Sleep Duration Is Associated With Subclinical Carotid Plaque Burden.

BACKGROUND: Sleep duration is associated with stroke risk and is 1 of 8 essential components of cardiovascular health according to the American Heart Association. As stroke disproportionately burdens Black and Hispanic populations in the United States, we hypothesized that long and short sleep duration would be associated with greater subclinical carotid atherosclerosis, a precursor of stroke, in the racially and ethnically diverse NOMAS (Northern Manhattan Study). METHODS: NOMAS is a study of community-dwelling adults. Self-reported nightly sleep duration and daytime sleepiness were collected between 2006 and 2011. Carotid plaque presence, total plaque area, and intima-media thickness were measured by ultrasound between 1999 and 2008. Linear and logistic regression models examined the cross-sectional associations of sleep duration groups (primary exposure) or daytime sleepiness (secondary exposure) with measures of carotid atherosclerosis. Models adjusted for age, time between ultrasound and sleep data collection, sex, race and ethnicity, education, health insurance, smoking, alcohol use, physical activity, body mass index, hypertension, diabetes, hypercholesterolemia, and cardiac disease. RESULTS: The sample (n=1553) had a mean age of 64.7±8.5 years and was 61.9% female, 64.8% Hispanic, and 18.2% non-Hispanic Black. Of the sample, 55.6% had carotid plaque, 22.3% reported nightly short sleep (<7 hours), 66.6% intermediate sleep (≥7 and <9 hours), and 11.1% had long sleep (≥9 hours). Compared with intermediate sleep, long sleep was associated with greater odds of carotid plaque presence relative to plaque absence (odds ratio, 1.6 [95% CI, 1.1-2.4]) and larger total plaque area (odds ratio, 1.4 [95% CI, 1.0-1.9]) after full covariate adjustment. Short sleep and daytime sleepiness were not significantly associated with any carotid measures. CONCLUSIONS: The association between long sleep and subclinical carotid atherosclerosis may explain prior associations between long sleep and stroke.

Immune Markers Are Associated With Asymptomatic Intracranial Large Artery Stenosis and Future Vascular Events in NOMAS.

BACKGROUND: Inflammation contributes to atherosclerosis but is incompletely characterized in intracranial large artery stenosis (ICAS). We hypothesized that immune markers would be associated with ICAS and modify the risk ICAS confers on future vascular events. METHODS: This study included a subsample of stroke-free participants in the prospective NOMAS (Northern Manhattan Study), who had blood samples analyzed with a 60-plex immunoassay (collected from 1993 to 2001) and ICAS assessment with time-of-flight magnetic resonance angiography (obtained from 2003 to 2008). We dichotomized ICAS as either ≥50% stenosis or not (including no ICAS). We ascertained post-magnetic resonance imaging vascular events. We used least absolute shrinkage and selection operator procedures to select immune markers independently associated with ICAS. Then, we grouped selected immune markers into a derived composite Z score. Using proportional odds regression, we quantified the association of the composite immune marker Z score, ICAS, and risk of vascular events. RESULTS: Among 1211 participants (mean age, 71±9 years; 59% women; 65% Hispanic participants), 8% had ≥50% ICAS. Using least absolute shrinkage and selection operator regression, we identified CXCL9 (C-X-C motif chemokine ligand 9), HGF (hepatocyte growth factor), resistin, SCF (stem cell factor), and VEGF-A(vascular endothelial growth factor A) to have the strongest positive relationships with ≥50% ICAS in fully adjusted models. Selected markers were used to derive a composite immune marker Z score. Over an average follow-up of 12 years, we found that each unit increase in immune marker Z scores was associated with an 8% (95% CI, 1.05-1.11), 11% (95% CI, 1.06-1.16), and 5% (95% CI, 1.01-1.09) increased hazard of death, vascular death, and any vascular event, respectively, in adjusted models. We did not find a significant interaction between immune marker Z scores and ICAS in their relationship with any longitudinal outcome. CONCLUSIONS: Among a diverse stroke-free population, selected serum immune markers were associated with ICAS and future vascular events. Further study is needed to better understand their role in the pathogenesis of ICAS and as a potential therapeutic target in stroke prevention.

