSIONS

The leading cause of morbidity and mortality in PVD patients is coronary and cerebrovascular disease. Despite this, the use of proven antithrombotic agents and other cardiac medications is suboptimal. Health professionals need to be aware of the high risk nature of the PVD population and to develop strategies to ensure that patient care is optimized.

Using ethnicity as a classification variable in health research: perpetuating the myth of biological determinism, serving socio-political agendas, or making valuable contributions to medical sciences?

There is a need for a valid way to classify the human species consistently and reliably, be it to highlight similarities between human populations such as intelligence or physical capacity, to dispel myths about group differences, or to discover 'novel' risk factors for diseases. In contrast to racial divisions, which are usually based on differences in skin colour and physical features, ethnicity is a complex concept which has both socio-cultural and biological components. However, because of the relative vagueness of the term, the interpretation of the 'Ethnicity' construct is not simple, and its definition is often unique to the research project at hand. Therefore conducting ethnicity-research necessitates being aware of the differences between the concept of ethnicity and race, acknowledgement of the complexity of the ethnicity construct, and requires that a clear definition of the use of this term be made explicit by the researcher.

Recurrent venous thrombosis and heparin therapy: an evaluation of the importance of early activated partial thromboplastin times

BACKGROUND

The presence of an association between early subtherapeutic activated partial thromboplastin times (aPTTs) and recurrent venous thromboembolism (VTE) remains controversial.

OBJECTIVE

To determine the relation between early subtherapeutic aPTTs and recurrent VTE in patients who were treated with intravenous (i.v.) unfractionated heparin (UFH).

PATIENTS AND METHODS

We studied 961 patients with acute VTE who received i.v. UFH in 3 randomized trials that compared the use of i.v. UFH (loading dose: 5000 U i.v.; initial infusion, 1250-1280 U/h) with that of subcutaneous low-molecular-weight heparin. According to aPTT criteria, patients were classified as being in a subtherapeutic or a therapeutic state during the first 24 and 48 hours of treatment. All episodes of possible recurrent VTE were adjudicated by an independent committee that was unaware of the aPTTs.

RESULTS

At 24 hours, in 886 patients who were eligible for the analysis, the rate of recurrent VTE in the subtherapeutic group was 6.7% (11/163) compared with 5.3% (38/723) in the therapeutic group. The odds ratio for recurrence in patients in the subtherapeutic vs the therapeutic group at 24 hours was 1.30 (95% confidence interval: 0.64-2.63; P = .46). At 48 hours, in 917 patients who were eligible for the analysis, the rate of recurrent VTE in the subtherapeutic group was 7.8% (5/64) compared with 5.7% (49/853) in the therapeutic group. The odds ratio for recurrence in patients in the subtherapeutic vs the therapeutic group at 48 hours was 1.32 (95% confidence interval: 0.51-3.44; P = .56).

CONCLUSION

In patients with acute VTE who receive an i.v. bolus of 5000 U, followed by a starting dose of at least 1250 U/h of UFH, a subtherapeutic aPTT response during the first 48 hours of treatment is not associated with a large increase in the risk of recurrent VTE.

The Organization to Assess Strategies for Ischemic Syndromes (OASIS) Pilot Study: evaluation of acute and long-term therapies for patients with acute coronary syndromes without ST elevation

The objectives of the Organization to Assess Strategies for Ischemic Syndromes (OASIS) Pilot Study (phase 2) were (1) to compare the efficacy, safety, and feasibility of recombinant hirudin versus unfractionated heparin as short-term therapy in patients with acute coronary syndromes without ST elevation and (2) to compare the efficacy and safety of long-term therapy with warfarin and aspirin versus standard therapy with aspirin alone in the same patient population. Investigators at 31 Canadian centers randomized 909 patients to receive either medium-dose hirudin, low-dose hirudin, or unfractionated heparin. The incidence of the 7-day primary composite outcome of cardiovascular death, new myocardial infarction (MI), or refractory angina was significantly lower among patients who received hirudin than among those assigned to unfractionated heparin. A subset of these patients was subsequently randomized to long-term, low-intensity (international normalized ratio [INR] < 1.5) or moderate-intensity (INR 2-2.5) anticoagulant treatment with warfarin or to standard therapy. In this substudy, promising results were observed in favor of moderate-intensity warfarin. These findings provided the rationale for the design and conduct of the large-scale, phase III OASIS-2 trial.

An evaluation of intelligent prognostic systems for colorectal cancer

In this paper we describe attempts at building a robust model for predicting the length of survival of patients with colorectal cancer. The aim of the research, reported in this paper, is to study the effective utilisation of artificial intelligence techniques in the medical domain. We suggest that an important research objective of proponents of intelligent prognostic systems must be to evaluate the additionality that AI techniques can bring to an already well-established field of medical prognosis. Towards this end, we compare a number of different AI techniques that lend themselves to the task of predicting survival in colorectal cancer patients. We describe the pros and cons of each of these methods using the usual metrics of accuracy and perspicuity. We then present the notion of intelligent hybrid systems and evaluate the role that they may potentially play in developing robust prognostic models. In particular we evaluate a hybrid system that utilises the k Nearest Neighbour technique in conjunction with Genetic Algorithms. We describe a number of innovations used within this hybrid paradigm used to build the prognostic model. We discuss the issue of censored patients and how this issue can be tackled within the various models used. In keeping with our objective of studying the additionality that AI techniques bring to building prognostic models, we use Cox's regression as a standard and compare each AI technique with it, attempting to discover their capabilities in enhancing prognostic methods in medicine. In doing so we address two main questions--which model fits the data best?, and are the results obtained by the various AI techniques significantly different from those of Cox's regression? We conclude this paper by discussing future enhancements to the work presented and lessons learned from the study to date.

