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.