Which Road to Recovery?: Factors Influencing Postacute Stroke Discharge Destinations: A Delphi Study.

BACKGROUND AND PURPOSE: The criteria for determining the level of postacute care for patients with stroke are variable and inconsistent. The purpose of this study was to identify key factors influencing the selection of postacute level of care for these patients. METHODS: We used a collaborative 4-round Delphi process to achieve a refined list of factors influencing postacute level of care selection. Our Delphi panel of experts consisted of 32 panelists including physicians, physical therapists, occupational therapists, speech-language pathologists, nurses, stroke survivors, administrators, policy experts, and individuals associated with third-party insurance companies. RESULTS: In round 1, 207 factors were proposed, with subsequent discussion resulting in consolidation into 15 factors for consideration. In round 2, 15 factors were ranked with consensus on 10 factors; in round 3,10 factors were ranked with consensus on 9 factors. In round 4, the final round, 9 factors were rated with Likert scores ranging from 5 (most important) to 1(not important). The percentage of panelists who provided a rating of 4 or above were as follows: likelihood to benefit from an active rehabilitation program (97%), need for clinicians with specialized rehabilitation skills (94%), need for active and ongoing medical management and monitoring (84%), ability to tolerate an active rehabilitation program (74%), need for caregiver training to return to the community (48%), family/caregiver support (39%), likelihood to return to community/home (39%), ability to return to physical home environment (32%), and premorbid dementia (16%). CONCLUSIONS: This study provides an expert, consensus-based set of key factors to be considered when determining where stroke patients are discharged for postacute care. These factors may be useful in developing a decision support tool for use in clinical settings.

Immune markers are associated with cognitive performance in a multiethnic cohort: The Northern Manhattan Study.

OBJECTIVE: To determine whether immune protein panels add significant information to correlates of cognition. BACKGROUND: Immune mechanisms in vascular cognitive aging are incompletely characterized. DESIGN/METHODS: A subsample of the prospective Northern Manhattan Study underwent detailed neuropsychological testing. Cognitive scores were converted into Z-scores and categorized into four domains (memory, language, processing speed, and executive function) based on factor analysis. Blood samples were analyzed using a 60-plex immunoassay. We used least absolute shrinkage and selection operator (LASSO) procedures to select markers and their interactions independently associated with cognitive scores. Linear regression models assessed cross-sectional associations of known correlates of cognition with cognitive scores, and assessed model fit before and after addition of LASSO-selected immune markers. RESULTS: Among 1179 participants (mean age 70 ± 8.9 years, 60% women, 68% Hispanic), inclusion of LASSO-selected immune markers improved model fit above age, education, and other risk factors (p for likelihood ratio test < 0.005 for all domains). C-C Motif Chemokine Ligand 11 (CCL 11, eotaxin), C-X-C Motif Chemokine Ligand 9 (CXCL9), hepatocyte growth factor (HGF), and serpin E1 (plasminogen activator inhibitor-1) were associated with each of the domains and with overall cognitive function. Immune marker effects were comparable to conventional risk factors: for executive function, each standard deviation (SD) increase in CCL11 was associated with an effect equivalent to aging three years; for memory, HGF had twice the effect of aging. CONCLUSIONS: Immune markers associate with cognitive function in a multi-ethnic cohort. Further work is needed to validate these findings and determine optimal treatment targets.

Classification of Covert Brain Infarct Subtype and Risk of Death and Vascular Events.

