Lin's Concordance Coefficient Research Articles

Prospective Validation Study of the Prediction of Alcohol Withdrawal Severity Scale (PAWSS) in Medically Ill Inpatients: A New Scale for the Prediction of Complicated Alcohol Withdrawal Syndrome.

The prevalence of alcohol use disorders (AUDs) among hospitalized medically ill patients exceeds 40%. Most AUD patients experience uncomplicated alcohol withdrawal syndrome (AWS), requiring only supportive medical intervention, while complicated AWS occurs in up to 20% of cases (i.e. seizures, delirium tremens). We aimed to prospectively test and validate the Prediction of Alcohol Withdrawal Severity Scale (PAWSS), a new tool to identify patients at risk for developing complicated AWS, in medically ill hospitalized patients. We prospectively considered all subjects hospitalized to selected general medicine and surgery units over a 12-month period. Participants were assessed independently and blindly on a daily basis with PAWSS, Clinical Institute Withdrawal Assessment-Alcohol, Revised (CIWA-Ar) and clinical monitoring throughout their admission to determine the presence and severity of AWS. Four hundred and three patients were enrolled in the study. Patients were grouped by PAWSS score: Group A (PAWSS < 4; considered at low risk for complicated AWS); Group B (PAWSS ≥ 4; considered at high risk for complicated AWS). The results of this study suggest that, using a PAWSS cutoff of 4, the tool's sensitivity for identifying complicated AWS is 93.1% (95%CI[77.2, 99.2%]), specificity is 99.5% (95%CI[98.1, 99.9%]), positive predictive value is 93.1% and negative predictive value is 99.5%; and has excellent inter-rater reliability with Lin's concordance coefficient of 0.963 (95% CI [0.936, 0.979]). PAWSS has excellent psychometric characteristics and predictive value among medically ill hospitalized patients, helping clinicians identify those at risk for complicated AWS and allowing for prevention and timely treatment of complicated AWS.

Accuracy of Vigileo/Flotrac monitoring system in morbidly obese patients

PurposeOur goal was to assess the accuracy of measuring cardiac output (CO) by the FloTrac/Vigileo (COV) device in comparison with thermodilution technique through pulmonary artery catheterization (PACTD) in morbidly obese patients. Material and methodsCardiac output in 8 morbidly obese patients was assessed twice at upright and lying position breathing ambient air. At least 4 consecutive CO measurements with 10 mL of ice-cold saline injections were performed each time. Simultaneous CO measurements were recorded with both single-bolus thermodilution and COV. ResultsOne hundred thirty-two CO data pairs were collected. The overall mean single-bolus thermodilution 6.2 ± 1.1 L/min was lower than the overall mean COV 7.8 ± 1.6 L/min (P < .001). Lin concordance coefficient indicated that overall agreement between PACTD and COV was poor, 0.29. Lin concordance coefficient in sitting position was 0.29, 95% confidence interval (0.17-0.40) and in lying position was 0.30, 95% confidence interval (0.15-0.44). The Bland-Altman plot analysis showed systematically higher values from COV in comparison with PACTD. These differences increased in presence of high CO measurements. In 3 of 8 patients, the percentage error was lower than 20%, whereas in the other 5, it was higher than 20%. Of these 5, in 2 cases, the percentage error was greater than 50%. ConclusionData obtained using COV vs PACTD measurements showed poor correlation. The results were not interchangeable.

Diagnostic ability of Chronic Kidney Disease Epidemiology Collaboration and Modification of Diet in Renal Disease-4 equations to estimate glomerular filtration rate in with multimorbidity patients

