Nomograms for Prediction of Disease Recurrence in Patients with Primary Ta, T1 Transitional Cell Carcinoma of the Bladder

We developed nomograms to predict disease recurrence in patients with Ta, T1 transitional cell carcinoma of the bladder. Thirty-eight training hospitals participated in this retrospective multicenter study. Between 1998 and 2002, a total of 1,587 patients with newly diagnosed non-muscle invasive bladder cancer were enrolled in this study. Patients with prior histories of bladder cancer, non-transitional cell carcinoma, or a follow-up duration of less than 12 months were excluded. With univariate and multivariate logistic regression analyses, we constructed nomograms to predict disease recurrence, and internal validation was performed using statistical techniques. Three-year and five-year recurrence-free rates were 64.3% and 55.3%, respectively. Multivariate analysis revealed that age (hazard ratio [HR]=1.437, p<0.001), tumor size (HR=1.328, p=0.001), multiplicity (HR=1.505, p<0.001), tumor grade (HR=1.347, p=0.007), concomitant carcinoma in situ (HR=1.611, p=0.007), and intravesical therapy (HR=0.681, p<0.001) were independent predictors for disease recurrence. Based on these prognostic factors, nomograms for the prediction of disease recurrence were developed. These nomograms can be used to predict the probability of disease recurrence in patients with newly diagnosed Ta, T1 transitional cell carcinoma of the bladder. They may be useful for patient counseling, clinical trial design, and patient follow-up planning.

Clinical Research Design and Biostatistical Methods / 대한비뇨기과학회지

Purpose: To proceed effectively with clinical research requires an understanding of the fundamental principles of study design and biostatistical methods. In this article, we identified and summarized basic clinical research designs and some of the key biostatistical methods that have been commonly used in clinical research. Materials and Methods: In an observational study, cross-sectional, case- control and Cohort designs were illustrated and compared. In a clinical trial study, parallel group design and cross-over designs were described according to their characteristics. Also, the biostatistical methods for their usages classified and summarized. Results: Understanding and evaluating research design are part of the process researchers must use to determine both the quality and usefulness of their research. Adequate applications to biostatistical methods are need; i.e., descriptive statistics, Student's t-test, ANOVA, nonparametrics, categorical data analysis, correlation and regression, and survival analysis. Conclusions: Research findings are used by clinical researcher to guide their practice and reduce their uncertainty in clinical decision making. However, to understand how to interpret research results, it is important to be able to understand basic statistical concepts and types of study design. Clinicians should also appropriately choose the biostatistical methods to suit their purposes.

Regression Methods for Overdispersed Dichotomous Response Data / 신경정신의학

In neuropsychiatrical research, many problems of statistical inference concern the relationship between the PTSD and traumatic experiences. The logistic model is widely used for modeling a relationship between the covariate and the magnitude of the PTSD. A common complication in the logistic model for dichotomous response data is overdispersion. In this study, two different methods for analyzing dichotomous response data are illustrated and compared. One method is the logistic regression approach, where the numbers of dichotomous responses are predicted by the logistic function of covariates. The other one is the overdispersed logistic regression approach, where the overdispersion is measured by a scale parameter in the variance function of the dichotomous response. In dichotomous response model, when reponses are overdispersed, the overdispersed logistic regression produces more appropriate standard errors of the regression coefficients and the 95% confidence intervals of odds ratios. Therefore, in neuropsychiatrical research, it is recommended to examine the overdispersion problems for their data set before applying the logistic regression model.

Regression Methods for Overdispersed Dichotomous Response Data / 신경정신의학

In neuropsychiatrical research, many problems of statistical inference concern the relationship between the PTSD and traumatic experiences. The logistic model is widely used for modeling a relationship between the covariate and the magnitude of the PTSD. A common complication in the logistic model for dichotomous response data is overdispersion. In this study, two different methods for analyzing dichotomous response data are illustrated and compared. One method is the logistic regression approach, where the numbers of dichotomous responses are predicted by the logistic function of covariates. The other one is the overdispersed logistic regression approach, where the overdispersion is measured by a scale parameter in the variance function of the dichotomous response. In dichotomous response model, when reponses are overdispersed, the overdispersed logistic regression produces more appropriate standard errors of the regression coefficients and the 95% confidence intervals of odds ratios. Therefore, in neuropsychiatrical research, it is recommended to examine the overdispersion problems for their data set before applying the logistic regression model.

Relationship between Traumatic Events and Posttraumatic Stress Disorder among North Korean Refugees / 신경정신의학

OBJECTIVES: The purpose of this study is to find out the relationship between the traumatic experiences and the prevalence of PTSD among North Korean refugees in South Korea. METHODS: Two hundred North Korean refugees in South Korea were voluntarily participated. Researchers conducted face-to-face interviews and assisted defectors in performing a self-report assessment of this survey. The study questionnaire consisted of demographic characteristics, Traumatic Experiences Scale for North Korean Defectors, and PTSD part of the Structured Clinical Interview for DSM-III-R Korean version. RESULTS: Prevalence rate of PTSD in defectors was 29.5%, with a higher rate for women. In factor analysis, the 25 items of traumatic events experienced in North Korea were divided into three factors: physical trauma, political-ideological trauma, and family-related trauma. In addition, the 19 items of traumatic events during defection were grouped into four factors: physical trauma, discovery and capture-related trauma, family-related trauma, and betrayal-related trauma. In multi-factorial logistic regression analysis, family-related trauma in North Korea had a significant odds ratio. CONCLUSION: Family-related trauma experienced in North Korea is related to the prevalence of PTSD among North Korean refugees in South Korea.

Use and Misuse of Biostatistical Analysis / 신경정신의학

OBJECTIVES: This study summarizes statistical methods which have been used in the 153 original articles of the Journal of Korean Neuropsychiatric Association published in 2002 and 2003. METHODS: It deals with the appropriate statistical methods and some common errors for researchers. RESULTS: Among the original articles, 41 statistical uses contain errors. Many cases of errors are found in the chi2-test and the t-test. This study detects uses of statistical errors and suggests right statistical methods. CONCLUSION: In order to improve the validity of original articles published in the Journal of Korean Neuropsychiatric Association, a more clearly stated statistical uses and closer editorial attention to statistical methods are needed.