Effects of 'SPRAT' programme for dietary and lifestyle education to improve psychosomatic symptoms and dietary habits among adolescents: a cluster randomised controlled trial.

BACKGROUND: Dietary and lifestyle modifications to reduce subjective psychosomatic symptoms (SPS) have become an important topic worldwide. We developed a school-based dietary and lifestyle education programme that involved parents/guardians in reducing SPS in adolescents (SPRAT). The programme encouraged parents/guardians to participate in adolescents' healthy dietary and lifestyle modifications to reduce SPS, increase enjoyment of school life, and foster appropriate dietary intake. This study evaluated the effectiveness of SPRAT in reducing SPS and in altering dietary behaviour among adolescents. METHODS: A 6-month cluster randomised controlled trial using SPRAT and the usual school programme (control) was performed. Participants were middle school students in Japan who provided informed consent. Outcomes were SPS scores assessed at baseline and 2, 4, and 6 months after baseline and the proportions of dietary and lifestyle factors achieved such as enjoyment of school life and dietary intakes assessed by FFQW82. Change from baseline (CFB) at 6 months was the primary endpoint. A linear mixed-effects model was applied. As for dietary intake, the treatment effect was estimated as an interaction term between baseline and treatment "baseline*treatment". RESULTS: The intention-to treat analysis included 951 (94.7%) and 1035 (89.8%) individuals in the SPRAT and control groups, respectively. The CFB in the 6-month SPS score adjusted for baseline was lower in the SPRAT group (-0.29) than in the control group (0.62), but the difference was not statistically significant -0.91 (p = 0.093). CONCLUSIONS: Although the primary endpoint tended to denote improvement in the SPRAT group compared to the control group, the improvement was not significant. Favourable effects were observed in some secondary outcomes and statistically significant treatment*baseline interactions were observed for several dietary intakes. These results imply that CFBs of dietary intake were increased or decreased in a favourable direction depending on the baseline intake, especially in the SPRAT group. TRIAL REGISTRATION: UMIN000026715. (27/03/2017).

Spatial clustering of suicide mortality and associated community characteristics in Kanagawa prefecture, Japan, 2011-2017.

BACKGROUND: Suicide mortality is high in Japan and early interventional strategies to solve that problem are needed. An accurate evaluation of the regional status of current suicide mortality would be useful for community interventions. A few studies in Kanagawa prefecture, located next to Tokyo and with the second largest population in Japan, have identified spatial clusters of suicide mortality at regional levels. This study examined spatial clustering and clustering over time of such events using spatial data from regional statistics on suicide deaths. METHODS: Data were obtained from regional statistics (58 regions in Kanagawa prefecture) of the National Vital Statistics of Japan from 2011 to 2017. The standardized mortality ratio (SMR) and Empirical Bayes estimator for the SMR (EBSMR) were used as measures. Spatial clusters were examined by Kulldorff's circular spatial scan statistic, Tango-Takahashi's flexible spatial scan statistic and Tango's test. Linear regression and conditional autoregressive (CAR) models were used not only to adjust for covariates but also to estimate regional effects. The analyses were conducted for each year, inclusive. RESULTS: Among male suicide deaths, being unemployed (50%) was most frequently related to suicide while among female health problem (50%) were frequent. Spatial clusters with significance detected by FlexScan, SatScan and Tango's test were few and varied somewhat according to the method used. Spatial clusters were detected in some regions including Kawasaki ward after adjustment by covariates. By the linear regression models, selected variables with significance were different between the sexes. For males, unemployment, family size, and proportion of higher education were detected for several of the years studied while for females, family size and divorce rate were detected over this period. These variables were also observed by the CAR model with 5 covariates. Regional effects were much clearer by considering the spatial parameter for both males and females and especially, Kawasaki ward was detected as a high risk region in many years. CONCLUSION: The present results detected some spatial clustering of suicide deaths within certain regions. Factors related to suicide deaths were also indicated. These results would provide important information in policy making for suicide prevention.

