Cut-off points of neck and waist circumference as predictors of obstructive sleep apnea in the Colombian population: a comparison with polysomnography

ABSTRACT BACKGROUND: Neck circumference (NC) is a useful anthropometric measure for predicting obstructive sleep apnea (OSA). Ethnicity and sex also influence obesity phenotypes. NC cut-offs for defining OSA have not been established for the Latin American population. OBJECTIVES: To evaluate NC, waist circumference (WC), and body mass index (BMI) as predictors of OSA in the Colombian population and to determine optimal cut-off points. DESIGN AND SETTING: Diagnostic tests were conducted at the Javeriana University, Bogota. METHODS: Adults from three cities in Colombia were included. NC, WC, and BMI were measured, and a polysomnogram provided the reference standard. The discrimination capacity and best cut-off points for diagnosing OSA were calculated. RESULTS: 964 patients were included (57.7% men; median age, 58 years) and 43.4% had OSA. The discrimination capacity of NC was similar for men and women (area under curve, AUC 0.63 versus 0.66, P = 0.39) but better for women under 60 years old (AUC 0.69 versus 0.57, P < 0.05). WC had better discrimination capacity for women (AUC 0.69 versus 0.57, P < 0.001). There were no significant differences in BMI. Optimal NC cut-off points were 36.5 cm for women (sensitivity [S]: 71.7%, specificity [E]: 55.3%) and 41 cm for men (S: 56%, E: 62%); and for WC, 97 cm for women (S: 65%, E: 69%) and 99 cm for men (S: 53%, E: 58%). CONCLUSIONS: NC and WC have moderate discrimination capacities for diagnosing OSA. The cut-off values suggest differences between Latin- and North American as well as Asian populations.

PCorteSoft - Sistema para la determinación del punto de corte óptimo en escalas predictivas y la categorización de variables continuas

Al desarrollar modelos de predicción para su aplicación en la práctica clínica, los profesionales de la salud suelen categorizar las variables clínicas que son de naturaleza continua. En muchas ocasiones estos modelos constituyen la base para la confección de escalas predictivas, a partir de las cuales se estratifica a los pacientes en varias categorías atendiendo al fenómeno estudiado. En estos casos se requiere la determinación de uno o varios puntos de cortes que permitan dividir el recorrido de la variable, variables continuas o puntuaciones de una escala, en dos o más categorías. El presente trabajo tiene como objetivo la automatización de diferentes métodos para dicotomizar variables continuas en modelos de predicción clínica, donde la variable respuesta es dicotómica, y determinar el punto de corte óptimo en la estratificación de pacientes en dos categorías, a partir de escalas de predicción. Para ello se elaboró un software en el lenguaje de programación R, que implementa diferentes métodos para la determinación del punto de corte óptimo, lo cual agiliza el trabajo investigativo de los especialistas de salud en el proceso de elaboración de modelos predictivos y/o escalas de predicción.

When developing predictive models for application in clinical practice, health professionals often categorize clinical variables that are continuous in nature. In many cases, these models are the basis for the development of predictive scales from which patients are stratified into various categories according to the phenomenon under study. In both cases, it is necessary to determine one or more cut-off points that allow dividing the path of the variable, continuous variables, or scores of a scale into two or more categories. The aim of the present work is to automate different existing methods for dichotomizing continuous variables in clinical prediction models where the response variable is dichotomous, as well as to determine the optimal cut-off point for stratifying patients into two categories, based on prediction scales. For this purpose, a software was developed in the R programming language, which implements different existing methods for the determination of the optimal cut-off point, speeding up the research work of health specialists in the process of developing predictive models and/or prediction scales.

Determinación de valores de corte de 17 hidroxiprogesterona ajustados por edad gestacional para la pesquisa neonatal de la hiperplasia suprarrenal congénita / Assessment of gestational age-adjusted 17-hydroxyprogesterone cut-off values for neonatal screening of congenital adrenal hyperplasia

