Autism spectrum disorder reporting in lower socioeconomic neighborhoods

Utilizing surveillance data from five sites participating in the Autism and Developmental Disabilities Monitoring Network, we investigated contributions of surveillance subject and census tract population sociodemographic characteristics on variation in autism spectrum disorder ascertainment and prevalence estimates from 2000 to 2008 using ordinal hierarchical models for 2489 tracts. Multivariable analyses showed a significant increase in ascertainment of autism spectrum disorder cases through both school and health sources, the optimal ascertainment scenario, for cases with college-educated mothers (adjusted odds ratio = 1.06, 95% confidence interval = 1.02–1.09). Results from our examination of sociodemographic factors of tract populations from which cases were drawn also showed that after controlling for other covariates, statistical significance remained for associations between optimal ascertainment and percentage of Hispanic residents (adjusted odds ratio = 0.93, 95% confidence interval = 0.88–0.99) and percentage of residents with at least a bachelor’s degree (adjusted odds ratio = 1.06, 95% confidence interval = 1.01–1.11). We identified sociodemographic factors associated with autism spectrum disorder prevalence estimates including race, ethnicity, education, and income. Determining which specific factors influence disparities is complicated; however, it appears that even in the presence of education, racial and ethnic disparities are still apparent. These results suggest disparities in access to autism spectrum disorder assessments and special education for autism spectrum disorder among ethnic groups may impact subsequent surveillance.

Autism spectrum disorder prevalence and associations with air concentrations of lead, mercury, and arsenic

Lead, mercury, and arsenic are neurotoxicants with known effects on neurodevelopment. Autism spectrum disorder (ASD) is a neurodevelopmental disorder apparent by early childhood. Using data on 4486 children with ASD residing in 2489 census tracts in five sites of the Centers for Disease Control and Prevention's Autism and Developmental Disabilities Monitoring (ADDM) Network, we used multi-level negative binomial models to investigate if ambient lead, mercury, and arsenic concentrations, as measured by the US Environmental Protection Agency National-Scale Air Toxics Assessment (EPA-NATA), were associated with ASD prevalence. In unadjusted analyses, ambient metal concentrations were negatively associated with ASD prevalence. After adjusting for confounding factors, tracts with air concentrations of lead in the highest quartile had significantly higher ASD prevalence than tracts with lead concentrations in the lowest quartile (prevalence ratio (PR) = 1.36; 95 '% CI: 1.18, 1.57). In addition, tracts with mercury concentrations above the 75th percentile (>1.7 ng/m(3)) and arsenic concentrations below the 75th percentile (≤0.13 ng/m(3)) had a significantly higher ASD prevalence (adjusted RR = 1.20; 95 % CI: 1.03, 1.40) compared to tracts with arsenic, lead, and mercury concentrations below the 75th percentile. Our results suggest a possible association between ambient lead concentrations and ASD prevalence and demonstrate that exposure to multiple metals may have synergistic effects on ASD prevalence.

Autism spectrum disorder prevalence and proximity to industrial facilities releasing arsenic, lead or mercury

Prenatal and perinatal exposures to air pollutants have been shown to adversely affect birth outcomes in offspring and may contribute to prevalence of autism spectrum disorder (ASD). For this ecologic study, we evaluated the association between ASD prevalence, at the census tract level, and proximity of tract centroids to the closest industrial facilities releasing arsenic, lead or mercury during the 1990s. We used 2000 to 2008 surveillance data from five sites of the Autism and Developmental Disabilities Monitoring (ADDM) network and 2000 census data to estimate prevalence. Multi-level negative binomial regression models were used to test associations between ASD prevalence and proximity to industrial facilities in existence from 1991 to 1999 according to the US Environmental Protection Agency Toxics Release Inventory (USEPA-TRI). Data for 2489 census tracts showed that after adjustment for demographic and socio-economic area-based characteristics, ASD prevalence was higher in census tracts located in the closest 10th percentile compared of distance to those in the furthest 50th percentile (adjusted RR=1.27, 95% CI: (1.00, 1.61), P=0.049). The findings observed in this study are suggestive of the association between urban residential proximity to industrial facilities emitting air pollutants and higher ASD prevalence.

Meta-Analysis of Cell-based CaRdiac stUdiEs (ACCRUE) in patients with acute myocardial infarction based on individual patient data

RATIONALE

The meta-Analysis of Cell-based CaRdiac study is the first prospectively declared collaborative multinational database, including individual data of patients with ischemic heart disease treated with cell therapy.

OBJECTIVE

We analyzed the safety and efficacy of intracoronary cell therapy after acute myocardial infarction (AMI), including individual patient data from 12 randomized trials (ASTAMI, Aalst, BOOST, BONAMI, CADUCEUS, FINCELL, REGENT, REPAIR-AMI, SCAMI, SWISS-AMI, TIME, LATE-TIME; n=1252).

METHODS AND RESULTS

The primary end point was freedom from combined major adverse cardiac and cerebrovascular events (including all-cause death, AMI recurrance, stroke, and target vessel revascularization). The secondary end point was freedom from hard clinical end points (death, AMI recurrence, or stroke), assessed with random-effects meta-analyses and Cox regressions for interactions. Secondary efficacy end points included changes in end-diastolic volume, end-systolic volume, and ejection fraction, analyzed with random-effects meta-analyses and ANCOVA. We reported weighted mean differences between cell therapy and control groups. No effect of cell therapy on major adverse cardiac and cerebrovascular events (14.0% versus 16.3%; hazard ratio, 0.86; 95% confidence interval, 0.63-1.18) or death (1.4% versus 2.1%) or death/AMI recurrence/stroke (2.9% versus 4.7%) was identified in comparison with controls. No changes in ejection fraction (mean difference: 0.96%; 95% confidence interval, -0.2 to 2.1), end-diastolic volume, or systolic volume were observed compared with controls. These results were not influenced by anterior AMI location, reduced baseline ejection fraction, or the use of MRI for assessing left ventricular parameters.

CONCLUSIONS

This meta-analysis of individual patient data from randomized trials in patients with recent AMI revealed that intracoronary cell therapy provided no benefit, in terms of clinical events or changes in left ventricular function.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01098591.

Bone marrow mononuclear cell therapy for acute myocardial infarction: a perspective from the cardiovascular cell therapy research network

To understand the role of bone marrow mononuclear cells in the treatment of acute myocardial infarction, this overview offers a retrospective examination of strengths and limitations of 3 contemporaneous trials with attention to critical design features and provides an analysis of the combined data set and implications for future directions in cell therapy for acute myocardial infarction.

Bone marrow mononuclear cell therapy for acute myocardial infarction: a perspective from the cardiovascular cell therapy research network

To understand the role of bone marrow mononuclear cells in the treatment of acute myocardial infarction, this overview offers a retrospective examination of strengths and limitations of 3 contemporaneous trials with attention to critical design features and provides an analysis of the combined data set and implications for future directions in cell therapy for acute myocardial infarction.

Implementation of cardovascular cell therapy network trials: challenges, innovation and lessons learned from experience in the CCTRN

The cardiovascular cell therapy network was developed by the National Heart, Lung and Blood Institute to design and conduct clinical trials to advance the field of cardiovascular (CV) cell-based therapy. The Cardiovascular Cell Therapy Network successfully completed three clinical trials involving approximately 300 subjects across five centers and six satellites. Although the concept of a network within clinical trials research is not new, the knowledge gained in the implementation of such large-scale trials, particularly in novel therapeutic areas such as cell therapy is not often detailed in the literature. The purpose of this communication is to summarize key factors in achieving network goals and share the knowledge gained to promote success in future cardiovascular disease cell therapy trials and networks.

Effect of the use and timing of bone marrow mononuclear cell delivery on left ventricular function after acute myocardial infarction: the TIME randomized trial

CONTEXT

While the delivery of cell therapy after ST-segment elevation myocardial infarction (STEMI) has been evaluated in previous clinical trials, the influence of the timing of cell delivery on the effect on left ventricular function has not been analyzed.

