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External Validation (external + validation)

Distribution by Scientific Domains

Medical Sciences	63%
Chemistry	22%
3 Other Domains	15%

Selected Abstracts

External Validation of the Clinical Dehydration Scale for Children With Acute Gastroenteritis

ACADEMIC EMERGENCY MEDICINE, Issue 6 2010
Benoit Bailey MD
Abstract Objectives:, The objective was to validate the clinical dehydration scale (CDS) for children with gastroenteritis in a different pediatric emergency department (ED) from where it was initially derived and validated. Methods:, A prospective cohort study was performed in a tertiary care pediatric ED over a 1-year period. A sample of triage nurses were trained in applying the CDS. The CDS consists of four clinical characteristics (general appearance, eyes, mucous membranes, and tears), each of which are scored 0, 1, or 2 for a total score of 0 to 8, with 0 representing no dehydration; 1 to 4, some dehydration; and 5 to 8, moderate/severe dehydration. Children 1 month to 5 years of age with vomiting and/or diarrhea who had the CDS documented at triage and a final diagnosis of gastroenteritis, gastritis, or enteritis were enrolled. Exclusion criteria included a chronic disease, treatment with intravenous (IV) rehydration within the previous 24 hours, visit to the ED for the same illness in the 7 days prior to arrival, and diarrhea of more than 10 days' duration. The primary outcome was the length of stay (LOS) in the ED from the time of seeing a physician to discharge, analyzed with a Kruskal-Wallis test. Results:, From April 2008 to March 2009, 150 patients with a mean (±SD) age of 22 (±14) months (range = 4 months to 4 years) were enrolled. Fifty-six patients had no dehydration, 74 had some dehydration, and 20 had moderate/severe dehydration. The median LOS in the ED after being seen by a physician was significantly longer as children appeared more dehydrated according to the CDS: 54 minutes (interquartile range [IQR] = 26,175 minutes), 128 minutes (IQR = 25,334 minutes), and 425 minutes (IQR = 218,673 minutes) for the no, some, and moderate/severe dehydration groups, respectively (p < 0.001). Conclusions:, The CDS has been further validated in children with gastroenteritis in a different pediatric center than the original one where it was developed. It is a good predictor of LOS in the ED after being seen by a physician. ACADEMIC EMERGENCY MEDICINE 2010; 17:583,588 © 2010 by the Society for Academic Emergency Medicine [source]

External validation of a risk group defined by recursive partitioning analysis in patients with head and neck carcinoma treated with surgery and postoperative radiotherapy

HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 9 2007
Xavier León MD
Abstract Background: Several clinical trials have proved that concurrent chemoradiotherapy is more efficacious than radiotherapy alone among high-risk patients with head and neck squamous cell carcinoma (HNSCC) who undergo surgery. A risk-group classification defined according to a recursive partitioning analysis (RPA) for these patients has been recently proposed. The objective of the present study was to carry out an external validation of this RPA-derived classification system. Methods: A retrospective study of 442 HNSCC patients treated with surgery and postoperative radiotherapy was conducted. The external validity of the RPA-derived classification system was assessed, and its ability to stage patients and to predict locoregional control of the disease was compared with the TNM system. Results: The RPA-derived classification system succeeded in obtaining a monotonic prognosis gradient in locoregional control of the disease with increasing stage, and achieved greater differences in survival between stages than the TNM and pTNM classifications. Besides, the RPA method had a better homogeneity of the categories included in each stage, and in the heterogeneity between stages. Conclusions: The RPA-derived classification system allowed for the clear definition of prognostic groups in surgically treated HNSCC patients, improving the prognostic capacity of the TNM and pTNM classifications. The RPA-derived classification system is a useful tool in the definition of patients who, given a poor prognosis, should be considered candidates to adjuvant chemoradiotherapy. © 2007 Wiley Periodicals, Inc. Head Neck, 2007 [source]