Background and Purpose- To test the hypothesis that covert brain infarcts (CBIs) are more likely to be located in noneloquent brain areas compared with clinical strokes and that CBI etiological subtypes carry a differential risk of vascular events compared with people without CBI. Methods- We used brain magnetic resonance imaging from 1290 stroke-free participants in the NOMAS (Northern Manhattan Study) to evaluate for CBI. We classified CBI as cardioembolic (ie, known atrial fibrillation), large artery atherosclerosis (extracranial and intracranial), penetrating artery disease, and cryptogenic (no apparent cause). CBI localized in the nonmotor areas of the right hemisphere were considered noneloquent. We then evaluated risk of events by CBI subtype with adjusted Cox proportional models. Results- At the time of magnetic resonance imaging, 236 participants (18%) had CBI (144 [61%] distal cryptogenic, 29 [12%] distal cardioembolic, 26 [11%] large artery atherosclerosis, and 37 [16%] penetrating artery disease). Smaller (per mm, odds ratio, 0.8 [0.8-0.9]) and nonbrain stem infarcts (odds ratio, 0.2 [0.1-0.6]) were more likely to be covert. During the follow-up period (10.4±3.1 years), 398 (31%) died (162 [13%] of vascular death) and 117 (9%) had a stroke (99 [85%]) were ischemic. Risks of events varied by CBI subtype, with the highest risk of stroke (hazard ratio, 2.2 [1.3-3.7]) and vascular death (hazard ratio, 2.24 [1.29-3.88]) noted in participants with intracranial large artery atherosclerosis-related CBI. Conclusions- CBI can be classified into subtypes that have differential outcomes. Certain CBI subtypes such as those related to intracranial large artery atherosclerosis have a high risk of adverse vascular outcomes and could warrant consideration of treatment trials.

A comparison of nurses' and physicians' perception of cancer treatment burden based on reported adverse events.

BACKGROUND: Cancer treatments are associated with a multitude of adverse events (AEs). While both nurses and physicians are involved in patient care delivery and AE assessment, very few studies have examined the differences between nurses' and physicians' reporting and perception of AEs. An approach was recently proposed to assess treatment burden based on reported AEs from the physician's perspective. In this paper, we use this approach to evaluate nurses' perception of burden, and compare nurses' and physicians' assessment of the overall and relative burden of AEs. METHODS: AE records for 334 cancer patients from a randomized clinical trial conducted by the SWOG Cancer Research Network were evaluated by 14 nurses at Columbia University Medical Center. Two nurses were randomly selected to assign a burden score from 0 to 10 based on their impression of the global burden of the captured AEs. These nurses did not interact directly with the patients. Scores were compared to previously obtained physicians scores using paired T-test and Kappa statistic. Severity scores for individual AEs were obtained using mixed-effects models with nurses assessments, and were qualitatively compared to physicians'. RESULTS: Given the same AEs, nurses' and physicians' perception of the burden of AEs differed. While nurses generally perceived the overall burden of AEs to be only slightly worse compared to physicians (mean average VAS score of 5.44 versus 5.14), there was poor agreement in the perception of AEs that were in mild to severe range. The percent agreement for a moderate or worse AE was 64% with a Kappa of 0.34. Nurses also assigned higher severity scores to symptomatic AEs compared to physicians (p < 0.05), such as gastrointestinal (4.77 versus 4.14), hemorrhage (5.07 versus 4.14), and pain (5.17 versus 4.14). CONCLUSIONS: These differences in the perception of burden of AEs can lead to different treatment decisions and symptom management strategies. Thus, having provider consistency, training, or a collaborative approach in follow-up care between nurses and physicians is important to ensure continuity in care delivery. Moreover, estimating overall burden from both physicians' and nurses' perspective, and comparing them may be useful for deciding when collaborations are warranted.

Long-Term Outcomes in Patients Aged ≤70 Years With Intravenous Glyburide From the Phase II GAMES-RP Study of Large Hemispheric Infarction: An Exploratory Analysis.