Background and objectiveThe Modification of Diet in Renal Disease (MDRD) equation is recommended by most scientific societies to calculate the estimated glomerular filtration rate (GFR). Recently the group Chronic Kidney Disease Epidemiology Collaboration (CKP-EPI) has published a new, more precise and accurate equation. We have analysed its behaviour in a group of polypathological patients (PP) and compared it with the classic MDRD-4.version. Patients and methodMulticenter, observational, descriptive and transversal study. We calculated GFR by MDRD-4 and CKD-EPI in 425 PP. Each stage was assigned according to the GFR: 1: >90; 2: 60–89; 3: 30–59; 4: 15–29; and 5 <15ml/min/1.73m2. We analysed the correlation between both and the patients reclassified by CKD-EPI. ResultsMean age was (mean [SD]) 81.7 (7.9) years. 55.3% were women. The mean estimated GFR was 58.6 (26.3)ml/min/1.73m2 by MDRD-4 and 52.7 (23.0)ml/min/1.73m2 by CKD-EPI (p<.001; Spearman's Rho correlation and Lin concordance coefficients: 0.993 and 0.948). The Bland–Altman plots reflected lower values for GFR for CKD-EPI equation. In the stage 2, 21.2% were reclassified by CKD-EPI to the stage 3, with women older than 83 years being the more disadvantaged subgroup with 27.3% or reclassification. ConclusionCKD-EPI equation applied to PP worsens the results of MDRD-4. In general, it originates low values of GFR and increases the degree of renal insufficiency, especially in older women.

Low Alberta Stroke Program Early CT Score (ASPECTS) Associated with Malignant Middle Cerebral Artery Infarction

Background: Early decompressive hemicraniectomy following malignant middle cerebral artery (MCA) infarction reduces mortality and improves clinical outcome. Imaging predictors of malignant infarction may serve as ‘red flags', prompting intensive neurological monitoring and timely intervention. Our objective is to investigate whether lower ASPECTS (Alberta Stroke Program Early CT Score) is associated with malignant MCA infarction. Methods: A retrospective cohort study of all patients with MCA territory ischemic strokes who were admitted to the Royal Melbourne Hospital (RMH) between 1 January 2009 and 31 December 2009 (226 patients included). The main outcome measures were ASPECTS on admission for each patient and the development of malignant MCA infarction. Results: One-hundred-and-eight patients out of 226 (48%) developed malignant MCA infarction. Good (>0.8) inter-rater agreement between observers scoring ASPECTS was observed using weighted kappa, intra-class correlation coefficient and Lin's concordance coefficients. Using receiver operating characteristic (ROC) curve analysis, we validated that ASPECTS 7 was the optimal cut-off score to determine progression to malignant infarction, providing 50% sensitivity and 86% specificity. One hundred and fifty six patients had ASPECTS >7 (69%) and 70 patients had ASPECTS ≤7 (31%). Patients with ASPECTS ≤7 were significantly younger than those with ASPECTS >7, with the median age of each group being 72.5 and 78 respectively (p = 0.02); otherwise the groups were well-matched. With ASPECTS ≤7, 54 out of 70 patients (77%) developed malignant MCA infarction, compared with 54 out of 156 patients (35%) with ASPECTS >7 (age-adjusted OR = 0.12, 95% CI: 0.06, 0.25; p < 0.0001). If ASPECTS ≤7 is a positive result, then the positive predictive value is 77% and the negative predictive value is 65%. The median ASPECTS for developing malignant MCA infarction was 7.5 (IQR: 5 to 10), while the median ASPECTS for not developing MCA infarction was 10 (IQR: 8 to 10), resulting in a significant age-adjusted median difference of 2 (95% CI: 0.8, 3.2; p < 0.0001). We also found that coma on admission is associated with the development of malignant MCA infarction (OR = 22.63, 95% CI: 1.3, 393.7; p = 0.0323) and that a history of hypertension is not associated with the development of malignant MCA infarction (OR = 0.9707, 95% CI: 0.54, 1.75; p = 0.9213). Conclusions: ASPECTS ≤7 on initial brain CT in a patient with MCA infarction is associated with the development of malignant MCA infarction. We recommend close monitoring of, and early consideration of decompressive hemicraniectomy for, acute stroke patients with ASPECTS ≤7.

Radiographic Interpretation of Distal Radius Fractures: Visual Estimations versus Digital Measuring Techniques