La pesquisa neonatal de hiperplasia suprarrenal congénita se realiza mediante la determinación de 17 hidroxiprogesterona (17OHP) en gotas de sangre seca en papel de filtro. Los bebés prematuros presentan valores más elevados que los bebés de término, siendo de utilidad contar con límites de corte apropiados. Nuestro objetivo fue actualizar los valores de corte de 17OHP ajustados por edad gestacional para la metodología en uso a nivel nacional por las jurisdicciones asistidas por el "Programa Nacional de Fortalecimiento de la Detección Precoz de Enfermedades Congénitas". La 17OHP se determinó utilizando el kit comercial de enzimo-inmunoanálisis (ELISA competitivo), Elizen Neonatal 17OHP Screening (Zentech, Bélgica). Se obtuvieron límites de corte utilizando percentiles de la distribución de los valores de 17OHP para cada edad gestacional. La sensibilidad obtenida fue 100%, especificidad 98,76 %, tasa de falsos positivos 1,24 % y el valor predictivo positivo 1,12 %. Destacamos la importancia de disponer de límites de corte adecuados a la población. La armonización de los mismos permitirá resultados comparables entre los programas regionales de pesquisa neonatal (AU)

Newborn screening for congenital adrenal hyperplasia is performed by the measurement of 17-hydroxyprogesterone (17OHP) in dried blood spots on filter paper. Premature infants have higher values than full-term infants, and appropriate cutoff values are useful. Our aim was to update the cut-off values of 17OHP adjusted for gestational age for the methodology used at a national level in regions assisted by the "National Program for Strengthening the Early Detection of Congenital Diseases". 17OHP was determined using the commercial enzyme-linked immunosorbent assay (competitive ELISA) kit, Elizen Newborn 17OHP Screening (Zentech, Belgium). Cut-off values were obtained using percentiles of the distribution of 17OHP values for each gestational age. Sensitivity was 100%, specificity 98.76%, false positive rate 1.24%, and positive predictive value 1.12%. It is important to have cut-off values that are adjusted to the population. Harmonization will allow for the comparison of results among regional newborn screening programs (AU)

The Chinese version of the Chelsea Critical Care Physical Assessment Tool applied in critically ill patients / 中国实用护理杂志

Objective:To explore the threshold and diagnostic value of Chinese version of the Chelsea Physical Function Assessment Tool (CPAx-Chi) for ICU acquired weakness(ICU-AW).Methods:To learn the details and precautions of the CPAx-Chi scale, and then two researchers used the CPAx-Chi scale and MRC-Score scale to independently evaluate 200 patients who come from a comprehensive ICU in a top first-class hospital in Gansu Province simultaneously. The best cut-off point and value of the CPAx-Chi scale in the diagnosis of ICU-AW were determined by calculating the Receiver Operating Characteristic (ROC) curve, the Youden index(YI) and the consistency test that are all based on the MRC-Score≤48.Results:The ROC Area Under Curve(AUC) of the CPAx-Chi scale diagnosis ICU-AW which based on the MRC-Score≤48 were as follows: ROC AUC of group A was 0.899 (95% CI 0.862-1.025); ROC AUC of group B was 0.874 (95% CI 0.824-0.925). When the best cut-off point of CPAx-Chi scale for diagnosis ICU-AW was 31.5, the maximum YI=0.643, the sensitivity was 87%, and the specificity was 77% in group A; and the maximum YI= 0.62, the sensitivity was 75%, and the specificity was 87% in group B. Meanwhile, when the best cut-off point of CPAx-Chi scale for diagnosis ICU-AW was 30.5, the maximum YI=0.62, the sensitivity was 79%, and the specificity was 83% in group B. Taking the CPAx -Chi≤31 as the best cut-off point, the score differences in ICU-AW group and the non-ICU-AW group were not detected, A group ( F value was 4.53, P=0.035) or B group ( F value was 6.51, P=0.011). The consistency of CPAx -Chi≤31 and MRC-Score≤48 in the diagnosis of ICU-AW was high, and the Kappa=0.845 ( P=0.02) in the group A; the Kappa=0.839( P=0.04) in the group B, and the group differences were detected. Conclusions:CPAx-Chi≤31 is the best cut-off point for diagnosing ICU-AW, and has good sensitivity and specificity. CPAx-Chi scale can be popularized and applied in the critical care medicine in China.

