Utility of Continuous Disease Subtyping Systems for Improved Evaluation of Etiologic Heterogeneity

Molecular pathologic diagnosis is important in clinical (oncology) practice. Integration of molecular pathology into epidemiological methods (i.e., molecular pathological epidemiology) allows for investigating the distinct etiology of disease subtypes based on biomarker analyses, thereby contributing to precision medicine and prevention. However, existing approaches for investigating etiological heterogeneity deal with categorical subtypes. We aimed to fully leverage continuous measures available in most biomarker readouts (gene/protein expression levels, signaling pathway activation, immune cell counts, microbiome/microbial abundance in tumor microenvironment, etc.). We present a cause-specific Cox proportional hazards regression model for evaluating how the exposure-disease subtype association changes across continuous subtyping biomarker levels. Utilizing two longitudinal observational prospective cohort studies, we investigated how the association of alcohol intake (a risk factor) with colorectal cancer incidence differed across the continuous values of tumor epigenetic DNA methylation at long interspersed nucleotide element-1 (LINE-1). The heterogeneous alcohol effect was modeled using different functions of the LINE-1 marker to demonstrate the method's flexibility. This real-world proof-of-principle computational application demonstrates how the new method enables visualizing the trend of the exposure effect over continuous marker levels. The utilization of continuous biomarker data without categorization for investigating etiological heterogeneity can advance our understanding of biological and pathogenic mechanisms.

Protecting Children From Tobacco Smoke Exposure: A Randomized Controlled Trial of Project Zero Exposure

INTRODUCTION

Young children are vulnerable to harm from tobacco smoke exposure (TSE). This study assessed the effect of Project Zero Exposure-an intervention program designed to help parents protect children from TSE-on children's exposure.

METHODS

Randomized controlled trial of a home-based, theory-driven intervention. Parents of young children (<8 y) in families with a smoking parent were eligible. The intervention included feedback on child TSE (hair nicotine), and home air quality (PM2.5), with motivational interviewing. Families were randomized to: intervention group (IG, N = 69), regular control group (RCG, N = 70), or to a secondary enhanced control group, (ECG, N = 20). Child hair samples were taken at baseline and follow-up. We report on child TSE in the IG versus RCG at six months.

RESULTS

Most enrolled families completed the trial (IG: 98.6%[68/69], RCG: 97.1%[68/70]). Log hair nicotine (LHN [ng/mg]) decreased in both the IG (Baseline: -1.78 ± 1.91, Follow-up: -2.82 ± 1.87, p = .003) and RCG (Baseline: -1.79 ± 1.54, Follow-up: -2.85 ± 1.73, p = .002), but did not differ between groups at study end (p = .635). Three of five parentally-reported outcomes showed improvement over time in the IG, and one in the RCG. Among IG participants, 90% found hair nicotine feedback useful.

CONCLUSIONS

No difference between the intervention and control groups was found on the objective biomarker, LHN. Child TSE decreased during the trial in intervention and control groups. Trial participation, which included hair nicotine monitoring, may have contributed to decreasing exposure in both groups. Concurrent control group improvements may partially explain lack of proven intervention benefit. Biomarker monitoring warrants further investigation for reduction of child TSE.

IMPLICATIONS

Project Zero Exposure is an intervention program designed to help parents protect their children from TSE. Results from the randomized controlled trial of the program showed no difference between groups at study end, but a clear and substantial reduction in child exposure to tobacco smoke from beginning to end of the trial, in both intervention and control groups. Biomarker monitoring, a key element of the trial, was used with all participants. Biomarker monitoring of child exposure to tobacco smoke may help parents become aware of their child's exposure and better protect them, and should be explored as a means to reduce child TSE. Clinical Trial Registration: NCT02867241.

Psychometric Characteristics and Validity of the PROMIS Cancer Function Brief 3D Profile

OBJECTIVE

To develop an item response theory (IRT)-calibrated, patient-reported outcome measure (the PROMIS Cancer Function Brief 3D Profile) of physical function, including associations with fatigue and social participation, in cancer rehabilitation patients.

DESIGN

Large-scale field testing, graded response model IRT analyses, and multivariate regression analysis.

SETTING

Six cancer rehabilitation clinics associated with cancer centers across the United States.

PARTICIPANTS

Adults (N=616) treated in outpatient cancer rehabilitation medicine clinics.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

The PROMIS(r) Cancer Function 3D Profile (including existing items from PROMIS(r) item banks).

RESULTS

A total of 616 patients completed 21 items in the initial item pool. Nine items were removed because of comparatively lower information that they provide according to the IRT item calibrations, low item-total correlations, or bimodal distributions. The remaining items generated a 12-item short form. Regression analyses determined that the items were responsive to and representative of the patient population across trait ranges and multiple domains and subdomains of function.

CONCLUSIONS

This psychometric investigation supports the use of the PROMIS Cancer Function Brief 3D Profile for evaluating function in outpatient cancer rehabilitation patients.

