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PubMed1990

Gastric adenocarcinoma: prognostic significance of several pathologic parameters and histologic classifications.

Considerable controversy exists about the value of histologic classifications of gastric adenocarcinoma in the prediction of patient survival. Histologic sections of 75 consecutive gastrectomies were used to compare Lauren and Ming classifications with emphasis on clinical stage, size, location of tumor, desmoplasia, inflammatory reaction, and 5-year survival. Both classifications generally correlated and, when combined, proved helpful in defining certain cases. At surgery, about one third of the total cases of intestinal (INT, Lauren) and expanding (ET, Ming) were in early stages, whereas almost all the diffuse (DT, Lauren) and infiltrative (INF, Ming) types were in late stages. When the Lauren classification was applied to preoperative endoscopic biopsies, a 72% diagnostic correlation with the surgical specimens was found. Followup revealed no survivors of the DT and INF and 12 and 11 survivors of INT and ET, respectively, regardless of stage. Inflammatory response was associated with good prognosis. Desmoplasia and size had no prognostic significance. Tumors of the cardia had worse prognoses than those in the body or antrum. Both Lauren and Ming classifications, and especially the degree of inflammation, were significant in predicting survival. Lauren INT and Ming ET should be declared only when they are the sole or predominant features.

Adenocarcinoma↗
PubMed1989

Challenges for receptor theory as a tool for drug and drug receptor classification.

Increased understanding in the field of receptor pharmacology, born of the sophisticated techniques now available to us, has confounded rather than simplified the problem of receptor classification. The International Union of Pharmacology (IUPHAR) is currently sponsoring a Receptor Nomenclature Committee whose aims are to recommend a rational system of classification, a formidable task given the complexity and volume of data in the literature (agonist/antagonist potencies, coupling mechanisms, primary structures, etc.) that will need to be incorporated. The Committee's chairman, Terry Kenakin, outlines here the limitations of classical receptor theory for drug receptor classification and suggests that any functional classification system must take into account not only affinity and intrinsic efficacy but also, at the very least, parameters relating to the transducing properties of receptors. If this is not done, then receptor classification data obtained from studies with agonists and antagonists may be different and lead to confusion.

Animals↗
PubMed1991

A proposed modification of the Ho stage-classification for nasopharyngeal carcinoma.

Based on the clinical data of a retrospective study of 659 NPC patients with routine computed tomography of the nasopharyngeal region, a refinement of Ho's stage-classification for NPC is proposed with reduction in the number of overall stages without sacrificing the accuracy in predicting prognosis in the short term. Classifying the cervical lymph nodal metastasis into supraclavicular (Ho's N3) and above supraclavicular (Ho's N1 + N2) and the nasopharyngeal primary into early (Ho's T1 + T2n + T20) and advanced (Ho's T2p + T3 + T3p) forms the conceptual backbone of the present proposed modification of the original Ho stage-classification. Power in predicting the occurrence of distant metastases and the local failures has been enhanced by the proposed T-stage and N-stage re-grouping. Retrospective comparison between Ho's and the UICC stage-classifications showed a more even patients number distribution among the overall stages and a greater power in predicting NPC prognosis for the former. Prospective studies to compare the value of the different stage-classifications are required for recommendation of a single classification for general acceptance to facilitate comparison of treatment results between centres.

Dose-Response Relationship, Radiation↗
PubMed1993

Severity of illness classification for infection control departments: a study in nosocomial pneumonia.