Vonoprazan versus proton-pump inhibitors for healing gastroesophageal reflux disease: A systematic review.

BACKGROUND AND AIM: Gastroesophageal reflux disease (GERD) is a common disease caused by reflux of gastric contents to the esophagus. Proton-pump inhibitors (PPIs) are recommended as a first-line therapy to treat GERD. Recently, a new potassium-competitive acid blocker, vonoprazan, was launched in Japan. We aimed to evaluate the comparative efficacy of vonoprazan and other PPIs in healing GERD. METHODS: We used MEDLINE and the Cochrane Central Register of Controlled Trials to search the literature. Double-blind randomized controlled trials for PPIs and/or vonoprazan that were published in English or Japanese and assessed healing effects in adult GERD patients were included. To estimate the comparative efficacy of treatments, we performed a Bayesian network meta-analysis to assess the consistency assumption. RESULTS: Of 4001 articles identified in the database, 42 studies were eligible. One study was hand-searched and added to the analysis. For the main analysis of healing effects at 8 weeks, odds ratios (ORs) of vonoprazan (20 mg daily) to esomeprazole (20 mg), rabeprazole (20 mg), lansoprazole (30 mg), and omeprazole (20 mg) were 2.29 (95% credible interval, 0.79-7.06), 3.94 (1.15-14.03), 2.40 (0.90-6.77), and 2.71 (0.98-7.90), respectively. Subgroup analysis for patients with severe esophagitis at baseline showed significantly higher ORs for vonoprazan versus most of the comparator PPIs. CONCLUSIONS: This analysis shows that the GERD healing effect of vonoprazan is higher than that of rabeprazole (20 mg) but not higher than other PPIs. Subgroup analysis indicated that vonoprazan is more effective than most PPIs for patients with severe erosive esophagitis.

Design and analysis of a 3-arm noninferiority trial with a prespecified margin for the hazard ratio.

A 3-arm trial design that includes an experimental treatment, an active reference treatment, and a placebo is useful for assessing the noninferiority of an experimental treatment. The inclusion of a placebo arm enables the assessment of assay sensitivity and internal validation, in addition to the testing of the noninferiority of the experimental treatment compared with the reference treatment. In 3-arm noninferiority trials, various statistical test procedures have been considered to evaluate the following 3 hypotheses: (i) superiority of the experimental treatment over the placebo, (ii) superiority of the reference treatment over the placebo, and (iii) noninferiority of the experimental treatment compared with the reference treatment. However, hypothesis (ii) can be insufficient and may not accurately assess the assay sensitivity for the noninferiority of the experimental treatment compared with the reference treatment. Thus, demonstrating that the superiority of the reference treatment over the placebo is greater than the noninferiority margin (the nonsuperiority of the reference treatment compared with the placebo) can be necessary. Here, we propose log-rank statistical procedures for evaluating data obtained from 3-arm noninferiority trials to assess assay sensitivity with a prespecified margin Δ. In addition, we derive the approximate sample size and optimal allocation required to minimize the total sample size and that of the placebo treatment sample size, hierarchically.

Economic impact of adalimumab treatment in Japanese patients with rheumatoid arthritis from the adalimumab non-interventional trial for up-verified effects and utility (ANOUVEAU) study.

OBJECTIVES: The objective of this study is to evaluate the economic impact of adalimumab (ADA) on Japanese rheumatoid arthritis (RA) patients. METHODS: ANOUVEAU was a 48-week multicenter, prospective, observational, single-cohort study. Work-related outcomes including absenteeism, presenteeism, overall work impairment (OWI), and activity impairment (AI) were evaluated using the RA-related work productivity and activity impairment (WPAI/RA). The amount of productivity loss was estimated via multiplication of absenteeism, presenteeism and OWI by the national average occupational wage for paid worker (PW) and part time worker (PTW), and via multiplication of AI by the estimated wage for domestic work for home maker (HM). RESULTS: In this analysis, 1196 patients were included. At week 48, measures of productivity loss due to absenteeism, presenteeism, OWI, and AI were significantly improved by administrating ADA to RA patients in all employment types (PW, PTW, and HM), compared to baseline (p < .01). Productivity loss of Japanese society by RA disease was estimated to be $9.80 billion. The annual decrease in productivity loss through ADA administration to Japanese RA patients was estimated to be $3.76 billion. CONCLUSIONS: The socioeconomic burden of RA is high, but ADA treatment may reduce productivity loss related to RA.