BACKGROUND AND PURPOSE: We aimed to determine whether subjects aged ≤70 years who were treated with intravenous glyburide (RP-1127; BIIB093; glibenclamide) would have better long-term outcomes than those who received placebo. METHODS: GAMES-RP (Glyburide Advantage in Malignant Edema and Stroke-Remedy Pharmaceuticals) was a prospective, double-blind, randomized, placebo-controlled phase 2 clinical trial. Eighty-six participants, aged 18 to 80 years, who presented to 18 centers with large hemispheric infarction (baseline diffusion-weighted imaging volumes, 82-300 cm3) randomized within 10 hours of symptom onset were enrolled. In the current exploratory analysis, we included participants aged ≤70 years treated with intravenous glyburide (n=35) or placebo (n=30) who met per-protocol criteria. Intravenous glyburide or placebo was administered in a 1:1 ratio. We analyzed 90-day and 12-month mortality, functional outcome (modified Rankin Scale, Barthel Index), and quality of life (EuroQol group 5-dimension). Additional outcomes assessed included blood-brain barrier injury (MMP-9 [matrix metalloproteinase 9]) and cerebral edema (brain midline shift). RESULTS: Participants ≤70 years of age treated with intravenous glyburide had lower mortality at all time points (log-rank for survival hazards ratio, 0.34; P=0.04). After adjustment for age, the difference in functional outcome (modified Rankin Scale) demonstrated a trend toward benefit for intravenous glyburide-treated subjects at 90 days (odds ratio, 2.31; P=0.07). Repeated measures analysis at 90 days, 6 months, and 12 months using generalized estimating equations showed a significant treatment effect of intravenous glyburide on the Barthel Index (P=0.03) and EuroQol group 5-dimension (P=0.05). Participants treated with intravenous glyburide had lower plasma levels of MMP-9 (189 versus 376 ng/mL; P<0.001) and decreased midline shift (4.7 versus 9 mm; P<0.001) compared with participants who received placebo. CONCLUSIONS: In this exploratory analysis, participants ≤70 years of age with large hemispheric infarction have improved survival after acute therapy with intravenous glyburide. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01794182.

Brain Arterial Diameters and Cognitive Performance: The Northern Manhattan Study.

OBJECTIVES: To test the hypothesis that brain arterial diameters are associated with cognitive performance, particularly in arteries supplying domain-specific territories. METHODS: Stroke-free participants in the Northern Manhattan Study were invited to have a brain MRI from 2003-2008. The luminal diameters of 13 intracranial arterial segments were obtained using time-of-flight magnetic resonance angiogram (MRA), and then averaged and normalized into a global score and region-specific arterial diameters. Z-Scores for executive function, semantic memory, episodic memory and processing speed were obtained at MRI and during follow-up. Adjusted generalized additive models were used to assess for associations. RESULTS: Among the 1034 participants with neurocognitive testing and brain MRI, there were non-linear relationships between left anterior (ACA) and middle cerebral artery (MCA) diameter and semantic memory Z-scores (χ2=10.00; DF=3; p=.019), and left posterior cerebral artery (PCA) and posterior communicating artery (Pcomm) mean diameter and episodic memory Z-scores (χ2=9.88; DF=3; p=.020). Among the 745 participants who returned for 2nd neuropsychological testing, on average 5.0±0.4 years after their MRI, semantic memory change was associated non-linearly with the left PCA/Pcomm mean diameter (χ2=13.09; DF=3; p=.004) and with the right MCA/ACA mean diameter (χ2=8.43; DF=3; p=.03). In both cross-sectional and longitudinal analyses, participants with the larger brain arterial diameters had more consistently lower Z-scores and greater decline than the rest of the participants. CONCLUSIONS: Brain arterial diameters may have downstream effects in brain function presenting as poorer cognition. Identifying the mechanisms and the directionality of such interactions may increase the understanding of the vascular contribution to cognitive impairment and dementia. (JINS, 2018, 24, 335-346).

An Overview of Research and Evaluation Designs for Dissemination and Implementation.

