• 응용통계연구
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• 제20권3호
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• pp.515-530
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• 2007

진단검사에서 민감도와 특이도가 선택편향에 영향을 받을 때, 진단검사의 각층에서의 민감도와 1-특이도의 비로 얻어지는 층화우도비도 편의가 존재하게 된다. 따라서 편의가 있는 층화우도비로 찾아진 최적절사점도 잘못된 값이 된다. 본 연구에서는 Begg과 Greenes (1983)에 의해 제안된 수정 민감도와 특이도를 층화우도비에 적용하여, 선택편향이 수정되는 최적절사점을 찾아보았다. 그리고 선택편향이 최적절사점에 미치는 영향을 선택편향 수정인자를 통해 설명하였다.

• 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.

• Clinical and Experimental Pediatrics
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• 제61권1호
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• pp.6-11
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• 2018

Purpose: Mid-upper-arm circumference (MUAC) is considered an alternative screening method for obesity. The aims of this investigation were to examine the ability of MUAC to correctly identify children with elevated body mass index (BMI) and to determine the best MUAC cutoff point for identification of children with high BMI. Methods: Anthropometric measurements (height, weight, and MUAC) from a cross-sectional sample of 7,921 Pakistani children aged 5-14 years were analyzed. Pearson correlation coefficients between MUAC and other anthropometric measurements were calculated. Receiver operating characteristic curve analysis was used to determine the optimal MUAC cutoff point for identifying children with high BMI. Results: Among 7,921 children, the mean (${\pm}$standard deviation) age, BMI, and MUAC were 10.00 (${\pm}2.86years$), 16.16 (${\pm}2.66kg/m^2$), and 17.73 (${\pm}2.59cm$), respectively. The MUAC had a strong positive correlation with BMI. The optimal MUAC cutoff points indicating elevated BMI in boys ranged from 16.76 to 22.73, while the corresponding values in girls ranged from 16.38 to 20.57. Conclusion: MUAC may be used as a simple indicator of overweight/obesity in children, with reasonable accuracy in clinical settings.

• 가정의학회지
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• 제39권6호
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• pp.333-339
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• 2018

Background: There is a distinction in alcohol consumption behavior between adults and college students. This study aims to verify the usability and the optimal cutoff point of Alcohol Use Disorders Identification Test-Korean revised version (AUDIT-KR) for screening alcohol use disorder in college students when the diagnostic and statistical manual of mental disorders (DSM), 5th edition diagnostic criteria is applied. Methods: A total of 922 college students living in Daejeon were enrolled and divided into two groups based on how many items they corresponded to among DSM-5 alcohol use disorder diagnostic criteria: those who corresponded to ${\geq}2$ of the 11 items were classified into the patient group (107 males, 89 females) while the others into the control group (311 males, 415 females). The participants were evaluated using AUDIT-KR to find the optimal cutoff point for screening alcohol use disorder, sensitivity, and specificity. Results: The mean${\pm}$standard deviation scores in the AUDIT-KR were $12.76{\pm}7.27$, $10.72{\pm}4.62$ for males and females, respectively, in the patient group. In contrast, in the control group the scores were $6.26{\pm}5.23$ and $3.95{\pm}3.59$ in males and females, respectively. The area under the receiver operating characteristic curve (95% confidence interval) regarding alcohol use disorder screening by AUDIT-KR was 0.768 (0.715-0.821) and 0.883 (0.848-0.919) for males and females, respectively. The optimal cutoff point of alcohol use disorder for males was >9, sensitivity 64.49%, and specificity 76.85%. The optimal cutoff point for females was >6, sensitivity 82.02%, and specificity 80.48%. Conclusion: This study suggested that AUDIT-KR can be used as a screening tool for alcohol use disorder in groups of college students when DSM-5 diagnosis criteria are applied.

• Asian Pacific Journal of Cancer Prevention
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• 제15권4호
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• pp.1655-1658
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• 2014