On the repeated measures designs and sample sizes for randomized controlled trials.

For the analysis of longitudinal or repeated measures data, generalized linear mixed-effects models provide a flexible and powerful tool to deal with heterogeneity among subject response profiles. However, the typical statistical design adopted in usual randomized controlled trials is an analysis of covariance type analysis using a pre-defined pair of "pre-post" data, in which pre-(baseline) data are used as a covariate for adjustment together with other covariates. Then, the major design issue is to calculate the sample size or the number of subjects allocated to each treatment group. In this paper, we propose a new repeated measures design and sample size calculations combined with generalized linear mixed-effects models that depend not only on the number of subjects but on the number of repeated measures before and after randomization per subject used for the analysis. The main advantages of the proposed design combined with the generalized linear mixed-effects models are (1) it can easily handle missing data by applying the likelihood-based ignorable analyses under the missing at random assumption and (2) it may lead to a reduction in sample size, compared with the simple pre-post design. The proposed designs and the sample size calculations are illustrated with real data arising from randomized controlled trials.

Effects of a lifestyle modification programme to reduce the number of risk factors for metabolic syndrome: a randomised controlled trial.

OBJECTIVE: To determine the effectiveness of a personal support lifestyle education programme (PSMetS) for reducing risk factors in individuals with metabolic syndrome (MetS). DESIGN: A two-arm randomised controlled trial. SETTING: Companies in metropolitan Tokyo, Japan. SUBJECTS: Male workers with diagnosed MetS or a high risk for MetS according to the Counselling Guidance Program, Japan (n 193). RESULTS: The reduction in the number of risk factors for MetS (as defined according to the criteria published by the Japanese Ministry of Health, Labor and Welfare in April 2007 (MHLW-MetS)) in the PSMetS group was not significantly different from that in the usual care group by van Elteren's test (baseline-adjusted P=0·075) for intention-to-treat (ITT), while it was significant (baseline-adjusted P=0·038) for per-protocol set (PPS). The proportion of MHLW-MetS was significantly different between groups by van Elteren's test (baseline-adjusted P=0·031). Two components of MHLW-MetS showed significant reductions in the PSMetS group: waist circumference (baseline-adjusted P=0·001) and BMI (baseline-adjusted P=0·002). PPS and ITT analyses showed similar results. CONCLUSIONS: For male workers with MHLW-MetS or a high risk of MHLW-MetS, PSMetS reduced the number of risk factors for MHLW-MetS.

Power and sample size for the S:T repeated measures design combined with a linear mixed-effects model allowing for missing data.

Tango (Biostatistics 2016) proposed a new repeated measures design called the S:T repeated measures design, combined with generalized linear mixed-effects models and sample size calculations for a test of the average treatment effect that depend not only on the number of subjects but on the number of repeated measures before and after randomization per subject used for analysis. The main advantages of the proposed design combined with the generalized linear mixed-effects models are (1) it can easily handle missing data by applying the likelihood-based ignorable analyses under the missing at random assumption and (2) it may lead to a reduction in sample size compared with the simple pre-post design. In this article, we present formulas for calculating power and sample sizes for a test of the average treatment effect allowing for missing data within the framework of the S:T repeated measures design with a continuous response variable combined with a linear mixed-effects model. Examples are provided to illustrate the use of these formulas.

Statistical inference for noninferiority of difference in proportions of clustered matched-pair data from multiple raters.

