• The Korean Journal of Applied Statistics
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• v.26 no.4
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• pp.581-594
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• 2013

A group sequential design can end a clinical trial early if a confirmed efficacy or a futility of study medication is found during clinical trials. Adaptation can adjust the design of clinical trials based on accumulated data. The key to this methodology is considered to control the overall type 1 error rate while maintaining the integrity of clinical trials. The estimation would be more complex and the sample size calculation will be more difficult if the clinical trials have repeated measurement data. Lee et al. (2002) suggested a repeated observation case by using the independent increments properties of the interim test statistics and investigated the properties of the proposed confidence interval based on the stage-wise ordering. This study extend Lee et al. (2002) to adaptive group sequential design. We suggest test statistics for the adaptation as redesigning the second stage of clinical trials and induce the stage-wise confidence interval of parameter of interests. The simulation will help to confirm the suggested method.

• Journal of the Korean Data and Information Science Society
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• v.15 no.4
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• pp.973-980
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• 2004

Phase I clinical trials are often pharmacologically oriented and usually attempt to find the best dose of drug to employ. However, other purposes like determination of sizes and types of side effects and toxicity and organ system involved are equally important. Estimation of treatment effects or side effects is usually ignored since it is usually based on too small sample, even though Phase II clinical trials would be designed based on the Phase I studies. Statistical methods for constructing the approximate confidence interval for population median in case of small sample are considered and an improved method is proposed. The proposed estimator is compared with current methods through simulation studies.

• The Korean Journal of Applied Statistics
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• v.25 no.1
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• pp.125-138
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• 2012

Recent assessments of the biosimilarity of biologic products have received considerable global attention. A clinical trial should be conducted to assess the biosimilarity of a biosimilar product and a innovator biological product. In this paper we will describe several methods for the implementation of clinical trials and statistical analysis, a real international case and related international guidelines.

• Radiation Oncology Journal
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• v.9 no.2
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• pp.361-367
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• 1991

This paper on the status of radiotherapy machine and related facilities, clinical activities and radiation safety management is based on the statistical data which collected through the questionaire sent to a total number of 37 hospitals holding the Department of Therapeutic Radiology in Korea. It is true that the quality of instruments installed in the hospitals equal to that of the instrument in the industrialized conuntries' hospitals. But the clinical specialists and physicists who can utilize such instruments fall short of the required number, which might be a main factor in hindering the development of therapeutic radiology of Korea. According to the nation-wide cancer statistics, we can estimate the number of annual cancer patients as 45,000 to 50,000. As a result, probably around 25,000 should receive radiation therapy. It is expected that in the future the number of cancer patients to whom radiation therapy should be applied will become twice as much as that of the cancer patients in 1990. Given such a condition, the problem facing the Korean Society of Therapeutic Radiology now is to increase the number of medical doctors and physicists.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.18 no.3
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• pp.300-309
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• 2011

Purpose: The purpose of this study was to investigate facilitators of evidence-based practice (EBP) in Clinical Nurses. Method: The instruments used in study were the EBP facilitator scale developed by Nagy et al. and a questionnaire on EBP-related characteristics. Data were collected from 230 nurses at a tertiary hospital and analyzed by descriptive statistics. Results: Compared to previous studies, this study showed that nurses had more experience related to research courses and clinical research. However, the proportion of nurses who reviewed relevant articles still remained low. The respondents had positive perceptions of organizational supports for EBP and belief in the value of EBP, whereas they had negative perceptions of skills in locating and evaluating research reports, knowledge of research terms and statistics, and time to devote to EBP. Conclusion: The findings of the study provide important basic data to develop and implement an EBP programs. In future, EBP programs should cover the nurses' skills to search and review research literature as well as their knowledge of research terms and statistics. Furthermore, nurses will require help to ensure that there is adequate time to devote to EBP.

• Communications for Statistical Applications and Methods
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• v.24 no.6
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• pp.561-581
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• 2017

Bayesian statistics can play a key role in the design and analysis of clinical trials and this has been demonstrated for medical device trials. By 1995 Bayesian statistics had been well developed and the revolution in computing powers and Markov chain Monte Carlo development made calculation of posterior distributions within computational reach. The Food and Drug Administration (FDA) initiative of Bayesian statistics in medical device clinical trials, which began almost 20 years ago, is reviewed in detail along with some of the key decisions that were made along the way. Both Bayesian hierarchical modeling using data from previous studies and Bayesian adaptive designs, usually with a non-informative prior, are discussed. The leveraging of prior study data has been accomplished through Bayesian hierarchical modeling. An enormous advantage of Bayesian adaptive designs is achieved when it is accompanied by modeling of the primary endpoint to produce the predictive posterior distribution. Simulations are crucial to providing the operating characteristics of the Bayesian design, especially for a complex adaptive design. The 2010 FDA Bayesian guidance for medical device trials addressed both approaches as well as exchangeability, Type I error, and sample size. Treatment response adaptive randomization using the famous extracorporeal membrane oxygenation example is discussed. An interesting real example of a Bayesian analysis using a failed trial with an interesting subgroup as prior information is presented. The implications of the likelihood principle are considered. A recent exciting area using Bayesian hierarchical modeling has been the pediatric extrapolation using adult data in clinical trials. Historical control information from previous trials is an underused area that lends itself easily to Bayesian methods. The future including recent trends, decision theoretic trials, Bayesian benefit-risk, virtual patients, and the appalling lack of penetration of Bayesian clinical trials in the medical literature are discussed.