Distal radius fractures are a common injury. In the emergency room, trainees regularly assess these fractures using visual estimation. Our hypothesis is that assessment of radiographic parameters has sufficient accuracy for rendering treatment consistent with formal measurements. This study compared visual measurements made by 25 orthopaedic residents and attending physicians to formal measurements made by a single fellowship trained musculoskeletal radiologist in a series of patients with distal radius fractures. A search was performed utilizing the ICD-9 code for distal radius fracture in all patients presenting to a single institution emergency department. Participants used visual estimation to rate 25 radiographs. Parameters estimated included radial inclination, radial height, volar tilt, and the presence of intra-articular displacement. Analysis using Lin concordance coefficients, Bland Altman plots, and the Kappa statistic evaluated the agreement between visual estimation and formal measurements. The proportion of raters whose estimates would have resulted in a course of treatment that conflicted with the formal reading quantified the potential impact of visual estimation on treatment. Concordance coefficients were poor for radial inclination (ρc = 0.13), radial height (ρc = 0.24), and volar tilt (ρc = 0.46). The Kappa statistic for intra-articular displacement was 0.4. Analysis performed according to level of training did not result in substantial improvements in these statistics. Treatment based on visual estimates conflicted with formal readings 34% of the time for radial inclination, 38% of the time for radial height, 27% of the time for volar tilt, and 31% of the time for intra-articular displacement. Visual estimation is not an adequate form of measurement for evaluation of patients with distal radius fractures. Physicians should be mindful of these results when developing treatment plans based solely upon visual estimation.

Statistical evaluation of reproducibility of automated ECG measurements: An example from arrhythmogenic right ventricular dysplasia/cardiomyopathy clinic

BackgroundArrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is characterized by delay in depolarization of the right ventricle, detected by prolonged terminal activation duration (TAD) in V1–V3. However, manual ECG measurements have shown moderate-to-low intra- and inter-reader agreement. The goal of this study was to assess reproducibility of automated ECG measurements in the right precordial leads. MethodsPairs of ECGs recorded in the same day from Johns Hopkins ARVD/C Registry participants [n=247, mean age 35.2±15.6 years, 58% men, 92% whites, 11(4.5%) with definite ARVD/C] were retrospectively analyzed. QRS duration, intrinsicoid deflection, TAD, and T-wave amplitude in the right precordial leads, as well as averaged across all leads QRS duration, QRS axis, T axis, QTc interval, and heart rate was measured automatically, using 12SL TM algorithm (GE Healthcare, Wauwatosa, WI, USA). Intrinsicoid deflection was measured as the time from QRS complex onset to the alignment point of the QRS complex. TAD was calculated as the difference between QRS duration and intrinsicoid in V1–V3. Reproducibility was quantified by Bland–Altman analysis (bias with 95% limits of agreement), Lin's concordance coefficient, and Bradley–Blackwood procedure. ResultsBland–Altman analysis revealed satisfactory reproducibility of tested parameters. V1 QRS duration bias was −0.10ms [95% limits of agreement −12.77 to 12.56ms], V2 QRS duration bias −0.09ms [−11.13 to 10.96ms]; V1 TAD bias 0.14ms [−13.23 to 13.51ms], V2 TAD bias 0.008ms [−12.42 to 12.44ms]. ConclusionComprehensive statistical evaluation of reproducibility of automated ECG measurements is important for appropriate interpretation of ECG. Automated ECG measurements are reproducible to within 25%.

Quantification of hepatic steatosis: A comparison of the accuracy among multiple magnetic resonance techniques

Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) are important diagnostic tools for the non-invasive assessment of hepatic steatosis (HS). This study was conducted to compare different magnetic resonance (MR) techniques and correlate the MR findings with histological and intracellular lipid density findings. In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant prospective study, 60 patients scheduled for liver resection were included in this study. Fat fraction in the non-tumorous liver parenchyma was estimated using double-echo MRI, triple-echo MRI (TE-MRI), and MRS. HS was defined by the histologic steatosis percentage (HSP), and intrahepatocellular triglyceride density (IHTGD) of the surgical specimen used as the reference standard. Imaging quantification results were evaluated using Pearson's correlation. Lin's concordance coefficient and Bland-Altman 95% limits of agreement were used to evaluate the concordance of IHTGDs estimated by the three MR techniques. The diagnostic performance was compared using receiver operating characteristic curve analysis. HS assessed by TE-MRI and MRS had a stronger relationship with HS assessed by HSP and IHTGD. The TE-MRI method had the highest concordance correlation coefficients (ρ = 0.881) and percentage (95%, 57/60) within the Bland-Altman 95% limits of agreement. Receiver operating characteristic curve analysis for diagnosing > 5% HSP showed significantly larger area under the curve (0.9783) for TE-MRI than for double-echo MRI (0.8773, P = 0.0121). Among the three MR techniques, TE-MRI and MRS may be the preferred techniques for non-invasive assessment of HS.