Objective: To find a more appropriate alternative to D-dimer cutoff value for the diagnosis of deep vein thrombosis (DVT) in cancer patients. Methods: A total of 711 cancer patients with symptoms suspicious of DVT were included in the study. D-dimer levels were assessed using ELISA. All patients were subjected to imaging procedures. Results: Among 711 patients with cancer, 466 (65.5%) were females and 245 (34.5%) were males, with an average age of $57.3{\pm}13.23$ years. The mean age in the DVT group was significantly higher than in the non-DVT group (P<0.05). The D-dimer levels of the DVT group were significantly higher than those of the non-DVT group (P<0.05). The incidence rate of DVT varied significantly according to cancer type (P<0.05). Increasing age and lung cancer were significantly correlated with D-dimer levels (P<0.05), and a one-year increase in age was associated with a 14.28 ng/ml increase in the D-dimer value. The optimal cutoff point for D-dimer was found to be 981 ng/ml, with a sensitivity of 86.4%, specificity of 79.4%, and accuracy of 82.6%. If the D-dimer cutoff point was set to 981ng/ml, the specificity would increase from 61.8% to 85.5% without loss of sensitivity in patients aged 40 years or younger. In patients aged more than 40 years, the new cutoff almost doubled the specificity with slightly reduced sensitivity. Conclusion: In cancer patients, a new cutoff value of 981 ng/ml effectively improved the exclusion of DVT, especially for patients aged more than 40 years.

• 대한간호학회지
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• 제46권1호
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• pp.59-68
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• 2016

Purpose: Increase in suicide rate for senior citizens which has become widespread in our society today. It is not a normal social phenomenon and is beyond the danger level. The contents of this study include Korean senior citizens' suicide related risk factors and warning signs, and the development of a simple Geriatric Suicide Risk Scale. Methods: This study is Methodological Research to verify reliability and validity of the Geriatric Suicide Risk Scale according to the tool development process suggested by Devellis (2012). Results: For predictive validity assessment, high suicide screening accuracy was showed with an Area under the ROC curve (AUC) of .93. For the optimal cutoff point of 11, sensitivity was 93.9%, and specificity, 75.7% which are excellence levels. Cross validity for assessment of generalization possibility showed the Area under the ROC curve (AUC) as .82 and in case of a cutoff point of 11, sensitivity was 73.7%, and specificity, 65.9%. Conclusion: When it comes to practical nursing, it is significant that the Korean Geriatric Suicide Risk Scale has high reliability and validity through adequate tool development and the tool assessment step to select degree of suicide risk of senior citizens. Also, it can be easily applied and does not take a long time to administer. Further, it can be used by health care personnel or the general public.

• Parasites, Hosts and Diseases
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• 제45권3호
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• pp.239-243
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• 2007

Many allergists are currently focusing on the development of new diagnostic tools, and are attempting to improve both the sensitivity and specificity. A multiple allergen simultaneous test-chemiluminescent assay (MAST-CLA) is one of the most popular diagnostic tools used in the Republic of Korea. However, there remains controversy among allergists with regard to the cut-off point for a positive result. The present study was conducted in order to determine the validity of MAST-CLA as compared with that of the skin prick test, with particular emphasis on arthropod allergens, on the basis of percentage agreement rates and k-values, and also to suggest the optimal positive cutoff points using receiver operating characteristic (ROC) curves. The study was conducted with 97 subjects (54 men, 43 women). Optimal individual cut-off points were calculated as follows; class II for Dermatophagoides farinae, class I for Dermatophagoides pteronyssinus, and trace for a cockroach mix. These findings suggest that attempting to apply optimal individual cut-off points will be a good way of improving diagnostic tests, particularly MAST-CLA.

• Journal of Preventive Medicine and Public Health
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• 제38권2호
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• pp.203-207
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• 2005

Objectives: Recently, the American Diabetes Association (ADA) redefined the criteria of prediabetes, which has lowered the diagnostic level of fasting plasma glucose (FPG) from 110 to 125 mg/dl, down to levels between 100 to 125mg/dl. The purpose of this study was to determine the predictive cutoff level of FPG as a risk for the development of diabetes mellitus in Korean men. Methods: A retrospective cohort study was conducted on 11,423 (64.5%) out of 17,696 males $\leq$30 years of age, and who met the FPG of $\leq$125 mg/dl and hemoglobin A1c of $\leq$ 6.4% criteria, without a history of diabetes, and who were enrolled at the screening center of a certain university hospital between January and December 1999. The subjects were followed from January 1999 to December 2002 (mean follow-up duration; 2.3(${\pm}0.7$) years). They were classified as normal (FPG <100mg/dl), high glucose (FPG $\geq$100mg/dl and <110mg/dl) and impaired fasting glucose (FPG $\geq$110mg/dl and $\leq$125mg/dl) on the basis of their fasting plasma glucose level measured in 1999. We compared the incidence of diabetes between the 3 groups by performing Cox proportional hazards model and used receiver operating characteristic analyses of the FPG level, in order to estimate the optimal cut-off values as predictors of incident diabetes. Results: At the baseline, most of the study subjects were in age in their 30s to 40s (mean age, 41.8(${\pm}7.1$) year). The incidence of diabetes mellitus in this study was 1.19 per 1,000 person-years (95% CI=0.68-1.79), which was much lower than the results of a community-based study that was 5.01 per 1,000 person-years. The relative risks of incident diabetes in the high glucose and impaired fasting glucose groups, compared with the normal glucose group, were 10.3 (95% CI=2.58-41.2) and 95.2 (95% CI= 29.3-309.1), respectively. After adjustment for age, body mass index, and log triglyceride, a FPG greater than 100mg/dl remained significant predictors of incident diabetes. Using the receiver operating characteristic (ROC) curve, the optimal cutoff level of FPG as a predictor of incident diabetes was 97.5 mg/dl, with a sensitivity and a specificity of 81.0% and 86.0%, respectively. Conclusion: These results suggest that lowering the criteria of impaired fasting glucose is needed in Korean male adults. Future studies on community-based populations, including women, will be required to determine the optimal cutoff level of FPG as a predictor of incident diabetes.

