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PubMed1999

The nature of psychiatric classification: issues beyond ICD-10 and DSM-IV.

OBJECTIVE: The aim of this paper is to provide an overview of the methodological underpinnings of current classification systems in psychiatry, their impact on clinical and social practices, and likely scenarios for future development, as an introduction to a series of related articles in this issue. METHOD: The method involved a selective literature review. RESULTS: The role and significance of psychiatric classifications is placed in a broader social and cultural context; the 'goodness of fit' between ICD-10 and DSM-IV on one hand, and clinical reality on the other hand, is examined; the nature of psychiatric classification, compared to biological classifications, is discussed; and questions related to the impact of advances in neuroscience and genetics on psychiatric classification are raised for further discussion. CONCLUSIONS: The introduction of explicit diagnostic criteria and rule-based classification, a major step for psychiatry, took place concurrently with the ascent to dominance of a biomedical paradigm and the synergistic effects of social and economic forces. This creates certain risks of conceptual closure of clinical psychiatry if phenomenology, intersubjectivity and the inherent historicism of key concepts about mental illness are ignored in practice, education and research.

Cultural Diversity↗
PubMed2000

Evaluation of the 1997 tumour, nodes and metastases classification of renal cell carcinoma: experience in 172 patients.

OBJECTIVE: To compare the prognostic relevance of the 1987 and 1997 tumour, nodes and metastases (TNM) systems for staging renal cell carcinoma (RCC) in predicting patient outcome. PATIENTS AND METHODS: A series of 172 consecutive patients with RCC who underwent radical nephrectomy from January 1990 to October 1997 was evaluated comparatively according to the 1987 and 1997 TNM classifications. The median (range) follow-up of the patients was 50 (19-112) months. The probability of survival was estimated by the Kaplan-Meier method, using the log-rank test to estimate differences among levels of the analysed variables. RESULTS: Using the 1997 TNM classification resulted in a redistribution of 99 patients from stage pT2 on the 1987 TNM classification to stage pT1. As the staging criteria for pT3 and pT4 did not change, there was no re-classification of these patients. Kaplan-Meier survival curves showed a similar separation in 5-year survival between stage pT1 and pT2 using both systems; 100% vs 80% for the 1987 TNM and 86% vs 69% for the 1997 TNM systems. This difference in survival rates between patients with pT1 and pT2 disease was statistically significant only for the 1997 TNM staging system. However, when the 1987 TNM staging classification was applied, the separation in 5-year survival rates between pT2 and pT3 disease was greater. CONCLUSION: This study confirms the prognostic relevance of the 1987 TNM system, as established in the present patients. The 1997 TNM classification resulted in a better stratification of patients with pT1-pT2 disease, but had similar prognostic value for pT2 and pT3 disease.

Adult↗
PubMed1999

Classification of hypertension in pregnancy.

In many ways there should be no need to classify hypertensive disorders in clinical practice. The very presence of rising blood pressure should alert the clinician to seek evidence for the development of pre-eclampsia and whether there are any emerging abnormalities of fetal growth and/or maternal renal, cerebral, hepatic or coagulation functions which may necessitate specific treatment, including delivery. While such a view may be appropriate for experienced clinicians with an understanding of the pathophysiology of the hypertensive disorders of pregnancy, it is of little help to junior or less experienced medical staff. Moreover, without an agreed international classification system it is impossible to compare truly clinical outcome, intervention or basic research studies from different units as entry criteria to these studies may differ considerably across individual units and certainly across countries. In this chapter we highlight the limitations of the existing classification systems and propose a system that is based on our present understanding of the pathophysiology of pre-eclampsia. The proposed system is not a radical departure from previous classifications, with grouping of hypertensive subjects into gestational hypertension, pre-eclampsia and chronic (usually essential) hypertension. Proteinuria, while remaining a hallmark of pre-eclampsia, is no longer considered a 'sine qua non' for this disorder to be diagnosed, reflecting our greater understanding of the maternal and fetal abnormalities in pre-eclampsia since previous classification systems were developed. This classification system has been compared with the traditional system of diagnosing proteinuric pre-eclampsia in a study of 1183 women with hypertension in pregnancy: diagnosing pre-eclampsia in this new manner still stratifies a high-risk group of pregnant women and the proposed diagnosis of gestational hypertension in this system stratifies a group of women at low maternal and fetal risk, provided that continual maternal and fetal monitoring is employed. We hope that this system of classification can be adopted uniformly, permitting appropriate triage of pregnant women into higher and lower clinical risk groups while allowing us to compare 'apples with apples' in future research studies.