OBJECTIVES

To determine the effect of intracoronary autologous bone marrow mononuclear cell (BMC) delivery after STEMI on recovery of global and regional left ventricular function and whether timing of BMC delivery (3 days vs 7 days after reperfusion) influences this effect.

DESIGN, SETTING, AND PATIENTS

A randomized, 2 × 2 factorial, double-blind, placebo-controlled trial, Timing In Myocardial infarction Evaluation (TIME) enrolled 120 patients with left ventricular dysfunction (left ventricular ejection fraction [LVEF] ≤ 45%) after successful primary percutaneous coronary intervention (PCI) of anterior STEMI between July 17, 2008, and November 15, 2011, as part of the Cardiovascular Cell Therapy Research Network sponsored by the National Heart, Lung, and Blood Institute.

INTERVENTIONS

Intracoronary infusion of 150 × 106 BMCs or placebo (randomized 2:1) within 12 hours of aspiration and cell processing administered at day 3 or day 7 (randomized 1:1) after treatment with PCI.

MAIN OUTCOME MEASURES

The primary end points were change in global (LVEF) and regional (wall motion) left ventricular function in infarct and border zones at 6 months measured by cardiac magnetic resonance imaging and change in left ventricular function as affected by timing of treatment on day 3 vs day 7. The secondary end points included major adverse cardiovascular events as well as changes in left ventricular volumes and infarct size.

RESULTS

The mean (SD) patient age was 56.9 (10.9) years and 87.5% of participants were male. At 6 months, there was no significant increase in LVEF for the BMC group (45.2% [95% CI, 42.8% to 47.6%] to 48.3% [95% CI, 45.3% to 51.3%) vs the placebo group (44.5% [95% CI, 41.0% to 48.0%] to 47.8% [95% CI, 43.4% to 52.2%]) (P = .96). There was no significant treatment effect on regional left ventricular function observed in either infarct or border zones. There were no significant differences in change in global left ventricular function for patients treated at day 3 (−0.9% [95% CI, −6.6% to 4.9%], P = .76) or day 7 (1.1% [95% CI, −4.7% to 6.9%], P = .70). The timing of treatment had no significant effect on regional left ventricular function recovery. Major adverse events were rare among all treatment groups.

CONCLUSION

Among patients with STEMI treated with primary PCI, the administration of intracoronary BMCs at either 3 days or 7 days after the event had no significant effect on recovery of global or regional left ventricular function compared with placebo.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00684021.

Cell tracking and the development of cell-based therapies: a view from the Cardiovascular Cell Therapy Research Network

Cell-based therapies are being developed for myocardial infarction (MI) and its consequences (e.g., heart failure) as well as refractory angina and critical limb ischemia. The promising results obtained in preclinical studies led to the translation of this strategy to clinical studies. To date, the initial results have been mixed: some studies showed benefit, whereas in others, no benefit was observed. There is a growing consensus among the scientific community that a better understanding of the fate of transplanted cells (e.g., cell homing and viability over time) will be critical for the long-term success of these strategies and that future studies should include an assessment of cell homing, engraftment, and fate as an integral part of the trial design. In this review, different imaging methods and technologies are discussed within the framework of the physiological answers that the imaging strategies can provide, with a special focus on the inherent regulatory issues.

Effect of transendocardial delivery of autologous bone marrow mononuclear cells on functional capacity, left ventricular function, and perfusion in chronic heart failure: the FOCUS-CCTRN trial

CONTEXT

Previous studies using autologous bone marrow mononuclear cells (BMCs) in patients with ischemic cardiomyopathy have demonstrated safety and suggested efficacy.

OBJECTIVE

To determine if administration of BMCs through transendocardial injections improves myocardial perfusion, reduces left ventricular end-systolic volume (LVESV), or enhances maximal oxygen consumption in patients with coronary artery disease or LV dysfunction, and limiting heart failure or angina.

DESIGN, SETTING, AND PATIENTS

A phase 2 randomized double-blind, placebo-controlled trial of symptomatic patients (New York Heart Association classification II-III or Canadian Cardiovascular Society classification II-IV) with a left ventricular ejection fraction of 45% or less, a perfusion defect by single-photon emission tomography (SPECT), and coronary artery disease not amenable to revascularization who were receiving maximal medical therapy at 5 National Heart, Lung, and Blood Institute-sponsored Cardiovascular Cell Therapy Research Network (CCTRN) sites between April 29, 2009, and April 18, 2011.

INTERVENTION

Bone marrow aspiration (isolation of BMCs using a standardized automated system performed locally) and transendocardial injection of 100 million BMCs or placebo (ratio of 2 for BMC group to 1 for placebo group).

MAIN OUTCOME MEASURES

Co-primary end points assessed at 6 months: changes in LVESV assessed by echocardiography, maximal oxygen consumption, and reversibility on SPECT. Phenotypic and functional analyses of the cell product were performed by the CCTRN biorepository core laboratory.

RESULTS

Of 153 patients who provided consent, a total of 92 (82 men; average age: 63 years) were randomized (n = 61 in BMC group and n = 31 in placebo group). Changes in LVESV index (-0.9 mL/m(2) [95% CI, -6.1 to 4.3]; P = .73), maximal oxygen consumption (1.0 [95% CI, -0.42 to 2.34]; P = .17), and reversible defect (-1.2 [95% CI, -12.50 to 10.12]; P = .84) were not statistically significant. There were no differences found in any of the secondary outcomes, including percent myocardial defect, total defect size, fixed defect size, regional wall motion, and clinical improvement.

CONCLUSION

Among patients with chronic ischemic heart failure, transendocardial injection of autologous BMCs compared with placebo did not improve LVESV, maximal oxygen consumption, or reversibility on SPECT.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00824005.

Quantification of myocardial segmental function in acute and chronic ischemic heart disease and implications for cardiovascular cell therapy trials: a review from the NHLBI-Cardiovascular Cell Therapy Research Network

Global left ventricular (LV) ejection fraction (LVEF) has been used as a measure of improvement in LV function following cell therapy. Although the impact of cell therapy on LVEF in short- and long-term follow-up has been generally positive, there is concern that research evaluating regional therapeutics (e.g., cell or gene therapy) may require analysis of regional LV function localized to the site of intervention. Regional LV assessment is traditionally performed with qualitative or quantitative analysis of wall thickening within 16 myocardial segments, but advances in noninvasive imaging permit an increasingly more detailed and accurate evaluation of LV function. Wall-thickness measurements can now include evaluation of over 1,000 myocardial segments. In addition to higher resolution measures of wall thickening, automated assessments of myocardial segment deformation, such as strain imaging, exist. Strain imaging allows for direct evaluation of the mechanical properties that may improve following regional therapeutic intervention. Improvements in regional LV function may also be assessed by determining regional ejection fraction (EF). Regional EF offers the advantage of summarizing the end result of all of the complex deformations in the adjacent myocardial segments. Although regional EF and strain imaging, as compared with wall thickening, enhance detection of improvement in complex measures of regional myocardial function, it remains unclear whether such measures are better able to predict meaningful improvement in clinical outcomes.

Factors affecting the turnaround time for manufacturing, testing, and release of cellular therapy products prepared at multiple sites in support of multicenter cardiovascular regenerative medicine protocols: a Cardiovascular Cell Therapy Research Network (CCTRN) study

BACKGROUND

Cellular therapy studies are often conducted at multiple clinical sites to accrue larger patient numbers. In many cases this necessitates use of localized good manufacturing practices facilities to supply the cells. To assure consistent quality, oversight by a quality assurance group is advisable. In this study we report the findings of such a group established as part of the Cardiovascular Cell Therapy Research Network (CCTRN) studies involving use of autologous bone marrow mononuclear cells (ABMMCs) to treat myocardial infarction and heart failure.