BACKGROUND: A subjective severity of illness classification was evaluated in a study of nosocomial pneumonia. This is a 5-category system based on the determination of the control of underlying illness and the risk of death during current hospital admission. METHODS: A case-control study was performed with 128 cases of nosocomial pneumonia and 252 control patients. An additional 60 case and 90 control patients were used to compare this classification with APACHE II scoring in intensive care unit patients. RESULTS: In univariate analysis, the severity illness classification was significantly associated with nosocomial pneumonia risk (p < 0.01). APACHE II adequately predicted mortality rate but was not statistically significantly associated with nosocomial pneumonia risk among intensive care unit patients. In logistic regression analysis, the severity of illness classification, surgery, age, nasogastric tube placement, and histamine blockers each showed significant independent association with nosocomial pneumonia. CONCLUSIONS: The role of the severity of illness classification for risk stratification in nosocomial pneumonia is valid. Its roles in the evaluation of surgical wound infection, nosocomial bacteremia, and quality of care remain to be determined in subsequent studies.

California↗
PubMed1984

Some thoughts on a possible regulatory approach at EEC level on the classification and labeling of dangerous preparations.

At the present time no European directives on classification, packaging, and labeling exist which cover all dangerous preparations of chemicals. To develop such a directive, the Commission of the European Economic Community services, at the request of and in close collaboration with experts of the member states, has conceived a method for evaluating the toxicity of mixtures of chemicals. This method consists of (a) the characterization of each constituent by means of an index and (b) the classification of preparations for each route of administration on the basis of their toxicity. The index is a figure representing the degree of dilution needed to render the substance not dangerous in the sense of the EEC Directives on the classification of dangerous substances; the highest index among those obtained for acute and chronic toxicity is taken to characterize the substances. An indication of toxicity is obtained by applying the simple equation sigma (P X I), where P is the percentage and I is the index of each constituent. The most stringent classification among those obtained for the three routes of administration is taken for the final classification of the preparation on the basis of its acute and chronic toxicity. Other toxicological effects such as irritation, corrosion, sensitization, mutagenesis, teratogenesis, and carcinogenesis are not considered.

Animals↗
PubMed1992

From DSM-I to III-R; voices of self, mastery and the other: a cultural constructivist reading of U.S. psychiatric classification.

The continual process of mental disease classification in U.S. psychiatry is assumed to reflect advancing professional knowledge of these disorders. To date, the American Psychiatric Association has developed four standard classifications, or nosologies, called Diagnostic and Statistical Manuals ('DSMs'). DSM-I, the earliest, appeared in 1952 while the most recent, DSM-III-R, appeared in 1987. This paper employs a cultural constructivist perspective to deconstruct these nosologies and the classificatory process itself. Constructivism's premises, which emphasize culture, history, meaning and the constructed nature of medical phenomena, serve as the framework for the analysis. The paper shows that professional psychiatric classification expresses an underlying cultural psychology which encompasses four phenomenological domains and one of three Western person conceptions. Classifications are found to be explorations of culturally meaningful etiologies that explain the absence of 'self control', a central ethnopsychological aspect of the idealized self. Consideration of the vantage point of the voice of classification indicates that the ideal self is gender- (male), ethnic- (German Protestant) and age-specific (adult). The ethnic self's essence, and that of the Other, is believed to be biological, itself assumed to be natural and beyond culture or bias. Consequently, the ethnopsychology constructs as biologically caused the real and imagined differences in the gender, age or culturally Other. This invidious ethnobiological essentialism acts to create and maintain self-worth through a radical differentiation of self from those represented as Other.

Anthropology, Cultural↗
PubMed1996

Interobserver variability in the classification of neonatal seizures based on medical record data.

This population-based, retrospective cohort study of neonatal seizures included all 16,428 neonates born to residents of Fayette County, Kentucky, from 1985 to 1989. Eighty potential cases were ascertained by computer search of hospital-based medical record systems, birth certificate data files, and multiple-cause-of-death mortality data files. Medical records for potential cases were abstracted, and relevant portions were reviewed independently by three neurologists using prospectively determined criteria. Both unweighted and weighted kappa statistics were used to measure agreement between each pair of observers in the classification of potential cases as seizures, possible seizures, or not seizures, adjusting for the proportion of agreement expected by chance. Agreement in the classification of potential cases was excellent (kappa = 0.72-0.79, average = 0.76; weighted kappa = 0.85-0.88, average = 0.87). The kappa extension statistic of Kraemer was used to assess agreement in the classification of seizure types by a simplification of the classification scheme of Volpe. This documented excellent agreement between raters in the classification of seizure types (kappa e = 0.72). Experienced raters can reliably classify potential cases of neonatal seizures using seizure descriptions transcribed from medical records.

