Objective To evaluate the sensitivity and specificity of body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) measurements in diagnosing abdominal visceral obesity. Methods BMI, WC, and WHR wer...Objective To evaluate the sensitivity and specificity of body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) measurements in diagnosing abdominal visceral obesity. Methods BMI, WC, and WHR were assessed in 690 Chinese adults (305 men and 385 women) and compared with magnetic resonance imaging (MRI) measurements of abdominal visceral adipose tissue (VA). Receiver operating characteristic (ROC) curves were generated and used to determine the threshold point for each anthropometric parameter. Results 1) MRI showed that 61.7% of overweight/obese individuals (BMI≥25 kg/m2) and 14.2% of normal weight (BMI<25 kg/m2) individuals had abdominal visceral obesity (VA≥100 cm2). 2) VA was positively correlated with each anthropometric variable, of which WC showed the highest correlation (r=0.73-0.77, P<0.001). 3) The best cut-off points for assessing abdominal visceral obesity were as followed: BMI of 26 kg/m2, WC of 90 cm, and WHR of 0.93, with WC being the most sensitive and specific factor. 4) Among subjects with BMI≥28 kg/m2 or WC≥95 cm, 95% of men and 90% of women appeared to have abdominal visceral obesity. Conclusion Measurements of BMI, WC, and WHR can be used in the prediction of abdominal visceral obesity, of which WC was the one with better accuracy.展开更多
Objective: To determine the endemic values of cutaneous leishmaniasis in different cities of Fars province, Iran. Methods: Totally, 29 201 cases registered from 2010 to 2015 in Iranian Fars province were selected, and...Objective: To determine the endemic values of cutaneous leishmaniasis in different cities of Fars province, Iran. Methods: Totally, 29 201 cases registered from 2010 to 2015 in Iranian Fars province were selected, and the endemic values of cutaneous leishmaniasis were determined by retrospective clusters derived from spatiotemporal permutation modeling on a time-series design. The accuracy of the values was assessed using receiver operating characteristic(ROC) curve. SPSS version 22, Arc GIS, and ITSM 2002 software tools were used for analysis. Results: Nine statistically significant retrospective clusters(P<0.05) resulted in finding seven significant and accurate endemic values(P<0.1). These valid endemic scores were generalized to the other 18 cities based on 6 different climates in the province. Conclusions: Retrospectively detected clusters with the help of ROC curve analysis could help determine cutaneous leishmaniasis endemic values which are essential for future prediction and prevention policies in the area.展开更多
In diagnostic trials, clustered data are obtained when several subunits of the same patient are observed. Within-cluster correlations need to be taken into account when analyzing such clustered data. A nonparametric m...In diagnostic trials, clustered data are obtained when several subunits of the same patient are observed. Within-cluster correlations need to be taken into account when analyzing such clustered data. A nonparametric method has been proposed by Obuchowski (1997) to estimate the Receiver Operating Characteristic curve area (AUC) for such clustered data. However, Obuchowski’s estimator gives equal weight to all pairwise rankings within and between cluster. In this paper, we modify Obuchowski’s estimate by allowing weights for the pairwise rankings vary across clusters. We consider the optimal weights for estimating one AUC as well as two AUCs’ difference. Our results in this paper show that the optimal weights depends on not only the within-patient correlation but also the proportion of patients that have both unaffected and affected units. More importantly, we show that the loss of efficiency using equal weight instead of our optimal weights can be severe when there is a large within-cluster correlation and the proportion of patients that have both unaffected and affected units is small.展开更多