STUDY DESIGN AND METHODS

Factors affecting cell manufacturing time were studied in 269 patients enrolled on three CCTRN protocols using automated cell processing system (Sepax, Biosafe SA)-separated ABMMCs. The cells were prepared at five good manufacturing practices cell processing facilities and delivered to local treatment sites or more distant satellite centers.

RESULTS

Although the Sepax procedure takes only 90 minutes, the total time for processing was approximately 7 hours. Contributing to this were incoming testing and device preparation, release testing, patient randomization, and product delivery. The mean out-of-body time (OBT), which was to be less than 12 hours, averaged 9 hours. A detailed analysis of practices at each center revealed a variety of factors that contributed to this OBT.

CONCLUSION

We conclude that rapid cell enrichment procedures may give a false impression of the time actually required to prepare a cellular therapy product for release and administration. Institutional procedures also differ and can contribute to delays; however, in aggregate it is possible to achieve an overall manufacturing and testing time that is similar at multiple facilities.

Effect of intracoronary delivery of autologous bone marrow mononuclear cells 2 to 3 weeks following acute myocardial infarction on left ventricular function: the LateTIME randomized trial

CONTEXT

Clinical trial results suggest that intracoronary delivery of autologous bone marrow mononuclear cells (BMCs) may improve left ventricular (LV) function when administered within the first week following myocardial infarction (MI). However, because a substantial number of patients may not present for early cell delivery, the efficacy of autologous BMC delivery 2 to 3 weeks post-MI warrants investigation.

OBJECTIVE

To determine if intracoronary delivery of autologous BMCs improves global and regional LV function when delivered 2 to 3 weeks following first MI.

DESIGN, SETTING, AND PATIENTS

A randomized, double-blind, placebo-controlled trial (LateTIME) of the National Heart, Lung, and Blood Institute-sponsored Cardiovascular Cell Therapy Research Network of 87 patients with significant LV dysfunction (LV ejection fraction [LVEF] ≤45%) following successful primary percutaneous coronary intervention (PCI) between July 8, 2008, and February 28, 2011.

INTERVENTIONS

Intracoronary infusion of 150 × 10(6) autologous BMCs (total nucleated cells) or placebo (BMC:placebo, 2:1) was performed within 12 hours of bone marrow aspiration after local automated cell processing.

MAIN OUTCOME MEASURES

Changes in global (LVEF) and regional (wall motion) LV function in the infarct and border zone between baseline and 6 months, measured by cardiac magnetic resonance imaging. Secondary end points included changes in LV volumes and infarct size.

RESULTS

A total of 87 patients were randomized (mean [SD] age, 57 [11] years; 83% men). Harvesting, processing, and intracoronary delivery of BMCs in this setting was feasible. Change between baseline and 6 months in the BMC group vs placebo for mean LVEF (48.7% to 49.2% vs 45.3% to 48.8%; between-group mean difference, -3.00; 95% CI, -7.05 to 0.95), wall motion in the infarct zone (6.2 to 6.5 mm vs 4.9 to 5.9 mm; between-group mean difference, -0.70; 95% CI, -2.78 to 1.34), and wall motion in the border zone (16.0 to 16.6 mm vs 16.1 to 19.3 mm; between-group mean difference, -2.60; 95% CI, -6.03 to 0.77) were not statistically significant. No significant change in LV volumes and infarct volumes was observed; both groups decreased by a similar amount at 6 months vs baseline.

CONCLUSION

Among patients with MI and LV dysfunction following reperfusion with PCI, intracoronary infusion of autologous BMCs vs intracoronary placebo infusion, 2 to 3 weeks after PCI, did not improve global or regional function at 6 months.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00684060.

Cell therapy and satellite centers: the Cardiovascular Cell Therapy Research Network experience

Due to the changing population in patients with myocardial infarction, recruiting patients in clinical trials continues to challenge clinical investigators. The Cardiovascular Cell Therapy Research Network (CCTRN) chose to expand the reach and power of its recruitment effort by incorporating both referral and treatment satellite centers. Eight treatment satellites were successfully identified and they screened patients over a two year period. The result of this effort was an increase in recruitment, with these treatment satellites contributing 30% of the patients to two of the three Network studies. The hurdles that these satellite treatment centers faced and how they surmounted them provide instruction to clinical research groups eager to expand to satellite systems and to health care practitioners who are interested in taking part in multicenter clinical trials.

Development of a network to test strategies in cardiovascular cell delivery: the NHLBI-sponsored Cardiovascular Cell Therapy Research Network (CCTRN)

The emerging sciences of stem cell biology and cellular plasticity have led to the development of cell-based therapies for advanced human disease. Pre-clinical studies which defined the potential of bone marrow-derived mononuclear cells to repair damaged and dysfunctional myocardium led to the rapid advancement of these strategies to the clinic. Such rapid advancement has led to controversy regarding the appropriate conduct of such studies. In the United States, the National Heart, Lung, and Blood Institute established the Cardiovascular Cell Therapy Research Network (CCTRN) to facilitate the early translation of clinical trials of cell therapy for left ventricular dysfunction. The premise upon which the CCTRN was established was that multiple clinical trial sites would interact effectively with a Data Coordinating Center to perform early phase 1 and 2 clinical trials within a highly coordinated network structure. In order to develop this network, the unmet needs of the community needed to be defined, the clinical trials identified, and the structure to perform the studies needed to be established. This manuscript highlights the challenges in the development of the CCTRN and the approaches faced to define a network to perform clinical trials in human cell therapy of cardiovascular disease.

Risk of all-cause mortality, recurrent myocardial infarction, and heart failure hospitalization associated with smoking status following myocardial infarction with left ventricular dysfunction

Patients with left ventricular (LV) systolic dysfunction after myocardial infarction (MI) are at particularly high risk for recurrent adverse outcomes. The magnitude of the decrease in risk associated with smoking cessation after MI has not been well described in patients with LV dysfunction after MI. We aimed to quantify the risk decrease associated with smoking cessation in subjects with LV dysfunction after MI. The Survival and Ventricular Enlargement (SAVE) trial randomized 2,231 subjects with LV dysfunction 3 to 16 days after MI. Smoking status was assessed at randomization and at regular intervals during a median follow-up of 42 months. Propensity score-adjusted Cox proportional hazard models were used to quantify the decrease in risk of all-cause mortality, death or recurrent MI, and death or heart failure (HF) hospitalization associated with smoking cessation. In baseline smokers who survived to 6 months without interval events, smoking cessation at 6-month follow-up was associated with a significantly lower adjusted risk of all-cause mortality (hazard ratio [HR] 0.57, 95% confidence interval [CI] 0.31 to 0.91), death or recurrent MI (HR 0.68, 95% CI 0.47 to 0.99), and death or HF hospitalization (HR 0.65, 95% CI 0.46 to 0.92). In conclusion, in patients with LV dysfunction after MI, smoking cessation is associated with a 40% lower hazard of all-cause mortality and a 30% lower hazard of death or recurrent MI or death or HF hospitalization. These findings indicate that smoking cessation is beneficial after high-risk MI and highlight the importance of smoking cessation as a therapeutic target in patients with LV dysfunction after MI.

Kids Identifying and Defeating Stroke (KIDS): development and implementation of a multiethnic health education intervention to increase stroke awareness among middle school students and their parents

The Kids Identifying and Defeating Stroke (KIDS) project is a 3-year prospective, randomized, controlled, multiethnic school-based intervention study. Project goals include increasing knowledge of stroke signs and treatment and intention to immediately call 911 among Mexican American (MA) and non-Hispanic White (NHW) middle school students and their parents. This article describes the design, implementation, and interim evaluation of this theory-based intervention. Intervention students received a culturally appropriate stroke education program divided into four 50-minute classes each year during the sixth, seventh, and eighth grades. Each class session also included a homework assignment that involved the students' parents or other adult partners. Interim-test results indicate that this educational intervention was successful in improving students' stroke symptom and treatment knowledge and intent to call 911 upon witnessing a stroke compared with controls. The authors conclude that this school-based educational intervention to reduce delay time to hospital arrival for stroke shows early promise.