Bringing prevost's sign into the third dimension: Artificial intelligence estimation of conjugate gaze adjusted length (CGAL) and correlation with acute ischemic stroke

Conjugate gaze deviation is associated with acute ischemic stroke (AIS), although previously only measured on a 2D plane. The current study evaluates 3D imaging efficacy to assess conjugate gaze deviation and correlate direction and strength of deviation to neuro-clinical findings.A retrospective analysis of 519 patients who had CT scans for suspected AIS at our institution. Direction and angle of eye deviation were calculated based on 2D axial images. Volumetric reconstruction of CT scans allowed for calculation of 3D conjugate gaze adjusted length (CGAL). Angle, direction, and vector strength of both 2D and 3D scans were calculated by an artificial intelligence algorithm and tested for agreement with hemispheric ischemia location. CGAL measurements were correlated to NIHSS scores. Follow up MRI data was used to evaluate the sensitivity and specificity of CGAL in the identification of AIS.The final analysis included 122 patients. A strong agreement was found between 3D gaze direction and hemispheric ischemia location. CGAL measurements were highly correlated with NIHSS score (r = .72, P = .01). A CGAL >0.25, >0.28, and >0.35 exhibited a sensitivity of 91%, 86%, and 82% and specificity of 66%, 89%, and 89%, respectively, in AIS identification. A CGAL >0.28 has the best sensitivity-specificity balance in the identification of AIS. A CGAL >0.25 has the highest sensitivity.Given CED's correlation with NIHSS score a 1/4 deviation in the ipsilateral direction is a sensitive ancillary radiographic sign to assist radiologists in making a correct diagnosis even when not presented with full clinical data.

Effect of Exercise on Taxane Chemotherapy-Induced Peripheral Neuropathy in Women With Breast Cancer: A Randomized Controlled Trial

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is a dose-limiting adverse effect of taxanes. We sought to evaluate the effect of exercise on taxane CIPN in women with breast cancer.

PATIENTS AND METHODS

Women (n = 27) were randomized to immediate exercise (IE, during taxane chemotherapy) or delayed exercise (DE, after chemotherapy). Supervised aerobic, resistance, and balance training was offered 3 days a week for 8-12 weeks. CIPN symptoms and quality of life were assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ) C30 and CIPN20 (scored from 0 to 100). The percentage of participants reporting moderate to severe sensory symptoms ('3/4' or '4/4' for CIPN20 sensory items) was also evaluated, along with clinical sensory testing at the lower limb (vibration sense and pinprick). Taxane treatment adherence, including relative dose intensity, was extracted from patient medical records. Assessments occurred at: baseline (before taxane chemotherapy), pre-cycle 4 (before the final taxane cycle), the end of chemotherapy, and follow-up (10-15 weeks after chemotherapy).

RESULTS

No differences in the EORTC QLQ CIPN20 symptom scores were detected between groups at any time point. At pre-cycle 4, there was a significant difference between groups in patient-reported moderate to severe numbness in the toes or feet (IE: n = 1, 9%, DE: n = 7, 50%, P = .04) and impaired vibration sense in the feet (IE: n = 2, 18%, DE: n = 10, 83%, P < .01). Overall global health status/quality of life was higher in IE compared to DE at the end of chemotherapy (P = .05), yet both groups had worse CIPN20 sensory (Δ24.3 ± 4.6, P < .01) and motor symptom scores (Δ10.5 ± 1.9, P < .01) relative to baseline. By the end of chemotherapy, no differences between groups were found for moderate to severe numbness in the toes or feet (P = 1.0) or impaired vibration sense in the feet (P = .71). More IE participants received ≥ 85% relative dose intensity (IE: n = 12, 100%, DE: n = 10, 67%, P < .05).

CONCLUSION

Exercise may attenuate CIPN over the course of taxane chemotherapy and possibly improve taxane adherence in women with breast cancer. These findings, as well as whether exercise can attenuate CIPN by the end of taxane chemotherapy, should be confirmed in larger trials.

Early developmental trajectories of preterm infants

BACKGROUND AND OBJECTIVES

Preterm infants are at risk for neuro-developmental impairments and atypical developmental trajectories. The aims of this study were to delineate early developmental trajectories of preterm and full-term infants.

METHODS

The cognitive, language, and motor development of 149 infants - 19 extremely preterm (EPT), 34 very preterm (VPT), 57 moderately preterm (MPT), and 39 full-term (FT) - was evaluated using Mullen Scales at 1, 4, 8, 12, and 18 months. Mixed models were applied to examine group differences. Gender, maternal education, and neurobehavior were included as predictors of developmental trajectories.