The wide variety of dissemination and implementation designs now being used to evaluate and improve health systems and outcomes warrants review of the scope, features, and limitations of these designs. This article is one product of a design workgroup that was formed in 2013 by the National Institutes of Health to address dissemination and implementation research, and whose members represented diverse methodologic backgrounds, content focus areas, and health sectors. These experts integrated their collective knowledge on dissemination and implementation designs with searches of published evaluations strategies. This article emphasizes randomized and nonrandomized designs for the traditional translational research continuum or pipeline, which builds on existing efficacy and effectiveness trials to examine how one or more evidence-based clinical/prevention interventions are adopted, scaled up, and sustained in community or service delivery systems. We also mention other designs, including hybrid designs that combine effectiveness and implementation research, quality improvement designs for local knowledge, and designs that use simulation modeling.

Systemic Atherosclerosis Relate to Brain Arterial Diameters: The Northern Manhattan Study.

BACKGROUND: Phenotypic expressions of arterial disease vary throughout the body and it is not clear to what extent systemic atherosclerosis influences brain arterial remodeling. We aim to test the hypothesis that systemic atherosclerosis is associated with brain arterial diameters. METHODS: Stroke-free participants in the Northern Manhattan Study MRI subcohort in whom carotid ultrasound, transthoracic echocardiogram, and brain MRA (n = 482) were performed were included in this analysis. Brain arterial diameters were measured with semi-automated software as continuous and categorical variables. Ultrasound and echocardiography provided the sum of maximum carotid plaque thickness (sMCPT) and aortic plaque thickness. Associations between brain arterial diameters and aortic and carotid plaque thickness were assessed with semi-parametric generalized additive models. RESULTS: Aortic plaque thickness was inversely and linearly associated with brain arterial diameters (B per mm = -0.073 ± 0.034, p = 0.03), while sMCPT was associated nonlinearly in a u-shaped curve with anterior brain arterial diameters (spline regression χ2 = 9.19, p = 0.02). Coexisting carotid and aortic atherosclerosis were more prevalent in participants with small luminal diameters (40%) compared with participants with average (30%) or with large (13%) luminal diameters, while carotid atherosclerosis without aortic atherosclerosis was more prevalent among participants with large luminal diameters (31%) compared with those with average (12%) or small luminal diameters (2%, p < 0.001 for both trends). CONCLUSIONS: We confirmed the hypothesis that systemic arterial disease is associated with brain arterial diameters. Gaining knowledge about the origin of these phenotypic expressions of atherosclerosis in the human body may lead to a better understanding of the cerebrovascular consequences of the systemic arterial disease.

Dimension of model parameter space and operating characteristics in adaptive dose-finding studies.

Adaptive, model-based, dose-finding methods, such as the continual reassessment method, have been shown to have good operating characteristics. One school of thought argues in favor of the use of parsimonious models, not modeling all aspects of the problem, and using a strict minimum number of parameters. In particular, for the standard situation of a single homogeneous group, it is common to appeal to a one-parameter model. Other authors argue for a more classical approach that models all aspects of the problem. Here, we show that increasing the dimension of the parameter space, in the context of adaptive dose-finding studies, is usually counter productive and, rather than leading to improvements in operating characteristics, the added dimensionality is likely to result in difficulties. Among these are inconsistency of parameter estimates, lack of coherence in escalation or de-escalation, erratic behavior, getting stuck at the wrong level, and, in almost all cases, poorer performance in terms of correct identification of the targeted dose. Our conclusions are based on both theoretical results and simulations. Copyright © 2016 John Wiley & Sons, Ltd.

Racial-ethnic disparities in the association between risk factors and diabetes: The Northern Manhattan Study.

