scholarly journals Minimal clinically important difference of improvement on the Arm Function in Multiple Sclerosis Questionnaire (AMSQ)

2019 ◽  
Vol 26 (4) ◽  
pp. 505-508 ◽  
Author(s):  
Caspar EP van Munster ◽  
Levent Kaya ◽  
Morgan Obura ◽  
Nynke F Kalkers ◽  
Bernard MJ Uitdehaag
Keyword(s):  
Multiple Sclerosis ◽  
Receiver Operating Characteristic ◽  
Sensitivity And Specificity ◽  
Roc Curve ◽  
Operating Characteristic ◽  
Minimal Clinically Important Difference ◽  
Threshold Value ◽  
Clinically Important Difference ◽  
Upper Extremity Function ◽  
Arm Function

Background: The Arm Function in Multiple Sclerosis Questionnaire (AMSQ) has been developed to assess upper extremity function of patients with multiple sclerosis (MS). A minimal clinically important difference (MCID) value has not been determined yet. Objective: The objective of this study is to determine an MCID for AMSQ. Methods: We used the sensitivity- and specificity-based approach with dichotomized global perceived effect as an anchor. Results: The receiver operating characteristic (ROC) curve yielded an optimal threshold value of 14.5 (sensitivity 0.68 and specificity 0.79). The area under the ROC curve value was 0.77. Conclusion: We identified an MCID of 15 points for the AMSQ (range 31–186).

scholarly journals Information Graphs Incorporating Predictive Values of Disease Forecasts

Entropy ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 361 ◽  
Author(s):  
Gareth Hughes ◽  
Jennifer Reed ◽  
Neil McRoberts
Keyword(s):  
Plant Pathology ◽  
Disease Management ◽  
Receiver Operating Characteristic ◽  
Sensitivity And Specificity ◽  
Roc Curve ◽  
Operating Characteristic ◽  
Additional Data ◽  
Predictive Values ◽  
Risk Variable ◽  
Expected Information

Diagrammatic formats are useful for summarizing the processes of evaluation and comparison of forecasts in plant pathology and other disciplines where decisions about interventions for the purpose of disease management are often based on a proxy risk variable. We describe a new diagrammatic format for disease forecasts with two categories of actual status and two categories of forecast. The format displays relative entropies, functions of the predictive values that characterize expected information provided by disease forecasts. The new format arises from a consideration of earlier formats with underlying information properties that were previously unexploited. The new diagrammatic format requires no additional data for calculation beyond those used for the calculation of a receiver operating characteristic (ROC) curve. While an ROC curve characterizes a forecast in terms of sensitivity and specificity, the new format described here characterizes a forecast in terms of relative entropies based on predictive values. Thus it is complementary to ROC methodology in its application to the evaluation and comparison of forecasts.

RECEIVER OPERATING CHARACTERISTIC ANALYSIS OF INTRAOPERATIVE PARATHYROID HORMONE MONITORING TO DETERMINE OPTIMUM SENSITIVITY AND SPECIFICITY: ANALYSIS OF 896 CASES

2019 ◽  
Vol 25 (11) ◽  
pp. 1117-1126
Author(s):  
Christina S. Foley ◽  
Edwina C. Moore ◽  
Mira Milas ◽  
Eren Berber ◽  
Joyce Shin ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Parathyroid Hormone ◽  
Primary Hyperparathyroidism ◽  
Receiver Operating Characteristic ◽  
Sensitivity And Specificity ◽  
Roc Curve ◽  
Roc Analysis ◽  
Operating Characteristic ◽  
Intraoperative Parathyroid Hormone ◽  
Receiver Operating