RESULTS

The EPT and VPT infants achieved significantly lower scores than the FT infants in all domains, with a significantly increasing gap over time. The MPT infants' trajectories were more favorable than those of the EPT and VPT infants yet lower than the FT infants on the Visual Reception, Gross, and Fine Motor subscales. Male gender and lower maternal education were associated with lower scores that declined over time. Abnormal neonatal neurobehavior was associated lower Mullen scores and with less stability in scores over time.

CONCLUSIONS

The EPT and VPT infants were found to have disadvantages across all domains. The MPT infants revealed more favorable developmental trajectories yet displayed vulnerability compared to the FT infants. Gender, maternal education, and neonatal neurobehavior are important in predicting the developmental outcomes of preterm infants.

Preterm-infant emotion regulation during the still-face interaction

Very-preterm (VPT), moderately-preterm (MPT), and full-term (FT) infants' emotion-regulation behaviors were assessed via the Still-Face procedure at a corrected age of four months. As a developmental task during the first year of life, emotion regulation is important for social and cognitive development. Although substantial evidence indicates that VPT infants exhibit emotion-regulation difficulties, little is known about MPT infants' emotion regulation capabilities, this group also possibly being at risk. The participants included 135 parent-infant dyads: 46 VPT (gestational age 24-32 weeks), 51 MPT (gestational age 32-34 weeks), and 38 FT (gestational age 37-41 weeks). The infants' affect, gaze-aversion, and self-comforting behaviors were coded. Preterm infants responded to parental still face in similar fashion to FT infants, displaying robust still-face and recovery effects. The preterm infants exhibited less developed emotion-regulation behaviors, however, manifested in less positive affect and more gaze aversion in the face-to-face and reunion episodes compared to FT infants. With respect to self-comforting behaviors, each group displayed a significantly different pattern of behaviors throughout the procedure, suggesting better emotion regulation skills among MPT infants compared to the VPT infants. The findings on gaze aversion and self-comforting behaviors could have implications for strategies to incorporate into intervention programs supporting development of emotion regulation skills.

Protecting Young Children From Tobacco Smoke Exposure: A Pilot Study of Project Zero Exposure

BACKGROUND

Tobacco smoke exposure (TSE) harms children, who are often "captive smokers" in their own homes. Project Zero Exposure is a parent-oriented, theory-based intervention designed to reduce child TSE. This paper reports on findings from the pilot study, which was conducted in Israel from 2013 to 2014.

METHODS

The intervention consisted of motivational interviews, child biomarker and home air quality feedback, a Web site, a video, and self-help materials. The primary outcome was child TSE as measured by hair nicotine. Secondary outcome measures were air nicotine and particulate matter, parental reports of TSE, parental smoking behavior, and TSE child protection. A single-group pre- and posttest design was used.

RESULTS

Twenty-six of the 29 recruited families completed the study. The intervention was feasible to implement and acceptable to participants. Among the 17 children with reliable hair samples at baseline and follow-up, log hair nicotine dropped significantly after the intervention (P = .04), hair nicotine levels decreased in 64.7% of children, and reductions to levels of nonexposed children were observed in 35.3% of children. The number of cigarettes smoked by parents (P = .001) and parent-reported child TSE declined (P = .01). Logistical issues arose with measurement of all objective measures, including air nicotine, which did not decline; home air particulate matter; and hair nicotine.

CONCLUSIONS

A program based on motivational interviewing and demonstrating TSE and contamination to parents in a concrete and easily understandable way is a promising approach to protect children from TSE. Further research is needed to enhance current methods of measurement and assess promising interventions.

The impact of covariate measurement error on risk prediction

In the development of risk prediction models, predictors are often measured with error. In this paper, we investigate the impact of covariate measurement error on risk prediction. We compare the prediction performance using a costly variable measured without error, along with error-free covariates, to that of a model based on an inexpensive surrogate along with the error-free covariates. We consider continuous error-prone covariates with homoscedastic and heteroscedastic errors, and also a discrete misclassified covariate. Prediction performance is evaluated by the area under the receiver operating characteristic curve (AUC), the Brier score (BS), and the ratio of the observed to the expected number of events (calibration). In an extensive numerical study, we show that (i) the prediction model with the error-prone covariate is very well calibrated, even when it is mis-specified; (ii) using the error-prone covariate instead of the true covariate can reduce the AUC and increase the BS dramatically; (iii) adding an auxiliary variable, which is correlated with the error-prone covariate but conditionally independent of the outcome given all covariates in the true model, can improve the AUC and BS substantially. We conclude that reducing measurement error in covariates will improve the ensuing risk prediction, unless the association between the error-free and error-prone covariates is very high. Finally, we demonstrate how a validation study can be used to assess the effect of mismeasured covariates on risk prediction. These concepts are illustrated in a breast cancer risk prediction model developed in the Nurses' Health Study.

