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Classifications in routine use: lessons from ICD-9 and ICPM in surgical practice.

OBJECTIVE: Classifications of diagnoses and procedures are very important for the economical as well as the quality assessment of surgical departments. They should reflect the morbidity of the patients treated and the work done. The authors investigated the fulfillment of these requirements by ICD-9 (International Classification of Diseases: 9th Revision) and OPS-301, a German adaptation of the ICPM (International Classification of Procedures in Medicine), in clinical practice. DESIGN: A retrospective study was conducted using the data warehouse of the Surgical Center II at the Medical Faculty in Essen, Germany. The sample included 28,293 operations from the departments of general surgery, neurosurgery, and trauma surgery. Distribution of cases per ICD-9 and OPS-301 codes, aggregation through the digits of the codes, and concordance between the classifications were used as measurements. Median and range were calculated as distribution parameters. The concentration of cases per code was graphed using Lorenz curves. The most frequent codes of diagnoses were compared with the most frequent codes of surgical procedures concerning their medical information. RESULTS: The total number of codes used from ICD-9 and OPS-301 went up to 14 percent, depending on the surgical field. The median number of cases per code was between 2 and 4. The concentration of codes was enormous: 10 percent of the codes were used for about 70 percent of the surgical procedures. The distribution after an aggregation by digit was better with OPS-301 than with ICD-9. The views with OPS-301 and ICD-9 were quite different. CONCLUSION: Statistics based on ICD-9 or OPS-301 will not properly reflect the morbidity in different surgical departments. Neither classification adequately represents the work done by surgical staff. This is because of an uneven granularity in the classifications. The results demand a replacement of the ICD-9 by an improved terminological system in surgery. The OPS-301 should be maintained and can be used at least in the medium term.

Disease↗

Histological grading of papillary urothelial carcinoma of the bladder: prognostic value of the 1998 WHO/ISUP classification system and comparison with conventional grading systems.

AIM: To test the prognostic value of the 1998 WHO/ISUP (World Health Organisation/International Society of Urologic Pathology) consensus classification system in Ta papillary urothelial neoplasms of the bladder. METHODS: The histological slides of 322 patients with a primary Ta tumour were classified according to the consensus classification system, and recurrence free survival (RFS) and progression free survival (PFS) were assessed for a mean follow up period of 79 months. In the same patient group, the RFS and PFS rates for the 1973 WHO grading system and a low grade/high grade system were analysed. RESULTS: Recurrent tumours were seen in all categories of the 1998 WHO/ISUP classification system and five year RFS was not significantly different between the groups (p = 0.12). The five year PFS showed a small but significant difference (p = 0.04) between papillary neoplasms of low malignant potential (PNLMP) and high grade papillary urothelial carcinomas (HGPUCs). In the 1973 WHO classification, no significant difference was found in RFS and PFS between the different grades. In the low grade/high grade classification PFS was significantly better for low grade tumours (p = 0.01). CONCLUSION: The prognostic value of the 1998 WHO/ISUP classification system is limited to predicting PFS, especially between PNLMP and HGPUC. The prognostic value of this system over other grading systems is questionable.

Adult↗

Computer-aided classification of BI-RADS category 3 breast lesions.

PURPOSE: To evaluate a system for computer-aided classification (CAC) of lesions assigned to Breast Imaging Reporting and Data System (BI-RADS) category 3 at conventional mammographic interpretation. MATERIALS AND METHODS: A CAC system was used to analyze 106 cases of lesions (42 malignant) that at blinded retrospective interpretation were assigned to BI-RADS category 3 by at least two of four radiologists. The CAC system automatically extracted from the digitized mammograms quantitative features that characterized the lesions. The system then used a classification scheme to score the lesions by the likelihood of their malignancy on the basis of these features. The classification scheme was trained with 646 pathologically proved cases (323 malignant), and the results were tested with receiver operating characteristic (ROC) analysis by using the jackknife method. Sensitivity, specificity, positive predictive value, and accuracy were calculated. Category 3 lesions were stratified among BI-RADS categories 2-5 according to CAC-assigned lesion score, and this classification was compared with the results of pathologic analysis. RESULTS: Jackknife analysis of CAC results in the training data set yielded a sensitivity of 94%, specificity of 78%, positive predictive value of 81%, and area under the ROC curve of 0.90. Of the 42 malignant lesions that had been classified at conventional interpretation as probably benign, nine were assigned by the CAC system to BI-RADS category 4, and 29 were assigned to category 5. The CAC system correctly upgraded the BI-RADS classification of these 38 lesions (sensitivity, 90%) and incorrectly upgraded the classification of only 20 benign lesions (specificity, 69%). CONCLUSION: The CAC system scored 38 of the 42 malignant lesions initially assigned to BI-RADS category 3 as BI-RADS category 4 or 5, and thus correctly upgraded the category in 90% of these lesions.

