SEARCH · Search PubMed

Results for “External validity”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,657 records · Page 92Linked to original sources

PubMed2005

[Validity of clinical records and information systems in studies of health-care delivery in primary care].

OBJECTIVES: To examine how well the clinical process was recorded in the clinical history (CH), and care delivery on the activity sheet (AS). To assemble a series of recommendations on the validity of these documents for recording health care delivery. DESIGN: Multi-centred, observational, and cross-sectonal study. SETTING: Four medical clinics at 12 health centres in the Community of Valencia, Spain. PARTICIPANTS: There were 2051 attendances, with 284 CH and 407 AS involved. Main measurements and results. The information recorded by doctors in the CH and on the AS was validated by external observers who collected directly at the consultation the working day's entire care activity. The following was analysed: 1) in the CH, filling out of the "SOAP" form (basic info.); 2) on the AS, mean per professional per day of scheduled and on-demand patients, home visits and length of consultations; 3) information in the documents validated on the organisation of consultations; 4) analysis of care delivery according to how predictable it is and its clinical content; 5) clinical practice guidelines with validity and clinical usefulness indicators and reliability index (kappa). CONCLUSIONS: The documents validated do not properly reflect the reality of health care demand. There was an under-recording bias and validity problems that may limit their usefulness as sources of information for health care planning and management.

Cross-Sectional Studies↗

PubMed2001

[The validity of the Hornheide questionnaire for psychosocial support in skin tumor patients: a survey in an Austrian and German outpatient population with melanoma].

Tumour patients are subject to different degrees of psychosocial distress depending on the course of disease, personality variables and amount of social support available. Often patients do not spontaneously talk about their distress and attending physicians fail to detect it. Therefore, it is important that the presence of distress is ascertained by specific screening instruments so that appropriate supportive measures can be instituted. The Hornheide Questionnaire (HQ) employed for investigating the need for psychosocial support in the case of patients with skin tumours and with tumours in the head and neck region represents such a specific screening instrument. The present study investigates the validity of the HQ on the basis of two representative samples from two different University Clinics for treatment and follow-ups of melanoma patients. With the help of the HQ, 215 patients at the Dermatology Out-patient Unit of the University of Innsbruck and 223 patients at the University of Freiburg were investigated with regard to their subjective experience of distress. The external constructive validity criteria were established on the basis of the Freiburg Questionnaire of Disease-Coping, the questionnaire of social support and Beck's Depression Inventory. There were significant differences between individuals in the severity of distress in different age groups and in patients in different tumour stages. The internal consistency of the HQ and its subscales proved to be satisfactory demarcation from other psychosocial dimensions and an adequate correlation with similar dimensions (depression, depressive illness coping, social support, compliance). The HQ appears to be an economical and valid screening instrument for detecting the need for psychosocial support in melanoma patients in the out-patient follow-up stage.

Adult↗

PubMed1975

Validity of the Internal-External Scale in its relationship with political position.

The study was designed to interpret previous reports of a relationship between left wing political position and externality on Rotter's (1966) Internal-External (I-E) Scale. I-E items phrased in the first person were associated with a criterion measure of locus of control, and externality on the scale predicted inferior performance in a skill-controlled task. However, political position was related to neither the criterion measure of locus of control nor to successful performance in a skill-controlled task. Thus, there was no evidence that political position was related to locus of control in spite of its relationship with the I-E Scale. There was discussion of implications for the validity of the I-E Scale and for studying relationships between personality and political variables.

Journal Article↗

PubMed1999

[Measurement of central venous pressure at the jugular pulse wave].

By measuring central venous pressure during physical examination one quickly obtains information about the patient's volume status and cardiac function. For such measurements to be reliable there must be a free communication between the jugular vein (usually the right external or internal) and the right atrium. Venous pulsations must be visible and the point of venous collapse has to be clearly identified. During measurement the flow of blood through the vein must be halted. The sternal angle of the second rib is used as reference point. It is recommendable to use an instrument rather than the eye to estimate venous pressure. Although several studies have been performed to validate the external measurement of venous pressure, most of these are methodologically unsound.

Blood Pressure Determination↗

PubMed2006

ICD-10 coding algorithms for defining comorbidities of acute myocardial infarction.