Results of a non-specific immunomodulation therapy in chronic heart failure (ACCLAIM trial): a placebo-controlled randomised trial

BACKGROUND

Evidence suggests that inflammatory mediators contribute to development and progression of chronic heart failure. We therefore tested the hypothesis that immunomodulation might counteract this pathophysiological mechanism in patients.

METHODS

We did a double-blind, placebo-controlled study of a device-based non-specific immunomodulation therapy (IMT) in patients with New York Heart Association (NYHA) functional class II-IV chronic heart failure, left ventricular (LV) systolic dysfunction, and hospitalisation for heart failure or intravenous drug therapy in an outpatient setting within the past 12 months. Patients were randomly assigned to receive IMT (n=1213) or placebo (n=1213) by intragluteal injection on days 1, 2, 14, and every 28 days thereafter. Primary endpoint was the composite of time to death from any cause or first hospitalisation for cardiovascular reasons. The study continued until 828 primary endpoint events had accrued and all study patients had been treated for at least 22 weeks. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00111969.

FINDINGS

During a mean follow-up of 10.2 months, there were 399 primary events in the IMT group and 429 in the placebo group (hazard ratio 0.92; 95% CI 0.80-1.05; p=0.22). In two prespecified subgroups of patients--those with no history of previous myocardial infarction (n=919) and those with NYHA II heart failure (n=689)--IMT was associated with a 26% (0.74; 0.57-0.95; p=0.02) and a 39% (0.61; 95% CI 0.46-0.80; p=0.0003) reduction in the risk of primary endpoint events, respectively.

INTERPRETATION

Non-specific immunomodulation may have a role as a potential treatment for a large segment of the heart failure population, which includes patients without a history of myocardial infarction (irrespective of their functional NYHA class) and patients within NYHA class II.

Bayesians in clinical trials: Asleep at the switch

The refreshing Bayes perspective has much to offer biostatistics. Yet, from its 225-year-old roots sprung difficulties that blocked its growth at the beginning of the 20th century. Computational obstacles in concert with an inability to identify the best indifferent prior revealed a weakness on which frequentists capitalized. It took Bayesians 40 years to recover, allowing the infant field of biostatistics to fall firmly in the hands of the frequentists. Recent disillusionment with the frequentist perspective, and its hegemony of p-values, has produced a second opportunity for the Bayesian philosophy to make solid contributions to clinical trials.However, difficulty with the applicability of the likelihood principle, problems with prevalent prior 'disinformation' in clinical medicine, in concert with the complexity of truly representative loss functions threaten again to thwart the Bayesian march into biostatistics. Seven suggestions are offered to the Bayesians to help them adapt to the rigors of clinical research.

Disciplined analyses in clinical trials: the dark heart of the matter

Clinical research analyses must balance the desire to `learn all that is learnable' from the database with the observation that sample-based data commonly lead to conclusions that are perfectly correct for the sample, but wholly incorrect for the population from which the data were based.

Investigators who defend exploratory analyses as reliable, misuse important tools that have taken over three hundred years to develop. Statistical estimators in clinical trials function appropriately when they incorporate random data that is gathered in response to a “xed research question. Their prediction ability degrades rapidly when the selection of the research question is itself random, that is, left to the data. Operating like blind guides, these estimators mislead the medical community about what it would see in the population, based on sample observations. The result is a wavering research focus, leaping from one provocative but misleading “nding to the next on the powerful waves of sampling error. Therefore, a primary purpose of the prospective design is to “x the research questions prospectively, thereby anchoring the analysis plan.

Prospective statements of the research questions and rejection of tempting databased changes to the protocol preserve the best estimates of effect sizes, standard errors, con“dence intervals and p-values. Embracing these principles promotes the prosecution of a successful research program, that is, the construction and protection of a research environment that permits an objective assessment of the therapy or exposure being studied. If there is any “xed star in the research constellation, it is that sample-based research must be hypothesis-driven and concordantly executed to have real meaning for both the scienti“c community and the patient populations that we serve.

Left ventricular end-diastolic pressure and risk of subsequent heart failure in patients following an acute myocardial infarction

Left ventricular end-diastolic pressure (LVEDP) is an important measure of ventricular performance and may identify patients at increased risk for developing late clinical symptoms of heart failure (HF). The primary outcome in this analysis of 744 patients from the Survival and Ventricular Enlargement (SAVE) trial was the development of death or HF over a mean time of 36 months. The mean LVEDP for all patients was 23+/-9 mm Hg, and 75% of participants (n=558) had an LVEDP >15 mm Hg. Patients with an LVEDP >30 mm Hg (n=187) had the highest risk of death or HF (unadjusted hazard ratio, 1.40; 95% confidence interval [CI], 1.00-1.97) when compared with the other 2 cohorts combined (n=603). After adjustment for other known predictors of cardiac risk, LVEDP no longer remained significant (adjusted hazard ratio, 1.12; 95% CI, 0.77-1.65). Elevated LVEDP is common following myocardial infarction; however, it is not an independent predictor of subsequent HF risk. The variability in LVEDP is not fully explained by infarct size and atherosclerotic burden.

A randomized, controlled trial to teach middle school children to recognize stroke and call 911: the kids identifying and defeating stroke project

BACKGROUND AND PURPOSE

Underutilization of acute stroke therapy is driven by delay to hospital arrival. We present the primary results of a pilot, randomized, controlled trial to encourage calling 911 for witnessed stroke among middle school children and their parents.

METHODS

This project occurred in Corpus Christi, an urban Texas community of 325,000. Three intervention and 3 control schools were randomly selected. The intervention contained 12 hours of classroom instruction divided among sixth, seventh, and eighth grades. Parents were educated indirectly through homework assignments. Two-sample t tests were used to compare pretest and posttest responses.

RESULTS

Domain 1 test questions involved stroke pathophysiology. Intervention students improved from 29% to 34% correct; control students changed from 28% to 25%. Domain 2 test questions involved stroke symptom knowledge. Intervention school students changed from 28% correct to 43%; control school students answered 25% correctly on the pretest and 29% on the posttest. Domain 3 test questions involved what to do for witnessed stroke. Intervention school students answered 36% of questions correctly on the pretest and 54% correctly on the posttest, whereas control students changed from 32% correct to 34%. A comparison of change in the mean proportion correct over time between intervention and control students was P<0.001 for each of the 3 individual domains. A poor parental response rate impaired the ability to assess parental improvement.

CONCLUSIONS

A scientific, theory-based, educational intervention can potentially improve intent to call 911 for stroke among middle school children. A different mechanism is needed to effectively diffuse the curriculum to parents.

A study to assess the effects of a broad-spectrum immune modulatory therapy on mortality and morbidity in patients with chronic heart failure: the ACCLAIM trial rationale and design

BACKGROUND

Evidence has accumulated regarding the importance of inflammatory mediators in the development and progression of heart failure (HF). Although targeted anticytokine treatment strategies, specifically antitumour necrosis factor-alpha, have yielded disappointing results, this may simply reflect the redundancy of the cytokine cascade and the fact that antitumour necrosis factor-alpha therapies do not stimulate increased activity of the anti-inflammatory arm of the immune system. Ex vivo exposure of autologous blood to controlled oxidative stress and subsequent intramuscular administration is a device-based procedure shown in experimental studies to have a broad-spectrum effect on a number of immune mediators. These studies have demonstrated that this approach downregulates inflammatory cytokines, whereas several anti-inflammatory cytokines are increased. In a feasibility study of 73 patients with moderate to severe HF, active therapy (versus placebo) had a significant benefit on both mortality and hospitalization, and was not associated with adverse hemodynamic or metabolic effects.