A DNA synthesis inhibitor is protective against proteotoxic stressors via modulation of fertility pathways in Caenorhabditis elegans

Loss of germline precursor cells in C. elegans has previously been shown to improve protein homeostasis and extend lifespan, possibly due to reallocation of resources to somatic cells. In contrast, mutants that are sterile simply due to loss of sperm or oocyte production have a normal lifespan, often leading to the conclusion that loss of reproduction per se may have minor effects on C. elegans. We have found that inhibiting reproduction in C. elegans via the DNA synthesis inhibitor 5-fluoro-2-deoxyuridine (FUdR) improves protein homeostasis, stress resistance, and healthspan in wild-type animals. We find that FUdR is dependent on oogenesis and oocytic maturation. The effects of FUdR are dependent on FEM pathways, which regulate initiation of spermatogenesis. Loss of FEM expression leads to feminized animals that maintain arrested oocytes and are refractory to the effects of FUdR. FUdR-dependence is restored by spermatogenic signals, which trigger oocytic maturation and ovulation. Further, loss of FEM-3, a novel protein required for spermatogenesis, is sufficient to improve aspects of proteostasis. These effects are independent of previously described germline signals, including the DAF-16/FOXO, DAF-12/VDR, and HSF-1 pathways. These findings suggest that genetic or chemical inhibition of oocyte production can improve protein homeostasis in C. elegans.

Meta-analysis of parental protection of children from tobacco smoke exposure

BACKGROUND AND OBJECTIVE

Worldwide, roughly 40% of children are exposed to the damaging and sometimes deadly effects of tobacco smoke. Interventions aimed at reducing child tobacco smoke exposure (TSE) have shown mixed results. The objective of this study was to perform a systematic review and meta-analysis to quantify effects of interventions aimed at decreasing child TSE.

METHODS

Data sources included Medline, PubMed, Web of Science, PsycNet, and Embase. Controlled trials that included parents of young children were selected. Two reviewers extracted TSE data, as assessed by parentally-reported exposure or protection (PREP) and biomarkers. Risk ratios and differences were calculated by using the DerSimonian and Laird random-effects model. Exploratory subgroup analyses were performed.

RESULTS

Thirty studies were included. Improvements were observed from baseline to follow-up for parentally-reported and biomarker data in most intervention and control groups. Interventions demonstrated evidence of small benefit to intervention participants at follow-up (PREP: 17 studies, n = 6820, relative risk 1.12, confidence interval [CI] 1.07 to 1.18], P < .0001). Seven percent more children were protected in intervention groups relative to control groups. Intervention parents smoked fewer cigarettes around children at follow-up than did control parents (P = .03). Biomarkers (13 studies, n = 2601) at follow-up suggested lower child exposure among intervention participants (RD -0.05, CI -0.13 to 0.03, P = .20).

CONCLUSIONS

Interventions to prevent child TSE are moderately beneficial at the individual level. Widespread child TSE suggests potential for significant population impact. More research is needed to improve intervention effectiveness and child TSE measurement.

Enabling Hygienic Behavior among Preschoolers: Improving Environmental Conditions through a Multifaceted Intervention

Purpose.

Environmental conditions often serve as critical enabling factors for health promotion. This article describes the effect of a preschool hygiene intervention program on classroom environmental conditions.

Design.

Cluster randomized trial, with randomization at the level of the preschool.

Setting.

State-run preschools in Jerusalem.

Subjects.

Forty secular and religious Jerusalem preschools (including 1029 children).

Intervention.

A multidisciplinary hygiene intervention that included changes to the preschool environment.

Measures.

Presence of soap, soap dispenser, paper towel, paper towel dispenser, cloth towels, communal cup, or personal cups.

Analysis.

Generalized estimating equations and Fisher's exact test were used to estimate the effect of the intervention program on environmental conditions.

Results.

Information was obtained from most (97.9%) visits. Baseline environmental hygienic conditions were poor. Relative to the control group, the following environmental conditions were better in the intervention group after program implementation: soap (odds ratio [OR] = 14.7; p < .01), paper towels (OR = 13.5; p < .01), communal cups (OR = .05; p < .01), soap dispensers (secular preschools only, p < .01), individual cups (secular, p < .01; religious, OR = 18.7; p < .02).

Conclusions.

Environmental hygiene in the Israeli preschools studied was deficient at baseline but amenable to change. Improvement in environmental conditions was a necessary enabling factor for the changes in hand-washing behavior that were observed among the children. Sustained environmental change is possible in the preschool environment. (Am J Health Promot 2011;25[4]:248–256.)

Spreading the handwashing message: an alternative to traditional media campaigns

Schools are a natural place from which to disseminate health messages to the community. Sending an entertaining handwashing video home with preschoolers as a component of a school-based program yielded impressive degrees of penetration and reach among families; consequently, this strategy offers a promising alternative to traditional media campaigns.

