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Prognostic Accuracy (prognostic + accuracy)

Distribution by Scientific Domains

Medical Sciences	70%

Selected Abstracts

Application of the Time-Dependent ROC Curves for Prognostic Accuracy with Multiple Biomarkers

BIOMETRICS, Issue 1 2006
Yingye Zheng
Summary The rapid advancement in molecule technology has led to the discovery of many markers that have potential applications in disease diagnosis and prognosis. In a prospective cohort study, information on a panel of biomarkers as well as the disease status for a patient are routinely collected over time. Such information is useful to predict patients' prognosis and select patients for targeted therapy. In this article, we develop procedures for constructing a composite test with optimal discrimination power when there are multiple markers available to assist in prediction and characterize the accuracy of the resulting test by extending the time-dependent receiver operating characteristic (ROC) curve methodology (Heagerty, Lumley, and Pepe, 2000, Biometrics56, 337,344). We employ a modified logistic regression model to derive optimal linear composite scores such that their corresponding ROC curves are maximized at every false positive rate. We provide theoretical justification for using such a model for prognostic accuracy. The proposed method allows for time-varying marker effects and accommodates censored failure time outcome. When the effects of markers are approximately constant over time, we propose a more efficient estimating procedure under such models. We conduct numerical studies to evaluate the performance of the proposed procedures. Our results indicate the proposed methods are both flexible and efficient. We contrast these methods with an application concerning the prognostic accuracies of expression levels of six genes. [source]

Comparative performances of staging systems for early hepatocellular carcinoma

HPB, Issue 5 2009
Hari Nathan
Abstract Background:, Several staging systems for patients with hepatocellular carcinoma (HCC) have been proposed, but studies of their prognostic accuracy have yielded conflicting conclusions. Stratifying patients with early HCC is of particular interest because these patients may derive the greatest benefit from intervention, yet no studies have evaluated the comparative performances of staging systems in patients with early HCC. Methods:, A retrospective cohort study was performed using data on 379 patients who underwent liver resection or liver transplantation for HCC at six major hepatobiliary centres in the USA and Europe. The staging systems evaluated were: the Okuda staging system, the International Hepato-Pancreato-Biliary Association (IHPBA) staging system, the Cancer of the Liver Italian Programme (CLIP) score, the Barcelona Clinic Liver Cancer (BCLC) staging system, the Japanese Integrated Staging (JIS) score and the American Joint Committee on Cancer/International Union Against Cancer (AJCC/UICC) staging system, 6th edition. A recently proposed early HCC prognostic score was also evaluated. The discriminative abilities of the staging systems were evaluated using Cox proportional hazards models and the bootstrap-corrected concordance index (c). Results:, Overall survival of the cohort was 74% at 3 years and 52% at 5 years, with a median survival of 62 months. Most systems demonstrated poor discriminatory ability (P > 0.05 on Cox proportional hazards analysis, c, 0.5). However, the AJCC/UICC system clearly stratified patients (P < 0.001, c= 0.59), albeit only into two groups. The early HCC prognostic score also clearly stratified patients (P < 0.001, c= 0.60) and identified three distinct prognostic groups. Discussion:, The early HCC prognostic score is superior to the AJCC/UICC staging system (6th edition) for predicting the survival of patients with early HCC after liver resection or liver transplantation. Other major HCC staging systems perform poorly in patients with early HCC. [source]

Systematic review: prognostic tests of paracetamol-induced acute liver failure

ALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 10 2010
D. G. N. CRAIG
Aliment Pharmacol Ther,31, 1064,1076 Summary Background, Paracetamol (acetaminophen) toxicity remains the leading cause of acute liver failure (ALF) in the developed world. In the UK, the recently modified King's College Criteria are used to list patients for emergency liver transplantation, but these criteria have been criticized for their low sensitivity and for spectrum bias in their application. Aim, To evaluate existing prognostic criteria critically for predicting death without transplantation in paracetamol-induced ALF. Methods, MEDLINE, EMBASE and CINAHL were searched to identify studies containing adult patients with paracetamol-induced ALF. Selected studies were evaluated and data were pooled if appropriate, to calculate sensitivity, specificity and diagnostic odds ratios (DORs) of applied prognostic tests. Results, Of 6507 studies identified, 14 were eligible for inclusion, evaluating 1960 patients. The original King's College Criteria had a pooled sensitivity of 58.2% and specificity of 94.6%, with a DOR of 27.7. Addition of arterial lactate to the King's College Criteria reduced the DOR to 26.1. Several other clinical and laboratory variables had higher DORs than the King's College Criteria, but were only evaluated in single studies of limited quality. Conclusions, The original King's College Criteria remain well-validated criteria with high prognostic accuracy. Other potential prognostic variables should be prospectively assessed in multicentre studies to refine the criteria further. [source]

Can inclusion of serum creatinine values improve the Child,Turcotte,Pugh score and challenge the prognostic yield of the model for end-stage liver disease score in the short-term prognostic assessment of cirrhotic patients?,