METHODS

The Advanced Chronic heart failure CLinical Assessment of Immune Modulation therapy (ACCLAIM) trial is a multicentre, randomized, double-blind, placebo-controlled clinical trial of New York Heart Association functional class II to IV chronic HF patients with left ventricular ejection fraction of 30% or less. Enrolling approximately 2400 subjects at 177 sites, the primary end point of the study was the cumulative incidence (time to first event) of the combined end point of total mortality or hospitalization for cardiovascular causes. The study was completed in late 2005, when 701 primary end point events had occurred and all patients had been treated for six months.

CONCLUSIONS

If the ACCLAIM trial confirms earlier results, this approach represents a novel nonpharmacological treatment for HF that targets a pathogenic mechanism contributing to progression of this syndrome not addressed by current therapies.

Kids Identifying and Defeating Stroke (KIDS): design of a school-based intervention to improve stroke awareness

BACKGROUND

We describe the design and baseline data of an educational intervention targeting predominantly Mexican American middle school students and their parents in an effort to improve stroke awareness. Increasing awareness in this group may increase the number of patients eligible for acute stroke treatment by encouraging emergency medical services (EMS) activation.

METHODS

This is a prospective, randomized study in which six middle schools were randomly assigned to receive a stroke education program or the standard health class. Primary outcome measures are the percentage of students and parents who recognize stroke symptoms and express the intent to activate EMS upon recognition of these findings.

RESULTS

A total of 547 students (271 control, 276 intervention) and 484 parents (231 control, 253 intervention) have been enrolled. Pretests were administered. The intervention has been successfully carried out in the parent and student cohorts over a three-year period. Posttests and persistence test results are pending.

CONCLUSION

Implementing a school-based stroke education initiative is feasible. Followup testing will demonstrate whether this educational initiative translates into a measurable and persistent improvement in stroke knowledge and behavioral intent to activate EMS upon recognition of stroke symptoms.

Ethnic differences in stroke recurrence

OBJECTIVE

To determine whether stroke recurrence and the effect of recurrence on mortality differ by ethnicity.

METHODS

Using methods from the Brain Attack Surveillance in Corpus Christi project, we prospectively identified first-ever ischemic strokes from emergency department logs and hospital admissions (January 2000 to December 2004). Recurrent strokes and deaths were identified for the same period. Cumulative probability of stroke recurrence was estimated. Cox proportional hazards models were used to examine ethnic differences in recurrence and to examine the relation among ethnicity, recurrence, and mortality.

RESULTS

During the time interval, 1,345 first-ever ischemic strokes were validated. Median age of patients was 72 years; 53% were Mexican American (MA). There were 126 recurrent strokes. Cumulative risk for recurrence at 30 days and 1 year was 2.6 and 7.5%, respectively. MAs had higher risk for stroke recurrence (risk ratio, 1.57; 95% confidence interval, 1.05-2.34) compared with non-Hispanic white patients, adjusted for demographics, stroke risk factors, and stroke severity. Stroke recurrence was related to mortality to a similar extent across ethnic groups (non-Hispanic white patients: risk ratio, 3.32; 95% confidence interval, 2.07-5.32; MAs: risk ratio, 2.35; 95% confidence interval, 1.42-3.88).

INTERPRETATION

MAs had higher stroke recurrence risk compared with non-Hispanic white patients. Stroke recurrence had an important impact on mortality. Efforts to reduce stroke recurrence in MAs are needed.

A Multinational Study to Establish the Value of Early Adenosine Technetium-99m Sestamibi Myocardial Perfusion Imaging in Identifying a Low-Risk Group for Early Hospital Discharge After Acute Myocardial Infarction

OBJECTIVES

The purpose of this study was to determine whether gated adenosine Tc-99m sestamibi single-photon emission computed tomography (ADSPECT) could accurately define risk and thereby guide therapeutic decision making in stable survivors of acute myocardial infarction (AMI).

BACKGROUND

Controversy continues as to the role of noninvasive stress imaging in stratifying risk early after AMI.

METHODS

The INSPIRE (Adenosine Sestamibi Post-Infarction Evaluation) trial is a prospective multicenter trial which enrolled 728 clinically stable survivors of AMI who had gated ADSPECT within 10 days of hospital admission and subsequent 1-year follow-up. Event rates were assessed within prospectively defined INSPIRE risk groups based on the adenosine-induced left ventricular perfusion defect size, extent of ischemia, and ejection fraction.

RESULTS

Total cardiac events/death and reinfarction significantly increased within each INSPIRE risk group from low (5.4%, 1.8%), to intermediate (14%, 9.2%), to high (18.6%, 11.6%) (p < 0.01). Event rates at 1 year were lowest in patients with the smallest perfusion defects but progressively increased when defect size exceeded 20% (p < 0.0001). The perfusion results significantly improved risk stratification beyond that provided by clinical and ejection fraction variables. The low-risk INSPIRE group, comprising one-third of all enrolled patients, had a shorter hospital stay with lower associated costs compared with the higher-risk groups (p < 0.001).

CONCLUSIONS

Gated ADSPECT performed early after AMI can accurately identify a sizeable low-risk group who have a <2% death and reinfarction rate at 1 year. Identifying these low-risk patients for early hospital discharge may improve utilization of health care resources at considerable cost savings.

An Initial Strategy of Intensive Medical Therapy Is Comparable to That of Coronary Revascularization for Suppression of Scintigraphic Ischemia in High-Risk But Stable Survivors of Acute Myocardial Infarction

OBJECTIVES

The purpose of this study was to determine the relative benefit of intensive medical therapy compared with coronary revascularization for suppressing scintigraphic ischemia.

BACKGROUND

Although medical therapies can reduce myocardial ischemia and improve patient survival after acute myocardial infarction, the relative benefit of medical therapy versus coronary revascularization for reducing ischemia is unknown.

METHODS

A prospective randomized trial in 205 stable survivors of acute myocardial infarction was made to define the relative efficacy of an intensive medical therapy strategy versus coronary revascularization for suppressing scintigraphic ischemia as assessed by serial gated adenosine Tc-99m sestamibi myocardial perfusion tomography. All patients at baseline had large total (> or =20%) and ischemic (> or =10%) adenosine-induced left ventricular perfusion defects and an ejection fraction > or =35%. Imaging was performed during 1 to 10 days of hospital admission and repeated in an identical fashion after optimization of therapy. Patients randomized to either strategy had similar baseline demographic and scintigraphic characteristics.

RESULTS

Both intensive medical therapy and coronary revascularization induced significant but comparable reductions in total (-16.2 +/- 10% vs. -17.8 +/- 12%; p = NS) and ischemic (-15 +/- 9% vs. -16.2 +/- 9%; p = NS) perfusion defect sizes. Likewise, a similar percentage of patients randomized to medical therapy versus coronary revascularization had suppression of adenosine-induced ischemia (80% vs. 81%; p = NS).

CONCLUSIONS

Sequential adenosine sestamibi myocardial perfusion tomography can effectively monitor changes in scintigraphic ischemia after anti-ischemic medical or coronary revascularization therapy. A strategy of intensive medical therapy is comparable to coronary revascularization for suppressing ischemia in stable patients after acute infarction who have preserved LV function.

Argatroban tPA Stroke Study

BACKGROUND

The benefit of intravenous recombinant tissue plasminogen activator (rtPA) in acute stroke is linked to clot lysis and artery recanalization. Argatroban is a direct thrombin inhibitor that safely augments the benefit of rtPA in animal stroke models. There are no human data on this combination.

DESIGN

We report the first phase of the Argatroban tPA Stroke Study, an ongoing prospective, open-label, dose-escalation, safety and activity study of argatroban and rtPA in patients with ischemic stroke. The primary outcome was incidence of intracerebral hemorrhage; secondary outcome, complete recanalization at 2 hours. After standard-dose intravenous rtPA administration, a 100-mug/kg bolus of argatroban followed by infusion of 1 mug/kg per minute for 48 hours was adjusted to a target partial thromboplastin time of 1.75 times that of the control group.