• Journal of Yeungnam Medical Science
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• 제36권3호
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• pp.241-248
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• 2019

Background: Heatstroke is one of the most serious heat-related illnesses. However, establishing public policies to prevent heatstroke remains a challenge. This study aimed to investigate the most relevant climate elements and their warning criteria to prevent outdoor heatstroke (OHS). Methods: We investigated heatstroke patients from five major hospitals in Daegu metropolitan city, Korea, from June 1 to August 31, 2011 to 2016. We also collected the corresponding regional climate data from Korea Meteorological Administration. We analyzed the relationship between the climate elements and OHS occurrence by logistic regression. Results: Of 70 patients who had heatstroke, 45 (64.3%) experienced it while outdoors. Considering all climate elements, only mean heat index (MHI) was related with OHS occurrence (p=0.019). Therefore, the higher the MHI, the higher the risk for OHS (adjusted odds ratio, 1.824; 95% confidence interval, 1.102-3.017). The most suitable cutoff point for MHI by Youden's index was $30.0^{\circ}C$ (sensitivity, 77.4%; specificity, 73.7%). Conclusion: Among the climate elements, MHI was significantly associated with OHS occurrence. The optimal MHI cutoff point for OHS prevention was $30.0^{\circ}C$.

• 한국심리학회지 : 문화 및 사회문제
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• 제14권4호
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• pp.103-117
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• 2008

한국의 검찰에서는 거짓말탐지검사(polygraph test)의 최종판정을 위한 기준 점수로써 관행적으로 -12점을 사용하고 있다. 이 판정기준 점수는 검사기법을 개발한 Backster(1963)가 제안한 판정기준 점수(-13점)와는 약간 다른 것으로 한국에서 거짓말탐지 검사를 표준화하기 위해서는 판정기준 점수에 대한 과학적 근거와 그 정확성에 대한 검증이 필요하다. 본 연구에서는 실제 범죄수사를 위하여 검찰에서 이루어진 거짓말탐지 검사 자료를 이용해서 거짓말탐지 검사의 판정기준 점수를 신호탐지이론에 기초하여 설정하고자 하였다. 또한 Backster가 제안한 판정기준 점수와 현재 검찰에서 사용하는 판정기준 점수, 신호탐지이론에 기초해서 본 연구가 설정한 판정기준 점수의 정확성을 비교하여 범죄수사를 위한 거짓말탐지검사의 검사 상황에 가장 적절한 판정기준 점수를 제시하고자 하였다. 신호탐지이론에 기초해서 거짓말탐지검사의 정확성을 최대화할 수 있는 판정기준 점수를 산출한 결과 -8점으로 나타났다. 또한 판정기준 점수를 도출한 표본자료와 다른 별도의 표본자료에서 판정기준 점수에 따른 정확성을 비교한 결과, -8점을 판정기준 점수로 사용했을 경우의 정확성(83.17%)이 가장 높았고, 검찰의 판정기준 점수(80.20%), Backster의 판정기준 점수(76.24%) 순으로 정확성이 감소하였다. 그러나 오류긍정과 오류부정의 비율을 비교한 결과에서는 -8점을 판정기준으로 사용할 때에 오류긍정이 가장 높은 것으로 나타났다. 따라서 범죄수사를 위한 거짓말탐지검사에서 전체적인 판단 정확률을 확보하는 것이 중요하다면 -8점을 기준 점수로 사용하고, 진실을 말하는 사람을 거짓이라고 판단하지 않는 것이 중요하다면 -12 또는 -13점을 판정기준 점수로 사용할 것이 권고 되었다.