Objective:To determine the clinical serum levels of carcinoembryonic antigen(CEA) and carbohydrate antigen 19-9(CA19-9),individually and in combination,for the diagnosis of 50 healthy subjects and 150 cases of esophag...Objective:To determine the clinical serum levels of carcinoembryonic antigen(CEA) and carbohydrate antigen 19-9(CA19-9),individually and in combination,for the diagnosis of 50 healthy subjects and 150 cases of esophageal,gastric,and colon cancers.Methods:The sensitivities of the two markers were compared individually and in combination,with specificity set at 100%.Receiver operating characteristic(ROC) curves were plotted.Results:Serum CEA levels were significantly higher in cancer patients than in the control group.The sensitivity of CEA was determined:in esophageal cancer,sensitivity=28%,negative predictive value(NPV)=61.72%,and AUC=0.742(SE=0.05),with a significance level of P<0.0001;in gastric cancer,sensitivity=30%,NPV=58.82%,and AUC=0.734(SE=0.05),with a significance level of P<0.0001;in colon cancer,sensitivity=74%,NPV=79.36%,and AUC=0.856(SE=0.04),with a significance level of P<0.0001.The sensitivity of CA19-9 was also evaluated:in esophageal cancer,sensitivity=18%,NPV=54.94%,and AUC=0.573(SE=0.05),with a significance level of P=0.2054.In gastric cancer,sensitivity=42%,NPV=63.29%,and AUC=0.679(SE=0.05),with a significance level of P<0.0011.In colon cancer,sensitivity=26%,NPV=57.47%,and AUC=0.580(SE=0.05),with a significance level of P=0.1670.The following were the sensitivities of CEA/CA19-9 combined:in esophageal cancer,sensitivity=42%,NPV=63.29%,SE=0.078(95% CI:0.0159-0.322);gastric cancer,sensitivity=58%,NPV=70.42%,SE=0.072(95% CI:-0.0866-0.198);and colon cancer,sensitivity=72%,NPV=78.12%,SE=0.070(95% CI:0.137-0.415).Conclusion:CEA exhibited the highest sensitivity for colon cancer,and CA19-9 exhibited the highest sensitivity for gastric cancer.Combined analysis indicated an increase in diagnostic sensitivity in esophageal and gastric cancer compared with that in colon cancer.展开更多
目的:甲状腺功能障碍性视神经病变(dysthyroid optic neuropathy,DON)严重危害甲状腺相关眼病患者视力。本研究观察DON患者的视觉功能改变,并评价DON检测指标的诊断价值。方法:回顾性分析2017年1月至2019年12月在中南大学湘雅医院就诊...目的:甲状腺功能障碍性视神经病变(dysthyroid optic neuropathy,DON)严重危害甲状腺相关眼病患者视力。本研究观察DON患者的视觉功能改变,并评价DON检测指标的诊断价值。方法:回顾性分析2017年1月至2019年12月在中南大学湘雅医院就诊的49例DON患者(98眼)的临床资料。所有患者均行最佳矫正视力(best corrected visual acuity,BCVA)、Humphrey视野、视觉诱发电位(visual evoked potential,VEP)和对比敏感度检测。将98眼分为DON组(45眼)和非DON组(53眼)。采用t检验比较2组患者上述各项检测的相关指标,受试者操作特征(receiver operating characteristic,ROC)曲线分析各指标的敏感度和特异度。结果:DON组的BCVA和视野指数(visual field index,VFI)均显著低于非DON组(均P<0.05),平均缺损(mean deviation,MD)和模式标准偏差(pattern standard deviation,PSD)均显著高于非DON组(均P<0.05)。DON组的低频对比敏感度(low frequency contrast sensitivity,CSL)、中频对比敏感度(medium frequency contrast sensitivity,CSM)、高频对比敏感度(high frequency contrast sensitivity,CSH)均明显低于非DON组(均P<0.05),CSH尤为明显。在15°、30°和60°空间频率时,与非DON组比较,DON组的N135波幅显著降低,N75波、P100波、N135波的潜伏期显著延长(均P<0.05);在15°和30°空间频率时,DON组较非DON组P100波幅明显降低(均P<0.05)。ROC曲线分析结果显示:VFI、CSL、CSM、CSH和15°P100波幅诊断DON的曲线下面积(area under the curve,AUC)分别为0.812、0.841、0.880、0.784和0.791,以CSM的敏感度和特异度最高。结论:DON患者的视觉功能均存在不同程度的受损。VFI、CSL、CSM、CSH和15°P100波幅可能成为早期诊断DON的有效指标。展开更多
文摘Objective To evaluate the sensitivity and specificity of body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) measurements in diagnosing abdominal visceral obesity. Methods BMI, WC, and WHR were assessed in 690 Chinese adults (305 men and 385 women) and compared with magnetic resonance imaging (MRI) measurements of abdominal visceral adipose tissue (VA). Receiver operating characteristic (ROC) curves were generated and used to determine the threshold point for each anthropometric parameter. Results 1) MRI showed that 61.7% of overweight/obese individuals (BMI≥25 kg/m2) and 14.2% of normal weight (BMI<25 kg/m2) individuals had abdominal visceral obesity (VA≥100 cm2). 2) VA was positively correlated with each anthropometric variable, of which WC showed the highest correlation (r=0.73-0.77, P<0.001). 3) The best cut-off points for assessing abdominal visceral obesity were as followed: BMI of 26 kg/m2, WC of 90 cm, and WHR of 0.93, with WC being the most sensitive and specific factor. 4) Among subjects with BMI≥28 kg/m2 or WC≥95 cm, 95% of men and 90% of women appeared to have abdominal visceral obesity. Conclusion Measurements of BMI, WC, and WHR can be used in the prediction of abdominal visceral obesity, of which WC was the one with better accuracy.
文摘Objective: To determine the endemic values of cutaneous leishmaniasis in different cities of Fars province, Iran. Methods: Totally, 29 201 cases registered from 2010 to 2015 in Iranian Fars province were selected, and the endemic values of cutaneous leishmaniasis were determined by retrospective clusters derived from spatiotemporal permutation modeling on a time-series design. The accuracy of the values was assessed using receiver operating characteristic(ROC) curve. SPSS version 22, Arc GIS, and ITSM 2002 software tools were used for analysis. Results: Nine statistically significant retrospective clusters(P<0.05) resulted in finding seven significant and accurate endemic values(P<0.1). These valid endemic scores were generalized to the other 18 cities based on 6 different climates in the province. Conclusions: Retrospectively detected clusters with the help of ROC curve analysis could help determine cutaneous leishmaniasis endemic values which are essential for future prediction and prevention policies in the area.