RESULTS

Fifteen patients (including 10 men) were enrolled, with a mean +/- SD age of 61 +/- 13 years. All patients had middle cerebral artery occlusions. Baseline median National Institute of Health Stroke Scale score was 14 (range, 4-25). The mean +/- SD time from symptom onset to argatroban bolus administration was 172 +/- 53 minutes. Symptomatic intracerebral hemorrhage occurred in 2 patients, including 1 with parenchymal hemorrhage type 2. Asymptomatic bleeding occurred in 1 patient and there was 1 death. Recanalization was complete in 6 patients and partial in another 4, and reocclusion occurred in 3 within 2 hours of rtPA bolus administration.

CONCLUSION

The safety of low-dose argatroban combined with intravenous rtPA may be within acceptable limits, and its efficacy for producing fast and complete recanalization is promising, but a larger cohort of patients is required to confirm these preliminary observations.

Dependence, hyper-dependence and hypothesis testing in clinical trials

While investigators designing clinical trials face the important issue of endpoint selection, an equally troublesome concern can be the a priori selection of the endpoint analysis. In this latter circumstance, there may be only one endpoint of interest in the clinical trial, but several competing endpoint analyses are available (e.g., an analysis of the endpoint that is adjusted for clinical center versus an analysis that is adjusted for geographic region versus an unadjusted analysis). An example that demonstrates the unsatisfactory conclusions that ambiguous choices can produce is offered. A procedure utilizing conditional probability is provided that permits the conservation of type I error when the investigators have one endpoint and several worthy competitor endpoint analyses that are each prospectively identified and carried out at the trial's conclusion. When the high levels of dependence among these analyses are taken into account, it is possible to carry out the hypothesis tests in a way that 1) provides practicable type I error levels for each analysis, and 2) conserves the familywise type I error. In circumstances in which the endpoint and all members of the family of analyses are selected during the design phase of the trial, this procedure provides confirmatory conclusions as opposed to exploratory findings.

A scoring system for ascertainment of incident stroke; the Risk Index Score (RISc)

OBJECTIVES

The main objective of this study was to develop and validate a computer-based statistical algorithm that could be translated into a simple scoring system in order to ascertain incident stroke cases using hospital admission medical records data.

METHODS

The Risk Index Score (RISc) algorithm was developed using data collected prospectively by the Brain Attack Surveillance in Corpus Christi (BASIC) project, 2000. The validity of RISc was evaluated by estimating the concordance of scoring system stroke ascertainment to stroke ascertainment by physician and/or abstractor review of hospital admission records.

RESULTS

RISc was developed on 1718 randomly selected patients (training set) and then statistically validated on an independent sample of 858 patients (validation set). A multivariable logistic model was used to develop RISc and subsequently evaluated by goodness-of-fit and receiver operating characteristic (ROC) analyses. The higher the value of RISc, the higher the patient's risk of potential stroke. The study showed RISc was well calibrated and discriminated those who had potential stroke from those that did not on initial screening.

CONCLUSION

In this study we developed and validated a rapid, easy, efficient, and accurate method to ascertain incident stroke cases from routine hospital admission records for epidemiologic investigations. Validation of this scoring system was achieved statistically; however, clinical validation in a community hospital setting is warranted.

Prognostic use of echocardiography 1 year after a myocardial infarction

BACKGROUND

Left ventricular (LV) and right ventricular (RV) function are known predictors of morbidity and mortality after an acute myocardial infarction (MI). However, the prognostic use of a late evaluation of cardiac function after an MI remains unclear.

METHODS

We analyzed echocardiograms obtained 1 year after MI in patients with LV dysfunction at baseline (ejection fraction [EF] < or = 40%) from 291 patients enrolled in the SAVE echocardiographic substudy who did not develop heart failure (HF) or a recurrent MI during this first year. Left ventricular EF and RV fractional area change were assessed.

RESULTS

After a median follow-up of 22 months after the 1-year echocardiogram, a low LVEF (< 30%) at 1 year was associated with an increased risk of death and/or HF (hazards ratio [HR] 2.7, 95% CI 1.3-5.3). Presence of RV dysfunction was also associated with an increased risk of death (HR 8.9, 95% CI 3.5-22.1), development of HF (HR 7.1, 95% CI 3.4-15.0), and the composite end point of death or HF (HR 7.6, 95% CI 4.1-14.2). In multivariate analyses, both low LVEF and RV dysfunction remained independently predictive of the composite end point of death or HF. Patients with biventricular dysfunction were at the greatest risk of death and/or HF (HR 19.4, 95% CI 8.2-46.0) in follow-up.

CONCLUSIONS

In a stable population of survivors of MI, impaired LV and RV function at 1 year after MI are independently and additively predictive of increased risk of HF or death.

Stroke burden in Mexican Americans: the impact of mortality following stroke

PURPOSE

To estimate ethnic-specific all-cause mortality risk following ischemic stroke and to compare mortality risk by ethnicity.

METHODS

DATA from the Brain Attack Surveillance in Corpus Christi Project, a population-based stroke surveillance study, were used. Stroke cases between January 1, 2000 and December 31, 2002 were identified from emergency department (ED) and hospital sources (n = 1,234). Deaths for the same period were identified from the surveillance of stroke cases, the Texas Department of Health, the coroner, and the Social Security Death Index. Ethnic-specific all-cause cumulative mortality risk was estimated at 28 days and 36 months using Kaplan Meier analysis. Cox proportional hazards regression was used to compare mortality risk by ethnicity.

RESULTS

Cumulative 28-day all-cause mortality risk for Mexican Americans (MAs) was 7.8% and for non-Hispanic whites (NHWs) was 13.5%. Cumulative 36-month all-cause mortality risk was 31.3% in MAs and 47.2% in NHWs. MAs had lower 28-day (RR = 0.58; 95% CI: 0.41, 0.84) and 36-month all-cause mortality risk (RR = 0.79, 95% CI: 0.64, 0.98) compared with NHWs, adjusted for confounders.

CONCLUSIONS

Better survival after stroke in MAs is surprising considering their similar stroke subtype and severity compared with NHWs. Social or psychological factors, which may explain this difference, should be explored.

Ischemic stroke subtypes among Mexican Americans and non-Hispanic whites: the BASIC Project

Ischemic stroke subtype distribution was compared between Mexican Americans (MAs) and non-Hispanic whites (NHWs) in a community-based stroke surveillance study in Nueces County, TX. There was no difference in the distribution of stroke subtype by ethnicity (p = 0.19). There was a similar proportion of small-vessel and large-artery strokes between the two ethnic groups (p = 0.32). Differences in stroke rates among MAs and NHWs are not explained by the distribution of ischemic stroke subtypes.

Chronic Kidney Disease, Cardiovascular Risk, and Response to Angiotensin-Converting Enzyme Inhibition After Myocardial Infarction

Background— Persons with end-stage renal disease and those with lesser degrees of chronic kidney disease (CKD) have an increased risk of death after myocardial infarction (MI) that is not fully explained by associated comorbidities. Future cardiovascular event rates and the relative response to therapy in persons with mild to moderate CKD are not well characterized.

Methods and Results— We calculated the estimated glomerular filtration rate (eGFR) using the 4-variable Modification of Diet in Renal Disease method in 2183 Survival And Ventricular Enlargement (SAVE) trial subjects. SAVE randomized post-MI subjects (3 to 16 days after MI) with left ventricular ejection fraction ≤40% and serum creatinine <2.5 mg/dL to captopril or placebo. Cox proportional hazards models were used to evaluate the relative hazard rates for death and cardiovascular events associated with reduced eGFR. Subjects with reduced eGFR were older and had more extensive comorbidities. The multivariable adjusted risk ratio for total mortality associated with reduced eGFR from 60 to 74, 45 to 59, and <45 mL · min −1 · 1.73 m −2 (compared with eGFR ≥75 mL · min −1 · 1.73 m −2 ) was 1.11 (0.86 to 1.42), 1.24 (0.96 to 1.60) and 1.81 (1.32 to 2.48), respectively ( P for trend =0.001). Similar adjusted trends were present for CV mortality ( P =0.001), recurrent MI ( P =0.017), and the combined CV mortality and morbidity outcome ( P =0.002). The absolute benefit of captopril tended to be greater in subjects with CKD: 12.4 versus 5.5 CV events prevented per 100 subjects with (n=719) and without (n=1464) CKD, respectively.