PURPOSE: To identify risk factors (RF) for diabetes within a multiethnic cohort and to examine whether race-ethnicity modified their effects. METHODS: Participants in the Northern Manhattan Study without diabetes at baseline were studied from 1993 to 2014 (n=2430). Weibull regression models with interval censoring data were fit to calculate hazard ratios and 95% confidence intervals for incident diabetes. We tested for interactions between RF and race-ethnicity. RESULTS: During a mean follow-up period of 11years, there were 449 diagnoses of diabetes. Being non-Hispanic black (HR 1.69 95% CI 1.11-2.59) or Hispanic (HR 2.25 95% CI 1.48-3.40) versus non-Hispanic white, and body mass index (BMI; HR 1.34 per SD 95% CI 1.21-1.49) were associated with greater risk of diabetes; high-density lipoprotein cholesterol (HR 0.75 95% CI 0.66-0.86) was protective. There were interactions by race-ethnicity. In stratified models, the effects of BMI, current smoking, and C-reactive protein (CRP) on risk of diabetes differed by race-ethnicity (p for interaction <0.05). The effects were greater among non-Hispanic whites than non-Hispanic blacks and Hispanics. CONCLUSIONS: Although Hispanics and non-Hispanic blacks had a greater risk of diabetes than whites, there were variations by race-ethnicity in the association of BMI, smoking, and CRP with risk of diabetes. Unique approaches should be considered to reduce diabetes as traditional RF may not be as influential in minority populations.

Electrocardiographic Left Atrial Abnormality and Risk of Stroke: Northern Manhattan Study.

BACKGROUND AND PURPOSE: Electrocardiographic left atrial abnormality has been associated with stroke independently of atrial fibrillation (AF), suggesting that atrial thromboembolism may occur in the absence of AF. If true, we would expect an association with cryptogenic or cardioembolic stroke rather than noncardioembolic stroke. METHODS: We conducted a case-cohort analysis in the Northern Manhattan Study, a prospective cohort study of stroke risk factors. P-wave terminal force in lead V1 was manually measured from baseline ECGs of participants in sinus rhythm who subsequently had ischemic stroke (n=241) and a randomly selected subcohort without stroke (n=798). Weighted Cox proportional hazard models were used to examine the association between P-wave terminal force in lead V1 and stroke etiologic subtypes while adjusting for baseline demographic characteristics, history of AF, heart failure, diabetes mellitus, hypertension, tobacco use, and lipid levels. RESULTS: Mean P-wave terminal force in lead V1 was 4452 (±3368) µV*ms among stroke cases and 3934 (±2541) µV*ms in the subcohort. P-wave terminal force in lead V1 was associated with ischemic stroke (adjusted hazard ratio per SD, 1.20; 95% confidence interval, 1.03-1.39) and the composite of cryptogenic or cardioembolic stroke (adjusted hazard ratio per SD, 1.31; 95% confidence interval, 1.08-1.58). There was no definite association with noncardioembolic stroke subtypes (adjusted hazard ratio per SD, 1.14; 95% confidence interval, 0.92-1.40). Results were similar after excluding participants with a history of AF at baseline or new AF during follow-up. CONCLUSIONS: ECG-defined left atrial abnormality was associated with incident cryptogenic or cardioembolic stroke independently of the presence of AF, suggesting atrial thromboembolism may occur without recognized AF.

Left atrial enlargement and stroke recurrence: the Northern Manhattan Stroke Study.