In clinical investigations of diagnostic procedures to indicate noninferiority, efficacy is generally evaluated on the basis of results from independent multiple raters. For each subject, if two diagnostic procedures are performed and some units are evaluated, the difference in proportions for matched-pair data is correlated between the two diagnostic procedures and within the subject, i.e. the data are clustered. In this article, we propose a noninferiority test to infer the difference in the correlated proportions of clustered data between the two diagnostic procedures. The proposed noninferiority test was validated in a Monte Carlo simulation study. Empirical sizes of the noninferiority test were close to the nominal level. The proposed test is illustrated on data of aneurysm diagnostic procedures for patients with acute subarachnoid hemorrhage.

Chronological, geographical, and seasonal trends of human cases of avian influenza A (H5N1) in Vietnam, 2003-2014: a spatial analysis.

BACKGROUND: Human cases of highly pathogenic avian influenza A (H5N1) virus infection continue to occur in Southeast Asia. The objective of this study was to identify when and where human H5N1 cases have occurred in Vietnam and how the situation has changed from the beginning of the H5N1 outbreaks in 2003 through 2014, to assist with implementing methods of targeted disease management. METHODS: We assessed the disease clustering and seasonal variation of human H5N1 cases in Vietnam to evaluate the geographical and monthly timing trends. The clustering of H5N1 cases and associated mortality were examined over three time periods: the outbreak period (2003-2005), the post-outbreak (2006-2009), and the recent period (2010-2014) using the flexibly shaped space-time scan statistic. The most likely cases to co-cluster and the elevated risks for incidence and mortality were assessed via calculation of the relative risk (RR). The H5N1 case seasonal variation was analysed as the cyclic trend in incidence data using Roger's statistical test. RESULTS: Between 2003 and 2005, H5N1 cases (RR: 2.15, p = 0.001) and mortality (RR: 2.49, p = 0.021) were significantly clustered in northern Vietnam. After 2010, H5N1 cases tended to occur on the border with Cambodia in the south, while H5N1 mortality clustered significantly in the Mekong delta area (RR: 6.62, p = 0.002). A significant seasonal variation was observed (p < 0.001), with a higher incidence of morbidity in December through April. CONCLUSIONS: These findings indicate that clinical preparedness for H5N1 in Vietnam needs to be strengthened in southern Vietnam in December-April.

[The association between subjective symptoms and lifestyle habits among junior high school students a cross-sectional survey in Kumamoto, Japan].

OBJECTIVES: This study aimed to examine the association between subjective symptoms and lifestyle habits among junior high school students by using a cross-sectional survey. METHODS: The survey was conducted during May-November 2012. The study subjects were 1229 adolescents (527 boys and 702 girls, age 12-13 years) from 10 junior high schools in Kumamoto Prefecture, Japan. Data from 1182 students (500 boys and 682 girls; response rate 96.2%) were used for the analyses. School nurses measured students' body weights and heights. A self-administered questionnaire examining dietary intake (FFQW82), subjective symptoms (12 items), lifestyle habits (18 items), and diet- and health-related topics (9 items) was used. The 4 categories of each of the 12 subjective symptoms were classified into dichotomous variables (1=always or sometimes; 0=occasionally or never). The subjective symptom score was calculated as a total score by summing up the dichotomous variables for the 12 subjective symptoms. Associations were examined using a chi-square test, Student's t-test, Wilcoxon rank sum test, and a stepwise regression model. The structure of factors was examined by factor analysis (varimax rotation) and associations among the question items were examined by principal component analysis. A significance level of 5% (two-sided) was applied and SAS ver. 9.3 software was used for the analyses. RESULTS: Students' body weights and heights were mostly at or near national averages. The ratio of energy intake at breakfast, lunch, and dinner for the 1-day total energy intake (kcal) was respectively 2:3:4, indicating decreased energy intake at breakfast. The percent energy (%E) from fat of the 1-day total energy intake was 29%E for boys and 30%E for girls. Using regression models, we found that the following lifestyle factors were significantly related to fewer subjective symptoms: "balanced diet," and "sleeping 6 hours or more per day" were for boys and girls, "regularly eating three meals a day," "strong appetite," and "having relaxation time" for girls. However, the following factors were significantly related to more subjective symptoms: "eating hurriedly," and "2 hours or more of watching television or playing video games" were for boys and girls, "cooking meals or sweets" for boys, "eating snacks and nighttime meals," and "eating dinner after 9 p.m.," and "preparing bento (boxed lunches)" for girls. Dietary intake was not significantly related to subjective symptoms. CONCLUSION: Findings from this study suggest that subjective symptoms are associated with lifestyle habits among junior high school students.