Lower Cut off Point for Blood Lead and Risk of Myocardial Infarction at a Tertiary Hospital in Malaysia: A Case-Control Study

@#Introduction Lead (Pb) is one of the pollutants that can cause adverse effects on human health. Exposure to Pb has received much attention in the past decades due to its nearly persistent properties in the environment. Blood Pb measurement is the most convenient as well as most feasible to indicate toxicity exceeded the standard limit of 10 μg/dL. This study aimed to assess the association between blood Pb and myocardial infarction. Methods This was a case-control study conducted at a tertiary hospital in Kuala Lumpur, Malaysia. This study enrolled about 109 respondents; 71 cases of myocardial infarction and 38 non-cases of myocardial infarction. Study instruments include questionnaires on demographic factors (age, gender, and ethnicity), socioeconomic factors (education, household income, occupation), and venous blood lead level. The blood Pb was measured using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Results The median (IQR) of blood Pb among the case group was higher compared to the control groups, 3.72 (0.04 – 96.09) μg/dL and 2.81 (0.73 – 6.23) μg/dL respectively. No difference between high (> 10 μg/dL) and normal (<10 μg/dL) blood Pb with CVD. However, there was a significant association between high normal blood Pb concentration (≥ 5.00 µg/dL) and myocardial infarction (χ2 = 4.397; p = 0.036). Conclusions There is a relationship between lower blood Pb level and the occurrence of myocardial infarction. No difference was found between the blood Pb limit of 10 μg/dL and CVD. The findings of this study are very important and provide new information regarding the lower cut off point for blood Pb and outcome of CVD especially myocardial infarction..

Translation and assessment about the Sexual Interest and Desire Inventory-Female / 中国实用护理杂志

Objective:To translate the English version of Sexual Interest and Desire Inventory-Female (SIDI-F) into Chinese, evaluate its reliability, validity and the proper cut-off point of diagnosis of hypoactive sexual desire disorder (HSDD) in China.Methods:Chinese version of SIDI-F was developed and 96 healthy women from January 1, 2019 to December 31, 2019 in Taihe Hospital, Shiyan City, Hubei Province were selected to fill in the Chinese version of SIDI-F and the Female Sexual Function Index (FSFI). Next, analyzed the reliability, validity and the cut-off point of diagnosis of HSDD of the SIDI-F.Results:The Cronbach coefficient of the Chinese version of SIDI-F was 0.931, split-half reliability was 0.922, the intra-group correlation coefficient was 0.805. Analysis of content validity of the SIDI-F indicated that the average of scale-level content validity index was 1.00, the item-level content validity index was 1.00, and the Pearson correlation coefficient between the score of SIDI-F and the erotica score of the FSFI (FSFI-D) was 0.802. Factor analysis of the Chinese version of SIDI-F showed good construct validity. The area under ROC was 0.835. With the SIDI-F score and the best cut-off point of 26.5, Youden index was the largest, at 0.635. The validity indicators were 76.7% for sensitivity, 86.8% for specificity, 5.95 for positive likelihood ratio.Conclusions:The Chinese version of SIDI-F has high reliability and validity in Chinese population, and these show 26.5 point can be used as the best cut-off value of diagnose HSDD.

Waist circumference cut-off points in children aged 7-14 years and its correlation with obesity in Haikou / 公共卫生与预防医学

Objective To analyze the cut-off point of waist circumference (WC) for overweight and obesity in school children aged 7-14 in Haikou, and to provide a scientific basis for the formulation of prevention and treatment strategies for overweight and obesity in children. Methods Using the 2016-2019 “Student Health Record Management System in Hainan Province”, 220 primary and secondary schools in Haikou were sampled using the PPS sampling method, and the height, weight and waist circumference of children aged 7-14 were collected and analyzed. Results A total of 283 054 children aged 7-14 years old were investigated. The average WC and percentile WC values of children in each age group were lower the national average WC values, and the WC continued to increase with age. The WC of boys was higher than that of the girls in all age groups (P < 0.0001), and the WC of urban children was higher than that of rural children of the same age (P < 0.0001). The WC cut-off points were P75-P80 (56.50-71.75 cm) in boys and P80-P85 (54.50-68.50 cm) in girls for overweight. For obesity, the WC cut-off points in boys of 7-11 years old and 12-14 years old were P85 (58.5-72.50 cm) and P90 (75.50-79.50 cm), respectively, and the WC cut-off points in girls of 7 years old and 8-14 years old were P85 (56.50 cm) and P90 (59.85-71.50 cm), respectively. Conclusion The cut-off points of WC for overweight are 56.50-71.75 cm in boys and 54.50-68.50 cm in girls, respectively. The cut-off points of WC for obesity are 58.50-79.50 cm in boys and 56.50-71.50 cm in girls, respectively. Except for the cut-off points for overweight in 7-year-old boys and 9-year-old girls and the cut-off points for obesity in 8 to 10-year-old girls before puberty, the cut-off points for overweight and obesity in other age groups are consistent with the national values.