Blood Pressure↗
PubMedDate not supplied

Fracture dislocations of the tarsometatarsal joints: Analysis of interrater reliability in using the modified Hardcastle classification system.

Fracture dislocations/subluxations of the tarsometatarsal joint are complex injuries that are often misdiagnosed. Prompt recognition and treatment of Lisfranc injuries decrease the likelihood of long-term sequelae. The original (1909) classification system was modified in 1982 and again in 1986. The 1986 classification system, developed by Hardcastle et al, is used most widely in clinical practice and is cited most often in the biomedical literature. For this-or any-classification system to be beneficial, however, multiple observers must be able to use it in a consistent manner, and a high level of interrater agreement should exist. This study examined interrater reliability among clinicians using the modified Hardcastle classification system for Lisfranc fracture dislocations. Thirteen Lisfranc injury radiographs were evaluated by 21 independent observers consisting of surgeons and residents (podiatric and orthopedic) as well as musculoskeletal radiologists, who classified radiographs according to the modified Hardcastle classification system. We used kappa statistics to evaluate the degree of interrater reliability for the entire group. A mean weighted kappa value of 0.54 was found for the group. Moderate interrater agreement was observed among clinicians interpreting the modified Hardcastle classification system for Lisfranc fracture dislocations.

Fractures, Bone↗
PubMed2005

A comparative review of classification systems in myelodysplastic syndromes (MDS).

Reliable classification and prognostic scoring systems for myelodysplastic syndromes (MDS) are needed to facilitate medically appropriate treatment and management decisions. The French-American-British (FAB) classification scheme for MDS was described in 1982 and has become the reference standard for subsequent MDS classification schemes. The FAB classification system divides MDS into five subgroups, based mainly on morphologic criteria and the percentage of myeloblasts in bone marrow (BM). More recently, the increasing availability of BM cytogenetics, immunologic markers, and molecular genetics has provided important information for staging, prognosis, and treatment of MDS. A World Health Organization panel incorporated this new diagnostic information into a revised classification system that modified the FAB criteria while retaining most of its basic features. The major changes included the creation of additional categories (eg, 5q- syndrome), distinction of unilineage from multilineage dysplasias in the refractory anemias, and subdivision of the heterogeneous refractory anemias with excess blasts into two categories based on BM blast percentage. Additionally, some MDS subtypes were removed or merged with other myeloid disorders into newly created categories. In independent validations, the World Health Organization revisions were shown to provide more-homogeneous subgroups of patients and greater prognostic power compared with the FAB system, although controversies remain. The International Prognostic Scoring System combines blast percentage, karyotype, and number of cytopenias to generate a scoring system that reliably estimates survival and risk of transformation to acute myeloid leukemia for patients with MDS. This universally accepted scoring system is often combined with FAB or World Health Organization morphologic criteria to provide a more complete clinical picture and the most accurate prognostic assessment possible. As more is learned about the pathogenesis of MDS at the molecular level, it is anticipated that these classification and scoring systems will continue to evolve to incorporate the new information.

Bone Marrow↗
PubMed2003

The Lichtman classification for Kienböck's disease: an assessment of reliability.