The Study of Health Assessment and Risk in Ethnic groups (SHARE): rationale and design. The SHARE Investigators

The Study of Health Assessment and Risk in Ethnic groups (SHARE) is a study to determine the risk factors for atherosclerosis among three ethnic populations in Canada. Three hundred and thirty South Asian Canadian, 320 Chinese Canadian and 320 European Canadian men and women between 35 and 75 years of age are being randomly sampled from communities in Hamilton and Toronto, Ontario and Edmonton, Alberta for assessment of conventional (i.e., smoking, dyslipidemia, diabetes and hypertension) and emerging (i.e., candidate genes for atherosclerosis, homocysteine, fibrinolytic parameters, neurohormones, glucose intolerance, markers of infection, socioeconomic status, psychosocial status and diet) cardiovascular disease risk factors. Subclinical atherosclerosis is measured by quantitative B-mode ultrasonography of the carotid arteries, and other objective measures of vascular disease are a 12-lead electrocardiogram, a two-dimensional echocardiogram, ankle to arm blood pressure ratio and urine microalbumin concentration. The relationship between the conventional and emerging risk factors, and atherosclerosis, vascular disease and markers of end-organ damage will be evaluated between and within ethnic groups.

Long-term oral anticoagulant therapy in patients with unstable angina or suspected non-Q-wave myocardial infarction: organization to assess strategies for ischemic syndromes (OASIS) pilot study results

BACKGROUND

Patients with acute ischemic syndromes (AIS) suffer high rates of recurrent ischemic events despite aspirin treatment. Long-term therapy with oral anticoagulants in addition to aspirin may reduce this risk. We studied the effects of long-term warfarin at 2 intensities in patients with AIS without ST elevation in 2 consecutive randomized controlled studies.

METHODS AND RESULTS

In phase 1, after the cessation of 3 days of intravenous antithrombotic therapy, 309 patients were randomized to receive fixed low-dose (3 mg/d) warfarin for 6 months that produced a mean international normalized ratio (INR) of 1.5+/-0.6 or to standard therapy. Eighty-seven percent of patients received aspirin in both groups. The rates of cardiovascular (CV) death, new myocardial infarction (MI), and refractory angina at 6 months were 6.5% in the warfarin group and 3.9% in the standard therapy group (relative risk [RR], 1. 66; 95% CI, 0.62 to 4.44; P=0.31). The rates of death, new MI, and stroke were 6.5% in the warfarin group and 2.6% in the standard therapy group (RR, 2.48; 95% CI, 0.80 to 7.75; P=0.10). The overall rate of rehospitalization for unstable angina was 21% and did not differ significantly between the groups. Four patients in the warfarin group (2.6%) and none in the control group experienced a major bleed (RR, 2.48; 95% CI, 0.80 to 7.75), and there was a significant excess of minor bleeds in the warfarin group (14.2% versus 2.6%; RR, 5.46; 95% CI, 1.93 to 15.5; P=0.001). In phase 2, the protocol was modified, and 197 patients were randomized <48 hours from the onset of symptoms to receive warfarin at an adjusted dose that produced a mean INR of 2.3+/-0.6 or standard therapy for 3 months. Eighty-five percent received aspirin in both groups. The rates of CV death, new MI, and refractory angina at 3 months were 5. 1% in the warfarin group and 12.1% in the standard group (RR, 0.42; 95% CI, 0.15 to 1.15; P=0.08). The rates of all death, new MI, and stroke were 5.1% in the warfarin group and 13.1% in the standard therapy group (RR, 0.39; 95% CI, 0.14 to 1.05; P=0.05). Significantly fewer patients were rehospitalized for unstable angina in the warfarin group than in the control group (7.1% and 17.2%, respectively; RR, 0.42; 95% CI, 0.18 to 0.96; P=0.03). Two patients in the warfarin group and 1 in the control group experienced a major bleed, and there was a significant excess of minor bleeds in the warfarin group (28.6% versus 12.1%; RR, 2.36; 95% CI, 1.37 to 4.36; P=0.004).

CONCLUSIONS

Long-term treatment with moderate-intensity warfarin (INR, 2.0 to 2.5) plus aspirin but not low-intensity warfarin (INR, 1.5) plus aspirin appears to reduce the rate of recurrent ischemic events in patients with AIS without ST elevation.

Does this patient have deep vein thrombosis?

OBJECTIVE

To review the validity of the clinical assessment and diagnostic tests in patients with suspected deep vein thrombosis (DVT).

METHODS

A comprehensive review of the literature was conducted by searching MEDLINE from 1966 to April 1997.

RESULTS

Individual symptoms and signs alone do not reliably predict which patients have DVT. Overall, the diagnostic properties of the clinical examination are poor; the sensitivity of the clinical examination ranges from 60% to 96%, and the specificity ranges from 20% to 72%. However, using specific combinations of risk factors, symptoms, and physical signs for DVT, clinicians can reliably stratify patients with suspected DVT into low, moderate, or high pretest probability categories of actually suffering from DVT. This stratification process in combination with noninvasive testing, such as compression ultrasonography, simplifies the management strategies for patients with suspected DVT.

CONCLUSIONS

Use of a clinical prediction guide that includes specific factors from both the history and physical examination in combination with noninvasive tests simplifies management strategies for patients with suspected DVT.

Elevated lipoprotein(a) levels in South Asians in North America

This report demonstrates that South Asians living in North America have elevated levels of Lp(a) compared with North American whites. Elevated Lp(a) levels may account, in part, for the tendency of South Asians to develop premature coronary heart disease (CHD).