Adult↗

Evaluation of cystic renal masses: comparison of CT and MR imaging by using the Bosniak classification system.

PURPOSE: To compare computed tomography (CT) and magnetic resonance (MR) imaging in the evaluation of cystic renal masses by using the Bosniak classification system. MATERIALS AND METHODS: Images of 69 renal masses in 59 patients (38 men, 21 women; mean age, 60.4 years; range, 30-86 years), who had undergone both CT and MR imaging examinations within 1 year (average, 60.5 days; range, 0-356 days), were retrospectively analyzed by two radiologists in consensus. For each lesion, images were compared for thickness of wall and septa, number of septa, and presence of enhancement. Each mass was categorized (Bosniak classification) first on CT images and then on MR images, and results were compared. Pathologic correlation was available in 25 lesions. RESULTS: On CT images, there were 15 category I, 16 category II, 10 category IIF, 19 category III, and nine category IV lesions. Findings on CT and MR images were similar in 56 (81%) lesions; in 13 (19%) lesions, there were differences. In eight (12%) lesions, MR imaging depicted more septa than did CT, which resulted in an upgrade of the classification at MR imaging in two cases. In seven (10%) lesions, MR imaging depicted increased wall and/or septa thickness compared with CT, resulting in a classification upgrade in six cases. Three lesions had both increased numbers of septa and thickening of the wall and/or septa. In two (3%) lesions, enhancement characteristics at CT and MR imaging were different. One of these lesions also had an increased number of septa. Overall, MR imaging results led to a cyst classification upgrade of seven lesions, from category II to IIF (n = 2), IIF to III (n = 3), or III to IV (n = 2). Pathologic correlation in 25 lesions revealed 20 malignant and five benign lesions. CONCLUSION: CT and MR imaging findings were similar in the majority of cystic renal masses. In some cases, however, MR images may depict additional septa, thickening of the wall and/or septa, or enhancement, which may lead to an upgraded Bosniak cyst classification and can affect case management.

Adult↗

Multiclass cancer classification by using fuzzy support vector machine and binary decision tree with gene selection.

We investigate the problems of multiclass cancer classification with gene selection from gene expression data. Two different constructed multiclass classifiers with gene selection are proposed, which are fuzzy support vector machine (FSVM) with gene selection and binary classification tree based on SVM with gene selection. Using F test and recursive feature elimination based on SVM as gene selection methods, binary classification tree based on SVM with F test, binary classification tree based on SVM with recursive feature elimination based on SVM, and FSVM with recursive feature elimination based on SVM are tested in our experiments. To accelerate computation, preselecting the strongest genes is also used. The proposed techniques are applied to analyze breast cancer data, small round blue-cell tumors, and acute leukemia data. Compared to existing multiclass cancer classifiers and binary classification tree based on SVM with F test or binary classification tree based on SVM with recursive feature elimination based on SVM mentioned in this paper, FSVM based on recursive feature elimination based on SVM can find most important genes that affect certain types of cancer with high recognition accuracy.

Journal Article↗

Prostate pathology of genetically engineered mice: definitions and classification. The consensus report from the Bar Harbor meeting of the Mouse Models of Human Cancer Consortium Prostate Pathology Committee.