LIVER INTERNATIONAL, Issue 5 2004
Edoardo Giannini
Abstract: Background: The model for end-stage liver disease (MELD) score is a useful tool to assess prognosis in critically ill cirrhotic patients. However, its short-term prognostic superiority over the traditional Child,Turcotte,Pugh (CTP) score has not been definitely confirmed. The creatinine serum level is an important predictor of survival in patients with liver cirrhosis. Aims: To evaluate and compare the short-term prognostic accuracy of the CTP, the creatinine-modified CTP, and the MELD scores in patients with liver cirrhosis. Methods: CTP, creatinine-modified CTP, and MELD scores were calculated in a cohort of 145 cirrhotic patients. The creatinine-modified CTP was calculated as follows: we assessed the mean creatinine serum level and standard deviation (SD) of the 145 study patients, then assigned a score of 1 to patients with creatinine serum levels , to the mean, a score of 2 to patients with creatinine levels between the mean and the mean+1 SD, and a score of 3 to patients with creatinine levels above the mean+1 SD. The creatinine-modified CTP was then calculated by simply adding each patients' creatinine score to their traditional CTP scores. We calculated and compared the accuracy (c -index) of the three parameters in predicting 3-month survival. Results: The creatinine-modified CTP score showed better prognostic accuracy as compared with the traditional CTP (P=0.049). However, the MELD score proved to be better at defining patients' prognosis in the short-term as compared with both the traditional CTP score (P=0.012) and the creatinine-modified CTP (P=0.047). The excellent short-term prognostic accuracy of the MELD score was confirmed even when patients with abnormal creatinine serum levels were excluded from the analysis (c -index=0.935). Conclusions: Adding creatinine values to the CTP slightly improves the prognostic usefulness of the traditional CTP score alone. The MELD score has a short-term prognostic yield that is better than what is provided by both the CTP and CTP creatinine-modified scores, even in cirrhotic patients who are not critically ill. The positive results obtained by using the MELD score were confirmed even after excluding patients with impaired renal function. [source]

Copeptin: A novel, independent prognostic marker in patients with ischemic stroke,

ANNALS OF NEUROLOGY, Issue 6 2009
Mira Katan MD
Objective Early prediction of outcome in patients with ischemic stroke is important. Vasopressin is a stress hormone. Its production rate is mirrored in circulating levels of copeptin, a fragment of provasopressin. We evaluated the prognostic value of copeptin in acute stroke patients. Methods In a prospective observational study, copeptin was measured using a new sandwich immunoassay on admission in plasma of 362 consecutive patients with an acute ischemic stroke. The prognostic value of copeptin to predict the functional outcome (defined as a modified Rankin Scale score of ,2 or ,3), mortality within 90 days, was compared with the National Institutes of Health Stroke Scale score and with other known outcome predictors. Results Patients with an unfavorable outcomes and nonsurvivors had significantly increased copeptin levels on admission (p <0.0001 and p <0.0001). Receiver operating characteristics to predict functional outcome and mortality demonstrated areas under the curve of copeptin of 0.73 (95% confidence interval [CI], 0.67,0.78) and 0.82 (95% CI, 0.76,0.89), which was comparable with the National Institutes of Health Stroke Scale score but superior to C-reactive protein and glucose (p <0.01). In multivariate logistic regression analysis, copeptin was an independent predictor of functional outcome and mortality, and improved the prognostic accuracy of the National Institutes of Health Stroke Scale to predict functional outcome (combined areas under the curve, 0.79; 95% CI, 0.74,0.84; p <0.01) and mortality (combined areas under the curve, 0.89; 95% CI, 0.84,0.94; p <0.01). Interpretation Copeptin is a novel, independent prognostic marker improving currently used risk stratification of stroke patients. Ann Neurol 2009;66:799,808 [source]

Comparison of Different Methods of ST Segment Resolution Analysis for Prediction of 1-Year Mortality after Primary Angioplasty for Acute Myocardial Infarction