Effectiveness of psychoeducational support on quality of life in early-stage breast cancer patients: a systematic review and meta-analysis of randomized controlled trials.

PURPOSE: Most breast cancer patients receive psychosocial support interventions. However, the effectiveness of these interventions has not yet been clarified. Quality of life (QOL) was an important construct that should be considered when assessing these interventions. The purpose was to evaluate the effectiveness of psychosocial and especially psychoeducational support interventions for early-stage breast cancer patients since the follow-up was bound up to 6 months after finishing the intervention. METHODS: We conducted a systematic review and meta-analysis to identify randomized controlled trials with early-stage breast cancer patients receiving psychosocial (psychoeducational and other) support in which QOL was measured as a treatment outcome. We compared mean differences at less than 6 months post-intervention with a control group. The primary outcome was Global Health Status/QOL scale (Global QOL), and secondary outcomes were the subscales of QOL. RESULTS: No significant effect was observed for Global QOL; however, individuals receiving psychosocial support scored higher on the Breast Cancer Symptoms subscale. For psychoeducational support in the psychosocial support, significant effect was observed on the Emotional subscale. CONCLUSIONS: Our analysis strengthens the evidence of the effectiveness of psychosocial support in improving breast cancer symptoms and psychoeducational support in improving emotional well-being within 6 months post-intervention.

Three-arm noninferiority trials with a prespecified margin for inference of the difference in the proportions of binary endpoints.

The design of a three-arm trial including the experimental treatment, an active reference treatment, and a placebo is recommended as a useful approach to the assessment of noninferiority of the experimental treatment. The inclusion of the placebo arm enables the assessment of assay sensitivity and internal validation, in addition to testing the noninferiority of the experimental treatment to the reference. Generally, the acceptable noninferiority margin Δ has been defined as the maximum clinically irrelevant difference between treatments in many two-arm noninferiority trials. However, many articles have considered a design in which the noninferiority margin Δ is relatively defined as a prespecified fraction f of the unknown effect size of the reference treatment. Therefore, these methods cannot be applied to cases where the margin is defined as a prespecified difference between treatments. In this article, we propose score-based statistical procedures for a three-arm noninferiority trial with a prespecified margin Δ for inference of the difference in the proportions of binary endpoints. In addition, we derive the approximate sample size and optimal allocation to minimize the total sample size and that of the placebo arm. A randomized controlled trial on major depressive disorder based on the difference in the proportions of remission is used to demonstrate our proposed method.

Effects of lifestyle education program for type 2 diabetes patients in clinics: a cluster randomized controlled trial.