The effect of a handwashing intervention on preschool educator beliefs, attitudes, knowledge and self-efficacy

This paper describes the effect of a preschool hygiene intervention program on psychosocial measures of educators regarding handwashing and communicable pediatric disease. A cluster-randomized trial, with randomization at the level of the preschool, was run in 40 Jerusalem preschool classrooms. Eighty preschool educators participated. The program used a multipronged approach which included elements aimed at staff, children, parents, school nurses and the classroom environment. Frontal lectures by medical, epidemiological and educational experts, along with printed materials and experiential learning, were provided to staff. Responses from a validated survey instrument were used to build four scales for each respondent regarding beliefs, attitudes, self-efficacy and knowledge. The scales were built on a Likert-type 1-7 scale (1 = minimum, 7 = maximum). The effect of the intervention was tested using mixed model analysis of variance. Response was received from 92.5% of educators. Educators believed that handwashing could affect health (mean = 5.5, SD = 1.1), had high levels of self-efficacy (mean = 6.1, SD = 0.9) and had positive attitudes toward handwashing (mean = 5.7, SD = 1.2). Knowledge was affected by the intervention (intervention: mean = 6.2, SD = 0.7; control: mean = 5.8, SD = 0.8). The combination of positive attitudes toward handwashing among educators and the program's effectiveness in imparting knowledge helped to create a sustained social norm of handwashing among many children in disparate locations.

Secondhand smoke in Israeli bars, pubs and cafes

BACKGROUND

Secondhand smoke poses a serious health hazard. In Israel the recent passage of a law designed to protect people from secondhand smoke in public places was greeted with controversy. The debate is taking place without data on actual levels of pollution for secondhand smoke in public places.

OBJECTIVES

To estimate levels of small respirable suspended particles, atmospheric markers of secondhand smoke, in Israeli bars, pubs and cafes, to compare them with levels in other countries, and to analyze RSP determinants.

METHODS

This study was conducted in bars, pubs and cafes in Jerusalem and Tel Aviv prior to passage of the enforcement bill. Venues were randomly sampled from lists available in the local mass media.

RESULTS

The average level of RSPs across all venues, 283 microg/m3, was nearly identical to levels in countries without enforced smoking bans. Bars and pubs had higher values than cafes (P = 0.0101). The effect of smoker concentration was borderline significant (P = 0.0540), with RSP levels increasing as smoker concentration increased. The effect of venue height was also borderline significant (P = 0.0642), with RSP levels decreasing as venue height increased.

CONCLUSIONS

Levels of indoor air pollution from secondhand smoke in Israeli bars, pubs and cafes prior to the recent passage of the enforcement bill were similar to levels in countries without enforced smoking bans, and roughly 10 times as high as countries with enforced smoking bans. Whether the new law will successfully promote clean air in Israeli bars, pubs, cafes, and other indoor places is yet to be seen.

Design of the Jerusalem Handwashing Study: meeting the challenges of a preschool-based public health intervention trial

BACKGROUND

Rates of communicable disease among young children are considerably higher in Israel than in other western countries. Strategies for reducing the disease rates are needed.

PURPOSE

The goal of the Jerusalem Handwashing Study (JHS) was to evaluate a preschool-based hygiene programme aimed at reducing illness absenteeism.

METHODS

The trial employed cluster randomization of preschools to intervention or control. The intervention programme was multifaceted, including various educational activities and environmental changes. The control group received the programme at the end of the study. A supplementary home component was tested using the innovative design strategy of an embedded individually-randomized trial. All-cause absenteeism and illness-related absenteeism was assessed by daily phone calls to the teachers, supplemented with phone calls to the parents to identify the cause of the absence. The primary endpoint was illness-related absenteeism. In an attempt to avoid bias, survey staff were blinded to the study design and the main outcome as well as intervention status. Validity checks were incorporated to assess the accuracy of educator absenteeism reports and were analysed for differences between the study arms. Observation of handwashing behaviour allowed assessment of behavioural change in the intervention group and spontaneous handwashing changes in the control group.

RESULTS

Cluster randomization with delayed implementation in the control group was a feasible and efficient strategy. The individually-randomized embedded sub-trial proved to be an efficient way to test a supplemental intervention component, and is particularly well-suited to programmes run in educational or other group settings, including workplaces, clinics, and community centres.

LIMITATIONS

The trial design did not permit analysis of the intervention effect on illness.

CONCLUSIONS

The techniques used in this trial made it possible for a rigorous study of a complex community-based health intervention to be carried out successfully. They should prove helpful to future researchers.

In defense of the randomized controlled trial for health promotion research

The overwhelming evidence about the role lifestyle plays in mortality, morbidity, and quality of life has pushed the young field of modern health promotion to center stage. The field is beset with intense debate about appropriate evaluation methodologies. Increasingly, randomized designs are considered inappropriate for health promotion research. We have reviewed criticisms against randomized trials that raise philosophical and practical issues, and we will show how most of these criticisms can be overcome with minor design modifications. By providing rebuttal to arguments against randomized trials, our work contributes to building a sound methodological base for health promotion research.