PURPOSE: The correct identification of Lichtman stage 3A and 3B Kienböck's disease is crucial for treatment purposes. The present study evaluates the reliability of the Lichtman classification, with specific attention to differentiating stage 3A and 3B. METHODS: Four reviewers evaluated wrist radiographs from 39 patients with Kienböck's disease. Radiographs were graded according to the traditional Lichtman classification, a modification of the Lichtman classification using a radioscaphoid angle of 60 degrees to subdivide stage 3, and 8 other radiographic measures. RESULTS: The interobserver reliability of the Lichtman classification was substantial (kappa coefficient 0.63), but Stage 3A was less reliably identified (kappa 0.38). The new modification of the Lichtman classification increased both the overall (kappa 0.81) and the stage 3A (kappa 0.75) interobserver reliability. CONCLUSION: The use of the radioscaphoid angle increases the interobserver reliability of the Lichtman classification. This should allow a better understanding of the clinically important distinction between stage 3A and 3B disease.

Humans↗
PubMed2002

Heterotopic ossification after total hip arthroplasty: a critical analysis of the Brooker classification and proposal of a simplified rating system.

We evaluated the reproducibility of the Brooker classification for heterotopic ossification (HO) and, based on the results and weaknesses observed, proposed a simplified system with addition of objective criteria. Six observers classified radiographs of 169 total hip arthroplasties, using the Brooker classification and a modified system consisting of i) absence of HO or islands measuring <1 cm in length, ii) islands >1 cm or spurs leaving at least 1 cm between femur and pelvis, and iii) spurs leaving <1 cm between opposing surfaces or bony ankylosis. Reproducibility was calculated using kappa statistics. For the Brooker classification, interobserver kappa averaged 0.43 (range, 0.74-0.18) (poor). Intraobserver kappa averaged 0.74 (fair). For the modified classification, interobserver kappa averaged 0.59 (range, 0.51-0.76) (fair). Intraobserver kappa averaged 0.78 (good). Interobserver differences were significant (P=.0085). Interobserver consistency to detect severe HO (Brooker 3 and 4, or grade C) improved from 52% to 76% with the modified system. The new classification showed adequate interobserver reproducibility, less variability, and improved consistency for classification of significant HO.

Arthroplasty, Replacement, Hip↗
PubMed2000

Intensive care nursing scoring system. Part 1: Classification of nursing diagnoses.

The introduction of computer-based information management systems to intensive care units offers new possibilities to describe and document the content of nursing. In different countries and health care organizations, the hospital culture and the approach taken by nurses and medical colleagues determine what, how and to what extent nursing is documented. There are nursing diagnosis classifications that are used in North America, such as NANDA (North American Nursing Diagnosis Association), and the European Union Telenurse project will promote the use of the ICNP (International Classifications of Nursing Practice) throughout Europe. The above classifications are used to describe individual, family or community responses to potential or actual health problems or life processes. But there is no nursing diagnosis classification that would take into account both the aims and the unique context of intensive care nursing. This first article describes part of our research: the action research process and the result of the development of a nursing diagnosis classification compatible with the goals of intensive care in three adult intensive care units in the Oulu University Hospital. The classification of nursing diagnoses is part of the Intensive Care Nursing Scoring System (ICNSS) which was developed in the course of this study. The other parts deal with nursing outcomes and nursing interventions. ICNSS is used to facilitate information exchange in the process of intensive care nursing and to describe the nursing workload.

Adult↗
PubMedDate not supplied

[CT morphometry for calcaneal fractures and comparison of the Zwipp and Sanders classifications].

AIM: The aim of the study is to correlate the CT-morphological changes of fractured calcaneus and the classifications of Zwipp and Sanders with the clinical outcome. METHOD: In a retrospective clinical study, the preoperative CT scans of 75 calcaneal fractures were analysed. The morphometry of the fractures was determined by measuring height, length diameter and calcaneo-cuboidal angle in comparison to the intact contralateral side. At a mean of 38 months after trauma 44 patients were clinically followed-up. The data of CT image morphometry were correlated with the severity of fracture classified by Zwipp or Sanders as well as with the functional outcome. RESULTS: There was a good correlation between the fracture classifications and the morphometric data. Both fracture classifying systems have a predictive impact for functional outcome. The more exacting and accurate Zwipp classification considers the most important cofactors like involvement of the calcaneo-cuboidal joint, soft tissue damage, additional fractures etc. The Sanders classification is easier to use during clinical routine. CONCLUSION: The Zwipp classification includes more relevant cofactors (fracture of the calcaneo-cuboidal-joint, soft tissue swelling, etc.) and presents a higher correlation to the choice of therapy. Both classification systems present a prognostic impact concerning the clinical outcome.

