• Journal of Digestive Cancer Reports
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• 제8권2호
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• pp.97-101
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• 2020

Metformin is a widely used first-line anti-diabetic drug worldwide. Epidemiologic studies using the large population-based cohort database have shown the association between metformin uses and reduced risk of various type cancers including gastric cancer. In the gastric cancer prevention, metformin use was associated with the significant reduction of gastric cancer risk, especially for long-term metformin users. However, there is no well-designed randomized controlled clinical trial investigating the effect of metformin as a chemopreventive drug for gastric cancer. Therefore, further well-designed clinical trials will be needed to implement metformin for chemoprevention of gastric cancer.

• 생물정신의학
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• 제19권4호
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• pp.172-178
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• 2012

Data from clinical studies are needed for psychiatrists to make quick and scientific decisions based on the best available evidence in clinical settings. Various methods of clinical studies are useful for clinicians to have reliable answers to unmet clinical needs. Although randomized controlled trials may provide high-quality information about major issues, well-designed, naturalistic and observational studies often give us unbiased explanation for real-world phenomena. Adequate selection of clinical variables and appropriate number of participants are key factors of well-designed clinical studies. Statistical methods can add an extra dimension to initial design of clinical studies. Given ethical issues in clinical studies on psychiatric disorders, special regards should be paid to participants' ability to provide informed consents. New strategies of clinical studies need to be developed to meet clinical needs and protect the rights and welfare of study participants.

• 대한치과교정학회지
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• 제35권5호
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• pp.381-387
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• 2005

본 연구의 목적은 교정치료 초기에 사용되는 스테인레스스틸, 다가닥철선. 초탄성 NiTi, 열활동성 NiTi재료로 이루어진 총 4가지 호선의 초기 치료효과를 비교하기 위하여 시행되었으며, 실험의 설계는 전향적 임상 실험(prospective randomized clinical trial)으로서 브라질 리오데자네이로 주립 치과대대학에 내원한 45명의 고정식 교정장치 환자를 대상으로 시행되었다. 각 호선의 재료는 환자의 치열에 무작위로 배당되었는데 스테인레스스틸은 20명, 다가닥철선은 22명, 초탄성 NiTi는 22명, 열활동성 NiTi는 20명에게 할당되었고. 8주 후에 모형을 다시 제작한 후 3차원 디지털영상 장비를 이용하여 모형의 치관에 설정된 해부학적 지표의 변화를 측정하였는데 치료전 및 치료후 치열불규칙지수(Dental Irregularity Index)의 차이로 초기 교정치료 효과를 비교하였다. 분산분석을 시행하여 불규칙지수의 변화를 살펴본 결과 호선의 재료에 따른 초기 치료 효과는 유의한 차이가 나타나지 않았다

• 생물정신의학
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• 제19권4호
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• pp.159-163
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• 2012

An appropriate research design for hypotheses and purposes leads to a good quality of research results. In this review article, we summarized the types of research methods and described the characteristics of clinical trials. Research designs are categorized into observational studies and experimental ones, depending on data collecting methods. In an observational study, there are cross-sectional, cohort and case-control studies. Parallel groups design and crossover trial studies are representative designs in a randomized controlled trial study, a kind of experimental study. Clinical researchers should understand the characteristics of clinical research designs including advantages and disadvantages and choose the suitable design according to their study purposes and the nature of collected data or subjects.

• Clinical and Experimental Pediatrics
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• 제55권11호
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• pp.403-407
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• 2012

Noninferiority trials test whether a new experimental treatment is not unacceptably less efficacious than an active control treatment already in use. With continuous improvements in health technologies, standard care, and clinical outcomes, the incremental benefits of newly developed treatments may be only marginal over existing treatments. Sometimes assigning patients to a placebo is unethical. In such circumstances, there has been increasing emphasis on the use of noninferiority trial designs. Noninferiority trials are more complex to design, conduct, and interpret than typical superiority trials. This paper reviews the concept of noninferiority trials and discusses some important issues related to them.

• Radiation Oncology Journal
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• 제35권3호
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• pp.198-207
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• 2017

Purpose: Whether preoperative chemoradiotherapy (CRT) is better than postoperative CRT in oncologic outcome and toxicity is contentious in prospective randomized clinical trials. We systematically analyze and compare the treatment result, toxicity, and sphincter preservation rate between preoperative CRT and postoperative CRT in stage II-III rectal cancer. Materials and Methods: We searched Medline, Embase, and Cochrane Library from 1990 to 2014 for relevant trials. Only phase III randomized studies performing CRT and curative surgery were selected and the data were extracted. Meta-analysis was used to pool oncologic outcome and toxicity data across studies. Results: Three randomized phase III trials were finally identified. The meta-analysis results showed significantly lower 5-year locoregional recurrence rate in the preoperative-CRT group than in the postoperative-CRT group (hazard ratio, 0.59; 95% confidence interval, 0.41-0.84; p = 0.004). The 5-year distant recurrence rate (p = 0.55), relapse-free survival (p = 0.14), and overall survival (p = 0.22) showed no significant difference between two groups. Acute toxicity was significantly lower in the preoperative-CRT group than in the postoperative-CRT group (p < 0.001). However, there was no significant difference between two groups in perioperative and chronic complications (p = 0.53). The sphincter-saving rate was not significantly different between two groups (p = 0.24). The conversion rate from abdominoperineal resection to low anterior resection in low rectal cancer was significantly higher in the preoperative-CRT group than in the postoperative-CRT group (p < 0.001). Conclusions: As compared to postoperative CRT, preoperative CRT improves only locoregional control, not distant control and survival, with similar chronic toxicity and sphincter preservation rate in rectal cancer patients.

• 대한정형외과스포츠의학회:학술대회논문집
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• 대한정형외과스포츠의학회 2001년도 제11차 학술대회
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• pp.1-2
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• 2001

• 대한견주관절학회:학술대회논문집
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• 대한견주관절학회 2009년도 제17차 학술대회
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• pp.205-205
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• 2009

• 대한견주관절학회:학술대회논문집
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• 대한견주관절학회 2009년도 제17차 학술대회
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• pp.7-7
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• 2009

• 대한생식의학회:학술대회논문집
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• 대한불임학회 2006년도 The 5th Biannual Meeting of Pacific Rim Society for Fertility and Sterility
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• pp.66-68
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• 2006