Cohort Studies↗
PubMed1992

Angle classification revisited. 1: Is current use reliable?

The Angle method for the classification of malocclusion has been the standard in orthodontics for 100 years, but many academics and private practitioners find difficulty applying the Angle system to malocclusions in between fully Class II and fully Class III. To evaluate whether orthodontists are consistent in classifying malocclusions accordings to Angle's method, study models were selected of three patients with ideal buccal occlusions, two patients with mutilated occlusions, and five patients with varying degrees of Class II tendency. One buccal view was photographed of each study model, and a questionnaire was printed and sent to 347 orthodontists. The 77.8% response demonstrated significant interest in the subject of dental classification and significant disagreement among orthodontists in their classification response with all patients except the two obvious ideal occlusions. Respondents were given the opportunity to comment on Angle classification and their recommendations for improved classification techniques. Many of their comments are quoted.

Humans↗
PubMed1995

Interobserver discordance in the classification of mechanisms of death in studies of heart failure.

Studies of the mechanism of death in heart failure are dependent on the reliability and validity of classification of deaths as pump failure or arrhythmias (sudden). Two recent trials differed in that the Vasodilator Heart Failure Trial II (V-HeFT II) reported a higher incidence of sudden death than the Studies of Left Ventricular Dysfunction Treatment Trial (SOLVD) and an effect of enalapril on sudden death was not observed in SOLVD. A similar classification system was used in the two studies, but deaths in V-HeFT were classified centrally from a narrative summary, whereas deaths in SOLVD were classified in the field by individual investigators. To examine reliability, 10 narratives used to classify V-HeFT deaths were independently classified by 21 SOLVD investigators. In only 5 of 10 cases did 75% of SOLVD investigators agree with the V-HeFT classification. In no deaths were all SOLVD investigators in agreement on classification. Although V-HeFT classified 5 of 10 cases as sudden death, 16 of 21 SOLVD investigators classified less than 5 deaths as sudden and 1 classified none as sudden. The kappa statistic for interobserver agreement of 0.22 (P < or = .01) indicated interobserver agreement only slightly better than chance agreement. Therefore, the incidence of sudden death in heart failure is critically dependent on the bias of the investigator. Central classification will minimize inconsistencies, but it does not solve the problem that the mechanism of death is difficult to assign. Total mortality may be the only reliable endpoint in heart failure trials.

Adult↗
PubMed2006

Emergency department patient classification systems: A systematic review.

BACKGROUND: The emergency department is a dynamic environment with a high throughput of patients. The clinical stability of patients varies considerably. In order to provide optimal care for patients a responsive staffing pattern is required. There is a need for a valid and reliable, prospective, emergency department patient classification system to set adequate nurse staffing levels in the UK. AIMS AND OBJECTIVES: To conduct a systematic review of the literature and determine the validity, reliability, strengths and weaknesses of emergency department patient classification systems. METHODS: The following electronic databases were searched for years 1985-2004: MEDLINE; CINAHL; COCHRANE Library databases DARE, CDSR, CCTR, BioMedNet Reviews, National Research Register (NRR). Manual searches were also conducted and relevant references retrieved from those listed in key papers, reports, theses and dissertations. Studies were also retrieved by contacting researchers in the field. RESULTS: Twelve patient classification systems met all the inclusion criteria. Only three systems reported evidence of good validity and reliability: the ED Patient Needs Matrix developed in the US, the Conner's Tool (a modified version of the ED Patient Needs Matrix) developed in Australia and the Jones Dependency Tool developed in the UK. CONCLUSION: There are very few patient classification systems developed for use in the ED setting that have demonstrated good validity and reliability. The Jones Dependency Tool is a simple, easy to use prospective, patient classification system that has demonstrated good validity and reliability in the UK.