The Malay Posttraumatic Stress Disorder Checklist for DSM-5 (MPCLC-5) as Screening Tool for PTSD: Determination of Cut-off Point Against Clinician Administered PTSD Scale for DSM-5 (CAPS-5)

@#Introduction: Posttraumatic stress disorder (PTSD) is a mental health condition which develops following exposure to life-threatening events. This cross-sectional study was conducted among adult patients from all walks of life who had injuries related to motor vehicle accidents to determine the cut-off point of the Malay Posttraumatic Stress Disorder Checklist For DSM-5 (MPCLC-5) for its use as a screening tool for PTSD in the Malaysian population. Methods: Using convenient sampling method, 204 subjects who fulfilled the inclusion criteria were recruited and they were given the 17 item self-rated MPCLC-5 to fill up. Subsequently, trained personnel administered the gold standard Clinician Administered PTSD Scale for DSM 5 (CAPS-5). ROC curve analysis was done to determine appropriate cut-off point for the MPCLC-5. Results: Cut off point of 42/43 would yield the most preferable sensitivity and specificity for MPCLC-5 when compared to CAPS-5 (Sensitivity: 67.56% (95%CI 55.68% to 78.00%); Specificity : 80% (95% CI 72.08% to 86.50%) ). Conclusion: The easy to administer MPCLC-5 is suitable for screening of PTSD among local patients with a proposed cut off point of 42/43.

Validity and reliability of the Chinese version of Mobile Phone Involvement Questionnaire in college students / 南方医科大学学报

OBJECTIVE@#To test the validity and reliability of the Chinese version of Mobile Phone Involvement Questionnaire (MPIQ) in college students.@*METHODS@#We assessed the degree of phone dependence using the MPIQ among 2122 college students. One month later, 60 students were randomly selected for assessment with the MPIQ, and the ROC curve was generated to evaluate the true positive rate (sensitivity) and false positive rate at different cutoff values to determine the optimal cutoff score of the MPIQ.@*RESULTS@#Among 98.9% of the participants who finished all the items, their MPIQ scores show a positive skew distribution and a one-factor structure. The load scores of the items ranged from 0.54 to 0.77. The Cronbach's α coefficient and the Spearman Brown split reliability were 0.84 and 0.83, respectively, the correlation coefficients between the items and total score ranged from 0.54 to 0.76, and the test-retest reliability was 0.48 ( < 0.001). At the optimal cut-off score of 32, the sensitivity and the specificity of the MPIQ were 0.634 and 0.652, respectively.@*CONCLUSIONS@#At the optimal cut-off score of 32, the MPIQ has good validity and reliability for assessing phone dependence among college students.

Valor de corte de la circunferencia de la cintura como predictor de disglucemia / Cut-off point of the waist circumference as a predictor of dysglycemia

Introducción: la circunferencia de la cintura es un parámetro clínico útil para identificar alteraciones en el metabolismo de los carbohidratos, pero la Organización Mundial de la Salud recomienda que cada país o región debe establecer sus propios valores de corte. Objetivo: determinar el punto de corte de la circunferencia de cintura como predictor de disglucemia en una población cubana. Métodos: se realizó un estudio descriptivo transversal basado en 982 pacientes (457 hombres y 525 mujeres) que asistieron a las consultas del Instituto Nacional de Endocrinología por sospecha de diabetes mellitus tipo 2, entre abril de 2008 y abril de 2013. La metodología consistió en la realización de un interrogatorio y un examen físico, que incluyó la medición de la circunferencia de cintura y estudios de laboratorio que se completaron con una prueba de tolerancia a la glucosa oral. Se determinaron distribuciones de frecuencia de las variables cualitativas y de las cuantitativas, media y desviación estándar. Además se utilizaron el coeficiente de correlación de Pearson, regresión lineal simple, el análisis de las curvas Receiver Operator Characteristics y la prueba de chi cuadrado. Resultados: se halló una correlación positiva entre la circunferencia de cintura y los valores de glucemia, insulinemia, ácido úrico y el índice Homeostasis Model Assessment Estimate of Insulin Resistance. La circunferencia de la cintura en ambos sexos fue la variable con mayor poder predictor de disglucemia, con un punto de corte de cintura de 86,75 cm en hombres y 80,5 cm en las mujeres. Conclusiones: el punto de corte óptimo de la circunferencia de cintura como predictor de disglucemia en hombres es de 86,75 cm (87) y en mujeres de 80,5 cm (81) en una población cubana(AU)