Comparison of carotid artery dimensions and lesion length measured by B‐mode ultrasonography and quantitative angiography in patients with severe stenosis undergoing percutaneous revascularization

To evaluate the correlation and agreement of the carotid artery landmarks necessary for carotid artery stenting obtained by B-mode ultrasonography (BMU), and by quantitative angiography (QCA) in patients with severe carotid artery stenosis. In 75 patients undergoing carotid artery stenting, the distal common (CCA), proximal internal (ICA) carotid artery diameter, and lesion length were measured preoperatively by BMU, and intraoperatively by QCA. In 96% of the subjects, BMU imaging was adequate for interpretation. BMU and QCA Pearson correlation and Lin concordance coefficients were 0.75 (p < 0.001) and 0.959 (95% CI: 0.930 - 0.996), respectively, for CCA diameter, 0.88 (p < 0.001) and 0.954 (95% CI: 0.928-0.983), respectively, for ICA diameter, and 0.62 (p < 0.001) and 0.734 (95% CI: 0.719-0.760), respectively, for lesion length, with a 0.765 bias correction factor and a wider data scatter by Bland Altman plots showing shorter lesion length by BMU than by QCA. In patients with carotid artery stenosis, BMU can provide reliable distal CCA and proximal ICA diameters in comparison with QCA, whereas lesion length measured by BMU has an acceptable correlation, but a poor agreement with QCA.

In women, no significant variances of calculated free testosterone (cFT) are observed when a fixed value of albumin (Alb: 4.3 g/dL) is used instead of measured albumin values.

Calculated free testosterone (cFT) is determined from the values of total testosterone (TT), sex hormone binding globulin (SHBG), and albumin (Alb) using mathematical formulae. We evaluated any potential cFT variance when determined with fixed Alb (4.3 g/dL) compared to measured Alb, and the point at which low SHBG and Alb combinations produced significant cFT variance. We analyzed 2050 data points in 1222 women. cFT values with fixed vs. the actual measured Alb values were evaluated and contrasted. cFT levels were determined theoretically for all possible combinations of TT, SHBG, and Alb. Agreement between the two measures was assessed with Lin's concordance coefficient. Statistical analyses were performed using R software version 2.12.1. Mean Alb was 4.05 ± 0.30 g/dL. Mean SHBG 73.0 ± 53.3 nmol/L. A fixed Alb of 4.3 g/dL produced no significant variance for most evaluations of cFT. The accuracy decreased with Alb ≤ 3.5 g/dL in combination with SHBG ≤ 30 nmol/L and exists in 1.0% of the samples. A fixed Alb of 4.3 g/dL is acceptable for most clinical evaluations. If Alb is ≤ 3.5 g/dL, along with SHBG ≤ 30 nmol/L, the variance increases and a free testosterone (FT) measurement by equilibrium dialysis is warranted for better accuracy.

Comparison of PET template-based and MRI-based image processing in the quantitative analysis of C11-raclopride PET

BackgroundQuantitative measures of 11C-raclopride receptor binding can be used as a correlate of postsynaptic D2 receptor density in the striatum, allowing 11C-raclopride positron emission tomography (PET) to be used for the differentiation of Parkinson’s disease from atypical parkinsonian syndromes. Comparison with reference values is recommended to establish a reliable diagnosis. A PET template specific to raclopride may facilitate direct computation of parametric maps without the need for an additional MR scan, aiding automated image analysis.MethodsSixteen healthy volunteers underwent a dynamic 11C-raclopride PET and a high-resolution T1-weighted MR scan of the brain. PET data from eight healthy subjects was processed to generate a raclopride-specific PET template normalized to standard space. Subsequently, the data processing based on the PET template was validated against the standard magnetic resonance imaging (MRI)-based method in 8 healthy subjects and 20 patients with suspected parkinsonian syndrome. Semi-quantitative image analysis was performed in Montreal Neurological Institute (MNI) and in original image space (OIS) using VOIs derived from a probabilistic brain atlas previously validated by Hammers et al. (Hum Brain Mapp, 15:165–174, 2002).ResultsThe striatal-to-cerebellar ratio (SCR) of 11C-raclopride uptake obtained using the PET template was in good agreement with the MRI-based image processing method, yielding a Lin’s concordance coefficient of 0.87. Bland-Altman analysis showed that all measurements were within the ±1.96 standard deviation range. In all 20 patients, the PET template-based processing was successful and manual volume of interest optimization had no further impact on the diagnosis of PD in this patient group. A maximal difference of <5% was found between the measured SCR in MNI space and OIS.ConclusionsThe PET template-based method for automated quantification of postsynaptic D2 receptor density is simple to implement and facilitates rapid, robust and reliable image analysis. There was no significant difference between the SCR values obtained with either PET- or MRI-based image processing. The method presented alleviates the clinical workflow and facilitates automated image analysis.