Objective: While intraoperative parathyroid hormone (IOPTH) monitoring with a ≥50% drop commonly guides the extent of exploration for primary hyperparathyroidism (pHPT), receiver operating characteristic (ROC) analysis has not been performed to determine whether other criteria yield better sensitivity and specificity. The aim of this study was to identify the optimum percent change of IOPTH following removal of the abnormal parathyroid pathology, in order to predict biochemical cure. Secondary aims were to identify patient subgroups with increased area under the ROC curve (AUC) and the need for moderated criteria. Methods: A retrospective review was performed on patients undergoing primary parathyroid surgery for sporadic pHPT between 1999 and 2010 at a tertiary center for endocrine surgery. Eight hundred and ninety-six patients with primary hyperparathyroidism were included. Multigland disease (MGD) was defined as the intraoperative detection of more than 1 enlarged hypercellular gland or persistent disease after single gland excision. ROC analysis was used to determine the value with the best performance at predicting MGD, following bilateral exploration. Results: MGD was diagnosed in 174 patients (19.4%). ROC analysis demonstrated an AUC of 0.69. An IOPTH drop of 72% was the point of optimal discrimination with a sensitivity of 55% and specificity of 76% for predicting MGD. Subgroup analysis by preoperative calcium, preoperative PTH, localization studies, or pre- and post-excision IOPTH, did not identify any factors associated with an improved AUC. Conclusion: To our knowledge, this is the first study to use ROC analysis in a large patient cohort. An IOPTH drop of 72% was found to have optimal discriminating ability. We failed to identify a subset of patients for whom there was substantial improvement in the AUC, sensitivity, or specificity. Abbreviations: AUC = area under the ROC curve; BE = bilateral neck exploration; FE = focal parathyroid exploration; IOPTH = intraoperative parathyroid hormone; MGD = multigland disease; MIBI = Tc99m-sestamibi I-123 subtraction single-photon emission computed tomography/computed tomography; pHPT = primary hyperparathyroidism; ROC = receiver operating characteristic; SGD = single gland disease; US = surgeon-performed neck ultrasound

scholarly journals Lesion-to-background ratio threshold value of SUVmax of simultaneous [68Ga]Ga-PSMA-11 PET/MRI imaging in patients with prostate cancer

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jing Zhao ◽  
Bernd Hamm ◽  
Winfried Brenner ◽  
Marcus R. Makowski
Keyword(s):  
Prostate Cancer ◽  
Receiver Operating Characteristic ◽  
Operating Characteristic ◽  
Absolute Threshold ◽  
Threshold Value ◽  
Imaging Findings ◽  
Characteristic Analysis ◽  
Psma Pet ◽  
The Absolute ◽  
Receiver Operating

Abstract Purpose This study aimed to calculate an applicable relative ratio threshold value instead of the absolute threshold value for simultaneous 68Ga prostate-specific membrane antigen/positron emission tomography ([68Ga]Ga-PSMA-11 PET) in patients with prostate cancer (PCa). Materials and methods Our study evaluated thirty-two patients and 170 focal prostate lesions. Lesions are classified into groups according to Prostate Imaging Reporting and Data System (PI-RADS). Standardized uptake values maximum (SUVmax), corresponding lesion-to-background ratios (LBRs) of SUVmax, and LBR distributions of each group were measured based on regions of interest (ROI). We examined LBR with receiver operating characteristic analysis to determine threshold values for differentiation between multiparametric magnetic resonance imaging (mpMRI)-positive and mpMRI-negative lesions. Results We analyzed a total of 170 focal prostate lesions. Lesions number of PI-RADS 2 to 5 was 70, 16, 46, and 38. LBR of SUVmax of each PI-RADS scores was 1.5 (0.9, 2.4), 2.5 (1.6, 3.4), 3.7 (2.6, 4.8), and 6.7 (3.5, 12.7). Based on an optimal threshold ratio of 2.5 to be exceeded, lesions could be classified into MRI-positive lesion on [68Ga]Ga-PSMA PET with a sensitivity of 85.2%, a specificity of 72.0%, with the corresponding area under the receiver operating characteristic curve (AUC) of 0.83, p < 0.001. This value matches the imaging findings better. Conclusion The ratio threshold value of SUVmax, LBR, has improved clinical and research applicability compared with the absolute value of SUVmax. A higher threshold value than the background’s uptake can dovetail the imaging findings on MRI better. It reduces the bias from using absolute background uptake value as the threshold value.

scholarly journals Diagnostic performances of manual and automated reticulocyte parameters in anaemic cats

2017 ◽  
Vol 20 (2) ◽  
pp. 122-127 ◽  
Author(s):  
Saverio Paltrinieri ◽  
Marco Fossati ◽  
Valentina Menaballi
Keyword(s):  
Receiver Operating Characteristic ◽  
Sensitivity And Specificity ◽  
Operating Characteristic ◽  
Positive Likelihood Ratio ◽  
Roc Curves ◽  
Blood Samples ◽  
Production Index ◽  
Instrumental Measurement ◽  
Sensitivity Specificity ◽  
Reticulocyte Production