The Pathological Classification of Prostate Lesions in Genetically Engineered Mice (GEM) is the result of a directive from the National Cancer Institute Mouse Models of Human Cancer Consortium Prostate Steering Committee to provide a hierarchical taxonomy of disorders of the mouse prostate to facilitate classification of existing and newly created mouse models and the translation to human prostate pathology. The proposed Bar Harbor Classification system is the culmination of three meetings and workshops attended by various members of the Prostate Pathology Committee of the Mouse Models of Human Cancer Consortium. A 2-day Pathology Workshop was held at The Jackson Laboratory in Bar Harbor, Maine, in October 2001, in which study sets of 93 slides from 22 GEM models were provided to individual panel members. The comparison of mouse and human prostate anatomy and disease demonstrates significant differences and considerable similarities that bear on the interpretation of the origin and natural history of their diseases. The recommended classification of mouse prostate pathology is hierarchical, and includes developmental, inflammatory, benign proliferative, and neoplastic disorders. Among the neoplastic disorders, preinvasive, microinvasive, and poorly differentiated neoplasms received the most attention. Specific criteria were recommended and will be discussed. Transitions between neoplastic states were of particular concern. Preinvasive neoplasias of the mouse prostate were recognized as focal, atypical, and progressive lesions. These lesions were designated as mouse prostatic intraepithelial neoplasia (mPIN). Some atypical lesions were identified in mouse models without evidence of progression to malignancy. The panel recommended that mPIN lesions not be given histological grades, but that mPIN be further classified as to the absence or presence of documented associated progression to invasive carcinoma. Criteria for recognizing microinvasion, for classification of invasive gland-forming adenocarcinomas, and for characterizing poorly differentiated tumors, including neuroendocrine carcinomas, were developed and are discussed. The uniform application of defined terminology is essential for correlating results between different laboratories and models. It is recommended that investigators use the Bar Harbor Classification system when characterizing new GEM models or when conducting experimental interventions that may alter the phenotype or natural history of lesion progression in existing models.

Animals↗

Phasic and process psychoses: a polydiagnostic comparison among the Frankfurt Classification System, DSM III, RDC, Feighner criteria and ICD-9.

The classification of endogenous psychoses is a controversial sector of psychiatry. Differences with regard to the evaluation of course and outcome contribute to this controversy. The course and outcome of a psychiatric illness are basic to the Frankfurt Classification System (FC) of endogenous psychoses. The main groups are process and phasic psychoses (typical and atypical). A third group, encompassing cases which could not be definitely classified at the time of examination, is entitled 'nonclassified endogenous psychoses'. This system was outlined according to the AMDP system and SANS using the cases of 100 patients admitted to the hospital (aged 18-86 years; 57 men, 43 women) and compared with four classifications (ICD-9, RDC, DSM III and Feighner). The listed definitions do not state whether or not a defective symptomatology is absolutely irreversible. Most of the atypic-phasic psychoses of the FC (50-78%) were schizoaffective psychoses according to the other classifications (Feighner, RDC, ICD-9) and most of the process psychoses (85-97%) were schizophrenias according to Feighner, ICD-9, RDC and DSM III. The major reason for the great correspondence (97%) between process psychoses (FC) and DSM III schizophrenias appears to be that 85% of the sample consisted of chronic and not subchronic schizophrenic disorders according to DSM III. On the other hand, about 45% of the ICD-9 and RDC schizophrenias (principally acute and subacute) were not diagnosed as process psychoses according to the FC. In the case of the typic-phasic psychoses, there was almost complete agreement with the other diagnostic systems. Most of the cases in which classification into the group 'process' or 'phasic psychosis' was unclear were diagnosed as schizophreniform disorders according to DSM III (70%) or into nearly equivalent groups according to RDC or ICD-9. Nonetheless, complete equivalency among these similar groups was not possible. In the context of some research aims (e.g. definitions of phenomenological or biological parameters), a classification system based on clearly-defined inclusion and exclusion criteria of such concepts as phasic and process psychoses (in shifts or insidious) is methodologically useful. The FC is suggested as a step in this direction.

Adolescent↗

Estimation of growth fraction in fine needle aspirates from non-Hodgkin's lymphoma using anti-proliferating cell nuclear antigen: correlation with the Kiel classification.