Comparison of ADHD symptom subtypes as source-specific syndromes

THE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 6 2004
Kenneth D. Gadow
Background:, This study examines differences between the three subtypes of attention-deficit/hyperactivity disorder (ADHD), inattentive (I), hyperactive-impulsive (H), and combined (C), in a heterogeneous sample of 248 boys (ages 6 to 10 years) with emotional and behavioral problems who were recruited for participation in a diagnostic study. Method:, The boys and their mothers participated in an extensive evaluation that involved multiple assessments of cognitive, behavioral, academic, and family functioning. ADHD subtypes were defined on the basis of teacher alone, mother alone, and mother/teacher ratings of DSM-IV symptoms. Results:, Results indicated ADHD symptom groups showed a differential pattern of impairment socially (H,C>I) and cognitively (I,C>H). The C and H groups were the most and least impaired overall, respectively, and all subtypes were differentiated from the nonADHD clinical control or NONE (N) group in a manner consistent with the primary findings. External validation of group differences was limited, and there were marked inconsistencies in the pattern of findings depending on how groups were defined. For the most part, although the mother/teacher grouping strategy (compared with either alone) captured a greater diversity of differences between subtypes, it also obscured some. Conclusions:, Observed findings are consistent with the notion that mothers and teachers interpret symptom statements in terms of behaviors that are most relevant for their daily concerns. [source]

Recommendations for the Assessment and Reporting of Multivariable Logistic Regression in Transplantation Literature

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 7 2010
A. C. Kalil
Multivariable logistic regression is an important method to evaluate risk factors and prognosis in solid organ transplant literature. We aimed to assess the quality of this method in six major transplantation journals. Eleven analytical criteria and four documentation criteria were analyzed for each selected article that used logistic regression. A total of 106 studies (6%) out of 1,701 original articles used logistic regression analyses from January 1, 2005 to January 1, 2006. The analytical criteria and their respective reporting percentage among the six journals were: Linearity (25%); Beta coefficient (48%); Interaction tests (19%); Main estimates (98%); Ovefitting prevention (84%); Goodness-of-fit (3.8%); Multicolinearity (4.7%); Internal validation (3.8%); External validation (8.5%). The documentation criteria were reported as follows: Selection of independent variables (73%); Coding of variables (9%); Fitting procedures (49%); Statistical program (65%). No significant differences were found among different journals or between general versus subspecialty journals with respect to reporting quality. We found that the report of logistic regression is unsatisfactory in transplantation journals. Because our findings may have major consequences for the care of transplant patients and for the design of transplant clinical trials, we recommend a practical solution for the use and reporting of logistic regression in transplantation journals. [source]

Re-calibration and external validation of an existing nomogram to predict aggressive recurrences after radical prostatectomy

BJU INTERNATIONAL, Issue 12 2010
Florian R. Schroeck
Study Type , Prognosis (case series) Level of Evidence 4 OBJECTIVE To re-calibrate the previously published Duke Prostate Center (DPC) nomogram for the prediction of biochemical recurrence (BCR) after radical prostatectomy (RP) to not only predict overall BCR but also the clinically more relevant endpoint of an aggressive recurrence (i.e. a BCR with a postoperative PSA doubling time (PSADT) of <9 months). PATIENTS AND METHODS Using the established point-scale system based upon the previously published DPC nomogram, we re-calibrated this point system to predict not just BCR, but also aggressive BCR within 2599 men treated with RP from the DPC database. PSADT was computed on all patients meeting the recurrence definition who had a minimum of two PSA values, separated by at least 3 months, and ,2 years after recurrence. External validation was performed using data from 1695 men treated with RP within the Shared Equal Access Regional Cancer Hospital (SEARCH) database by calculating the concordance index c and by plotting calibration curves. RESULTS The median follow-up for patients with no BCR was 56 and 47 months for DPC and SEARCH, respectively. In the DPC modelling cohort and the SEARCH validation cohort, 645 (25%) and 557 (33%) men had BCR, while 83 (3.2%) and 71 (4.2%) patients had an aggressive recurrence. In external validation, predictive accuracy for an aggressive BCR was high (c = 0.83) and the nomogram showed good calibration. CONCLUSIONS We re-calibrated an existing nomogram to not only predict overall BCR after RP but also aggressive recurrence after RP. Our new tool can provide valuable information for patient counselling and patient selection for adjuvant therapy trials. [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 2004
P. 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]