Introduction: waist circumference is a useful clinical parameters to identify alterations in carbohydrate metabolism; however the World Health Organization recommends that each country or region should set its own cut off point values. Objective: to determine the cut-off point of the waist circumference as a predictor of dysglycemias in a Cuban population. Methods: a cross-sectional descriptive study was conducted in 982 patients (457 men and 525 females) who went to the medical offices of the National Institute of Endocrinology on suspicion of diabetes mellitus type 2 from April 2008 to April 2013. The methodology consisted of administration of questionnaires and physical examination including the measurement of waist circumference and lab studies that were completed with the oral glucose tolerance test. Frequency distributions of the qualitative and quantitative variables, the median and standard deviation were all determined. Additionally, Pearson´s correlation coefficient, the simple linear regressions, analysis of Receiver Operator Characteristic curves and the Chi-square test were also used. Results: positive correlation was found between the waist circumference and the glycemia, insulinemia, uric acid and the homeostasis model assessment estimate of insulin resistance. Waist circumference in both sexes was the variable with greatest predictive power for dysglycemia, with a cutoff point of 86.75 cm for men and 80.5 cm for women. Conclusions: the optimal cutoff point of waist circumference as a dysglycemia predictor in men is 86.75 cm (87) and in women is 80.5 (81) in a Cuban population(AU)

Relationship between optimal cutoff value of serum homocysteine and risk factors of premature delivery and its logistic regression analysis / 实用医学杂志

Objective To investigate the relationship between the optimal cutoff point of serum homocyste-ine(Hcy)and premature delivery in pregnant women ,and to analyze the influence of Hcy levels on the outcome of preterm infants. Methods Totally 114 cases of pregnant women were chosen as observation group and 103 cases of normal as control group. Hcy,D-D and hypersensitive C reactive protein were detected;analysis of the ROC curve was conducted by using the SPSS 13 software and the risk factors for preterm delivery were analyzed using logistic multivariate regression analysis. Results (1)The levels of Hcy,HS-CRP and D-D in preterm pregnant women were higher than those in control group and the difference was statistically significant (P < 0.05). (2) Logistic regression analysis showed that the relative risk coefficient(OR)of Hcy was 9.736,and the regression equation of premature birth probability was obtained.(3)ROC curve to evaluate the predictive value of Hcy in risk factors of preterm birth was 0.931;when Hcy was 13.8μmol/L,the Youden index was 0.784.(4)Elevated levels of Hcy in preterm women led to a marked increase in the likelihood of SGA. Conclusion When predicting risk factors for preterm birth,the best predictive cutoff value for Hcy is 13.8μmol/L,which is one of the independent risk factors for preterm birth.

Relationship between optimal cutoff value of serum homocysteine and risk factors of premature delivery and its logistic regression analysis / 实用医学杂志

Objective To investigate the relationship between the optimal cutoff point of serum homocyste-ine(Hcy)and premature delivery in pregnant women ,and to analyze the influence of Hcy levels on the outcome of preterm infants. Methods Totally 114 cases of pregnant women were chosen as observation group and 103 cases of normal as control group. Hcy,D-D and hypersensitive C reactive protein were detected;analysis of the ROC curve was conducted by using the SPSS 13 software and the risk factors for preterm delivery were analyzed using logistic multivariate regression analysis. Results (1)The levels of Hcy,HS-CRP and D-D in preterm pregnant women were higher than those in control group and the difference was statistically significant (P < 0.05). (2) Logistic regression analysis showed that the relative risk coefficient(OR)of Hcy was 9.736,and the regression equation of premature birth probability was obtained.(3)ROC curve to evaluate the predictive value of Hcy in risk factors of preterm birth was 0.931;when Hcy was 13.8μmol/L,the Youden index was 0.784.(4)Elevated levels of Hcy in preterm women led to a marked increase in the likelihood of SGA. Conclusion When predicting risk factors for preterm birth,the best predictive cutoff value for Hcy is 13.8μmol/L,which is one of the independent risk factors for preterm birth.