OBJECTIVE: This study was undertaken to assess whether fine needle aspirates from non-Hodgkin's lymphoma (NHL) could be used for growth fraction analysis with proliferating cell nuclear antigen (PCNA) staining and if there was a relationship between the growth fraction and cytomorphologic classification according to the Kiel classification. STUDY DESIGN: The study group consisted of 40 patients with NHL diagnosed by fine needle aspiration (FNA) cytology. The cytologic classification of the lymphomas was made by two cytopathologists on May-Grünwald-Giemsa-stained slides using the Kiel classification. There were 27 cases of low and 13 of high grade lymphoma. The estimation of the growth fraction was made by PCNA immunoreactivity. The PCNA index was quantitated in smears by counting an average of 1,000 cells, and the count was correlated with the cytomorphologic classification. RESULTS: There was a strong correlation between the PCNA index and lymphoma grading. High grade lymphomas exhibited a mean PCNA positivity of 74.0%, which was significantly higher (P < .001) than that of low grade lymphomas (17.6%). CONCLUSION: Our study showed that PCNA evaluation is suitable for smears obtained by FNA on NHL, correlates with increasing grades of lymphoma according to the Kiel classification and may offer a method of monitoring treatment of lymphoma.

Adolescent↗

Prediction of stroke by self-measurement of blood pressure at home versus casual screening blood pressure measurement in relation to the Joint National Committee 7 classification: the Ohasama study.

BACKGROUND AND PURPOSE: To compare the predictive power of self-measured home blood pressure (HBP) and casual blood pressure (CBP) for stroke risk in relation to the Joint National Committee 7 (JNC-7) classification. METHODS: HBP and CBP measurements were taken in 1702 subjects (> or =40 years) without a history of stroke, who were followed up for an average of 11 years. Subjects were classified into 4 groups on the basis of either HBP or CBP, according to the JNC-7 criteria: group 1 (HBP <115/75 mm Hg; CBP <120/80 mm Hg); group 2 (115/75< or =HBP<135/85 mm Hg; 120/80< or =CBP<140/90 mm Hg); group 3 (135/85< or =HBP<150/95 mm Hg; 140/90< or =CBP<160/100 mm Hg); and group 4 (HBP> or =150/95 mm Hg; CBP > or =160/100 mm Hg). Groups 2, 3, and 4 were further divided into 2 subgroups (a and b): those without and with cardiovascular disease risks, respectively. The risk of the first stroke in these groups was examined by the Cox hazards model adjusted for age and sex. RESULTS: The stroke risk in groups 3b and 4b (defined by HBP and CBP) was 2 to 5x higher than that in group 1 with significant differences. The risk in groups 2a, 3a, and even 4a was not significantly different from that in group 1 by the CBP-based classification, but the risk in group 4a was significantly higher than that in group 1 by the HBP-based classification, which also showed a stepwise increase in risk from groups 2a to 4a. CONCLUSIONS: The JNC-7 classification had a stronger predictive power using HBP-based classification compared with CBP-based classification, suggesting the usefulness of HBP in the management of hypertension.

Aged↗

Classification of faces in man and machine.

We attempt to shed light on the algorithms humans use to classify images of human faces according to their gender. For this, a novel methodology combining human psychophysics and machine learning is introduced. We proceed as follows. First, we apply principal component analysis (PCA) on the pixel information of the face stimuli. We then obtain a data set composed of these PCA eigenvectors combined with the subjects' gender estimates of the corresponding stimuli. Second, we model the gender classification process on this data set using a separating hyperplane (SH) between both classes. This SH is computed using algorithms from machine learning: the support vector machine (SVM), the relevance vector machine, the prototype classifier, and the K-means classifier. The classification behavior of humans and machines is then analyzed in three steps. First, the classification errors of humans and machines are compared for the various classifiers, and we also assess how well machines can recreate the subjects' internal decision boundary by studying the training errors of the machines. Second, we study the correlations between the rank-order of the subjects' responses to each stimulus-the gender estimate with its reaction time and confidence rating-and the rank-order of the distance of these stimuli to the SH. Finally, we attempt to compare the metric of the representations used by humans and machines for classification by relating the subjects' gender estimate of each stimulus and the distance of this stimulus to the SH. While we show that the classification error alone is not a sufficient selection criterion between the different algorithms humans might use to classify face stimuli, the distance of these stimuli to the SH is shown to capture essentials of the internal decision space of humans. Furthermore, algorithms such as the prototype classifier using stimuli in the center of the classes are shown to be less adapted to model human classification behavior than algorithms such as the SVM based on stimuli close to the boundary between the classes.