Capacidad diagnóstica de las ecuaciones Chronic Kidney Disease Epidemiology Collaboration y Modification of Diet in Renal Disease-4 en la estimación del filtrado glomerular en pacientes pluripatológicos

Background and objectiveThe Modification of Diet in Renal Disease (MDRD) equation is recommended by most scientific societies to calculate the estimated glomerular filtration rate (GFR). Recently the group Chronic Kidney Disease Epidemiology Collaboration (CKP-EPI) has published a new, more precise and accurate equation. We have analyzed its behavior in a group of polypathological patients (PP) and compared it with the classic MDRD-4.version Patients and methodMulticenter, observational, descriptive and transversal study. We calculated GFR by MDRD-4 and CKD-EPI in 425 PP. Each stage was assigned according to the GFR: 1:>90; 2: 60-89; 3: 30-59; 4: 15-29; and 5<15ml/min/1.73m2. We analyzed the correlation between both and the patients reclassified by CKD-EPI. ResultsMean age was (mean [SD]) 81.7 (7.9) years. 55.3% were women. The mean estimated GFR was 58.6 (26.3) ml/min/1,73m2 by MDRD-4 and 52.7 (23.0) ml/min/1.73m2 by CKD-EPI (P<.001; Spearman's Rho correlation and Lin concordance coefficients: 0.993 and 0.948). The Bland-Altman plots reflected lower values for GFR for CKD-EPI equation. In the stage 2, 21.2% were reclassified by CKD-EPI to the stage 3, with women older than 83 years being the more disadvantaged subgroup with 27.3% or reclassification. ConclusionCKD-EPI equation applied to PP worsens the results of MDRD-4. In general, it originates low values of GFR and increases the degree of renal insufficiency, especially in older women.

Quantification of cervical spine muscle fat: a comparison between T1-weighted and multi-echo gradient echo imaging using a variable projection algorithm (VARPRO)

BackgroundPrevious data using T1-weighted MRI demonstrated neck muscle fat infiltration (MFI) in patients with poor functional recovery following whiplash. Such findings do not occur in those with milder symptoms of whiplash, chronic non-traumatic neck pain or healthy controls, suggesting traumatic factors play a role. Muscle degeneration could potentially represent a quantifiable marker of poor recovery, but the temporal constraints of running a T1-weighted sequence and performing the subsequent analysis for muscle fat may be a barrier for clinical translation. The purpose of this preliminary study was to evaluate, quantify and compare MFI for the cervical multifidus muscles with T1-weighted imaging and a more rapid quantitative 3D multi-echo gradient echo (GRE) Dixon based method in healthy subjects.Methods5 asymptomatic participants with no history of neck pain underwent cervical spine MRI with a Siemens 3 Tesla system. The muscle and fat signal intensities on axial spin-echo T1-weighted images were quantitatively classified for the cervical multifidii from C3-C7, bilaterally. Additional axial GRE Dixon based data for fat and water quantification were used for comparison via paired t-tests. Inter-tester reliability for fat and water measures with GRE images were examined using 1) Pearson’s Intra-class correlation coefficient 2) Bland-Altman Plots and 3) Lin’s-Concordance Coefficient. P < 0.05 was used to indicate significance.ResultsTotal mean (SD) MFI (C3-C7) for the multifidii obtained with T1-weighted imaging and GRE were 18.4% (3.3) (range 14-22%) and 18.8% (2.9) (range 15-22%), respectively. The Pearson correlation coefficients for inter-tester reliability on the GRE sequences for the C3-C7 multifidii ranged from .83 - .99, indicating high levels of agreement with segmental MFI measures. Bland-Altman Plots revealed all data points were within 2 SDs and concordance was established between 2-blinded raters, suggesting good agreement between two raters measuring fat and water with GRE imaging.ConclusionsResults of this preliminary study demonstrate reliability between 2 raters of varying experience for MRI analysis of MFI with 3D GRE MRI. The quantification of MFI for healthy cervical musculature is comparable to T1-weighted images. Inclusion of larger samples of symptomatic data and histological comparison with the reference standard biopsy is warranted.