APACHE↗
PubMed2006

Clinical classification schemes for predicting hemorrhage: results from the National Registry of Atrial Fibrillation (NRAF).

BACKGROUND: Although warfarin and other anticoagulants can prevent ischemic events, they can cause hemorrhage. Quantifying the rate of hemorrhage is crucial for determining the risks and net benefits of prescribing antithrombotic therapy. Our objective was to find a bleeding classification scheme that could quantify the risk of hemorrhage in elderly patients with atrial fibrillation. METHODS: We combined bleeding risk factors from existing classification schemes into a new scheme, HEMORR2HAGES, and validated all bleeding classification schemes. We scored HEMORR2HAGES by adding 2 points for a prior bleed and 1 point for each of the other risk factors: hepatic or renal disease, ethanol abuse, malignancy, older (age > 75 years), reduced platelet count or function, hypertension (uncontrolled), anemia, genetic factors, excessive fall risk, and stroke. We used data from quality improvement organizations representing 7 states to assemble a registry of 3791 Medicare beneficiaries with atrial fibrillation. RESULTS: There were 162 hospital admissions with an International Classification of Diseases, Ninth Revision, Clinical Modification code for hemorrhage. With each additional point, the rate of bleeding per 100 patient-years of warfarin increased: 1.9 for 0, 2.5 for 1, 5.3 for 2, 8.4 for 3, 10.4 for 4, and 12.3 for > or =5 points. In patients prescribed warfarin, HEMORR2HAGES had greater predictive accuracy (c statistic 0.67) than other bleed prediction schemes (P < .001). CONCLUSIONS: Adaptations of existing classification schemes, especially a new bleeding risk scheme, HEMORR2HAGES, can quantify the risk of hemorrhage and aid in the management of antithrombotic therapy.

Aged↗
PubMed2004

Assessment of the standardized reporting guidelines ECG classification system: the presenting ECG predicts 30-day outcomes.

STUDY OBJECTIVE: Standardized reporting criteria for risk stratification studies of patients with potential acute coronary syndromes have been proposed. We sought to determine whether the categories in the recommended 6-item ECG classification system predict rates of 30-day death, myocardial infarction, and revascularization. METHODS: We conducted a prospective cohort study of emergency department (ED) chest pain patients who presented to a tertiary care center during a 32-month period. The treating physician classified all ECGs into defined categories. Patients were followed up for 30 days to determine death, myocardial infarction, and revascularization. Our main outcome was the rate of triple composite endpoint of death, myocardial infarction, or revascularization at 30 days from ED presentation in relation to the ECG classification category. RESULTS: There were 3,814 patients who presented to the ED a total of 4,487 times during the study period. Patients had a mean (+/-SD) age of 51.8+/-15.9 years, were more likely to be women (59%) than men, and were most commonly black (68%). The relationship between initial ECG classification and 30-day outcome was highly significant (P<.001), with event rates ranging from 3.2% to 72.7%, depending on ECG classification category. CONCLUSION: The ECG classification system that is being recommended in the standardized guidelines predicts 30-day composite rates of death, acute myocardial infarction, and revascularization.

Adult↗
PubMed2006

Multiple hierarchical classification of free-text clinical guidelines.