Clinical Value of Captopril Test for Primary Aldosteronism Diagnosis / 中国循环杂志

Objective: To evaluate the clinical value of Captopril test for diagnosing primary aldosteronism (PA) and to calculate the best cut-off point for PA diagnosis. Methods: We retrospectively analyzed 96 PA patients with conifrmed diagnosis by clinical situation, laboratory test and auxiliary examination in our hospital from 1994-06 to 2012-05, and meanwhile, studied 45 highly suspicious PA patients with final exclusion by confirmed diagnosis of primary hypertension (PH). All patients received the in-hospital Captopril test, the area under the curve of receiver operating characteristic (AUCROC) was applied to evaluate plasma aldosterone level and the ratio of aldosterone/renin after Captopril test and to obtain the best cut-off point with the corresponding sensitivity and speciifcity for PA diagnosis. Results: At 1h and 2h after Captopril test, AUCROC for plasma levels of aldosterone were 0.831 and 0.818, the ratios of aldosterone/rennin were 0.909 and 0.922 respectively. At 1h after Captopril test, the cut-off point of aldosterone level was 544.95 pmol/L and the diagnostic sensitivity was 70%, speciifcity was 90.7%; at 2h after Captopril test, the cut-off point of aldosterone level was 466.8 pmol/L and the diagnostic sensitivity was 69.8%, speciifcity was 70.5%. At 1h after Captopril test, the ratio of aldosterone/rennin was 34.6 [ng/dl: μg/(ml·h)] with the sensitivity at 78.3% and speciifcity at 88.4%. At 2h after Captopril test, the maximum AUCROC for the ratio of aldosterone/rennin was obtained, when cut-off point of aldosterone level was 42.2[ng/dl: μg/(ml·h)] , the diagnostic sensitivity was 76.7%, speciifcity was 95.3%. Conclusion: At 1h and 2h after Captopril test, plasma aldosterone level and the ratio of aldosterone/rennin had been valuable for PA diagnosis, the maximum diagnostic value could be obtained at 2h after Captopril test.

Selecting the Best Cut-off Point of Serum HE-4 in Ovarian Cancer by ROC Curve / 现代检验医学杂志

Objective Using ROC curve to determine the best cut-off point of serum HE-4 in the diagnosis of ovarian cancer and provide important value to diagnosis early ovarian cancer.Methods The levels of serum HE-4 in 68 ovarian cancer pa-tients,42 ovarian benign tumor patients and 30 healthy female were detected by electrochemistry irradiance method.The ROC curve was drawn and the cut-off point of HE-4 was determined by statistical software.Results The levels of serum HE-4 were all non-normal distribution in the groups of ovarian cancer,ovarian benign tumor and healthy controls.Whats more,there was no significant difference between ovarian benign tumor group and normal control group.And compared with benign ovarian tumors and normal control group,the level of HE-4 in ovarian cancers was significantly increased (P <0.01).It would be best for diagnosis when the level of serum HE-4 was 108pmol/L in ovarian cancer.Youden’s index showed the maximum (0.713)and the sensitivity and specificity of diagnosing were 77.9% and 93.1% respectively.The positive predictive value was 91.4% and negative predictive value was 91.4%.At the same time,the positive likelihood ratio was 11.6 and the negative likelihood ratio was 0.2,odds ratio reached to 47.3.Conclusion The detection of HE-4 is an ideal mark for diagnosing and excluding ovarian cancer.Selecting 108 pmol/L as ovarian cancer diagnosis point is relative appro-priate.