Validity of a Portable Glucose, Total Cholesterol, and Triglycerides Multi-Analyzer in Adults

This study investigated the accuracy and precision of the Accutrend Plus system to determine blood glucose, total cholesterol, and plasma triglycerides in adults and evaluated its efficiency in measuring these blood variables. The sample consisted of 53 subjects (≥ 18 years). For blood variable laboratory determination, venous blood samples were collected and processed in a Labmax 240 analyzer. To measure blood variables with the Accutrend Plus system, samples of capillary blood were collected. In the analysis, the following tests were included: Wilcoxon and Student's t-tests for paired samples, Lin's concordance coefficient, Bland-Altman method, receiver operating characteristic curve, McNemar test, and k statistics. The results show that the Accutrend Plus system provided significantly higher values (p ≤ .05) of glucose and triglycerides but not of total cholesterol (p > .05) as compared to the values determined in the laboratory. However, the system showed good reproducibility (Lin's coefficient: glucose = .958, triglycerides = .992, total cholesterol = .940) and high concordance with the laboratory method (Lin's coefficient: glucose = .952, triglycerides = .990, total cholesterol = .944) and high sensitivity (glucose = 80.0%, triglycerides = 90.5%, total cholesterol = 84.4%) and specificity (glucose = 100.0%, triglycerides = 96.9%, total cholesterol = 95.2%) in the discrimination of high values of the three blood variables analyzed. It could be concluded that despite the tendency to overestimate glucose and triglyceride levels, a portable multi-analyzer is a valid alternative for the monitoring of metabolic disorders and cardiovascular risk factors.

Skinfold Anthropometry –The Accurate Method for Fat Free Mass Measurement in COPD

Purpose: Fat free mass index (FFMI) is an independent predictor of metabolic and functional consequences in COPD. For its measurement dual energy X-ray absorptiometry (DEXA), skin-fold anthropometry (SFA), bioelectrical impedance analysis (BIA) and bioimpedance spectroscopy (BIS) are used in clinical practice. The aim of our pilot study was to analyse precisely and critically which method is most accurate and available for common use in clinical practice for measurement of FFM by assessment against relevant DEXA in patients with COPD. Methods: This was an observational cross-sectional study of consecutive COPD subjects. FFM by methods of SFA, two versions of BIA, and BIS was compared with that from clinically relevant DEXA in 41 outpatients (mean age 66.5 ± 7.7 yrs) with stable COPD, 34 men and 7 women, with mean BMI 28.2 ± 6.1 kg.m−2. Results: All methods underestimate FFM in comparison with DEXA. In the general evaluation non-significant differences with the smallest mean bias were demonstrated for SFA (1.2 kg) and BIA (3.8 kg), but there was a difference of more than 9 kg using BIS and BIA COPD methods (p < 0.0001). The best agreement between DEXA and SFA was demonstrated via Lin's concordance coefficient and Bland–Altman test. Conclusions: SFA has been demonstrated as an accurate, available and cheap method for determination of FFM and FM with application of the Durnin Womersley equation for body density and with the Siri equation for FM in patients with COPD. SFA can be easily applied in routine clinical practice.

Plasma Malondialdehyde as Biomarker of Lipid Peroxidation: Effects of Acute Exercise