Characteristics of environmental reporters on the OM Stockholm exchange

BUSINESS STRATEGY AND THE ENVIRONMENT, Issue 5 2002
Pontus Cerin
External validation of company environmental performance is normally based on corporate environmental reports, due to the lack of other information. Critics of these reports, however, claim that these are no more than public relations exercises, consisting mainly of wordy descriptions and glossy pictures. It is therefore important to turn the spotlight on the real character of the companies behind the reports. Fewer than 10% of the companies listed on the OM Stockholm Exchange, however, provide documented environmental reports on the Internet (DERI) annually. The highest DERI percentages are found among those industry sectors that began reporting some ten years ago. Data from the Dow Jones Country Index Sweden shows that DERI producers have an average market capitalization some six times greater than non-producers. Moreover, the DERI producers emitted twice as much CO2 per turnover as the non-DERI producers. The fact that less than half of the companies on the OM Stockholm Exchange presented CO2 emission data somewhat weakens the conclusions on emissions. The fact that 60% of the DERI producers could not provide complete CO2 emission data for their companies does say something concrete about the usefulness of current DERIs as a tool for externally determining company environmental performance characteristics. Copyright © 2002 John Wiley & Sons, Ltd and ERP Environment. [source]

SCALES: a large-scale assessment model of soil erosion hazard in Basse-Normandie (northern-western France)

EARTH SURFACE PROCESSES AND LANDFORMS, Issue 8 2010
P. Le Gouée
Abstract The cartography of erosion risk is mainly based on the development of models, which evaluate in a qualitative and quantitative manner the physical reproduction of the erosion processes (CORINE, EHU, INRA). These models are mainly semi-quantitative but can be physically based and spatially distributed (the Pan-European Soil Erosion Risk Assessment, PESERA). They are characterized by their simplicity and their applicability potential at large temporal and spatial scales. In developing our model SCALES (Spatialisation d'éChelle fine de l'ALéa Erosion des Sols/large-scale assessment and mapping model of soil erosion hazard), we had in mind several objectives: (1) to map soil erosion at a regional scale with the guarantee of a large accuracy on the local level, (2) to envisage an applicability of the model in European oceanic areas, (3) to focus the erosion hazard estimation on the level of source areas (on-site erosion), which are the agricultural parcels, (4) to take into account the weight of the temporality of agricultural practices (land-use concept). Because of these objectives, the nature of variables, which characterize the erosion factors and because of its structure, SCALES differs from other models. Tested in Basse-Normandie (Calvados 5500,km2) SCALES reveals a strong predisposition of the study area to the soil erosion which should require to be expressed in a wet year. Apart from an internal validation, we tried an intermediate one by comparing our results with those from INRA and PESERA. It appeared that these models under estimate medium erosion levels and differ in the spatial localization of areas with the highest erosion risks. SCALES underlines here the limitations in the use of pedo-transfer functions and the interpolation of input data with a low resolution. One must not forget however that these models are mainly focused on an interregional comparative approach. Therefore the comparison of SCALES data with those of the INRA and PESERA models cannot result on a convincing validation of our model. For the moment the validation is based on the opinion of local experts, who agree with the qualitative indications delivered by our cartography. An external validation of SCALES is foreseen, which will be based on a thorough inventory of erosion signals in areas with different hazard levels. Copyright © 2010 John Wiley & Sons, Ltd. [source]

