• 제목/요약/키워드: Clinical statistics

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반복측정자료를 가지는 적응적 집단축차검정에서의 신뢰구간 추정 (Confidence Bounds following Adaptive Group Sequential Tests with Repeated Measures in Clinical Trials)

  • 조숙정;이재원
    • 응용통계연구
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    • 제26권4호
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    • pp.581-594
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    • 2013
  • 집단축차설계법은 중간분석을 실시하여 임상시험용 의약품의 유효성 또는 무용성이 조기에 발견되면 임상시험을 조기에 종료할 수 있는 시험설계법이다. 적응적 설계법은 중간분석 결과를 이용하여 시험설계를 변경하거나, 확률적으로 독립인 두개의 임상시험 결과를 결합하는 등 다양한 적응법으로 임상시험의 설계를 수정할 수 있는 시험설계법이다. 집단축차설계법과 적응적 설계법에서 주요하게 고려할 점은, 시험 전체적으로 제1종 오류를 적절히 분배하고 통제하여 임상시험 전체의 일관성을 유지하도록 하는 것이다. 반복측정자료 또는 경시적자료의 통계적 모형이 고려되는 경우에는 통계적 추론이 더욱 복잡하고 어려워진다. Lee 등 (2002)에서는 반복측정치를 가지는 임상시험에서 집단축차설계에서 미리 정한 기준에 의하여 임상시험이 종료된 후, 독립증분과 단계적 순서관계를 고려한 신뢰구간 추정법을 제안한 바 있다. 본 연구는 Lee 등 (2002)를 적응적 설계로 확장하였다. 적응법을 실시한 전과 후의 임상시험을 확률적으로 독립인 관계로 정의하는 검정통계량을 유도하여 적응적 집단축차검정법이 가능하게 하였다. 또한, 임상시험이 종료된 후 단계적 순서관계를 고려한 신뢰구간 추정법을 제안하였으며, 모의실험을 통하여 그 안정성을 확인하였다.

An Improved Method for Constructing Confidence Interval of Median : Small Sample Case

  • Park, Sang-Gue;Choi, Ji-Yun
    • Journal of the Korean Data and Information Science Society
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    • 제15권4호
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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.

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바이오시밀러 개발에 필요한 통계방법들에 대한 고찰 (Statistical Consideration of the Development of Biosimilar Products)

  • 강승호;남주선
    • 응용통계연구
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    • 제25권1호
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    • pp.125-138
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    • 2012
  • 최근 들어 바이오시밀러에 대한 국내외 관심이 매우 증가하고 있다. 바이오시밀러가 오리지널 생물의약품과 효능과 안전성이 유사함을 보이기 위해서는 최종적으로 임상시험을 수행하여야 한다. 본 논문에서는 이러한 임상시험의 수행과 통계적 분석에 필요한 여러 방법들과 외국의 사례 그리고 관련된 가이드라인들을 살펴볼 것이다.

방사선 치료 전국 통계 -1990- (Annual Statistics of Radiation Therapy -1990-)

  • 대한치료방사선과학회
    • Radiation Oncology Journal
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    • 제9권2호
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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.

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일개 상급종합병원 간호사의 근거기반실무(Evidence-Based Practice) 촉진요인에 대한 인식 (Nurses' Perceptions regarding Evidence-Based Practice Facilitators in a Tertiary Hospital)

  • 조명숙;송미라;차선경
    • 기본간호학회지
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    • 제18권3호
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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.

임상실습을 경험한 치기공(학)과 학생들의 임상실습 만족도, 전공 만족도가 취업 의향에 미치는 영향에 관한 연구 (Study on the effect of clinical practice satisfaction and major satisfaction on employment intention of students in the department of dental technology who experienced clinical practice)

  • 정혜은;이현식
    • 대한치과기공학회지
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    • 제45권4호
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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.

Acceptable Values of Kappa for Comparison of Two Groups

  • Seigel Daniel G.;Podgor Marvin J.;Remaley Nancy A.
    • 대한예방의학회:학술대회논문집
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    • 대한예방의학회 1994년도 교수 연수회(역학)
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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.

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R을 이용한 결과 변수에 따른 최적의 Cut-off Point 결정 (Determining the Optimal Cut-off Point According to the Outcome Variables Using R)

  • 양주연;이혜선
    • Journal of Digestive Cancer Research
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    • 제10권2호
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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.

Bayesian methods in clinical trials with applications to medical devices

  • Campbell, Gregory
    • Communications for Statistical Applications and Methods
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    • 제24권6호
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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.

마취·회복실 간호사의 환자안전문화와 환자안전역량이 안전간호활동에 미치는 영향 (Effect of Patient Safety Culture and Patient Safety Competence on Safety Nursing Activity among Nurses working in Anesthetic and Recovery Rooms)

  • 김진주;정향미
    • 임상간호연구
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    • 제26권2호
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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.