Can a handwashing intervention make a difference? Results from a randomized controlled trial in Jerusalem preschools

BACKGROUND

Preschools are often focal points for the spread of illness among young children. The objective of this preschool intervention trial was to determine whether a hygiene program can promote handwashing and thereby reduce illness absenteeism.

METHODS

This cluster randomized trial included 40 Jerusalem preschools with 1029 children for 6 baseline days and 66 study days, yielding 73,779 child days. The main outcomes were rates of handwashing and illness absenteeism. The intervention included an educational program and environmental changes. A simultaneous subtrial was run to test a home component.

RESULTS

This multi-site intervention program produced sustained behavioral and environmental changes over a 6-month period. An approximately threefold increase in handwashing with soap was observed among preschool children exposed to the intervention. Neither the preschool nor the home intervention program reduced illness absenteeism or overall absenteeism.

CONCLUSIONS

This trial illuminates the potential of the preschool as a promising venue for health promotion activities leading to sustained behavioral change, yet suggests the need for enhanced approaches for reducing illness absenteeism.

The great tocolytic debate: some pitfalls in the study of safety

The controversy surrounding the use of tocolytic agents has been raging for decades. Tocolytic drugs play a pivotal role in the prevention of preterm birth, which is the major cause of neonatal morbidity and mortality. Studies on the efficacy and safety of these drugs are of the utmost importance to many disciplines within the medical community. Unfortunately, many clinical decisions regarding tocolytic agents are based on incorrect information resulting from flawed studies. In this article we discuss the major design flaws common to many studies of tocolytic safety and in so doing explain some of the conflicting evidence regarding safety. Each of the two major types of study designs, preterm birth retrospective studies and prospective randomized trials, is associated with a serious flaw. Retrospective preterm birth studies give misleading and inconclusive results to the question of safety because of the use of incomplete cohorts. The inadequately sized prospective studies in the current literature lack the power to detect important clinical differences.

Florida's "truth" campaign: a counter-marketing, anti-tobacco media campaign

The "truth" campaign was created to change youth attitudes about tobacco and to reduce teen tobacco use throughout Florida by using youth-driven advertising, public relations, and advocacy. Results of the campaign include a 92 percent brand awareness rate among teens, a 15 percent rise in teens who agree with key attitudinal statements about smoking, a 19.4 percent decline in smoking among middle school students, and a 8.0 percent decline among high school students. States committed to results-oriented youth anti-tobacco campaigns should look to Florida's "truth" campaign as a model that effectively places youth at the helm of anti-tobacco efforts.

Internal pilot studies I: type I error rate of the naive t-test

When sample size is recalculated using unblinded interim data, use of the usual t-test at the end of a study may lead to an elevated type I error rate. This paper describes a numerical quadrature investigation to calculate the true probability of rejection as a function of the time of the recalculation, the magnitude of the detectable treatment effect, and the ratio of the guessed to the true variance. We consider both 'restricted' designs, those that require final sample size at least as large as the originally calculated size, and 'unrestricted' designs, those that permit smaller final sample sizes than originally calculated. Our results indicate that the bias in the type I error rate is often negligible, especially in restricted designs. Some sets of parameters, however, induce non-trivial bias in the unrestricted design.

Variation in mortality among seven hemodialysis centers as a quality indicator

OBJECTIVES

To identify patient attributes that were associated with increased mortality; variables that were associated with process of care that were correlated with mortality; and outlier centers after adjustment for patient attributes.

DESIGN

Standard interviews were conducted by trained nurses with all patients. Detailed information regarding primary renal diagnosis, comorbidity, and results of laboratory tests were obtained from the medical charts. The vital status of the patients was obtained from the records of each of the centers. We used the Cox hazard method to identify variables that correlated with a 1-year mortality. Centers with observed mortality exceeding the 95% confidence interval (CI95) of the expected probability of death were marked as outliers.

SETTING

Seven dialysis centers located in large teaching hospitals in Israel.

PATIENTS

The current study included patients > 16 years of age who had undergone hemodialysis > 4 weeks prior to the day of data collection.

RESULTS

The study included 564 patients. Significant differences were found in patient demographics and process variables among the centers. The following variables correlated with mortality; diabetes (odds ratio [OR], 2.03; CI95, 1.28-3.21); ischemic heart disease (OR, 2.2; CI95, 1.39-3.49); each year of age (OR, 1.04; CI95, 1.02-1.06); each 1 g% of albumin (OR, 0.51; CI95, 0.30-0.86). The average observed mortality in all centers was 17.4%. After adjustment for casemix, one center showed excess mortality (24% observed compared to 15% expected after adjustment for patient attributes; CI95, 6.2-23.7).

CONCLUSIONS

The ability to compare mortality rates among dialysis centers to detect possible quality outliers depends on thorough consideration of patient attributes and random variation.