External validation of a risk group defined by recursive partitioning analysis in patients with head and neck carcinoma treated with surgery and postoperative radiotherapy

Development and Validation of the Headache Needs Assessment (HANA) Survey

HEADACHE, Issue 4 2001
Joyce A. Cramer BS
Objective.,To develop and validate a brief survey of migraine-related quality-of-life issues. The Headache Needs Assessment (HANA) questionnaire was designed to assess two dimensions of the chronic impact of migraine (frequency and bothersomeness). Methods.,Seven issues related to living with migraine were posed as ratings of frequency and bothersomeness. Validation studies were performed in a Web-based survey, a clinical trial responsiveness population, and a retest reliability population. Headache characteristics (eg, frequency, severity, and treatment), demographic information, and the Headache Disability Inventory were used for external validation. Results.,The HANA was completed in full by 994 adults in the Web survey, with a mean total score of 77.98 ± 40.49 (range, 7 to 175). There were no floor or ceiling effects. The HANA met the standards for validity with internal consistency reliability (Cronbach , = .92, eigenvalue for the single factor = 4.8, and test-retest reliability = 0.77). External validity showed a high correlation between HANA and Headache Disability Inventory total scores (0.73, P<.0001), and high correlations with disease and treatment characteristics. Conclusions.,These data demonstrate the psychometric properties of the HANA. The brief questionnaire may be a useful screening tool to evaluate the impact of migraine on individuals. The two-dimensional approach to patient-reported quality of life allows individuals to weight the impact of both frequency and bothersomeness of chronic migraines on multiple aspects of daily life. [source]

A self-adaptive genetic algorithm-artificial neural network algorithm with leave-one-out cross validation for descriptor selection in QSAR study

JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 10 2010
Jingheng Wu
Abstract Based on the quantitative structure-activity relationships (QSARs) models developed by artificial neural networks (ANNs), genetic algorithm (GA) was used in the variable-selection approach with molecule descriptors and helped to improve the back-propagation training algorithm as well. The cross validation techniques of leave-one-out investigated the validity of the generated ANN model and preferable variable combinations derived in the GAs. A self-adaptive GA-ANN model was successfully established by using a new estimate function for avoiding over-fitting phenomenon in ANN training. Compared with the variables selected in two recent QSAR studies that were based on stepwise multiple linear regression (MLR) models, the variables selected in self-adaptive GA-ANN model are superior in constructing ANN model, as they revealed a higher cross validation (CV) coefficient (Q2) and a lower root mean square deviation both in the established model and biological activity prediction. The introduced methods for validation, including leave-multiple-out, Y-randomization, and external validation, proved the superiority of the established GA-ANN models over MLR models in both stability and predictive power. Self-adaptive GA-ANN showed us a prospect of improving QSAR model. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010 [source]

Quick prediction of the retention of solutes in 13 thin layer chromatographic screening systems on silica gel by classification and regression trees

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 15 2008
ukasz Komsta
Abstract The use of classification and regression trees (CART) was studied in a quantitative structure,retention relationship (QSRR) context to predict the retention in 13 thin layer chromatographic screening systems on a silica gel, where large datasets of interlaboratory determined retention are available. The response (dependent variable) was the rate mobility (RM) factor, while a set of atomic contributions and functional substituent counts was used as an explanatory dataset. The trees were investigated against optimal complexity (number of the leaves) by external validation and internal crossvalidation. Their predictive performance is slightly lower than full atomic contribution model, but the main advantage is the simplicity. The retention prediction with the proposed trees can be done without computer or even pocket calculator. [source]

Are Mechanistic and Statistical QSAR Approaches Really Different?