Algorithms↗

Classification of chronic venous insufficiency: a review.

Chronic venous insufficiency (CVI) is a very variable and complex entity that has stimulated different attempts at classification. Several proposals have been made in recent years, based on objective and anatomical criteria, most of them incomplete and unsatisfactory. Finally the CEAP classification was presented in 1994. This certainly is the most nearly complete classification, since it takes into consideration not only the main aspects of CVI: Clinical, Etiological, Anatomical, and Pathophysiological, but also the degrees of severity, reported in the form of scores. It is now accepted internationally although it still has some flaws (such as the absence of the corona phlebectactica sign) and inaccuracies (above all in the clinical part and the scoring). Recently, some members of the Promoting Committee proposed a substantial modification of the part on scores, coming closest to the clinical reality, instrumental diagnosis, and current therapies. The characteristics of CEAP enable us to affirm that this represents the most original and useful classification, not only for clinical studies, but also in the assessment of therapeutic results and in patient follow-up. Like all classifications, CEAP also needs to be validated by means of clinical studies in order to demonstrate its applicability. For this purpose, a European Working Group was set up in 1997. The first interesting results of 872 dossiers collected by means of a computerized program (European Phlebological File) were presented at several international congresses and concentrated on the consistency and reproducibility of the clinical part of the CEAP classification in different clinical settings.

Chronic Disease↗

Staging of maxillary cancer. Which classification?

Of the many proposed classifications for staging maxillary sinus cancer, none has been adopted universally and none is known to be superior to the others. This study identified the best of six currently used classifications using data from 53 previously untreated patients with squamous cell carcinoma of the maxillary sinus. Analysis of each classification's ability to stage the majority of patients, produce a balanced distribution of T stages, and correlate T stage with treatment and prognosis revealed Harrison's classification to be the best. Harrison's classification should be adopted worldwide as the classification of choice for staging squamous cell carcinoma of the maxillary sinus.

Algorithms↗

Methodological issues in the classification of attention-related disorders.

The classification and identification of children with attention deficit-hyperactivity disorder and related disorders involving learning and behavior are only rudimentarily developed. A major problem is the substantial overlap among children with attention, learning, and behavioral problems. The science of classification provides conceptual and methodological approaches addressing these problems. For successful classification of these children, major issues include (a) the need to provide explicit studies of identification criteria, (b) the need for systematic sampling strategies, (c) development of hypothetical classifications, and (d) systematic assessment of reliability and validity of hypothetical classifications. With the methodological advances provided by classification-oriented research, investigators and practitioners may be able to address issues involving definition and identification of children with attention and related disorders.

Attention Deficit Disorder with Hyperactivity↗

Classification algorithms for hip fracture prediction based on recursive partitioning methods.

This article presents 2 modifications to the classification and regression tree. The authors improved the robustness of a split in the test sample approach and developed a cost-saving classification algorithm by selecting noninferior to the optimum splits from variables with lower cost or being used in parent splits. The new algorithm was illustrated by 43 predictive variables for 5-year hip fracture previously documented in the Study of Osteoporotic Fractures. The authors generated the robust optimum classification rule without consideration of classification variable costs and then generated an alternative cost-saving rule with equivalent diagnostic utility. A 6-fold cross-validation study proved that the cost-saving alternative classification is statistically noninferior to the optimal one. Their modified classification and regression tree algorithm can be useful in clinical applications. A dual X-ray absorptiometry hip scan and information from clinical examinations can identify subjects with elevated 5-year hip fracture risk without loss of efficiency to more costly and complicated algorithms.

Absorptiometry, Photon↗

Evaluation of the prognostic accuracy of Astler-Coller's and Jass' classifications of colorectal cancer.

