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Operator Characteristic Curve (operator + characteristic_curve)
Kinds of Operator Characteristic Curve Selected AbstractsNormal values of pulmonary capillary wedge pressure and the blood pressure response to the Valsalva manoeuvre in healthy elderly subjectsCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 6 2005Jaap J. Remmen Summary The blood pressure response to the Valsalva manoeuvre is related to pulmonary capillary wedge pressure (PCWP) and can be used to diagnose heart failure. However, this has never been studied specifically in the elderly, in whom the prevalence of heart failure is highest. Furthermore, normal values of the Valsalva manoeuvre are lacking. We aimed to obtain normal values of PCWP and the blood pressure response to the Valsalva manoeuvre in elderly subjects. Therefore, 28 healthy subjects, aged 70 ± 4 years, performed Valsalva manoeuvres before and after anti-G garment inflation, which was used for temporary increase of PCWP. Before inflation, PCWP was 9·8 ± 1·9 mmHg in supine and 8·9 ± 2·1 in semi-recumbent position. From the blood pressure response, measured with Finapres, the systolic blood pressure ratio (SBPR), pulse pressure ratio (PPR), stroke volume ratio (SVR) and heart rate ratio (HRR) were calculated. In supine position, SBPR was 0·76 ± 0·11, PPR 0·51 ± 0·16, SVR 0·42 ± 0·11, and HRR 1·17 ± 0·12. Semi-recumbently, SBPR was 0·74 ± 0·10, PPR 0·46 ± 0·14, SVR 0·41 ± 0·10, and HRR 1·24 ± 0·23. After inflation of the anti-G garment, the areas under the Receiver Operator Characteristics curves of SBPR, PPR and SVR for elevated (,15 mmHg) PCWP were >0·85 in supine position. In conclusion, this is the first study to obtain normal values of the blood pressure response to the Valsalva manoeuvre and PCWP in healthy elderly subjects, which is essential for the interpretation of patient data. The Valsalva manoeuvre showed significant discriminatory power in the detection of elevated PCWP, which underscores its potential in the non-invasive diagnosis of heart failure. [source] Diagnostic performance of clinical motor and non-motor tests of Parkinson disease: a matched case,control studyEUROPEAN JOURNAL OF NEUROLOGY, Issue 7 2008N. I. Bohnen Background and purpose:, The diagnosis of Parkinson disease (PD) is made typically on the basis of motor abnormalities. PD is now recognized to have both motor and non-motor manifestations, indicating a need for the development of reliable non-motor diagnostic tests for PD. The aim of the present study was to compare the accuracy of various clinical motor and non-motor tests for the diagnosis of PD. Methods:, Forty-five PD patients (Hoehn and Yahr stages 1,3; mean age 59.5 ± 10.0 years) and 45 healthy controls matched for gender and age completed a clinimetric motor test battery to assess limb bradykinesia, tremor and balance. Non-motor tests consisted of depression, anxiety and smell identification ratings. Area under the receiver operator characteristic curve (AUC) analysis was used. Results:, We found that smell identification was the most accurate predictor of the presence of PD within the overall group of patients and matched control subjects (AUC = 0.886) and also in the subgroups of mild severity (Hoehn and Yahr stages 1,1.5; AUC = 0.923), young-onset (AUC = 0.888) and female PD patients (AUC = 0.797). The second best diagnostic test was the grooved pegboard test for the clinically most affected body side. Conclusions:, We conclude that olfactory function is the most accurate diagnostic predictor within a heterogeneous sample of patients with PD. [source] RIFLE classification as predictive factor of mortality in patients with cirrhosis admitted to intensive care unitJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 10 2009Evangelos Cholongitas Abstract Background and Aim:, To evaluate the association of the Risk, Injury, Failure, Loss and End-stage renal failure (RIFLE) score on mortality in patients with decompensated cirrhosis admitted to intensive care unit (ICU). Methods:, A cohort of 412 patients with cirrhosis consecutively admitted to ICU was classified according to the RIFLE score. Multivariable logistic regression analysis was used to evaluate the factors associated with mortality. Liver-specific, Acute Physiology and Chronic Health Evaluation (APACHE) II, Sequential Organ Failure Assessment (SOFA) and RIFLE scores on admission, were compared by receiver,operator characteristic curves. Results:, The overall mortality during ICU stay or within 6 weeks after discharge from ICU was 61.2%, but decreased over time (76% during first interval, 1989,1992 vs 50% during the last, 2005,2006, P < 0.001). Multivariate analysis showed that RIFLE score (odds ratio: 2.1, P < 0.001) was an independent factor significantly associated with mortality. Although SOFA had the best discrimination (area under receiver,operator characteristic curve = 0.84), and the APACHE II had the best calibration, the RIFLE score had the best sensitivity (90%) to predict death in patients during follow up. Conclusions:, RIFLE score was significantly associated with mortality, confirming the importance of renal failure in this large cohort of patients with cirrhosis admitted to ICU, but it is less useful than other scores. [source] Validation of model for end-stage liver disease score to serum sodium ratio index as a prognostic predictor in patients with cirrhosisJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 9 2009Xiao-Hui Lv Abstract Aim:, To evaluate the prognostic ability of model for end-stage liver disease (MELD) to serum sodium (SNa) ratio (MESO) index and to compare the predictive accuracy of the MESO index with the MELD score and the modified Child,Turcotte,Pugh (CTP) score for short-term survival in cirrhotic patients. Methods:, A total of 256 patients with cirrhosis were retrospectively evaluated. The predictive accuracy of the MESO index, MELD score and modified CTP score were compared by the area under the receiver,operator characteristic curve (AUC). Results:, Using 1-month and 3-month mortality as the end-point, overall, MESO and MELD were significantly better than the CTP score in predicting the risk of mortality at 1 month (AUC, 0.866,0.819 vs 0.722, P < 0.01) and 3 months (AUC, 0.875,0.820 vs 0.721, P < 0.01). In the low MELD group, the AUC of MESO index (0.758, 0.759) and CTP score (0.754, 0.732) were higher than that of the MELD score (0.608, 0.611) at 1 month and 3 months, respectively (P < 0.01). However, in the high MELD group, the AUC of MESO index (0.762, 0.779) and MELD (0.737, 0.773) were higher than that of the CTP score (0.710, 0.752) at 1 month and 3 months, respectively, although there were no significant differences (P > 0.05). With appropriate cut-offs for the MESO index, the mortality rate of patients in high MESO was higher (57.1% at 1 month and 69.2% at 3 months) than that of the low MESO (5.5% at 1 month and 7.9% at 3 months) (P < 0.01). Conclusions:, The MESO index, which adds SNa to MELD, is a useful prognostic marker and is found to be superior to the MELD score and modified CTP score for short-term prognostication of patients with cirrhosis. [source] Testing alternative models for the conservation of koalas in fragmented rural,urban landscapesAUSTRAL ECOLOGY, Issue 4 2006CLIVE A. MCALPINE Abstract Predicting the various responses of different species to changes in landscape structure is a formidable challenge to landscape ecology. Based on expert knowledge and landscape ecological theory, we develop five competing a priori models for predicting the presence/absence of the Koala (Phascolarctos cinereus) in Noosa Shire, south-east Queensland (Australia). A priori predictions were nested within three levels of ecological organization: in situ (site level) habitat (<1 ha), patch level (100 ha) and landscape level (100,1000 ha). To test the models, Koala surveys and habitat surveys (n = 245) were conducted across the habitat mosaic. After taking into account tree species preferences, the patch and landscape context, and the neighbourhood effect of adjacent present sites, we applied logistic regression and hierarchical partitioning analyses to rank the alternative models and the explanatory variables. The strongest support was for a multilevel model, with Koala presence best predicted by the proportion of the landscape occupied by high quality habitat, the neighbourhood effect, the mean nearest neighbour distance between forest patches, the density of forest patches and the density of sealed roads. When tested against independent data (n = 105) using a receiver operator characteristic curve, the multilevel model performed moderately well. The study is consistent with recent assertions that habitat loss is the major