The marker most frequently used to indicate the level of lipid peroxidation in the field of exercise and sports is malondialdehyde (MDA), which can be determined by many different techniques. However, there are few studies discussing differences and advantages of the methods for MDA assay in sports science field. The aim of the present study was to compare three techniques for quantification of MDA in plasma of humans subjected to acute exercise. MDA was determined by high performance liquid chromatography (MDA-HPLC), thiobarbituric acid reactive species (MDA-TBARS) and 1-methyl-2-phenylindole (MDA-MP) techniques in the plasma of 8 healthy male soccer athletes before and after acute exercise. Acute exercise significantly increased (P<0.05) plasma MDA concentration determined by MDA-HPLC (18%) and MDA-TBARS (56%) techniques. MDA-MP technique did not reveal significant differences, although it increased 25% after exercise. When correlated to the gold standard (MDA-HPLC), MDA-TBARS and MDA-MP techniques showed weak Lin concordance coefficients and non-significant correlation. Also, MDA-TBARS and MDA-MP techniques overestimated the MDA-HPLC technique by 100 and 122%, respectively. In conclusion, MDA-HPLC and MDA-TBARS are sensitive to detect change in MDA induced by acute exercise. MDA-HPLC is the most suitable technique for accurate detection of MDA in sports and exercise area due to its sensitivity and accuracy.

Concordance between Self and Standardized Patient Ratings of Medical Students' Communication Skills.

The purpose of this study was to examine the concordance between self and standardized patient (SP) ratings of medical students' communication skills. Forty-three students interviewed SPs. The students were asked to complete a communication skills questionnaire that comprised 2 measures (empathy and interpersonal communication) before the interview. After each student's interview with the SP, the latter completed the same questionnaire as the students. Based on Lin's concordance coefficient, there was strong disconcordance between students' self-ratings and the SPs' ratings. With regard to empathic communication, more than 50% of students who considered themselves higher than middle level were regarded by SP as low level. On interpersonal communication, 39% of students who assessed themselves as higher than middle level were scored low level by SPs. There was strong disconcordance between students' self-ratings and the SPs' ratings-students tended to overevaluate themselves regarding their communication skills. These differences might result in patient dissatisfaction and noncompliance. Further, it could become a serious hindrance to the development of a good doctor-patient relationship. Medical educators should make sincere efforts to reduce this gap by teaching medical students the importance of the patients' perception of his doctors' communication skills.

Are There Variances Of Calculated Free Testosterone Attributed To Variations In Albumin And Sex Hormone-Binding Globulin Concentrations In Men?

Calculated free testosterone (cFT) is determined from total testosterone (TT), sex hormone binding globulin (SHBG), and albumin (Alb) levels using mathematical formulae. Variations in cFT due to changes in SHBG or Alb have not been investigated. We evaluated potential cFT variances determined with fixed Alb (4.3 g/dL) and measured Alb, and the point at which low SHBG and Alb combinations produced significant cFT variance. We analyzed 11,176 data points from 5,797 men. cFT values with fixed versus actual Alb values were evaluated and compared. cFT levels were theoretically determined for all possible combinations of TT, SHBG, and Alb (8,343,552 combinations). Agreement between the 2 measures was assessed with Lin's concordance coefficient. Mean Alb was 4.06 ± 0.32 g/dL. Mean SHBG was 39.0 ± 23.6 nmol/L. A fixed Alb of 4.3 g/dL did not produce significant variance for most cFT evaluations. Accuracy decreased when Alb was ≤3.5 g/dL in combination with SHBG ≤30 nmol/L, and this occurred in 1.2% of all data points. A fixed Alb of 4.3 g/dL is acceptable for most clinical evaluations. If Alb is ≤3.5 g/dL and SHBG is ≤30 nmol/L, the variance increases, and a free testosterone (FT) measurement by equilibrium dialysis is warranted for better accuracy.

Validation of body adiposity index as a measure of obesity in overweight and obese postmenopausal white women and its comparison with body mass index

The purpose of this study was to evaluate whether the recently developed body adiposity index (BAI) in Mexican American and African American women could be validated in postmenopausal American white women and to determine if it is a better obesity classification measure than body mass index (BMI) is in the latter population. Total body percentage adiposity (%adiposity) measured by dual-energy x-ray absorptiometry (DXA) was compared with total body %adiposity predicted by BAI in 187 overweight/obese postmenopausal white women (mean ± SD %adiposity, 45.9 ± 4.9% and 38.3 ± 6.2% for DXA and BAI, respectively). SPSS 19.0 and Medcalc 11.6.1.0 were used to conduct Pearson's correlations (r), paired t test, receiver operating curve, and Lin's concordance coefficient (ρc) and to create Bland and Altman's limit-of-agreement plot. Pearson's correlation analysis revealed a strong association between DXA %adiposity and BAI (r = 0.78, P < 0.001), DXA %adiposity and BMI (r = 0.75, P < 0.001), and BMI and BAI (r = 0.90, P < 0.001). Bias correction factor was 0.51 between DXA %adiposity and BAI. Paired t test showed a significant mean difference between measurements (P < 0.0001), and the plot showed that BAI underestimated DXA %adiposity by 7.56%. Concordance coefficient (ρc = 0.39; 95% CI, 0.33-0.46) revealed a poor agreement strength. There was no difference between the area under the curve statistic for BAI and BMI. Based on our results, BAI has limitations for use in a clinical setting in overweight/obese postmenopausal white women but may be practical for research applications and eventually developed into an easy method to estimate overweight/obesity in other settings.