AIM: The study aim was to determine whether the Jass classification is superior to that of Astler-Coller (modification of Dukes' stage) in determining prognosis of patients treated for colorectal carcinoma. STUDY DESIGN: The authors used Jass' classification to restage 263 patients who had undergone radical colorectal surgery and classified according to Astler-Coller. RESULTS: The results revealed that: 1) Astler-Coller's classification enables more accurate selection of patient groups where life expectancy can be predicted; 2) Jass' classification enables statistically significant (P <0.05) improved prognostic discrimination of Astler-Coller's B2 patients, for which the probability of nonrecurrence of the disease is around 60%. CONCLUSIONS: Although Astler-Coller's classification is still valid, Jass' classification is useful for the prognostic discrimination of Astler-Coller's B2 patients.

Adult↗

Nosology and statistical classification.

There is a fundamental difference between nosology and a statistical classification, and the two should not be confused. The discipline of nosology uses scientific methods to arrive at a classification of psychiatric disorders and is concerned with the validity of its entities. A statistical classification aims to attain the widest compliance in spite of differences in the theoretical orientation of its users. It must therefore be atheoretical, and must represent a widely negotiated agreement between its future users. The most important statistical classification is the "International Classification of Diseases, Injuries and Causes of Death" (ICD-9) endorsed by the member states of the World Health Organization. The DSM III (Diagnostic and Statistical Manual), a newly accepted classification of the American Psychiatric Association, departs in many ways from the ICD-9, and Canada will have to decide whether adherence to ICD-9 should continue, or be replaced by the adoption of DSM III. Advantages and disadvantages of the DSM III are briefly discussed.

Diagnosis, Differential↗

The triple classification of dry eye for practical clinical use.

PURPOSE: "Dry Eye is a condition produced by the inadequate interrelation between lacrimal film and ocular surface epithelium, and is caused by quantitative and qualitative deficits in one or both of them. It can be produced by one or combined etiologic causes, affecting one or several of the secretions of the glands serving the ocular surface, and producing secondary manifestations of different grades of severity". Clinicians need a practical classification to face diagnosis, prognosis and treatment. Dry eyes have many etiologies and pathogenesis, different affectation of the various dacryoglands and ocular surface epithelium, and diverse grades of severity. The specialists in xero-dacryology must know these three parameters to evaluate any case of dry eye, and to establish an adequate treatment. METHODS: To facilitate this, an open session in the 8th congress of the International Society of Dacryology and Dry Eye (Madrid, April, 2005) proposed modifying the Triple Classification of dry eye approved in the XIV congress of the European Society of Ophthalmology (Madrid, June, 2003). There was consensus of all conclusions. CONCLUSIONS: The following classification has been established: First, a classification of the etio-pathogenesis, distributed in ten groups: age-related, hormonal, pharmacologic, immunopathic, hyponutritional, dysgenic, infectious/inflammatory, traumatic, neurologic and tantalic. Second, a classification of the affected glands and tissues, which under the acronym of ALMEN includes the Aqueo-serousdeficient, Lipodeficient, Mucindeficient and Epitheliopatic dry eyes, and the Non dacryological affected exocrine glands (saliva, nasal secretion, tracheo-pharyngeal secretion, etc). And thirdly, a classification of severity, in three grades: Grade 1 or mild (symptoms without slitlamp signs), grade 2 or moderate (symptoms with reversible signs), and grade 3 or severe (symptoms with permanent signs).

Aging↗

Automated classification of blood cell neutrophils.

The classification of white blood cell neutrophils into band neutrophils (bands) and segmented neutrophils (segs) is a subproblem of the white blood cell differential count. This classification problem is not well defined for at least two reasons: (a) there are no unique quantitative definitions for bands and segs and (b) existing definitions use the shape of the nucleus as the only discriminating criterion. When cells are classified on a slide, decisions are made from the two-dimensional views of these three-dimensional cells. A problem arises because the exact shape of the nucleus becomes indeterminate when the nucleus overlaps so that the filament is hidden. To assess the importance of this problem, this paper quantitates the classification errors due to overlapped nuclei (ON). The results indicate that, using only neutrophils without ON, the classification accuracy is 89%. For neutrophils with ON, the classification accuracy is 65%. This suggests a classification strategy of first classifying neutrophils into three categories: (a) bands without ON, (b) segs without ON and (c) neutrophils with ON. Category III can then be further classified into segs and bands by other stretegies.

Autoanalysis↗