Conclusions— CKD was associated with a heightened risk for all major CV events after MI, particularly among subjects with an estimated glomerular filtration rate <45 mL · min −1 · 1.73 m −2 . Randomization to captopril resulted in a reduction of CV events irrespective of baseline kidney function.

Ultrasound-enhanced systemic thrombolysis for acute ischemic stroke

BACKGROUND

Transcranial Doppler ultrasonography that is aimed at residual obstructive intracranial blood flow may help expose thrombi to tissue plasminogen activator (t-PA). Our objective was to determine whether ultrasonography can safely enhance the thrombolytic activity of t-PA.

METHODS

We treated all patients who had acute ischemic stroke due to occlusion of the middle cerebral artery with intravenous t-PA within three hours after the onset of symptoms. The patients were randomly assigned to receive continuous 2-MHz transcranial Doppler ultrasonography (the target group) or placebo (the control group). The primary combined end point was complete recanalization as assessed by transcranial Doppler ultrasonography or dramatic clinical recovery. Secondary end points included recovery at 24 hours, a favorable outcome at three months, and death at three months.

RESULTS

A total of 126 patients were randomly assigned to receive continuous ultrasonography (63 patients) or placebo (63 patients). Symptomatic intracerebral hemorrhage occurred in three patients in the target group and in three in the control group. Complete recanalization or dramatic clinical recovery within two hours after the administration of a t-PA bolus occurred in 31 patients in the target group (49 percent), as compared with 19 patients in the control group (30 percent; P=0.03). Twenty-four hours after treatment of the patients eligible for follow-up, 24 in the target group (44 percent) and 21 in the control group (40 percent) had dramatic clinical recovery (P=0.7). At three months, 22 of 53 patients in the target group who were eligible for follow-up analysis (42 percent) and 14 of 49 in the control group (29 percent) had favorable outcomes (as indicated by a score of 0 to 1 on the modified Rankin scale) (P=0.20).

CONCLUSIONS

In patients with acute ischemic stroke, continuous transcranial Doppler augments t-PA-induced arterial recanalization, with a nonsignificant trend toward an increased rate of recovery from stroke, as compared with placebo.

Excess stroke in Mexican Americans compared with non-Hispanic Whites: the Brain Attack Surveillance in Corpus Christi Project

Mexican Americans are the largest subgroup of Hispanics, the largest minority population in the United States. Stroke is the leading cause of disability and third leading cause of death. The authors compared stroke incidence among Mexican Americans and non-Hispanic Whites in a population-based study. Stroke cases were ascertained in Nueces County, Texas, utilizing concomitant active and passive surveillance. Cases were validated on the basis of source documentation by board-certified neurologists masked to subjects' ethnicity. From January 2000 to December 2002, 2,350 cerebrovascular events occurred. Of the completed strokes, 53% were in Mexican Americans. The crude cumulative incidence was 168/10,000 in Mexican Americans and 136/10,000 in non-Hispanic Whites. Mexican Americans had a higher cumulative incidence for ischemic stroke (ages 45-59 years: risk ratio = 2.04, 95% confidence interval: 1.55, 2.69; ages 60-74 years: risk ratio = 1.58, 95% confidence interval: 1.31, 1.91; ages >or=75 years: risk ratio = 1.12, 95% confidence interval: 0.94, 1.32). Intracerebral hemorrhage was more common in Mexican Americans (age-adjusted risk ratio = 1.63, 95% confidence interval: 1.24, 2.16). The subarachnoid hemorrhage age-adjusted risk ratio was 1.57 (95% confidence interval: 0.86, 2.89). Mexican Americans experience a substantially greater ischemic stroke and intracerebral hemorrhage incidence compared with non-Hispanic Whites. As the Mexican-American population grows and ages, measures to target this population for stroke prevention are critical.

Alcohol consumption and prognosis in patients with left ventricular systolic dysfunction after a myocardial infarction

OBJECTIVES

We assessed the influence of alcohol intake on the development of symptomatic heart failure (HF) in patients with left ventricular (LV) dysfunction after a myocardial infarction (MI).

BACKGROUND

In contrast to protection from coronary heart disease, alcohol consumption has been linked to cardiodepressant effects and has been considered contraindicated in patients with HF.

METHODS

The Survival And Ventricular Enlargement (SAVE) trial randomized 2231 patients with a LV ejection fraction (EF) <40% following MI to an angiotensin-converting enzyme inhibitor or placebo. Patients were classified as nondrinkers, light-to-moderate drinkers (1 to 10 drinks/week), or heavy drinkers (>10 drinks/week) based on alcohol consumption reported at baseline. The primary outcome was hospitalization for HF or need for an open-label angiotensin-converting enzyme inhibitor. Analyses were repeated using alcohol consumption reported three months after MI.

RESULTS

Nondrinkers were older and had more comorbidities than light-to-moderate and heavy drinkers. In univariate analyses, baseline light-to-moderate alcohol intake was associated with a lower incidence of HF compared with nondrinkers (hazard ratio [HR] 0.71; 95% confidence interval [CI] 0.57 to 0.87), whereas heavy drinking was not (HR 0.91; 95% CI 0.67 to 1.23). After adjustment for baseline differences, light-to-moderate baseline alcohol consumption no longer significantly influenced the development of HF (light-to-moderate drinkers HR 0.93; 95% CI 0.75 to 1.17; heavy drinkers HR 1.25; 95% CI 0.91 to 1.72). Alcohol consumption reported three months after the MI similarly did not modify the risk of adverse outcome.

CONCLUSIONS

In patients with LV dysfunction after an MI, light-to-moderate alcohol intake either at baseline or following MI did not alter the risk for the development of HF requiring hospitalization or an open-label angiotensin-converting enzyme inhibitor.

Designing multi-ethnic stroke studies: the Brain Attack Surveillance in Corpus Christi (BASIC) project

The Brain Attack Surveillance in Corpus Christi (BASIC) project is a population-based stroke study comparing Mexican Americans and non-Hispanic whites. Extensive effort is made to detect all patients regardless of ethnicity and ensure equal participation in the interview among both groups. We describe here the study's design and process evaluation with a focus on reducing bias in case ascertainment and participation. During the first 28 months of the project, 11,829 subjects were screened. Availability of neuroimaging did not differ by ethnicity (P=0.22), nor did confidence in the validated diagnosis of stroke (P=0.10). Participation rate in the interview also did not differ by ethnicity (P=0.92). There was excellent agreement of ethnic classification between chart abstraction and self-report (kappa=0.94, P<0.001). We conclude that multi-ethnic stroke comparison studies are feasible. Utilizing epidemiologic principles to design, recruit and analyze data are critical. Process evaluation to examine for sources of bias is important to study conduct.

Access to Care, Acculturation, and Risk Factors for Stroke in Mexican Americans

Background and Purpose— Mexican Americans are the largest subgroup of Hispanic Americans, now the most numerous US minority population. We compared access to care, acculturation, and biological risk factors among Mexican American and non-Hispanic white stroke patients and the general population.

Methods— The Brain Attack Surveillance in Corpus Christi project is a population-based stroke surveillance study conducted in southeast Texas. All stroke cases were ascertained through active and passive surveillance from January 2000 through April 2002 and compared with population estimates from a random-digit telephone survey.