Optimal cut-off point of waist-to-height ratio for predicting metabolic syndrome / 中华临床营养杂志

Objective To investigate the relationship between waist-to-height ratio and metabolic syndrome,in order to identify the optimal cut-off point of waist-to-height ratio for predicting metabolic syndrome.Methods In this cross-sectional study,we recruited 343 people who received physical examination in First Hospital of Quanzhou between January 2012 and June 2014,and collected the information of their waist circumference,height,weight,blood pressure,laboratory test results (including fasting blood glucose,2-hour glucose after oral glucose tolerance test,triglyceride,high-density lipoprotein cholesterol) and visceral fat area assessed by computed tomography.Then a receiver operating characteristic (ROC) curve analysis was used to estimate the optimal cut-off points of waist-to-height ratio for the prediction of metabolic syndrome.Results Among the 343 people,there were 195 metabolic syndrome patients,the prevalence rate was 56.8％,which was 70.2％ in men (127/181) and 42.0％ in women (68/162).In ROC curve analysis,the area under the curve of waist-to-height ratio for the prediction of metabolic syndrome was 0.664 for men,and 0.673 for women.The optimal cut-off point of waist-to-height ratio for predicting metabolic syndrome was 0.543 0 (sensitivity 88.2％,specificity 44.4％) for men,and 0.568 3 (sensitivity 86.8％,specificity 46.8％).Conclusion The optimal cut-off point of waist-to-height ratio for predicting metabolic syndrome in Quanzhou population is 0.543 0 for men and 0.568 3 for women.

Significance of insulin tolerance test in the diagnosis of adult growth hormone deficiency / 中华内分泌代谢杂志

Objective To assess the significance of insulin tolerance test(ITT) in clinical diagnosis of adult growth hormone deficiency(GHD).Methods Eighty-two patients with an established diagnosis of adult GHD [53males,29 females,mean age (30.9 ± 12.3) years (18-65 years)] were reviewed retrospectively for evaluating the GH response to ITT in the General Hospital of the People' s Liberation Army.Control data for peak GH after ITT were obtained in 15 healthy subjects [9 males,6 females,mean age (26.7 ± 5.6) years (22-41 years)].Receiver operating characteristic (ROC) curve analysis and the area under the curve (AUC) were used to evaluate the diagnostic cut-off point of peak GH and GH increment response to ITT.Results (1) Mean peak GH response to ITT was significantly higher in 15 controls compared with 82 patients (the median 14 μg/L vs 0.62 μg/L,P =0.001).The cut-off point of the peak GH(chemiluminescent immunoassay,CLIA) response to ITT in adult GHD was 4.935 μg/L (AUC 0.993).(2) Mean GH increment was significantly higher in 15 controls compared with 82 patients (the median 13.17 μg/L vs 0.19 ug/L,P＜0.001).The cut-off point of the GH increment was 4.088 μg/L(AUC 0.937),with a 91.5％ sensitivity and 100％ specificity.(3) The peak GH showed even higher diagnostic value than the GH increment after ITT.(4)The above mentioned cut-off points (peak GH less than 4.935 μg/L and 5 μg/L) had a coincidence with a 95.1％ sensitivity and 100％ specificity,respectively.Conclusion The current guidelines for the diagnosis of adult GHD based on the optimal cut-off point of the peak GH(CLIA) response to ITT less than 5 μg/L turned to be of reliable diagnostic value in our country.

Receiver Operating Characteristic (ROC) Curve for Medical Researchers.

Sensitivity and specificity are two components that measure the inherent validity of a diagnostic test for dichotomous outcomes against a gold standard. Receiver operating characteristic (ROC) curve is the plot that depicts the trade-off between the sensitivity and (1-specificity) across a series of cut-off points when the diagnostic test is continuous or on ordinal scale (minimum 5 categories). This is an effective method for assessing the performance of a diagnostic test. The aim of this article is to provide basic conceptual framework and interpretation of ROC analysis to help medical researchers to use it effectively. ROC curve and its important components like area under the curve, sensitivity at specified specificity and vice versa, and partial area under the curve are discussed. Various other issues such as choice between parametric and non-parametric methods, biases that affect the performance of a diagnostic test, sample size for estimating the sensitivity, specificity, and area under ROC curve, and details of commonly used softwares in ROC analysis are also presented.