MOLECULAR INFORMATICS, Issue 6-7 2010
MLR Studies on 158 Cycloalkyl-Pyranones
Abstract Two parallel approaches for quantitative structure-activity relationships (QSAR) are predominant in literature, one guided by mechanistic methods (including read-across) and another by the use of statistical methods. To bridge the gap between these two approaches and to verify their main differences, a comparative study of mechanistically relevant and statistically relevant QSAR models, developed on a case study of 158 cycloalkyl-pyranones, biologically active on inhibition (Ki) of HIV protease, was performed. Firstly, Multiple Linear Regression (MLR) based models were developed starting from a limited amount of molecular descriptors which were widely proven to have mechanistic interpretation. Then robust and predictive MLR models were developed on the same set using two different statistical approaches unbiased of input descriptors. Development of models based on Statistical I method was guided by stepwise addition of descriptors while Genetic Algorithm based selection of descriptors was used for the Statistical II. Internal validation, the standard error of the estimate, and Fisher's significance test were performed for both the statistical models. In addition, external validation was performed for Statistical II model, and Applicability Domain was verified as normally practiced in this approach. The relationships between the activity and the important descriptors selected in all the models were analyzed and compared. It is concluded that, despite the different type and number of input descriptors, and the applied descriptor selection tools or the algorithms used for developing the final model, the mechanistical and statistical approach are comparable to each other in terms of quality and also for mechanistic interpretability of modelling descriptors. Agreement can be observed between these two approaches and the better result could be a consensus prediction from both the models. [source]

Principles of QSAR models validation: internal and external

MOLECULAR INFORMATICS, Issue 5 2007
Paola Gramatica
Abstract The recent REACH Policy of the European Union has led to scientists and regulators to focus their attention on establishing general validation principles for QSAR models in the context of chemical regulation (previously known as the Setubal, nowadays, the OECD principles). This paper gives a brief analysis of some principles: unambiguous algorithm, Applicability Domain (AD), and statistical validation. Some concerns related to QSAR algorithm reproducibility and an example of a fast check of the applicability domain for MLR models are presented. Common myths and misconceptions related to popular techniques for verifying internal predictivity, particularly for MLR models (for instance cross-validation, bootstrap), are commented on and compared with commonly used statistical techniques for external validation. The differences in the two validating approaches are highlighted, and evidence is presented that only models that have been validated externally, after their internal validation, can be considered reliable and applicable for both external prediction and regulatory purposes. [source]

Use of Topological Indices of Organic Sulfur Compounds in Quantitative Structure-Retention Relationship Study

MOLECULAR INFORMATICS, Issue 9 2005
F. Safa
Abstract Structure-gas chromatographic retention index models were developed for some organic sulfur compounds at four different temperatures (60, 80, 100 and 120,°C) using only topological descriptors. At first, regression models were generated for each temperature separately with high values of multiple correlation coefficient and Fisher-ratio statistics. The results of cross validation test using leave-one-out (Q2,0.956) and leave-two-out (Q2,0.953) methods showed good predictive ability of the models developed. Then, a single combined quantitative structure-retention relationship model, added temperature as a parameter, was also developed for all the temperatures, showing good statistical parameters (R=0.991 and F=728.474). The stability and validity of the combined model were verified by both internal (Q2>0.970) and external validation (Q=0.993) techniques. The results of the study indicated the efficiency of the classical topological descriptors in simultaneous prediction of retention index values of sulfur compounds at different temperatures. The topological descriptors well covered the molecular properties known to be relevant for gas chromatographic retention data, such as molecular size and degree of branching. [source]