BACKGROUND: The prevalence of type 2 diabetes is rising worldwide, as has been the global mean fasting plasma glucose level. This study aimed to evaluate the effectiveness of a structured individual-based lifestyle education (SILE) program to reduce the hemoglobin A1c (HbA1c) level in type 2 diabetes patients delivered by registered dietitians in primary care clinical settings. METHODS: This was a 6-month prospective cluster randomized controlled trial in a primary care setting with randomization at the practice level. Twenty general practitioners in 20 clinics in Kanagawa prefecture, Japan, were involved. 193 adults (51% men, mean age 61.3 years) with type 2 diabetes and HbA1c ≥6.5% who received treatment in medical clinics were the participants. A SILE program was implemented through 4 sessions with trained registered dietitians during the 6-month study period. Results were compared with those of a control group who received usual care. The primary endpoint was the change in HbA1c levels at 6 months from baseline. Secondary endpoints were the changes at 6 months from baseline in fasting plasma glucose, lipid profile, blood pressure, BMI, energy, and nutrient intakes (whole day and each meal). Intention-to-treat analysis was conducted. Mixed-effects linear models were used to examine the effects of the treatment. RESULTS: The mean change at 6 months from baseline in HbA1c was a 0.7% decrease in the intervention group (n = 100) and a 0.2% decrease in the control group (n = 93) (difference -0.5%, 95%CI: -0.2% to -0.8%, p = 0.004). After adjusting for baseline values and other factors, the difference was still significant (p = 0.003 ~ 0.011). The intervention group had a significantly greater decrease in mean energy intake at dinner compared with the control group and a greater increase in mean vegetable intake for the whole day, breakfast, and lunch as shown in crude and adjusted models. A tendency toward improvement was observed in the other secondary endpoints but the improvement was not statistically significant. These results were confirmed by several sensitivity analyses. CONCLUSIONS: The SILE program that was provided in primary care settings for patients with type 2 diabetes resulted in greater improvement in HbA1c levels than usual diabetes care and education. TRIAL REGISTRATION: http://UMIN000004049.

Effects of lifestyle modification on metabolic syndrome: a systematic review and meta-analysis.

BACKGROUND: To evaluate the effect of lifestyle modifications on metabolic syndrome (MetS) as assessed by its resolution and improved values for its components. METHODS: This was a systematic review and meta-analysis. Searches were performed of MEDLINE and the Cochrane Database from January 1966 to October 2011 to identify randomized controlled trials (RCTs) related to the study objective. The included studies were RCTs restricted to the English language, with a follow-up period of 6 months or more, which reported overall resolution of MetS or values of MetS components (fasting blood glucose, waist circumference, high-density lipoprotein (HDL), triglycerides, and systolic and diastolic blood pressure (SBP, DBP)). Two investigators independently assessed study eligibility. The effect sizes were the relative proportion of patients with resolved MetS and mean differences in MetS component values from baseline to 1-year follow-up in a lifestyle-modification intervention (LMI) group versus a control (conventional lifestyle education or no treatment) group. Meta-analyses were conducted using a random-effects model. RESULTS: Eleven interventions in eight RCTs were used for the meta-analyses. The relative proportion of patients with resolved MetS in the intervention group was approximately 2.0 (95% CI 1.5 to 2.7) times greater in the intervention group compared with the control group (7 interventions, n = 2.839). LMI (5 interventions, n = 748) significantly reduced mean values for SBP by -6.4 mmHg (95% CI -9.7 to -3.2), DBP by -3.3 mmHg (95% CI -5.2 to -1.4), triglycerides by -12.0 mg/dl (95% CI -22.2 to -1.7), waist circumference by -2.7 cm (95% CI -4.6 to -0.9), and fasting blood glucose by -11.5 mg/dl (95% CI -22.4 to -0.6) (5 interventions), but reductions were not significant for HDL (1.3 mg/dl; 95% CI -0.6 to 3.1). CONCLUSIONS: The LMI was effective in resolving MetS and reducing the severity of related abnormalities (fasting blood glucose, waist circumference, SBP and DBP, and triglycerides) in subjects with MetS.

A flexible spatial scan statistic with a restricted likelihood ratio for detecting disease clusters.