driver of population decline, however, landscape configuration and roads have an important effect that needs to be incorporated into Koala conservation strategies. [source] The predictive value of serum 1,5-anhydro-D-glucitol in pregnancies at increased risk of gestational diabetes mellitus and gestational impaired glucose toleranceBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 7 2001Wing-Hung Tam The objective of the study was to determine the efficacy of 1,5-anhydro-D-glucitol (1,5 AG) for the prediction of gestational diabetes and gestational impaired glucose tolerance (GIGT). One hundred and eighty-five pregnant women with epidemiological risk factors of gestational diabetes or GIGT underwent 75 g oral glucose tolerance test and plasma 1,5 AG assay at 26 to 28 weeks of gestation. There was no significant difference in plasma 1,5 AG either before or after an oral glucose load. The area under the receiver operator characteristic curve for 1,5 AG was only 0.485 which implies that 1,5 AG is a poor predictor of GIGT or gestational diabetes. [source] Clinical prognostic scoring system to aid decision-making in gastro-oesophageal cancerBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 12 2007D. A. C. Deans Background: Accurate prediction of prognosis in gastro-oesophageal cancer remains challenging. The aim of this study was to develop a robust model for outcome prediction. Methods: The study included 220 patients with gastric or oesophageal cancer newly diagnosed over a 2-year period. Patients were staged and underwent treatment following discussion at a multidisciplinary team (MDT) meeting. Clinical and investigative variables were collected, including performance and nutritional status, and serum C-reactive protein (CRP) level. Primary endpoints were death within 12 and 24 months. Results: Overall median survival was 13 months. Advanced clinical stage (P < 0·001), reduced performance score (P < 0·001), weight loss exceeding 2·75 per cent per month (P = 0·026) and serum CRP concentration above 5 mg/l (P = 0·031) were identified as independent prognostic indicators in multivariable analysis. A prognostic score was constructed using these four variables to estimate a probability of death. Applying the model gave an area under the receiver,operator characteristic curve of 0·84 and 0·85 for prediction of death at 12 and 24 months respectively (both P < 0·001). Conclusion: This model accurately estimated the probability of death within 12 and 24 months. This may aid the MDT decision-making process. Copyright © 2007 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Glasgow Aneurysm Score predicts survival after endovascular stenting of abdominal aortic aneurysm in patients from the EUROSTAR registryBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 2 2006F. Biancari Background: The aim of the present study was to evaluate the efficacy of the Glasgow Aneurysm Score (GAS) in predicting the survival of 5498 patients who underwent endovascular repair (EVAR) of an abdominal aortic aneurysm (AAA) and were enrolled in the EUROpean collaborators on Stent-graft Techniques for abdominal aortic Aneurysm Repair (EUROSTAR) Registry between October 1996 and March 2005. Methods: The GAS was calculated in patients who underwent EVAR and was correlated to outcome measurements. Results: The median GAS was 78·8 (interquartile range 71·9,86·4, mean 79·2). Tertile 30-day mortality rates were 1·1 per cent for patients with a GAS less than 74·4, 2·1 per cent for those with a score between 74·4 and 83·6, and 5·3 per cent for patients with a score over 83·6 (P < 0·001). Multivariate analysis showed that GAS was an independent predictor of postoperative death (P < 0·001). The receiver,operator characteristic curve showed that the GAS had an area under the curve of 0·70 (95 per cent confidence interval 0·66 to 0·74; s.e. 0·02; P < 0·001) for predicting immediate postoperative death. At its best cut-off value of 86·6, it had a sensitivity of 56·1 per cent, specificity 76·2 per cent and accuracy 75·6 per cent. Multivariable analysis showed that overall survival was significantly different among the tertiles of the GAS (P < 0·001). Conclusion: The GAS was effective in predicting outcome after EVAR. Because its efficacy has also been shown in patients undergoing open repair of AAA, it can be used to aid decisions about treatment in all patients with