Making self-assessment more effective

THE JOURNAL OF CONTINUING EDUCATION IN THE HEALTH PROFESSIONS, Issue 1 2008
Robert M. Galbraith MD
Abstract Self-assessment has been held out as an important mechanism for lifelong learning and self-improvement for health care professionals. However, there is growing concern that individual learners often interpret the results inaccurately. This idea has led to skepticism that self-assessment in its current form can ever be truly useful for lifelong professional development. We examine the proposal that self-assessment can and should be made more effective. First, relevance should be improved. The process should be tied more explicitly to the individual's actual practice profile, rather than being loosely relevant to broader constructs around the permitted scope of practice (eg, certification or licensure). In addition, self-assessment should include not only knowledge and reasoning but also what is done every day in practice, thereby broadening from competence in simulated settings to performance in real settings. Second, the impact of self-assessment should be substantially strengthened by periodic external validation of self-assessment results, together with goals set as a result and plans for further improvement. This offers to the individual the very tangible benefit of satisfying external mandates (eg, licensure and certification). In addition, impact should be reinforced by linking the results of self-assessment to subsequent learning activities including Continuing Medical Education (CME). Although these enhancements individually may not cure all of what ails self-assessment, they might ensure greater effectiveness for the purposes of lifelong learning. [source]

Diagnosing Rejection in Renal Transplants: A Comparison of Molecular- and Histopathology-Based Approaches

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 8 2009
J. Reeve
The transcriptome has considerable potential for improving biopsy diagnoses. However, to realize this potential the relationship between the molecular phenotype of disease and histopathology must be established. We assessed 186 consecutive clinically indicated kidney transplant biopsies using microarrays, and built a classifier to distinguish rejection from nonrejection using predictive analysis of microarrays (PAM). Most genes selected by PAM were interferon-,,inducible or cytotoxic T-cell associated, for example, CXCL9, CXCL11, GBP1 and INDO. We then compared the PAM diagnoses to those from histopathology, which are based on the Banff diagnostic criteria. Disagreement occurred in approximately 20% of diagnoses, principally because of idiosyncratic limitations in the histopathology scoring system. The problematic diagnosis of ,borderline rejection' was resolved by PAM into two distinct classes, rejection and nonrejection. The diagnostic discrepancies between Banff and PAM in these cases were largely due to the Banff system's requirement for a tubulitis threshold in defining rejection. By examining the discrepancies between gene expression and histopathology, we provide external validation of the main features of the histopathology diagnostic criteria (the Banff consensus system), recommend improvements and outline a pathway for introducing molecular measurements. [source]

Development and Validation of the Excess Mortality Ratio,adjusted Injury Severity Score Using the International Classification of Diseases 10th Edition

ACADEMIC EMERGENCY MEDICINE, Issue 5 2009
Jaiyong Kim MD
Abstract Objectives:, This study aimed to develop and validate a new method for measuring injury severity, the excess mortality ratio,adjusted Injury Severity Score (EMR-ISS), using the International Classification of Diseases 10th Edition (ICD-10). Methods:, An injury severity grade similar to the Abbreviated Injury Scale (AIS) was converted from the ICD-10 codes on the basis of quintiles of the EMR for each ICD-10 code. Like the New Injury Severity Score (NISS), the EMR-ISS was calculated from three maximum severity grades using data from the Korean National Injury Database. The EMR-ISS was then validated using the Hosmer-Lemeshow goodness-of-fit chi-square (HL chi-square, with lower values preferable), the area under the receiver operating characteristic curve (AUC-ROC), and the Pearson correlation coefficient to compare it with the International Classification of Diseases 9th Edition,based Injury Severity Score (ICISS). Nationwide hospital discharge abstract data (DAD) from stratified-sample general hospitals (n = 150) in 2004 were used for an external validation. Results:, The total number of study subjects was 29,282,531, with five subgroups of particular interest identified for further study: traumatic brain injury (TBI, n = 3,768,670), traumatic chest injury (TCI, n = 1,169,828), poisoning (n = 251,565), burns (n = 869,020), and DAD (n = 26,374). The HL chi-square was lower for EMR-ISS than for ICISS in all groups: 42,410.8 versus 55,721.9 in total injury, 7,139.6 versus 20,653.9 in TBI, 6,603.3 versus 4,531.8 in TCI, 2,741.2 versus 9,112.0 in poisoning, 764.4 versus 4,532.1 in burns, and 28.1 versus 49.4 in DAD. The AUC-ROC for death was greater for EMR-ISS than for ICISS: 0.920 versus 0.728 in total injury, 0.907 versus 0.898 in TBI, 0.675 versus 0.799 in TCI, 0.857 versus 0.900 in poisoning, 0.735 versus 0.682 in burns, and 0.850 versus 0.876 in DAD. The Pearson correlation coefficient between the two scores was ,0.68 in total injury, ,0.76 in TBI, ,0.86 in TCI, ,0.69 in poisoning, ,0.58 in burns, and ,0.75 in DAD. Conclusions:, The EMR-ISS showed better calibration and discrimination power for prediction of death than the ICISS in most injury groups. The EMR-ISS appears to be a feasible tool for passive injury surveillance of large data sets, such as insurance data sets or community injury registries containing diagnosis codes. Additional further studies for external validation on prospectively collected data sets should be considered. [source]