Cutoff Value of PB CD34+ Cells for Optimization of PBSC Collection / 대한수혈학회지

BACKGROUND: Peripheral hematopoietic stem cell mobilization is increasing due to its advantages. For successful engraftment, obtaining sufficient stem cells is prerequisite. The number of CD34+ cells of collected blood are widely used to predict the engraftment potential. To determine the optimal point for collection of peripheral blood stem cell (PBSC), enumeration of the number of CD34+ cells in peripheral blood (PB) is known to be helpful. The purpose of this study is to analyze cutoff value of CD34+ cells in PB. METHODS: We analyzed 407 cases of autologous PBSC collection and 107 cases of allogenic PBSC collection during 2004~2009 in Pusan National University Hospital. Complete blood count, HPC fraction and number, CD34+ cells in PB and product of PBSC collection were analyzed. RESULTS: The each number of mononuclear cells and HPC in PB showed a strong correlation with CD34+ cells in PB. A strong correlation between the number of circulation CD34+ cells in PB on the day of collection and the number of collected CD34+ cells was found. The ROC curve revealed that the cutoff point having the optimal sensitivity and specificity at 8.5/uL for target CD34+ cells > or =1.0x10(6)/kg, 10.5/uL for target CD34+ cells > or =1.5x10(6)/kg and 13.5/uL for target CD34+ cells > or =2.0x10(6)/kg in this study. CONCLUSION: To obtain a sufficient yield of CD34+ cells during PBSC collection, determination of cut off point for each target CD34+ cells//kg is helpful to decide the collection.

Cut-off points of fasting fingertip capillary blood glucose for detecting both undiagnosed diabetes and pre-diabetes / 中华流行病学杂志

Objective To determine the efficient cut-off points of fasting fingertip blood glucose test for undiagnosed diabetes mellitus(DM), impaired glucose tolerance(IGT), and impaired fasting glucose(IFG)in community-based residents aged above 45 years old. Methods A cluster-randomized study was conducted from May 2008 to January 2009. A total of 3250 subjects aged above 45 years in two communities of Baoding city received questionnaire investigation and tested for fingertip blood glucose. Those subjects whose capillary blood glucose level ≥5.1 mmol/L were subjected to 75 g oral glucose tolerance test. Undiagnosed diabetes mellitus and pre- diabetes were identified by fasting plasma glucose and OGTT. In this study, the cut-off points of fasting capillary blood glucose for detecting undiagnosed diabetes and pre-diabetes were evaluated, using receiver operator characteristic curve(ROC). Results Of 1351 subjects that having had oral glucose tolerance test, 230 cases were diagnosed as diabetes mellitus(7.3%), 166 cases(5.2%)as IFG, and 204(6.7%)as IGT under fasting capillary blood glucose as test variable and state variables according to the following criteria.(1)FPG≥7.0 mmol/L or/and 2hPG≥11.1 mmol/L(2)FPG<5.6 mmol/L (3)FPG<7.0 mmol/L and 7.8 mmol/L≤2hPG≤ 11.1 mmol/L, areas under three ROC curves were 0.905, 0.633 and 0.719, respectively. The cut-offvalues of screening for undiagnosed DM, IGT and IFG were 6.0 mmol/L, 5.7 mmol/L, and 5.7 mmol/L, respectively. When cut-off value of screening for undiagnosed DM was 6.0 mmol/L, the maximal sensitivity was 78.0% and specificity was 89.3%.But there were both lower sensitivity and specificity in screening for IFG and IGT according to the best predicting value(5.7 mmol/L)from the ROC curves(50.3% and 28.0% vs. 60.8% and 28.0%). Conclusion Fasting capillary blood glucose with the lower cut-point of 6.0 mmol/L in screening for undiagnosed diabetes mellitus alone, was relatively reliable, whereas for both IFG and IGT the fasting fingertip blood glucose tests were fallible. It was convenient and could be used in screening the DM at the community level.

Evaluation of vascular endothelial growth factor in early diagnosis of non-typical ectopic pregnancy / 中国综合临床

Objective To investigate the best dignostic cut-off point of non-typical ectopic pregnancy(EP) through the determination of vascular endothelial growth factor(VEGF)in 154 cases of suspected ectopic pregnancy patients.Methods The serum level of VEGF in 154 cases with suspected EP was determined by means of immunossay technique,and the results were made into ROC-Curve.Results The acreage behind the curve was 0.95,illustrating that the VEGF can be as a better marker for early diagnosis of EP.The serum VEGF level of 200pg/ml was the cut-off point for early diagnosis of EP throash ROC-Curve.Condusion The serum VEGF can be considered as an early diagnostic marker of EP,which cut-off point is benifical to reducing misdiagnosis of EP.