Differences in quality of life among patients receiving dialysis replacement therapy at seven medical centers

The purpose of this study is to investigate the variations in quality of life (QOL) among patients with end-stage renal disease (ESRD) who are receiving replacement therapy in several dialysis centers. This observational study includes interviews with nurses and data extraction from medical charts for all 680 adults who had been on dialysis therapy for more than 4 weeks in seven dialysis centers. By using multivariate analysis, we generated a model to explain the variance in QOL as measured by the QL index score (developed by Spitzer et al., J Chronic Dis 1981; 34:585-597) among patients pooled from all centers. The expected mean QL index score and 95% confidence interval were computed for each dialysis center. Centers with observed mean QL index scores outside of the expected confidence range were marked as possible outliers. We found the following patient attributes to be independently associated with QOL: age, education, occupation, and certain comorbidities (e.g., diabetes, stroke). After adjustment for case mix, we could identify four outlier centers. After further adjustment for albumin in serum, a possible process indicator, two centers were no longer considered as outliers. These findings indicate that the variance in QOL of ESRD patients at different centers is not entirely explained by known case-mix factors. Further research should explore whether such variations are related to dissimilarity in the process of care at different centers.

An application of the Zucker-Wittes modified ratio estimate statistic in the Post Coronary Artery Bypass Graft (CABG) clinical trial

In the Post Coronary Artery Bypass Graft (POST CABG) clinical trial, the primary outcome is substantial worsening (i.e., narrowing of the lumen diameter) of the vein grafts upon comparison of the baseline and follow-up angiograms. The patients had one to five non-occluded vein grafts at entry, so there may be from one to five primary outcome responses per patient. A modified ratio estimate (MRE) statistic, as described previously by Zucker and Wittes, may be used to analyze data of this kind. In the present paper we propose a more powerful MRE statistic when the event rates and/ or intraclass correlations vary according to number of grafts per patient. We also adapt this statistic to the factorial treatment design of the POST CABG clinical trial.

Method for separating patient and procedural factors while analyzing interdepartmental differences in rates of surgical infections: the Israeli Study of Surgical Infection in Abdominal Operations

The objective of this study was to develop a method for analyzing differences in the performance of hospitals with respect to outcome by separating patient factors from procedural factors. The setting included a prospective follow-up of a sample of 5571 patients undergoing all types of surgical procedures in general surgery departments of 11 hospitals (20 surgical departments) across Israel. Of these, 769 underwent surgery involving the opening of the bowel, and they are the subjects of this report. Our method consisted of a prospective follow-up by a nurse epidemiologist, including detailed clinical data from the day of admission to hospital discharge. Analysis was directed at identifying reasons for the observed variability in wound infections among departments. Observed rates were compared with "expected" rates calculated from a logistic model pooled over departments. An attempt was made to separate patient-inherent characteristics, such as age, sex, and diagnosis, from procedural factors, depicting the patient's experience during his hospitalization. Results indicated that the marked interdepartmental differences in the observed infection rates were not accounted for by differences in the "case mix" among departments. Procedural risk factors in this data set played the main role in explaining the observed variability among surgical departments. We conclude that the simple method presented here used the data pooled over departments to define the main risk determinants for infection in this data set. It separated intrinsic patient factors from procedural characteristics, and could be used in studies where the main interest is to compare institutions, and point at reasons behind the differences in outcomes.

Ten-year results of the randomized control trials of coronary artery bypass graft surgery: tabular data compiled by the collaborative effort of the original trial investigators. Part 2 of 2

This metaanalysis has some important general implications for conducting studies to evaluate other treatments as well as for patient management. To avoid missing clinically important differences (eg, 15-20% differences in mortality at 5 years) between the methods of revascularization, study populations should be several times larger than those in our metaanalysis, should include a high proportion of the types of patients for whom surgery is known to be superior to medical therapy, and should be complemented by a systematic overview. We recommend that researchers running large randomized trials consider prospective collaboration with researchers from other trials with a common protocol.

Ten-year results of the randomized control trials of coronary artery bypass graft surgery: tabular data compiled by the collaborative effort of the original trial investigators. Part 1 of 2

OBJECTIVE

To make available 10-year mortality data compiled and analyzed on patients with stable coronary heart disease (angina not severe enough to necessitate surgery) from all studies in which patients were randomized to initial coronary artery bypass graft (CABG) surgery or initial medical treatment and to determine whether the effects are influenced by the extent of coronary artery disease and degree of left-ventricular function. Data and analyses are presented in tabular form; text is published simultaneously in Lancet.

METHODS

We collected individual patient data using standardized forms and, whenever possible, uniform definitions. We used Mantel-Haentel methods to combine data. Restricted means analyses were applied to quantify the extension in survival, and logistic regression analyses were applied to assess whether any baseline covariate affected the treatment differences.