OBJECTIVE: Manual classification of free-text documents within a predefined hierarchy, commonly required in the medical domain, is highly time consuming task. We present an approach based on supervised learning to automate the classification of clinical guidelines into predefined hierarchical conceptual categories. METHODS AND MATERIAL: Given a set of hierarchically categorized documents in the training stage the learning algorithm exploits the hierarchical structure of the concepts in order to overcome the low number of training examples. The classification task is thus decomposed into a continuous decision process, unlike searching within a decision tree, which follows the concept hierarchy and makes a single decision at each node on the path, multiple paths can be chosen. Classification is based on applying a similarity function at each concept. Several evaluation measures were used, based on the intended use of the hierarchy. In addition, conservative and aggressive stop-criterion strategies for stopping the search through the concept hierarchy were formulated. An evaluation of the approach, including several training methods and multiple evaluation measures, has been performed using a training set of 1136 guidelines from the National Guideline Clearing House set. RESULTS: Based on a test collection consisting of 1038 clinical practice guidelines (CPGs) classified along two hierarchies, of roughly 5000 concepts, in which each CPG was classified by a mean of 10 concepts, a variable precision was observed from 44% to 60% depending on the settings of the training methods. CONCLUSION: These results demonstrate the feasibility of the approach, especially when considering the low ratio of guidelines to classification indices (concepts) in the evaluation data set used here.

Algorithms↗
PubMed2006

Auditory brainstem response classification: a hybrid model using time and frequency features.

OBJECTIVE: The auditory brainstem response (ABR) is an evoked response obtained from brain electrical activity when an auditory stimulus is applied to the ear. An audiologist can determine the threshold level of hearing by applying stimuli at reducing levels of intensity, and can also diagnose various otological, audiological, and neurological abnormalities by examining the morphology of the waveform and the latencies of the individual waves. This is a subjective process requiring considerable expertise. The aim of this research was to develop software classification models to assist the audiologist with an automated detection of the ABR waveform and also to provide objectivity and consistency in this detection. MATERIALS AND METHODS: The dataset used in this study consisted of 550 waveforms derived from tests using a range of stimulus levels applied to 85 subjects ranging in hearing ability. Each waveform had been classified by a human expert as 'response=Yes' or 'response=No'. Individual software classification models were generated using time, frequency and cross-correlation measures. Classification employed both artificial neural networks (NNs) and the C5.0 decision tree algorithm. Accuracies were validated using six-fold cross-validation, and by randomising training, validation and test datasets. RESULTS: The result was a two stage classification process whereby strong responses were classified to an accuracy of 95.6% in the first stage. This used a ratio of post-stimulus to pre-stimulus power in the time domain, with power measures at 200, 500 and 900Hz in the frequency domain. In the second stage, outputs from time, frequency and cross-correlation classifiers were combined using the Dempster-Shafer method to produce a hybrid model with an accuracy of 85% (126 repeat waveforms). CONCLUSION: By combining the different approaches a hybrid system has been created that emulates the approach used by an audiologist in analysing an ABR waveform. Interpretation did not rely on one particular feature but brought together power and frequency analysis as well as consistency of subaverages. This provided a system that enhanced robustness to artefacts while maintaining classification accuracy.

Acoustic Stimulation↗
PubMed2006

Acute renal failure after cardiac surgery: evaluation of the RIFLE classification.

BACKGROUND: Acute renal failure increases risk of death after cardiac surgery. However, the definition of acute renal failure is not standardized. The Acute Dialysis Quality Initiative Workgroup has outlined consensus criteria. The aim of the present study was to evaluate this determination of postoperative renal impairment in cardiac surgical patients, and its association with mortality. METHODS: The 813 consecutive patients undergoing cardiac surgery at Helsinki University Central Hospital were analyzed. According to the RIFLE classification (named by the severity of renal impairment: Risk, Injury, Failure, Loss, End-stage kidney disease) patients were divided into three levels based on either plasma creatine level or urine output. The discrimination with death within 90 days after surgery was determined. RESULTS: According to the RIFLE criteria, 19.3% of patients had renal impairment after cardiac surgery. Patients in the more severe category, RIFLE-F (failure), had a 90-day mortality rate of 32.5% compared with 8.0% for those in RIFLE-R (risk) and 21.4% for RIFLE-I (injury) patients. The RIFLE classification discriminated 90-day mortality quite well (area under curve 0.824) compared with the change of plasma creatinine and the change of estimated gromerular filtration rate (areas under curve 0.849 and 0.829, respectively). The results of the multivariate forward stepwise logistic regression analysis found that RIFLE classification was an independent risk factor for 90-day mortality (p < 0.0001), unlike change in glomerular filtration rate and change in plasma creatinine. CONCLUSIONS: We propose that the RIFLE classification is a valuable method to evaluate acute renal failure after cardiac surgery. The severity of RIFLE classification may be associated with increased 90-day mortality rate.