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 1 2007
Jakub Przyluski M.D.
Background: Resolution of ST segment elevation corresponds with myocardial tissue reperfusion and correlates with clinical outcome after ST elevation myocardial infarction. Simpler method evaluating the extent of maximal deviation persisting in a single ECG lead was an even stronger mortality predictor. Our aim was to evaluate and compare prognostic accuracy of different methods of ST segment elevation resolution analysis after primary percutaneous coronary intervention (PCI) in a real-life setting. Methods: Paired 12-lead ECGs were analyzed in 324 consecutive and unselected patients treated routinely with primary PCI in a single high-volume center. ST segment resolution was quantified and categorized into complete, partial, or none, upon the (1) sum of multilead ST elevations (sumSTE) and (2) sum of ST elevations plus reciprocal depressions (sumSTE+D); or into the low-, medium-, and high-risk groups by (3) the single-lead extent of maximal postprocedural ST deviation (maxSTE). Results: Complete, partial, and nonresolution groups by sumSTE constituted 39%, 40%, and 21% of patients, respective groups by sumSTE+D comprised 40%, 39%, and 21%. The low-, medium-, and high-risk groups constituted 43%, 32%, and 25%. One-year mortality rates for rising risk groups by sumSTE were 4.7%, 10.2%, and 14.5% (P = 0.049), for sumSTE+D 3.8%, 9.6%, and 17.6% (P = 0.004) and for maxSTE 5.1%, 6.7%, and 18.5% (P = 0.001), respectively. After adjustment for multiple covariates only maxSTE (high vs low-risk, odds ratio [OR] 3.10; 95% confidence interval [CI] 1.11,8.63; P = 0.030) and age (OR 1.07; 95% CI 1.02,1.11; P = 0.002) remained independent predictors of mortality. Conclusions: In unselected population risk stratifications based on the postprocedural ST resolution analysis correlate with 1-year mortality after primary PCI. However, only the single-lead ST deviation analysis allows an independent mortality prediction. [source]

Application of the Time-Dependent ROC Curves for Prognostic Accuracy with Multiple Biomarkers

Stage migration in localized prostate cancer has no effect on the post-radical prostatectomy Kattan nomogram

BJU INTERNATIONAL, Issue 5 2010
Ruban Thanigasalam
Study Type , Prognosis (case series) Level of Evidence 4 OBJECTIVE To investigate the effect of prostate-specific antigen (PSA) testing on stage migration in an Australian population, and its consequences on the prognostic accuracy of the post-radical prostatectomy (RP) Kattan nomogram, as in North America widespread PSA testing has resulted in prostate cancer stage migration, questioning the utility of prognostic nomograms in this setting. PATIENTS AND METHODS The study comprised 1008 men who had consecutive RP for localized prostate cancer between 1991 and 2001 at one institution. Two groups were assessed, i.e. those treated in 1991,96 (group 1, the early PSA era), and 1997,2001 (group 2, the contemporary PSA era). Differences in clinicopathological features between the groups were analysed by chi-squared testing and survival modelling. Individual patient data were entered into the post-RP Kattan nomogram and the efficacy assessed by receiver- operating characteristic curve analysis. RESULTS Patients in group 2 had lower pathological stage disease (P = 0.01) and fewer cancers with Gleason score ,8 (P < 0.001) than group 1. Multivariate analysis identified preoperative serum PSA level (P < 0.01) and Gleason score (P < 0.01) as strong predictors of biochemical relapse in both groups. In group 2 pathological stage was not significant, but margin involvement became highly significant (P = 0.004). There was no difference in the predictive accuracy of the Kattan nomogram between the groups (P = 0.253). CONCLUSIONS These findings show a downward stage migration towards organ-confined disease after the introduction of widespread PSA testing in an Australian cohort. Despite this, the Kattan nomogram remains a robust prognostic tool in clinical practice. [source]

Serum amyloid A is a better early predictor of severity than C-reactive protein in acute pancreatitis,

BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 2 2002
J. M. Mayer
Background: Serum amyloid A (SAA) is an early and sensitive marker of the extent of tissue trauma and inflammation. The aim of this study was to compare the early prognostic accuracy of SAA with that of serum C-reactive protein (CRP) in acute pancreatitis. Methods: In a prospective multicentre trial, plasma SAA and CRP levels were measured in patients with severe and mild acute pancreatitis, and in a control group with acute abdominal pain. Plasma samples were collected on admission and at 6-h intervals for 48 h, every 12 h between 48 and 72 h, then daily for 5 days. Plasma SAA was measured by a new enzyme-linked immunosorbent assay and CRP was measured by immunoturbidometry. Results: There were 137 patients with mild and 35 with severe acute pancreatitis, and 74 control patients. SAA levels were significantly higher in patients with severe acute pancreatitis than in those with mild acute pancreatitis, on admission, at 24 h or less after symptom onset, and subsequently. Whereas plasma CRP concentration was also significantly higher in patients with severe acute pancreatitis on admission, it failed to distinguish mild from severe acute pancreatitis until 30,36 h after symptom onset. SAA levels predicted severity (sensitivity 67 per cent, specificity 70 per cent, negative predictive value 89 per cent, mean(s.d.) area under curve 0·7(0·05)) significantly better than CRP (57 per cent, 60 per cent, 84 per cent, 0·59(0·06) respectively) on admission (P = 0·02) and at 24 h following symptom onset (area under curve 0·65(0·09) versus 0·58(0·09) respectively; P , 0·02). Conclusion: Plasma SAA concentration is an early marker of severity in acute pancreatitis and is superior to CRP estimation on hospital admission and at 24 h or less after symptom onset. This study suggests that plasma SAA concentration is clinically useful, with the potential to replace CRP in the management of acute pancreatitis. © 2002 British Journal of Surgery Society Ltd [source]