an AAA. Copyright © 2006 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] RIFLE classification as predictive factor of mortality in patients with cirrhosis admitted to intensive care unitJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 10 2009Evangelos Cholongitas Abstract Background and Aim:, To evaluate the association of the Risk, Injury, Failure, Loss and End-stage renal failure (RIFLE) score on mortality in patients with decompensated cirrhosis admitted to intensive care unit (ICU). Methods:, A cohort of 412 patients with cirrhosis consecutively admitted to ICU was classified according to the RIFLE score. Multivariable logistic regression analysis was used to evaluate the factors associated with mortality. Liver-specific, Acute Physiology and Chronic Health Evaluation (APACHE) II, Sequential Organ Failure Assessment (SOFA) and RIFLE scores on admission, were compared by receiver,operator characteristic curves. Results:, The overall mortality during ICU stay or within 6 weeks after discharge from ICU was 61.2%, but decreased over time (76% during first interval, 1989,1992 vs 50% during the last, 2005,2006, P < 0.001). Multivariate analysis showed that RIFLE score (odds ratio: 2.1, P < 0.001) was an independent factor significantly associated with mortality. Although SOFA had the best discrimination (area under receiver,operator characteristic curve = 0.84), and the APACHE II had the best calibration, the RIFLE score had the best sensitivity (90%) to predict death in patients during follow up. Conclusions:, RIFLE score was significantly associated with mortality, confirming the importance of renal failure in this large cohort of patients with cirrhosis admitted to ICU, but it is less useful than other scores. [source] Development of a dedicated risk-adjustment scoring system for colorectal surgery (colorectal POSSUM),,BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 9 2004P. P. Tekkis Background: The aim of the study was to develop a dedicated colorectal Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (CR-POSSUM) equation for predicting operative mortality, and to compare its performance with the Portsmouth (P)-POSSUM model. Methods: Data were collected prospectively from 6883 patients undergoing colorectal surgery in 15 UK hospitals between 1993 and 2001. After excluding missing data and 93 patients who did not satisfy the inclusion criteria, 4632 patients (68·2 per cent) underwent elective surgery and 2107 had an emergency operation (31·0 per cent); 2437 operations (35·9 per cent) for malignant and 4267 (62·8 per cent) for non-malignant diseases were scored. Stepwise logistic regression analysis was used to develop an age-adjusted POSSUM model and a dedicated CR-POSSUM model. A 60 : 40 per cent split-sample validation technique was adopted for model development and testing. Observed and expected mortality rates were compared. Results: The operative mortality rate for the series was 5·7 per cent (387 of 6790 patients) (elective operations 2·8 per cent; emergency surgery 12·0 per cent). The CR-POSSUM, age-adjusted POSSUM and P-POSSUM models had similar areas under the receiver,operator characteristic curves. Model calibration was similar for CR-POSSUM and age-adjusted POSSUM models, and superior to that for the P-POSSUM model. The CR-POSSUM model offered the best overall accuracy, with an observed : expected ratio of 1·000, 0·998 and 0·911 respectively (test population). Conclusion: The CR-POSSUM model provided an accurate predictor of operative mortality. External validation is required in hospitals different from those in which the model was developed. Copyright © 2004 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Anal vector volume analysis complements endoanal ultrasonographic assessment of postpartum anal sphincter injuryBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 9 2000M. M. Fynes Background The aim of this study was to determine the role of anal vector manometry in the assessment of postpartum anal sphincter injury and to establish the most suitable method of anal vector volume analysis for identifying significant external anal sphincter (EAS) injury in an at-risk parous population. Methods A total of 101 consecutive women with a history of instrumental or traumatic vaginal delivery was recruited. Anal ultrasonography and anal vector manometry were performed. Receiver,operator