Adult↗
PubMed1997

[Antegrade scrotal phlebography of the v. spermatica in left-sided testicular varicocele--are retrograde phlebographic classifications suitable for typing?].

PURPOSE: The study was conducted to clarify whether the use of classifications in base of retrograde phlebography would be sufficiently suitable for typifying the findings of antegrade phlebography examinations of the internal spermatic vein with regard to antegrade sclerotherapy. SUBJECTS AND METHODS: In course of antegrade sclerotherapy in 236 patients with previously untreated idiopathic left-sided varicocele, phlebography via scrotal approach was performed. The results were compared with the relevant findings of the pre-existing classifications of the retrograde exams. RESULTS: Comparison with the classifications of Bähren and Braedel showed distinct discrepancies. In 28.8% (Bähren) respectively 36.4% (Braedel) of our findings, typification was unsuccessful. Correspondence was found with the Riedl-classification. Collateral vessels however, are not sufficiently differentiated. CONCLUSION: Retrograde classifications proved insufficient in typifying the findings of antegrade phlebography of the internal spermatic vein. A more subtle classification is required. This has been worked out and presented.

Contrast Media↗
PubMed1995

[The Bethesda system--an improvement in classification of cervix cytology?].

Cervical cytology screening programmes have significantly reduced cervical cancer mortality. In 1988 the National Cancer Institute developed a new classification for reporting cervical cytology--"The Bethesda System". The aim of our study was to compare the clinical usefulness of this new classification with the classification used in German-speaking countries (which discriminates cytologically between moderate and severe dysplasia) including a verbal classification predicting the histological grade of cervical intraepithelial neoplasia (CIN I, II, III). 671 patients with abnormal cervical cytology results and subsequent conisation or hysterectomy were included. We correlated cytological and histological diagnosis (gold standard). In cases of cytologically suggested moderate dysplasia we found histologically CIN I, CIN II and CIN III in 11%, 41% and 42%, respectively. Our results show that discrimination of CIN II and CIN III by means of cytology is limited. Using our therapy schedules we found that adequate therapy is possible by each of the cytological classification systems. The cervical smear is used as a screening test to determine which women require further examination using colposcopy. Under these circumstances an adequate therapy is possible with both classifications. The results underline the importance of colposcopy in the management of cervical dysplasia. As long as conisation is commonly used in German-speaking countries as the only diagnostic tool after an abnormal cervical smear the Bethesda System increases the risk of overtreatment.

Adult↗
PubMedDate not supplied

[Comparison of the prognostic value of the Catterall and Herring classification in patients with Perthes disease].

QUESTION: Investigation of the predictive value of the Catterall- as compared to the Herring-classification in patients with Perthes disease. METHOD: A radiological follow-up study including 53 patients with a total of 59 affected hips was carried out. In the initial diagnosis the Catterall-, Waldenström- and Herring-stages were assessed. The epiphyseal ratio, the head-neck ratio and the lateral subluxation were measured and compared at the time of diagnosis, fragmentation stage and in a follow-up examination, which was carried out 4, 9 years after diagnosis on the average. The results of the follow-up examination were assessed using the Mose-classification and compared as well. In addition the two classifications were compared as to the necessity of an upgrading. RESULTS: Both classifications yielded similar descriptions of the radiomorphometric course. There was a good correlation between the results of Herring A and Catterall I, Herring B and Catterall II and III and Herring C and Catterall IV. Upgradings were necessary in the Herring- and the Catterall-classification in 21 cases, and 18 cases, respectively. CONCLUSION: The predictive values of both classifications are comparable.