Objectives The objective of this study was to evaluate the diagnostic performances of manual and instrumental measurement of reticulocyte percentage (Ret%), reticulocyte number (Ret#) and reticulocyte production index (RPI) to differentiate regenerative anaemia (RA) from non-regenerative anaemia (NRA) in cats. Methods Data from 106 blood samples from anaemic cats with manual counts (n = 74; 68 NRA, six RA) or instrumental counts of reticulocytes (n = 32; 25 NRA, seven RA) collected between 1995 and 2013 were retrospectively analysed. Sensitivity, specificity and positive likelihood ratio (LR+) were calculated using either cut-offs reported in the literature or cut-offs determined from receiver operating characteristic (ROC) curves. Results All the reticulocyte parameters were significantly higher in cats with RA than in cats with NRA. All the ROC curves were significantly different ( P <0.001) from the line of no discrimination, without significant differences between the three parameters. Using the cut-offs published in literature, the Ret% (cut-off: 0.5%) was sensitive (100%) but not specific (<75%), the RPI (cut-off: 1.0) was specific (>92%) but not sensitive (<15%), and the Ret# (cut-off: 50 × 10³/µl) had a sensitivity and specificity >80% and the highest LR+ (manual count: 14; instrumental count: 6). For all the parameters, sensitivity and specificity approached 100% using the cut-offs determined by the ROC curves. These cut-offs were higher than those reported in the literature for Ret% (manual: 1.70%; instrumental: 3.06%), lower for RPI (manual: 0.39; instrumental: 0.59) and variably different, depending on the method (manual: 41 × 10³/µl; instrumental: 57 × 10³/µl), for Ret#. Using these cut-offs, the RPI had the highest LR+ (manual: 22.7; instrumental: 12.5). Conclusions and relevance This study indicated that all the reticulocyte parameters may confirm regeneration when the pretest probability is high, while when this probability is moderate, RA should be identified using the RPI providing that cut-offs <1.0 are used.

Minimal clinically important difference of the 6-min walking test in patients with asthma

2021 ◽  
Vol 25 (3) ◽  
pp. 215-221
Author(s):  
E. Zampogna ◽  
N. Ambrosino ◽  
R. Centis ◽  
F. Cherubino ◽  
G. B. Migliori ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Operating Characteristic ◽  
Minimal Clinically Important Difference ◽  
Walking Ability ◽  
Walking Test ◽  
Receiver Operating Characteristic Curves ◽  
Clinically Important Difference ◽  
Copd Assessment Test ◽  
Before And After ◽  
Perceived Change

BACKGROUND: The 6‐min walking test (6MWT) is responsive to physiological changes and pulmonary rehabilitation (PR) in patients with asthma. The minimal clinically important difference (MCID) has not been established yet.OBJECTIVE: To determine the MCID of 6MWT in patients with asthma.METHODS: Using the perceived change in walking ability and the modified Medical Research Council (mMRC) score as anchors, receiver operating characteristic curves and quantile regression, we evaluated 6MWT before and after PR in these patients. The St George Respiratory Questionnaire (SGRQ), the COPD assessment test (CAT) and other outcome measures were also assessed.RESULTS: Of 142 patients with asthma, 37 were enrolled. After PR, 6MWT increased from 453.4 m ± 88.8 to 493.0 m ± 97.2 (P = 0.0001); other outcome measures also increased. There was a slight correlation between baseline 6MWT and SGRQ, CAT and mMRC. No significant correlations were found between post‐PR changes in 6MWT and in other outcome measures. Comparing different methods of assessment, the MCID ranged from 26 m to 27 m.CONCLUSION: The most conservative estimate of the MCID of 6MWT after PR was 26 m in patients with asthma. This estimate may be useful in clinical interpretation of data, particularly in response to intervention studies.

scholarly journals Evaluation of Ocular Biomechanical Indices to Distinguish Normal from Keratoconus Eyes

2012 ◽  
Vol 1 (3) ◽  
pp. 145-150
Author(s):  
Bernardo Lopes ◽  
Allan Luz ◽  
Bruno Fontes ◽  
Isaac C Ramos ◽  
Fernando Correia ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Receiver Operating Characteristic ◽  
Linear Model ◽  
Roc Curve ◽  
Operating Characteristic ◽  
Predictive Accuracy ◽  
Corneal Resistance Factor ◽  
Corneal Deformation ◽  
Eye Examination ◽  
The Individual