Acute Kidney Injury↗
PubMed2006

A simple classification for standardisation of nomenclature in free flap outcome.

The numbers of free flap donor site as well as their indications are constantly increasing. Despite increasing popularity of microvascular reconstructive procedures, literature lacks clear and objective outcome criteria. This paper reports on a simple outcome classification that has become a routine part of the unit's large workload of microvascular outcome recording. The classification was formed through a retrospective analysis of 241 consecutive cases from 2000 to 2001 and is a five graded numerical classification. Grade 1 equates to total success without co-morbidity and grade 5 to a major complication such as amputation, etc., whatever the status of the flap itself. From 2002 to 2005 the classification was prospectively used on 527 consecutive cases with ease of integration into routine clinical practice. The Classification would enable a more objective record keeping thus analysis of the outcome. It would allow a more realistic comparison of different techniques or donor types as well set a benchmarking level for further improvement of the results.

Female↗
PubMed2005

Classification of dopamine antagonists using functional feature hypothesis and topological descriptors.

The designing of selective dopamine antagonists for their own subreceptors can be useful in individual therapy of various neuropsychiatric disorders. Three-dimensional pharmacophore hypothesis and two-dimensional topological descriptors were used to investigate and compare different classes of dopamine antagonists. The structurally diverse D(3) and D(4) antagonists above preclinical trials were selected to map common structural features of highly selective and efficacious antagonists. The generated pharmacophore hypotheses were successfully employed as discriminative probe for database screening. To filter out the false positive from screening hits, the classification models by two-dimensional topological descriptors were built. Molconn-Z and BCUT topological descriptors were employed to develop a classification model for 1328 dopamine antagonists from MDDR database. The soft independent modeling of class analogy and artificial neural network, two supervised classification techniques, successfully classified D(1), D(3), and D(4) antagonists at the average of 80% rates into their own active classes. The mean classification rates for D(2) antagonists were obtained to 60% due to insufficient selective D(2) antagonists. In this paper, we report the validity of our models generated using functional feature hypotheses and topological descriptors. The combining both of classification using functional feature hypotheses and topological descriptors would be a useful tool to predict selective antagonists.

Algorithms↗
PubMed2006

An evolutionary Michigan recurrent fuzzy system for nuclei classification in cytological images using nuclear chromatin distribution.

OBJECTIVE: The objective of this research is to carry out the classification of cellular nuclei in cytological pleural fluid images. The article focuses on the feature extraction and classification processes. The extracted feature is a spatial measurement of the chromatin distribution in cellular nuclei. The designed classifiers are fuzzy classifiers that carry out supervised classification. The classifier system's inputs are data series that represent these texture measurements. METHODS AND MATERIAL: The classifier is built on a Recurrent Fuzzy System (RFS). An evolutionary algorithm inspired by the Michigan approach is used to find an optimal RFS to classify different patterns expressed as data series. RESULTS: The effectiveness of the proposed classifier system is compared with other existing classification methods and evaluated via Receiver Operating Characteristic (ROC) analysis. We have obtained RFS based classifiers that perform with sensitivity values between 82.26 and 93.55% and with specificity values between 80.65 and 90.32%. The behavior of the proposed chromatin measurement is also compared with other texture measurements. CONCLUSION: The RFS based classifiers were successfully applied to the proposed data series that represent the chromatin distribution in cellular nuclei. These fuzzy classifiers present the highest classification efficiency and the ROC analysis confirms their suitable behavior.

Algorithms↗