Adolescent↗
PubMed1988

Classification in neuropsychology: a theoretical framework and research paradigm.

Classification research is not well understood in neuropsychology. A major purpose of classification research is to establish and investigate inclusion and exclusion criteria for group formation. Therefore, classification represents the foundations of clinical assessment as well as traditional contrasting groups research designs in neuropsychology. Null results in neuropsychological research do not pinpoint the basis for the absence of group differences. The most frequent research focuses on the original theory or the validity of the dependent variables. Classification research focuses on a third potential problem area, which has received little attention: poor subject classifications (invalid independent variables). The purpose of this paper is to describe a general theoretical framework and outline a set of decisions for conducting classification research in neuropsychology.

Brain Damage, Chronic↗
PubMed1995

Computer-aided classification of mammographic masses and normal tissue: linear discriminant analysis in texture feature space.

We studied the effectiveness of using texture features derived from spatial grey level dependence (SGLD) matrices for classification of masses and normal breast tissue on mammograms. One hundred and sixty-eight regions of interest (ROIS) containing biopsy-proven masses and 504 ROIS containing normal breast tissue were extracted from digitized mammograms for this study. Eight features were calculated for each ROI. The importance of each feature in distinguishing masses from normal tissue was determined by stepwise linear discriminant analysis. Receiver operating characteristic (ROC) methodology was used to evaluate the classification accuracy. We investigated the dependence of classification accuracy on the input features, and on the pixel distance and bit depth in the construction of the SGLD matrices. It was found that five of the texture features were important for the classification. The dependence of classification accuracy on distance and bit depth was weak for distances greater than 12 pixels and bit depths greater than seven bits. By randomly and equally dividing the data set into two groups, the classifier was trained and tested on independent data sets. The classifier achieved an average area under the ROC curve, Az, of 0.84 during training and 0.82 during testing. The results demonstrate the feasibility of using linear discriminant analysis in the texture feature space for classification of true and false detections of masses on mammograms in a computer-aided diagnosis scheme.

Biophysical Phenomena↗
PubMed2004

A Bayesian network classification methodology for gene expression data.

We present new techniques for the application of a Bayesian network learning framework to the problem of classifying gene expression data. The focus on classification permits us to develop techniques that address in several ways the complexities of learning Bayesian nets. Our classification model reduces the Bayesian network learning problem to the problem of learning multiple subnetworks, each consisting of a class label node and its set of parent genes. We argue that this classification model is more appropriate for the gene expression domain than are other structurally similar Bayesian network classification models, such as Naive Bayes and Tree Augmented Naive Bayes (TAN), because our model is consistent with prior domain experience suggesting that a relatively small number of genes, taken in different combinations, is required to predict most clinical classes of interest. Within this framework, we consider two different approaches to identifying parent sets which are supported by the gene expression observations and any other currently available evidence. One approach employs a simple greedy algorithm to search the universe of all genes; the second approach develops and applies a gene selection algorithm whose results are incorporated as a prior to enable an exhaustive search for parent sets over a restricted universe of genes. Two other significant contributions are the construction of classifiers from multiple, competing Bayesian network hypotheses and algorithmic methods for normalizing and binning gene expression data in the absence of prior expert knowledge. Our classifiers are developed under a cross validation regimen and then validated on corresponding out-of-sample test sets. The classifiers attain a classification rate in excess of 90% on out-of-sample test sets for two publicly available datasets. We present an extensive compilation of results reported in the literature for other classification methods run against these same two datasets. Our results are comparable to, or better than, any we have found reported for these two sets, when a train-test protocol as stringent as ours is followed.

Bayes Theorem↗
PubMed2005

Automatic 3D protein structure classification without structural alignment.