文摘In diagnostic trials, clustered data are obtained when several subunits of the same patient are observed. Within-cluster correlations need to be taken into account when analyzing such clustered data. A nonparametric method has been proposed by Obuchowski (1997) to estimate the Receiver Operating Characteristic curve area (AUC) for such clustered data. However, Obuchowski’s estimator gives equal weight to all pairwise rankings within and between cluster. In this paper, we modify Obuchowski’s estimate by allowing weights for the pairwise rankings vary across clusters. We consider the optimal weights for estimating one AUC as well as two AUCs’ difference. Our results in this paper show that the optimal weights depends on not only the within-patient correlation but also the proportion of patients that have both unaffected and affected units. More importantly, we show that the loss of efficiency using equal weight instead of our optimal weights can be severe when there is a large within-cluster correlation and the proportion of patients that have both unaffected and affected units is small.
基金the financial support provided by the Biotechnology Information Service–Sub-Distributed Information Centre(supported by the Department of Biotechnology,Government of India)Advanced Bioinformatics Centre(supported by the Government of Rajasthan)at Birla Institute of Scientific Research for the infrastructure and facilities for conducting statistical work
文摘Objective:To determine the clinical serum levels of carcinoembryonic antigen(CEA) and carbohydrate antigen 19-9(CA19-9),individually and in combination,for the diagnosis of 50 healthy subjects and 150 cases of esophageal,gastric,and colon cancers.Methods:The sensitivities of the two markers were compared individually and in combination,with specificity set at 100%.Receiver operating characteristic(ROC) curves were plotted.Results:Serum CEA levels were significantly higher in cancer patients than in the control group.The sensitivity of CEA was determined:in esophageal cancer,sensitivity=28%,negative predictive value(NPV)=61.72%,and AUC=0.742(SE=0.05),with a significance level of P<0.0001;in gastric cancer,sensitivity=30%,NPV=58.82%,and AUC=0.734(SE=0.05),with a significance level of P<0.0001;in colon cancer,sensitivity=74%,NPV=79.36%,and AUC=0.856(SE=0.04),with a significance level of P<0.0001.The sensitivity of CA19-9 was also evaluated:in esophageal cancer,sensitivity=18%,NPV=54.94%,and AUC=0.573(SE=0.05),with a significance level of P=0.2054.In gastric cancer,sensitivity=42%,NPV=63.29%,and AUC=0.679(SE=0.05),with a significance level of P<0.0011.In colon cancer,sensitivity=26%,NPV=57.47%,and AUC=0.580(SE=0.05),with a significance level of P=0.1670.The following were the sensitivities of CEA/CA19-9 combined:in esophageal cancer,sensitivity=42%,NPV=63.29%,SE=0.078(95% CI:0.0159-0.322);gastric cancer,sensitivity=58%,NPV=70.42%,SE=0.072(95% CI:-0.0866-0.198);and colon cancer,sensitivity=72%,NPV=78.12%,SE=0.070(95% CI:0.137-0.415).Conclusion:CEA exhibited the highest sensitivity for colon cancer,and CA19-9 exhibited the highest sensitivity for gastric cancer.Combined analysis indicated an increase in diagnostic sensitivity in esophageal and gastric cancer compared with that in colon cancer.
文摘目的:甲状腺功能障碍性视神经病变(dysthyroid optic neuropathy,DON)严重危害甲状腺相关眼病患者视力。本研究观察DON患者的视觉功能改变,并评价DON检测指标的诊断价值。方法:回顾性分析2017年1月至2019年12月在中南大学湘雅医院就诊的49例DON患者(98眼)的临床资料。所有患者均行最佳矫正视力(best corrected visual acuity,BCVA)、Humphrey视野、视觉诱发电位(visual evoked potential,VEP)和对比敏感度检测。将98眼分为DON组(45眼)和非DON组(53眼)。采用t检验比较2组患者上述各项检测的相关指标,受试者操作特征(receiver operating characteristic,ROC)曲线分析各指标的敏感度和特异度。结果:DON组的BCVA和视野指数(visual field index,VFI)均显著低于非DON组(均P<0.05),平均缺损(mean deviation,MD)和模式标准偏差(pattern standard deviation,PSD)均显著高于非DON组(均P<0.05)。DON组的低频对比敏感度(low frequency contrast sensitivity,CSL)、中频对比敏感度(medium frequency contrast sensitivity,CSM)、高频对比敏感度(high frequency contrast sensitivity,CSH)均明显低于非DON组(均P<0.05),CSH尤为明显。在15°、30°和60°空间频率时,与非DON组比较,DON组的N135波幅显著降低,N75波、P100波、N135波的潜伏期显著延长(均P<0.05);在15°和30°空间频率时,DON组较非DON组P100波幅明显降低(均P<0.05)。ROC曲线分析结果显示:VFI、CSL、CSM、CSH和15°P100波幅诊断DON的曲线下面积(area under the curve,AUC)分别为0.812、0.841、0.880、0.784和0.791,以CSM的敏感度和特异度最高。结论:DON患者的视觉功能均存在不同程度的受损。VFI、CSL、CSM、CSH和15°P100波幅可能成为早期诊断DON的有效指标。