• 대한예방의학회:학술대회논문집
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• 1994.02b
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• pp.129-136
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• 1994

A model was developed for a simple clinical trial in which graders had defined probabilities of misclassifying pathologic material to disease present or absent. The authors compared Kappa between graders, and efficiency and bias in the clinical trial in the presence of misclassification. Though related to bias and efficiency, Kappa did not predict these two statistics well. These results pertain generally to evaluation of systems for encoding medical information, and the relevance of Kappa in determining whether such systems are ready for use in comparative studies. The authors conclude that, by itself, Kappa is not informative Enough to evaluate the appropriateness of a grading scheme for comparative studies. Additional, and perhaps difficult, questions must be addressed for such evaluation.

• Journal of Digestive Cancer Research
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• v.10 no.2
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• pp.99-106
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• 2022

Clinical research ultimately aimed to promptly diagnose and prevent diseases through precise biomarker development. Finding the optimal cut-off point of a regularly measured biomarker can help its interpretation and ultimately help in disease investigation and diagnosis, more specifically in determining the presence of diseases. Therefore, this study aimed to use the characteristics of outcome variables in clinical research to explain how to determine the optimal cutoff point. The outcome variables can be divided into dichotomous, ordinal, and survival types. The optimal cut-off point can be determined by finding points that maximize the Youden index, extended Youden index, and log-rank statistics. This study will enable clinical researchers to accurately determine the optimal cut-off points for regularly measured biomarkers, thereby enabling prompt disease diagnosis for effective treatment.

• Journal of Technologic Dentistry
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• v.45 no.4
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• pp.95-101
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• 2023

Purpose: This study examines the clinical practice satisfaction and major satisfaction of dental technology students who have experienced clinical practice to identify whether there is an effect on employment intention of satisfaction level as a basis for increasing the employment rate of dental technicians. Methods: A survey was distributed among 150 dental technology students, and the data were analyzed using descriptive statistics and frequency and correlation analyses. Finally, multiple regression analysis was used to verify the research hypotheses. All statistical analyses were carried out using IBM SPSS Statistics ver. 27.0 (IBM). Results: The students exhibited high levels of satisfaction with their clinical practice (4.20) and dental technology major (4.07). Further analysis showed a positive correlation between intention to work in dental laboratories and satisfaction with a dental technology major (practice; r=0.437, p<0.05); clinical practice organization (r=0.682, p<0.05); and satisfaction with the clinical practice institution (r=0.650, p<0.05). Statistically significant positive associations (p<0.05) were also observed between clinical practice form and environment, satisfaction with dental technology major, and school region (i.e., metropolitan area). Conclusion: The findings of this study suggest that high levels of satisfaction with clinical practice and dental technology major can contribute to increased employment rates among dental technicians by promoting their intention to work in the related industry.

• Journal of Korean Clinical Nursing Research
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• v.26 no.2
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• pp.164-174
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• 2020

Purpose: This study was to investigate the relationships among patient safety culture, safety competence and safety nursing activity among nurses in anesthetic and recovery rooms, and to identify the factors contributing to safety nursing activity. Methods: A descriptive correlational study was conducted. Participants were 156 nurses from 13 hospitals. Data were collected from February 11 to March 15th, 2019, and analyzed using descriptive statistics, t-test, Mann-Whitney U test, one-way ANOVA, Pearson's correlation and multiple regression analysis with SPSS statistics 24.0 Program. Results: Safety nursing activity was significantly different in relation to nurses' level of education, position at work, clinical career, clinical career at anesthetic and recovery rooms, and work experience in patient safety. Safety nursing activity demonstrated a significant positive correlation with patient safety culture and patient safety competence. Factors contributing to safety nursing activity were patient safety knowledge, skill and attitude, clinical career, clinical career at anesthetic and recovery rooms, and the patient safety improvement system which explained 57.0% of total variance of safety nursing activity. Conclusion: To improve safety nursing activities at anesthetic and recovery rooms, it is necessary to develop patient safety programs with enhanced knowledge, skill and attitude to take patient safety as a top priority.