ABSTRACT Purpose To compare and assess the ability of pressure-derived parameters and corneal deformation waveform signal-derived parameters of the ocular response analyzer (ORA) measurement to distinguish between keratoconus and normal eyes, and to develop a combined parameter to optimize the diagnosis of keratoconus. Materials and methods One hundred and seventy-seven eyes (177 patients) with keratoconus (group KC) and 205 normal eyes (205 patients; group N) were included. One eye from each subject was randomly selected for analysis. Patients underwent a complete clinical eye examination, corneal topography (Humphrey ATLAS), tomography (Pentacam Oculus) and biomechanical evaluations (ORA Reichert). Differences in the distributions between the groups were assessed using the Mann- Whitney test. The receiver operating characteristic (ROC) curve was used to identify cutoff points that maximized sensitivity and specificity in discriminating keratoconus from normal corneas. Logistic regression was used to identify a combined linear model (Fisher 1.0). Results Significant differences in all studied parameters were detected (p < 0.05), except for W2. For the corneal resistance factor (CRF): Area under the ROC curve (AUROC) 89.1%, sensitivity 81.36%, specificity 84.88%. For the p1area: AUROC 91.5%, sensitivity 87.1%, specificity 81.95%. Of the individual parameters, the highest predictive accuracy was for the Fisher 1.0, which represents the combination of all parameters (AUROC 95.5%, sensitivity 88.14%, specificity 93.17%). Conclusion Waveform-derived ORA parameters displayed greater accuracy than pressure-derived parameters for identifying keratoconus. Corneal hysteresis (CH) and CRF, a diagnostic linear model that combines different parameters, provided the greatest accuracy for differentiating keratoconus from normal corneas. How to cite this article Luz A, Fontes B, Ramos IC, Lopes B, Correia F, Schor P, Ambrósio R. Evaluation of Ocular Biomechanical Indices to Distinguish Normal from Keratoconus Eyes. Int J Kerat Ect Cor Dis 2012;1(3):145-150.

scholarly journals Accuracy and adequacy of waist circumference cut-off points currently recommended in Brazilian adults

2013 ◽  
Vol 17 (4) ◽  
pp. 861-869 ◽  
Author(s):  
Carolina Avila Vianna ◽  
Rogério da Silva Linhares ◽  
Renata Moraes Bielemann ◽  
Eduardo Coelho Machado ◽  
David Alejandro González-Chica ◽  
...  
Keyword(s):  
Cardiovascular Risk ◽  
Waist Circumference ◽  
Receiver Operating Characteristic ◽  
Sensitivity And Specificity ◽  
Operating Characteristic ◽  
Characteristic Curve ◽  
Predictive Ability ◽  
Youden Index ◽  
Southern Brazil ◽  
Receiver Operating

AbstractObjectiveTo evaluate the adequacy and accuracy of cut-off values currently recommended by the WHO for assessment of cardiovascular risk in southern Brazil.DesignPopulation-based study aimed at determining the predictive ability of waist circumference for cardiovascular risk based on the use of previous medical diagnosis for hypertension, diabetes mellitus and/or dyslipidaemia. Descriptive analysis was used for the adequacy of current cut-off values of waist circumference, receiver operating characteristic curves were constructed and the most accurate criteria according to the Youden index and points of optimal sensitivity and specificity were identified.SettingPelotas, southern Brazil.SubjectsIndividuals (n2112) aged ≥20 years living in the city were selected by multistage sampling, since these individuals did not report the presence of previous myocardial infarction, angina pectoris or stroke.ResultsThe cut-off values currently recommended by WHO were more appropriate in men than women, with overestimation of cardiovascular risk in women. The area under the receiver operating characteristic curve showed moderate predictive ability of waist circumference in men (0·74, 95 % CI 0·71, 0·76) and women (0·75, 95 % CI 0·73, 0·77). The method of optimal sensitivity and specificity showed better performance in assessing the accuracy, identifying the values of 95 cm in men and 87 cm in women as the best cut-off values of waist circumference to assess cardiovascular risk.ConclusionsThe cut-off values currently recommended for waist circumference are not suitable for women. Longitudinal studies should be conducted to evaluate the consistency of the findings.

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