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.

Background: Polypharmacy, the use of multiple drugs, is a growing concern in older adults. It has been reported that the prevalence of polypharmacy in elderly patients is higher in Korea than in other countries. The objective of this study was to investigate the prevalence and associated factors of polypharmacy in elderly outpatients who visited a Seoul Medical Center. Methods: We retrospectively reviewed medical records of 12,551 elderly patients aged ≥65 years who visited outpatient clinics in a public hospital in Seoul between January 1, 2018 and December 31, 2018. We defined “polypharmacy” as the use of ≥6 medications per person; “major polypharmacy,” ≥11 medications per person; and “excessive polypharmacy,” ≥21 medications per person. Multivariate logistic regression analysis was performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs) to investigate the risk factors for polypharmacy. Results: Among the elderly outpatients studied, 40.7% had polypharmacy, 11.9% major polypharmacy, and 0.8% excessive polypharmacy. The lowerincome medical aid population is associated with polypharmacy (OR, 1.70; 95% CI, 1.47–1.97). Conclusion We observed a high prevalence of polypharmacy in elderly outpatients, especially the medical aid population, who visited a Korean public hospital. Nationwide vigorous efforts to assess and reduce the prevalence of polypharmacy are urgently required for the Korean older population.

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.
Dataset ; Logistic Models ; Odds Ratio ; Stress Disorders, Post-Traumatic

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.
Dataset ; Logistic Models ; Odds Ratio ; Stress Disorders, Post-Traumatic

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.
Biostatistics ; Cohort Studies ; Cross-Over Studies ; Decision Making ; Observational Study ; Research Design* ; Statistics as Topic ; Uncertainty

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.
Democratic People's Republic of Korea ; Female ; Humans ; Korea ; Logistic Models ; Odds Ratio ; Prevalence ; Surveys and Questionnaires ; Refugees* ; Stress Disorders, Post-Traumatic*

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.
Aged ; Carcinoma in Situ/diagnosis/epidemiology ; Carcinoma, Transitional Cell/*diagnosis/*epidemiology ; Disease-Free Survival ; Female ; Humans ; Male ; Multivariate Analysis ; *Nomograms ; Predictive Value of Tests ; Prognosis ; Proportional Hazards Models ; Recurrence ; Regression Analysis ; Reproducibility of Results ; Urinary Bladder Neoplasms/*diagnosis/*epidemiology

Background: Mycobacterium avium subspecies paratuberculosis (MAP) causes a chronic and progressive granulomatous enteritis and economic losses in dairy cattle in subclinical stages.Subclinical infection in cattle can be detected using serum MAP antibody enzyme-linked immunosorbent assay (ELISA) and fecal polymerase chain reaction (PCR) tests. Objectives: To investigate the differences in blood parameters, according to the detection of MAP using serum antibody ELISA and fecal PCR tests. Methods: We divided 33 subclinically infected adult cattle into three groups: seronegative and fecal-positive (SNFP, n = 5), seropositive and fecal-negative (SPFN, n = 10), and seropositive and fecal-positive (SPFP, n = 18). Hematological and serum biochemical analyses were performed. Results: Although the cows were clinically healthy without any manifestations, the SNFP and SPFP groups had higher platelet counts, mean platelet volumes, plateletcrit, lactate dehydrogenase levels, lactate levels, and calcium levels but lower mean corpuscular volume concentration than the SPFN group (p < 0.017). The red blood cell count, hematocrit, monocyte count, glucose level, and calprotectin level were different according to the detection method (p < 0.05). The SNFP and SPFP groups had higher red blood cell counts, hematocrit and calprotectin levels, but lower monocyte counts and glucose levels than the SPFN group, although there were no significant differences (p > 0.017). Conclusions The cows with fecal-positive MAP status had different blood parameters from those with fecal-negative MAP status, although they were subclinically infected. These findings provide new insights into understanding the mechanism of MAP infection in subclinically infected cattle.

PURPOSE: Primary prostate sarcomas are a rare type of prostate cancer that account for less than 0.1% of primary prostate malignancies. We analyzed the experience of a single institution with prostate sarcoma over 20 years. MATERIALS AND METHODS: In this case series, the medical records of 20 patients with prostate sarcoma were reviewed from June 1990 to December 2013 to identify symptoms at presentation, diagnostic procedures, metastasis presence and development, histologic subtype, French Federation Nationale des Centres de Lutte Contre le Cancer grade, primary tumor grade and size, and treatment sequence, including surgery and preoperative and postoperative therapies. The average follow-up period was 23.6 months (range, 1.4-83.3 months). RESULTS: The average patient age was 46.3+/-16.7 years. Most patients presented with lower urinary tract symptoms (55%). The histologic subtype was spindle cell sarcoma in five patients (25%), rhabdomyosarcoma in three patients (15%), synovial sarcoma in three patients (15%), liposarcoma in three patients (15%), stromal sarcoma in three patients (15%), and Ewing sarcoma, nerve sheath tumor, and adenocarcinoma with sarcomatoid component (5% each). For liposarcoma, two patients were alive after complete surgical resection and had a good prognosis. At last follow-up, 15 patients had died of sarcoma. The 2- and 5-year actuarial survival rates for all 20 patients were 53% and 12%, respectively (medial survival, 20 months). CONCLUSIONS: The disease-specific survival rate of prostate sarcoma is poor. However, sarcoma that is detected early shows a better result with proper management including surgical intervention with radio-chemotherapy than with no treatment. Early diagnosis and complete surgical resection offer patients the best curative chance.
Adult ; Aged ; Humans ; Kaplan-Meier Estimate ; Male ; Middle Aged ; Prognosis ; Prostatectomy/methods ; Prostatic Neoplasms/diagnosis/*pathology/therapy ; Retrospective Studies ; Sarcoma/diagnosis/*pathology/secondary/therapy ; Treatment Outcome ; Young Adult