BACKGROUND AND PURPOSE: Although left atrial enlargement (LAE) increases incident stroke risk, the association with recurrent stroke is less clear. Our aim was to determine the association of LAE with recurrent stroke most likely related to embolism (cryptogenic and cardioembolic) and all ischemic stroke recurrences. METHODS: We followed 655 first ischemic stroke patients in the Northern Manhattan Stroke Study for ≤5 years. LA size from 2D echocardiography was categorized as normal LAE (52.7%), mild LAE (31.6%), and moderate-severe LAE (15.7%). We used Cox proportional hazard models to calculate the hazard ratios and 95% confidence intervals for the association of LA size and LAE with recurrent cryptogenic/cardioembolic and total recurrent ischemic stroke. RESULTS: LA size was available in 529 (81%) patients. Mean age at enrollment was 69±13 years; 45.8% were male, 54.0% Hispanic, and 18.5% had atrial fibrillation. Over a median of 4 years, there were 65 recurrent ischemic strokes (29 were cardioembolic or cryptogenic). In multivariable models adjusted for confounders, including atrial fibrillation and heart failure, moderate-severe LAE compared with normal LA size was associated with greater risk of recurrent cardioembolic/cryptogenic stroke (adjusted hazard ratio 2.83, 95% confidence interval 1.03-7.81), but not total ischemic stroke (adjusted hazard ratio 1.06, 95% confidence interval, 0.48-2.30). Mild LAE was not associated with recurrent stroke. CONCLUSION: Moderate to severe LAE was an independent marker of recurrent cardioembolic or cryptogenic stroke in a multiethnic cohort of ischemic stroke patients. Further research is needed to determine whether anticoagulant use may reduce risk of recurrence in ischemic stroke patients with moderate to severe LAE.

Cigarette Smoking and Carotid Plaque Echodensity in the Northern Manhattan Study.

BACKGROUND: We sought to determine the association between cigarette smoking and carotid plaque ultrasound morphology in a multiethnic cohort. METHODS: We analyzed 1,743 stroke-free participants (mean age 65.5 ± 8.9 years; 60% women; 18% white, 63% Hispanic, 19% black; 14% current and 38% former smokers, 48% never smoked) from the Northern Manhattan Study using an ultrasound index of plaque echodensity, the Gray-Scale Median (GSM). Echolucent plaque (low GSM) represents soft plaque and echodense (high GSM) more calcified plaque. The mean GSM weighted by plaque area for each plaque was calculated for those with multiple plaques. Quintiles of GSM were compared to no plaque. Multinomial logistic regression models were used to assess associations of cigarette smoking with GSM, adjusting for demographics and vascular risk factors. RESULTS: Among subjects with carotid plaque (58%), the mean GSM scores for quintiles 1-5 were 48, 72, 90, 105, and 128, respectively. Current smokers had over a two fold increased risk of having GSM in quintile 1 (odds ratio (OR) = 2.17; 95% confidence interval (CI), 1.34-3.52), quintile 2 (OR = 2.33; 95% CI, 1.42-3.83), quintile 4 (OR = 2.05; 95% CI, 1.19-3.51), and quintile 5 (OR = 2.13; 95% CI, 1.27-3.56) but not in quintile 3 (OR = 1.18; 95% CI, 0.67-2.10) as compared to never smokers in fully adjusted models. Former smokers had increased risk in quintile 2 (OR = 1.46; 95% CI, 1.00-2.12), quintile 3 (OR = 1.56; 95% CI, 1.09-2.24), quintile 4 (OR = 1.66; 95% CI, 1.13-2.42), and quintile 5 (OR = 1.73; 95% CI, 1.19-2.51), but not in quintile 1 (OR = 1.05; 95% CI, 0.72-1.55). CONCLUSIONS: A nonlinear, V-shaped-like relationship between current cigarette smoking and plaque echodensity was observed. Former smokers were at the highest risk for plaques in high GSM quintiles. Thus, current smokers were more likely to have either soft or calcified plaques and former smokers were at greater risk of having only echodense plaques when compared to those who have never smoked. Further research is needed to determine if plaque morphology mediates an association between smoking and clinical vascular events.

Sample size considerations for clinical research studies in nuclear cardiology.

Sample size calculation is an important element of research design that investigators need to consider in the planning stage of the study. Funding agencies and research review panels request a power analysis, for example, to determine the minimum number of subjects needed for an experiment to be informative. Calculating the right sample size is crucial to gaining accurate information and ensures that research resources are used efficiently and ethically. The simple question "How many subjects do I need?" does not always have a simple answer. Before calculating the sample size requirements, a researcher must address several aspects, such as purpose of the research (descriptive or comparative), type of samples (one or more groups), and data being collected (continuous or categorical). In this article, we describe some of the most frequent methods for calculating the sample size with examples from nuclear cardiology research, including for t tests, analysis of variance (ANOVA), non-parametric tests, correlation, Chi-squared tests, and survival analysis. For the ease of implementation, several examples are also illustrated via user-friendly free statistical software.