Re-calibration and external validation of an existing nomogram to predict aggressive recurrences after radical prostatectomy

A novel algorithm to improve pathologic stage prediction of clinically organ-confined muscle-invasive bladder cancer

CANCER, Issue 7 2009
David Margel MD
Abstract BACKGROUND: An algorithm was created to predict pathologic stage in patients with clinically organ-confined muscle-invasive bladder cancer. METHODS: The sample consisted of 133 consecutive patients scheduled to undergo cystectomy. To develop a tool to predict nonorgan-confined disease before surgery, principal component analysis (PCA) was applied. Patients were stratified into a training set (n = 89) and a validation set (n = 44), and 7 parameters were evaluated: levels of carcinoembryonic antigen, cancer antigen (CA) 125, and carbohydrate antigen (CA) 19-9; clinical stage; presence of hydronephrosis; presence of carcinoma in situ; and initial tumor size >3 cm. PCA was applied to the training set to determine the weight of each parameter. A PCA score was generated for each patient in the set, and a cutoff defining nonorgan-confined disease was established. The accuracy of the cutoff was quantified by the area under the receiver operator characteristics curve (AUC). The model was then applied to the validation set without recalculation; the AUC and the positive and negative predictive values of the validation set were calculated. RESULTS: On pathologic evaluation, 71 patients (53%) were found to have organ-confined tumors and 62 patients (47%) had extravesical disease. The AUC was 0.85 in the training group (95% confidence interval [95% CI], 0.71-0.97) and 0.84 in the validation group (95% CI, 0.75-0.93). The positive and negative predictive values in the validation group were 88% (95% CI, 71%-96%) and 94% (95% CI, 71%-99%), respectively. CONCLUSIONS: The newly devised, internally validated, algorithm was 85% accurate in predicting nonorgan-confined bladder disease before cystectomy. Further external validation in a large cohort was recommended as still necessary. Cancer 2009. © 2009 American Cancer Society. [source]

Prognostic scoring of patients with parotid carcinoma: external validation using the nationwide NWHHT database

CLINICAL OTOLARYNGOLOGY, Issue 4 2001
V.L.M. Vander Poorten
Introduction. The objective was validation of prognostic indices1 for disease-free intervals of patients with parotid carcinoma. Methods. The NWHHT database contains 231 consecutive patients with parotid carcinoma from six tertiary referral centres from 1985 to 1994. This database was used to validate the predictive value of the prognostic indices PS1 (preoperative) and PS2 (postoperative). Results. The 5 year disease-free percentage was 62% (SE 5%). The previously set cut-off points for PS1 resulted in 5 year disease-free percentages ranging from 92% (PS1 = 1) to 42% for the least favourable group (PS1 = 4). The concordance (C) between score and prognosis was 0.74. The cut-off points for PS2 resulted in 5 year disease-free percentages ranging from 94% (PS2 = 1) to 49% (PS2 = 4). The concordance measure C was 0.71. Attempts to improve the PS1 and PS2 scoring in this material did not give any better results. Conclusion. The prognostic indices PS1 and PS2 are also of prognostic value in this series. [source]