Thermodilution versus Saline Dilution Method for Vascular Access Blood Flow Measurement in High-Flux and On-Line Hemodiafiltration

Purpose Access blood flow (Qa) measurements are one of the most important components in vascular access monitoring programs, even though these indirect methods have only been validated with high-flux hemodialysis (HF; pump flow [Qb] 300 mL/min). This study was to assess the utility from thermodilution (BTM) with respect to the saline dilution method (SDM) in HF and on-line hemodiafiltration (OL-HDF) with routinely prescribed parameters in comparison with validation conditions. Methods Three consecutive sessions were assessed in 31 hemodialysis patients (27AVF). The Bland-Altman method and Lin's concordance coefficient (ρc) were used to study accuracy and precision. We used the student t test for the analysis of Qa-value in the different subgroups. Results In HF-hemodialysis 1 (Qb 300 mL/min), Qa was 1109 ± 541 mL/min SDMa and 1213 ± 639 mL/min BTM (P=.993a; bias 103.7 mL/min and ρc 0.78). In HF-hemodialysis 2 (Qb 420 mL/min) Qa 1071 ± 578 mL/min SDM (P=1.0a; -38.2 mL/min and 0.96) and 1216 ± 667 mL/min BTM (P=.992a; 127.3 mL/min and 0.70). In OL-HDF hemodialysis 3 (Qb 420 mL/min) Qa 1071 ± 510 mL/min SDM (P=1.0a; -48.4 mL/min and 0.96) and 1219 ± 580 mL/min BTM (P=.977a; 99.2 mL/min and 0.75). Statistically significant differences were only obtained in patients aged ≥ 65 years old (P=.016) and peripheral vascular disease (P=.007). Conclusions Our results demonstrate how the saline dilution method was more accurate than thermodilution in the HF and OL-HDF modalities with routinely prescribed parameters. Finally, in this study, advanced age (&gt;65 years old) and peripheral vascular disease were associated with a significantly lower Qa-value.

Calibration of unified Parkinson's disease rating scale scores to Movement Disorder Society-unified Parkinson's disease rating scale scores.

The aim of this study was to develop formulas to convert the UPDRS to Movement Disorder Society (MDS)-UPDRS scores. The MDS-UPDRS is a revision of the UPDRS with sound clinimetric properties. Reliable formulas to recalculate UPDRS scores into MDS-UPDRS equivalents are pivotal to the practical transition and definitive adoption of the MDS-UPDRS. UPDRS and MDS-UPDRS scores were collected on 875 PD patients. A developmental sample was used to regress UPDRS scores on corresponding MDS-UPDRS scores based on three H & Y groupings (I/II, III, and IV/V). Regression weighting factors and intercept terms provided formulas for UPDRS conversions to be tested in a validation sample. Concordance between the true MDS-UPDRS Part scores and those derived from the formulas was compared using Bland-Altman's plots and Lin's concordance coefficient (LCC). Significant concordance between UPDRS-estimated MDS-UPDRS scores was achieved for Parts II (Motor Experiences of Daily Living) (LCC = 0.93) and III (Motor Examination) (LCC = 0.97). The formulas resulted in mean differences between the true MDS-UPDRS and estimated MDS-UPDRS scores of less than 1 point for both Parts II and III. Concordance was not achieved for Parts I and IV (Non-motor Experiences of Daily Living and Complications of Therapy). Formulas allow archival UPDRS Parts II and III individual patient data to be accurately transferred to MDS-UPDRS scores. Because Part I collects data on much more extensive information than the UPDRS, and because Part IV is structured differently in the two versions, old ratings for these parts cannot be converted. © 2012 Movement Disorder Society.