Trials of Intervention Principles: Evaluation Methods for Evolving Behavioral Intervention Technologies.

In recent years, there has been increasing discussion of the limitations of traditional randomized controlled trial (RCT) methodologies for the evaluation of eHealth and mHealth interventions, and in particular, the requirement that these interventions be locked down during evaluation. Locking down these interventions locks in defects and eliminates the opportunities for quality improvement and adaptation to the changing technological environment, often leading to validation of tools that are outdated by the time that trial results are published. Furthermore, because behavioral intervention technologies change frequently during real-world deployment, even if a tested intervention were deployed in the real world, its shelf life would be limited. We argue that RCTs will have greater scientific and public health value if they focus on the evaluation of intervention principles (rather than a specific locked-down version of the intervention), allowing for ongoing quality improvement modifications to the behavioral intervention technology based on the core intervention principles, while continuously improving the functionality and maintaining technological currency. This paper is an initial proposal of a framework and methodology for the conduct of trials of intervention principles (TIPs) aimed at minimizing the risks of in-trial changes to intervention technologies and maximizing the potential for knowledge acquisition. The focus on evaluation of intervention principles using clinical and usage outcomes has the potential to provide more generalizable and durable information than trials focused on a single intervention technology.

Design of implementation studies for quality improvement programs: an effectiveness-cost-effectiveness framework.

Translational research applies basic science discoveries in clinical and community settings. Implementation research is often limited by tremendous variability among settings; therefore, generalization of findings may be limited. Adoption of a novel procedure in a community practice is usually a local decision guided by setting-specific knowledge. The conventional statistical framework that aims to produce generalizable knowledge is inappropriate for local quality improvement investigations. We propose an analytic framework based on cost-effectiveness of the implementation study design, taking into account prior knowledge from local experts. When prior knowledge does not indicate a clear preference between the new and standard procedures, local investigation should guide the choice. The proposed approach requires substantially smaller sample sizes than the conventional approach. Sample size formulae and general guidance are provided.

Optimizing Contingency Management with Reinforcement Learning.

Contingency Management (CM) is a psychological treatment that aims to change behavior with financial incentives. In substance use disorders (SUDs), deployment of CM has been enriched by longstanding discussions around the cost-effectiveness of prized-based and voucher-based approaches. In prize-based CM, participants earn draws to win prizes, including small incentives to reduce costs, and the number of draws escalates depending on the duration of maintenance of abstinence. In voucher-based CM, participants receive a predetermined voucher amount based on specific substance test results. While both types have enhanced treatment outcomes, there is room for improvement in their cost-effectiveness: the voucher-based system requires enduring financial investment; the prize-based system might sacrifice efficacy. Previous work in computational psychiatry of SUDs typically employs frameworks wherein participants make decisions to maximize their expected compensation. In contrast, we developed new frameworks that clinical decision-makers choose actions, CM structures, to reinforce the substance abstinence behavior of participants. We consider the choice of the voucher or prize to be a sequential decision, where there are two pivotal parameters: the prize probability for each draw and the escalation rule determining the number of draws. Recent advancements in Reinforcement Learning, more specifically, in off-policy evaluation, afforded techniques to estimate outcomes for different CM decision scenarios from observed clinical trial data. We searched CM schemas that maximized treatment outcomes with budget constraints. Using this framework, we analyzed data from the Clinical Trials Network to construct unbiased estimators on the effects of new CM schemas. Our results indicated that the optimal CM schema would be to strengthen reinforcement rapidly in the middle of the treatment course. Our estimated optimal CM policy improved treatment outcomes by 32% while maintaining costs. Our methods and results have broad applications in future clinical trial planning and translational investigations on the neurobiological basis of SUDs.