Results— Compared with non-Hispanic white stroke patients (n=405), Mexican American stroke patients (n=403) were less likely to have graduated from high school (odds ratio [OR], 15.4; 95% confidence interval [CI], 10.6 to 22.4) and more likely to earn less than $20 000 per year (OR, 6.5; 95% CI, 4.5 to 9.4). Mexican American stroke patients were more likely to have diabetes (OR, 2.7; 95% CI, 2.0 to 3.7) and less likely to have atrial fibrillation (OR, 0.5; 95% CI, 0.4 to 0.8). Compared with population estimates (n=719), stroke was associated with diabetes (Mexican Americans: OR, 3.6; 95% CI, 2.2 to 5.8; non-Hispanic whites: OR, 3.0; 95% CI, 1.7 to 5.5), hypertension (Mexican Americans: OR, 2.8; 95% CI, 1.8 to 4.3; non-Hispanic whites: OR, 3.3; 95% CI, 2.2 to 5.0), lower incomes (Mexican Americans: OR, 3.4; 95% CI, 2.1 to 5.4; non-Hispanic whites: OR, 3.0; 95% CI, 1.7 to 5.2), and lower educational attainment (Mexican Americans: OR, 5.1; 95% CI, 3.2 to 8.1; non-Hispanic whites: OR, 4.5; 95% CI, 2.2 to 9.3).

Conclusions— Biological and social variables are associated with stroke to a similar extent in both Mexican Americans and non-Hispanic whites. Health behavior interventions for both populations may follow from this work. Stroke disparities between these populations may be explained only partially by differences in the prevalence of currently identified biological and social factors.

Improving efficiency of stroke research: the Brain Attack Surveillance in Corpus Christi study

We studied whether a computer algorithm or abstractor could diagnose stroke as well as a fellowship-trained stroke neurologist. As part of an ongoing prospective, community-based stroke surveillance project, a diagnostic algorithm was developed, and patients' neurologic signs and symptoms were collected in a computerized database. The abstractors were blinded to the results of this algorithm and were asked to verify whether the patient had a stroke. The separate results of the computer and abstractor were compared with the final diagnosis given by the blinded neurologist. From 1 January through 31 July 2000, 3418 cases were screened. The abstractors yielded sensitivity 91%, specificity 97%, positive predictive value (PPV) 85%, and negative predictive value (NPV) 99%. Three computer algorithms were evaluated. The sensitivities ranged from 83% to 96%, specificity ranged from 88% to 97%, PPV ranged from 54% to 81%, and NPV ranged from 97% to 99%. The use of computer verification or abstractors may obviate the need for physician stroke verification and may greatly improve study efficiency.

Perils of the random experiment

Most medical research is executed on samples selected from large populations. Nevertheless, health care researchers often blur the difference between interpreting sample-based research and evaluating research that included the entire population of interest. This is an implication-critical distinction; in population research, every result applies to the population (because the entire population was included in the analysis), although only a few results from sample-based research can be extended to the population at large. Treating every result from sample-based research as if that result applies to the population is misleading. Using nonmathematic terminology, this article develops the reason for the differences in the implications of these two research perspectives. In sample-based research, the best indicators of which results should be extended from the sample to the population are the presence of (1) a prospective plan for that experiment; and (2) the execution of the experiment according to that plan (concordant execution). The absence of these two features produces execution and analysis decisions based on the incoming data stream-the hallmark of the random experiment. In this latter paradigm, allowing the data to influence the execution and analysis decisions renders the usual estimates of effect size, standard errors, confidence intervals, and P values untrustworthy. Readers of clinical trial results must be vigilant for nonprotocol-driven research and understand that the results from these programs are at best exploratory and cannot be used to answer scientific questions.

Sample size for biomarker studies: more subjects or more measurements per subject?

PURPOSE

In molecular epidemiologic studies, optimizing the use of available biological specimens while minimizing the cost is always a challenge. This is particularly true in pilot studies, which often have limited funding and involve small numbers of biological samples too small for assessment of recently developed biomarkers.

METHODS

In this study we examined several statistical approaches for determining how many experimental subjects to use in a biomarker study and how many repeated measurements to make on each sample, given specific funding considerations and the correlated nature of the repeated measurements.

RESULTS

A molecular epidemiology study of DNA repair and aging in basal cell carcinoma was used to illustrate the application of the statistical methods proposed.

CONCLUSIONS

Our methods extend traditional designs on biomarker studies with repeated measurements to including funding constraints.

Comparison of active and passive surveillance for cerebrovascular disease: The Brain Attack Surveillance in Corpus Christi (BASIC) Project

To provide a scientific rationale for choosing an optimal stroke surveillance method, the authors compared active surveillance with passive surveillance. The methods involved ascertaining cerebrovascular events that occurred in Nueces County, Texas, during calendar year 2000. Active methods utilized screening of hospital and emergency department logs and routine visiting of hospital wards and out-of-hospital sources. Passive means relied on International Classification of Diseases, Ninth Revision (ICD-9), discharge codes for case ascertainment. Cases were validated by fellowship-trained stroke neurologists on the basis of published criteria. The results showed that, of the 6,236 events identified through both active and passive surveillance, 802 were validated to be cerebrovascular events. When passive surveillance alone was used, 209 (26.1%) cases were missed, including 73 (9.1%) cases involving hospital admission and 136 (17.0%) out-of-hospital strokes. Through active surveillance alone, 57 (7.1%) cases were missed. The positive predictive value of active surveillance was 12.2%. Among the 2,099 patients admitted to a hospital, passive surveillance using ICD-9 codes missed 73 cases of cerebrovascular disease and mistakenly included 222 noncases. There were 57 admitted hospital cases missed by active surveillance, including 13 not recognized because of human error. This study provided a quantitative means of assessing the utility of active and passive surveillance for cerebrovascular disease. More uniform surveillance methods would allow comparisons across studies and communities.

The fragility of cardiovascular clinical trial results

BACKGROUND

Clinical trials that have their prospective analysis plan altered are difficult to interpret.

METHODS AND RESULTS

After providing 4 examples of problematic trial results that have had their findings reversed, the necessity of a fixed research protocol is developed. Investigators generally wish to extend the results from their research sample to the larger population; however, this delicate extension is complicated by the presence of sampling error. No computational or statistical tools can remove sampling error--the most that researchers can do is to provide to the medical and regulatory communities a measure of the distorting effect that sampling error can produce. Investigators accomplish this by providing an estimate of how likely it is that the population produced a misleading sample for them to study. However, studies in which the data determine the analysis plan damage these estimators. When they are damaged, these estimators produce untrustworthy assessments of the degree to which the study results reflect the population findings.

CONCLUSIONS

The way to avoid these complications is to design the experiment carefully, then carefully execute the experiment as it was designed.

Right ventricular dysfunction and risk of heart failure and mortality after myocardial infarction

OBJECTIVES

The aim of this study was to determine the prognostic value of right ventricular (RV) function in patients after a myocardial infarction (MI).

BACKGROUND

Right ventricular function has been shown to predict exercise capacity, autonomic imbalance and survival in patients with advanced heart failure (HF).

METHODS

Two-dimensional echocardiograms were obtained in 416 patients with left ventricular (LV) dysfunction (ejection fraction [LVEF] < or = 40%) from the Survival And Ventricular Enlargement (SAVE) echocardiographic substudy (mean 11.1 +/- 3.2 days post infarction). Right ventricular function from the apical four-chamber view, assessed as the percent change in the cavity area from end diastole to end systole (fractional area change [FAC]), was related to clinical outcome.

RESULTS

Right ventricular function correlated only weakly with the LVEF (r = 0.12, p = 0.013). On univariate analyses, the RV FAC was a predictor of mortality, cardiovascular mortality and HF (p < 0.0001 for all) but not recurrent MI. After adjusting for age, gender, diabetes mellitus, hypertension, previous MI, LVEF, infarct size, cigarette smoking and treatment assignment, RV function remained an independent predictor of total mortality, cardiovascular mortality and HF. Each 5% decrease in the RV FAC was associated with a 16% increased odds of cardiovascular mortality (95% confidence interval 4.3% to 29.2%; p = 0.006).

CONCLUSIONS

Right ventricular function is an independent predictor of death and the development of HF in patients with LV dysfunction after MI.