characteristic curves were used to determine the usefulness of anal manometry and anal vector volume analysis in the identification of significant EAS disruption (full thickness, more than one quadrant involved) detected by ultrasonography. Results Seventeen women had significant EAS disruption identified by anal ultrasonography. Anal vector manometry provided complementary functional information. Anal vector symmetry index (VSI), determined by analysis of mean maximum squeeze pressure, yielded 100 per cent sensitivity for significant EAS disruption, with a positive predictive value of 61 per cent. Conclusion Anal vector manometry complements endoanal ultrasonography. VSI, determined by means of the squeeze pressure profile, correlates best with significant EAS disruption identified at anal ultrasonography. © 2000 British Journal of Surgery Society Ltd [source] Predicting neurodevelopmental impairment in preterm infants by standardized neurological assessments at 6 and 12 months corrected ageACTA PAEDIATRICA, Issue 4 2010I Grimmer Abstract Aim:, Neurodevelopmental impairment in very preterm infants can be reasonably diagnosed by 18,24 months corrected age, whereas the predictive value of earlier assessments is debated. We hypothesized that neurological findings at 6 and 12 months indicative of subsequent cerebral palsy predict 18,24 months' neurodevelopmental impairment. Methods:, Neurodevelopmental examinations (Griffiths scales) at 20 months of age in 561 preterm infants (birth weight <1 500 g) were compared with results of standardized neurological examinations (Early Motor Pattern Profile; EMPP) and Griffiths scales at 6 (n = 451) and 12 months (n = 496) corrected age. Results:, Griffiths developmental quotients at 20 months were weakly but significantly related to EMPP scores at 6 (Rs = 0.328) and 12 months (Rs = 0.493). Areas under receiver operator characteristic curves for the EMPP to predict neurodevelopmental impairment (Griffiths scores ,75) at 20 months were 0.772 (0.890) at 6 (12) months, compared to 0.915 (0.962) for Griffiths scores. By contrast, EMPP and Griffiths scores had equal power to predict unability to walk unaided at 2 years of age (EMPP 6/12 months: 0.946/0.983; Griffiths 6/12 months: 0.935/0.985). Conclusion:, Neurological examinations with the EMPP at 6 and 12 months corrected age are of limited value to predict neurodevelopmental impairment at 20 months. [source] Favorable Long-Term Survival in Patients Undergoing Stent PCI of Unprotected Left Main Coronary Artery Compared to Predicted Short-Term Prognosis of CABG Estimated by EuroSCORE: Clinical Determinants of Long-Term OutcomeJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 4 2009RALF LEHMANN M.D. Aims/Methods: The long-term outcome of patients (pts) undergoing percutaneous coronary intervention (PCI) of unprotected left main coronary artery (LMCA) is unclear so far. We prospectively investigated the outcome of 102 consecutive patients who underwent stent PCI of unprotected LMCA. Patients were divided according to clinical indication for PCI: stable coronary artery disease (CAD) (N = 60), NSTEMI (N = 18), STEMI (N = 24). Expected in-hospital mortality of coronary artery bypass grafting (CABG) was calculated using the European System for Cardiac Operative Risk Evaluation (EuroSCORE) and compared to the observed survival rate during long-term follow-up (mean 1.8 ± 1.2 years). Results: The observed 30-day mortality was 1.7% (1/60 pts) in patients with stable CAD, 11% (2/18 pts) in NSTEMI patients, and 13% (3/24 pts) in STEMI patients. The observed mortality was lower than the predicted mortality of CABG as calculated by the logistic EuroSCORE. Using receiver-operator characteristics curves (ROC), EuroSCORE demonstrated a high predictive value for both 30-day mortality as well as 1-year mortality (AUC > 0.8; P < 0.01). Prognostically relevant patient related factors (P < 0.01) included severely reduced left ventricular ejection fraction (HR 3.24), ACS (HR 3.18), STEMI (HR: 3.01), Killip class IV (HR 7.69), occurrence of neoplastic disease (HR 3.97), and elevated CRP (HR 3.86). Conclusions: LMCA-PCI was associated with lower long-term mortality rates compared to the estimated mortality of CABG. This prospective observational study suggests that DES-PCI of unprotected LMCA in "all-comers" can be carried out with reasonable risk. [source] | ||||||||||