Spatial scan statistics are widely used tools for detection of disease clusters. Especially, the circular spatial scan statistic proposed by Kulldorff (1997) has been utilized in a wide variety of epidemiological studies and disease surveillance. However, as it cannot detect noncircular, irregularly shaped clusters, many authors have proposed different spatial scan statistics, including the elliptic version of Kulldorff's scan statistic. The flexible spatial scan statistic proposed by Tango and Takahashi (2005) has also been used for detecting irregularly shaped clusters. However, this method sets a feasible limitation of a maximum of 30 nearest neighbors for searching candidate clusters because of heavy computational load. In this paper, we show a flexible spatial scan statistic implemented with a restricted likelihood ratio proposed by Tango (2008) to (1) eliminate the limitation of 30 nearest neighbors and (2) to have surprisingly much less computational time than the original flexible spatial scan statistic. As a side effect, it is shown to be able to detect clusters with any shape reasonably well as the relative risk of the cluster becomes large via Monte Carlo simulation. We illustrate the proposed spatial scan statistic with data on mortality from cerebrovascular disease in the Tokyo Metropolitan area, Japan.

A scan statistic to extract causal gene clusters from case-control genome-wide rare CNV data.

BACKGROUND: Several statistical tests have been developed for analyzing genome-wide association data by incorporating gene pathway information in terms of gene sets. Using these methods, hundreds of gene sets are typically tested, and the tested gene sets often overlap. This overlapping greatly increases the probability of generating false positives, and the results obtained are difficult to interpret, particularly when many gene sets show statistical significance. RESULTS: We propose a flexible statistical framework to circumvent these problems. Inspired by spatial scan statistics for detecting clustering of disease occurrence in the field of epidemiology, we developed a scan statistic to extract disease-associated gene clusters from a whole gene pathway. Extracting one or a few significant gene clusters from a global pathway limits the overall false positive probability, which results in increased statistical power, and facilitates the interpretation of test results. In the present study, we applied our method to genome-wide association data for rare copy-number variations, which have been strongly implicated in common diseases. Application of our method to a simulated dataset demonstrated the high accuracy of this method in detecting disease-associated gene clusters in a whole gene pathway. CONCLUSIONS: The scan statistic approach proposed here shows a high level of accuracy in detecting gene clusters in a whole gene pathway. This study has provided a sound statistical framework for analyzing genome-wide rare CNV data by incorporating topological information on the gene pathway.

A space-time scan statistic for detecting emerging outbreaks.

As a major analytical method for outbreak detection, Kulldorff's space-time scan statistic (2001, Journal of the Royal Statistical Society, Series A 164, 61-72) has been implemented in many syndromic surveillance systems. Since, however, it is based on circular windows in space, it has difficulty correctly detecting actual noncircular clusters. Takahashi et al. (2008, International Journal of Health Geographics 7, 14) proposed a flexible space-time scan statistic with the capability of detecting noncircular areas. It seems to us, however, that the detection of the most likely cluster defined in these space-time scan statistics is not the same as the detection of localized emerging disease outbreaks because the former compares the observed number of cases with the conditional expected number of cases. In this article, we propose a new space-time scan statistic which compares the observed number of cases with the unconditional expected number of cases, takes a time-to-time variation of Poisson mean into account, and implements an outbreak model to capture localized emerging disease outbreaks more timely and correctly. The proposed models are illustrated with data from weekly surveillance of the number of absentees in primary schools in Kitakyushu-shi, Japan, 2006.

On the three-arm non-inferiority trial including a placebo with a prespecified margin.

Three-arm trials including the experimental treatment, an active reference treatment and a placebo are recommended in the guidelines of the ICH and EMEA/CPMP as a useful approach to the assessment of assay sensitivity. Generally, the acceptable non-inferiority margin Δ has been defined as the maximum clinically irrelevant difference between treatments in many two-arm non-inferiority trials. However, many recent articles discussing three-arm trials have considered a design with unknown Δ which is the prespecified fraction f of unknown effect size of the reference drug, where the prespecified fraction f is treated as if it were a revised margin. Therefore, these methods cannot be applied to the case where the acceptable non-inferiority margin must be a prespecified difference between treatments. In this paper, we propose a statistical test procedure for three-arm non-inferiority trials with the margin Δ defined as a prespecified difference between treatments under the situation that the primary endpoints are normally distributed with a common, but unknown, variance. In addition, we derive the optimal allocation that minimizes the total sample size. The proposed method is illustrated with data on a randomized controlled trial on major depressive disorder.