RESULTS

Of 2,649 patients, 1,324 were assigned to receive CABG surgery and 1,325 to the medical group. Mean age was 50.8 years; 98.8% were men. 93.7% of the CABG group underwent surgery. 25% of the medical group had undergone surgery at 5 years, 33% at 7 years, and 41% at 10 years. Initial CABG surgery reduced mortality significantly at 5 years (10.2% vs 15.8%; OR = 0.61; P < 0.001), 7 years (15.8% vs 21.7%; OR = 0.68; P < 0.001), and 10 years (26.4% vs 30.5%; OR = 0.83; P < 0.03). Risk reductions were most pronounced in patients with left-main disease compared to those with 3- or 1-2-vessel disease (at 5 years OR = 0.32, 0.58, and 0.77, respectively).

CONCLUSIONS

Initial CABG surgery compared to initial medical management reduces mortality, especially in high- and medium-risk patients.

Effect of coronary artery bypass graft surgery on survival: overview of 10-year results from randomised trials by the Coronary Artery Bypass Graft Surgery Trialists Collaboration

We carried out a systematic overview using individual patient data from the seven randomised trials that have compared a strategy of initial coronary artery bypass graft (CABG) surgery with one of initial medical therapy to assess the effects on mortality in patients with stable coronary heart disease (stable angina not severe enough to necessitate surgery on grounds of symptoms alone, or myocardial infarction). 1324 patients were assigned CABG surgery and 1325 medical management between 1972 and 1984. The proportion of patients in the medical treatment group who had undergone CABG surgery was 25% at 5 years, 33% at 7 years, and 41% at 10 years: 93.7% of patients assigned to the surgery group underwent CABG surgery. The CABG group had significantly lower mortality than the medical treatment group at 5 years (10.2 vs 15.8%; odds ratio 0.61 [95% CI 0.48-0.77], p = 0.0001), 7 years (15.8 vs 21.7%; 0.68 [0.56-0.83], p < 0.001), and 10 years (26.4 vs 30.5%; 0.83 [0.70-0.98]; p = 0.03). The risk reduction was greater in patients with left main artery disease than in those with disease in three vessels or one or two vessels (odds ratios at 5 years 0.32, 0.58, and 0.77, respectively). Although relative risk reductions in subgroups defined by other baseline characteristics were similar, the absolute benefits of CABG surgery were most pronounced in patients in the highest risk categories. This effect was most evident when several prognostically important clinical and angiographic risk factors were integrated to stratify patients by risk levels and the extension of survival at 10 years was examined (change in survival -1.1 [SE 3.1] months in low-risk group, 5.0 [4.2] months in moderate-risk group, and 8.8 [5.4] months in high-risk group; p for trend < 0.003). A strategy of initial CABG surgery is associated with lower mortality than one of medical management with delayed surgery if necessary, especially in high-risk and medium-risk patients with stable coronary heart disease. In low-risk patients, the limited data show a non-significant trend towards greater mortality with CABG.

Testing for differences in changes in the presence of censoring: parametric and non-parametric methods

Some commonly used parametric and non-parametric methods for analysing repeated measures with incomplete observations are briefly reviewed. The performances of these methods in the presence of completely random, as well as informative censoring are compared in simulated experiments generated under the linear random effects model with parameter values derived from realistic examples. The effects of some moderate model deviations are also compared. The results indicate that in the presence of informative censoring, the usual parametric and nonparametric methods derived under the assumption of random censoring could either suffer severe loss of power or provide false positive results. The conditional linear model for informative censoring when used in conjunction with the bootstrap variance estimation procedure performed well under both random and informative censoring mechanisms. The non-parametric procedure obtained by ranking the individual summary statistics, although not as efficient as the conditional linear model with robust variance, also performed relatively well in most situations. Therefore, in situations in which informative censoring is likely to occur it is important to select the proper method of analysis to test for the informativeness of censoring and to account for its effects.

Testing the effect of treatment in experiments with correlated binary outcomes

This paper considers the problem of testing for treatment effect in a randomized experiment with correlated binary outcomes, representing success or failure for different "parts" of a randomized unit. Attention is restricted to tests that are based on a summary score for each individual randomized, and thus are valid regardless of the precise nature of the correlation among parts. The focus is on the efficiency of such tests under various correlation structures, with special emphasis on the case in which the correlation among parts within an individual differs across treatment groups. A class of summary score statistics is defined, and optimal testing is discussed for some simple situations. Three potential general-purpose tests also are described: (1) the ratio estimate test discussed by Henderson et al. (1988, Controlled Clinical Trials 9, 189-205); (2) a modified ratio estimate test with adjusted weighting based on the within-individual correlation between parts; (3) a test defined by applying the Mantel-Haenszel procedure to the proportion of individuals with at least one failure, stratifying by the number of parts. For these general-purpose tests, numerical calculations of asymptotic efficiency are presented under a wide range of designs and correlation structures. On the basis of these results, some practical recommendations for choosing a test are made.