In this paper, we present a new scheme named ProtClass for automatic classification of three-dimensional (3D) protein structures. It is a dedicated and unified multiclass classification scheme. Neither detailed structural alignment nor multiple binary classifications are required in this scheme. We adopt a nearest neighbor-based classification strategy. We use a filter-and-refine scheme. In the first step, we filter out the improbable answers using the precalculated parameters from the training data. In the second, we perform a relatively more detailed nearest neighbor search on the remaining answers. We use very concise and effective encoding schemes of the 3D protein structures in both steps. We compare our proposed method against two other dedicated protein structure classification schemes, namely SGM and CPMine. The experimental results show that ProtClass is slightly better in accuracy than SGM and much faster. In comparison with CPMine, ProtClass is much more accurate, while their running times are about the same. We also compare ProtClass against a structural alignment-based classification scheme named DALI, which is found to be more accurate, but extremely slow. The software is available upon request from the authors. The supplementary information on ProtClass method can be found at: http://xena1.ddns.comp.nus.edu.sg/ approximately genesis/PClass.htm.

Algorithms↗
PubMed2004

Gene selection for sample classifications in microarray experiments.

DNA microarray technology provides useful tools for profiling global gene expression patterns in different cell/tissue samples. One major challenge is the large number of genes relative to the number of samples. The use of all genes can suppress or reduce the performance of a classification rule due to the noise of nondiscriminatory genes. Selection of an optimal subset from the original gene set becomes an important prestep in sample classification. In this study, we propose a family-wise error (FWE) rate approach to selection of discriminatory genes for two-sample or multiple-sample classification. The FWE approach controls the probability of the number of one or more false positives at a prespecified level. A public colon cancer data set is used to evaluate the performance of the proposed approach for the two classification methods: k nearest neighbors (k-NN) and support vector machine (SVM). The selected gene sets from the proposed procedure appears to perform better than or comparable to several results reported in the literature using the univariate analysis without performing multivariate search. In addition, we apply the FWE approach to a toxicogenomic data set with nine treatments (a control and eight metals, As, Cd, Ni, Cr, Sb, Pb, Cu, and AsV) for a total of 55 samples for a multisample classification. Two gene sets are considered: the gene set omegaF formed by the ANOVA F-test, and a gene set omegaT formed by the union of one-versus-all t-tests. The predicted accuracies are evaluated using the internal and external crossvalidation. Using the SVM classification, the overall accuracies to predict 55 samples into one of the nine treatments are above 80% for internal crossvalidation. OmegaF has slightly higher accuracy rates than omegaT. The overall predicted accuracies are above 70% for the external crossvalidation; the two gene sets omegaT and omegaF performed equally well.

Colonic Neoplasms↗
PubMed2006

Comparison of SWAN and WISE menopausal status classification algorithms.

BACKGROUND: Classification of menopausal status is important for epidemiological and clinical studies as well as for clinicians treating midlife women. Most epidemiological studies, including the Study of Women's Health Across the Nation (SWAN), classify women based on self-reported bleeding history. METHODS: The Women's Ischemia Syndrome Evaluation (WISE) study developed an algorithm using menstrual and reproductive history and serum hormone levels to reproduce the menopausal status classifications assigned by the WISE hormone committee. We applied that algorithm to women participating in SWAN and examined characteristics of women with concordant and discordant SWAN and WISE classifications. RESULTS: Of the 3215 SWAN women with complete information at baseline (1995-1997), 2466 (76.7%) received concordant classifications (kappa = 0.52); at the fifth annual follow-up visit, of the 1623 women with complete information, 1154 (72.7%) received concordant classifications (kappa = 0.57). At each time point, we identified subgroups of women with discordant SWAN and WISE classifications. These subgroups, ordered by chronological age, showed increasing trends for menopausal symptoms and follicle-stimulating hormone (FSH) and a decreasing trend for estrogen (p < 0.001). CONCLUSIONS: The WISE algorithm is a useful tool for studies that have access to blood samples for hormone data unrelated to menstrual cycle phase, with or without an intact uterus, and no resources for adjudication. Future studies may want to combine aspects of the SWAN and WISE algorithms by adding hormonal measures to the series of bleeding questions in order to determine more precisely where women are in the perimenopausal continuum.

Adult↗