BACKGROUND: With the introduction of ICD-10 throughout Canada, it is important to ensure that Acute Myocardial Infarction (AMI) comorbidities employed in risk adjustment methods remain valid and robust. Therefore, we developed ICD-10 coding algorithms for nine AMI comorbidities, examined the validity of the ICD-10 and ICD-9 coding algorithms in detection of these comorbidities, and assessed their performance in predicting mortality. The nine comorbidities that we examined were shock, diabetes with complications, congestive heart failure, cancer, cerebrovascular disease, pulmonary edema, acute renal failure, chronic renal failure, and cardiac dysrhythmias. METHODS: Coders generated a comprehensive list of ICD-10 codes corresponding to each AMI comorbidity. Physicians independently reviewed and determined the clinical relevance of each item on the list. To ensure that the newly developed ICD-10 coding algorithms were valid in recording comorbidities, medical charts were reviewed. After assessing ICD-10 algorithms' validity, both ICD-10 and ICD-9 algorithms were applied to a Canadian provincial hospital discharge database to predict in-hospital, 30-day, and 1-year mortality. RESULTS: Compared to chart review data as a 'criterion standard', ICD-9 and ICD-10 data had similar sensitivities (ranging from 7.1-100%), and specificities (above 93.6%) for each of the nine AMI comorbidities studied. The frequencies for the comorbidities were similar between ICD-9 and ICD-10 coding algorithms for 49,861 AMI patients in a Canadian province during 1994-2004. The C-statistics for predicting 30-day and 1 year mortality were the same for ICD-9 (0.82) and for ICD-10 data (0.81). CONCLUSION: The ICD-10 coding algorithms developed in this study to define AMI comorbidities performed similarly as past ICD-9 coding algorithms in detecting conditions and risk-adjustment in our sample. However, the ICD-10 coding algorithms should be further validated in external databases.

Adult↗

PubMed2006

Validated multi-component CZE-UV procedure for the quantification of human hemorphin LVV-H7 in plasma stability studies.

The human hemorphin LVV-H7 is an endogenous cleavage product of the hemoglobin beta, gamma, epsilon or delta chain exhibiting potential pharmaceutical relevance for blood pressure regulation, the treatment of Alzheimer's disease or learning deficiencies. Here we present the development of a multi-component capillary zone electrophoretic method (CZE-UV), allowing the simultaneous quantification of LVV-H7 and four N-terminal degradation products generated in EDTA plasma. Hemorphins in the supernatant of precipitated plasma samples are quantified by external calibration. Validation of the procedure oriented towards international pharmaceutical guidelines and demonstrated excellent linearity (r2 > or = 0.999), good precision (repeatability and reproducibility below 11%), accuracy (-8.4%-4%), ruggedness and an appropriate lower limit of quantification (LLOQ 1.0 microg mL(-1)). This procedure was applied to stability studies of LVV-H7 in human EDTA plasma attended by profiling metabolites using qualitative MALDI-TOF MS analysis. We detected the activity of a soluble plasma form of aminopeptidase M causing successive N-terminal truncation. This is the first time that LVV-H7 degradation as well as its metabolite production have systematically been monitored by a quantitative CZE-UV procedure, underlining the growing importance of such techniques in peptide analysis. In addition, our results give useful hints for future drug development of LVV-H7.

Alzheimer Disease↗

PubMed2001

Completeness and accuracy of voluntary reporting to a national case registry of laparoscopic cholecystectomy.

OBJECTIVE: To validate completeness and accuracy of registry data reported from three randomly chosen departments contributing to The Danish National Registry of Laparoscopic Cholecystectomy, covering all departments offering chole cystectomy. DATA SOURCES: A total of 431 case reports representing cases of laparoscopic cholecystectomy in a 2-year period in three surgical departments. DESIGN: Comparison of case reports with reported data in The Danish National Registry of Laparoscopic Cholecystectomy. MAIN OUTCOME MEASURES: Rates of discrepancies, comparison of complication rates for cases in the registry and cases not reported to the registry. RESULTS: Completeness of registration was 69%, 80% and 99% respectively. A significantly higher degree of completeness was found in the only department with a formalized registration procedure. Inaccuracies were found in 28-49% of the cases, but none regarding serious complications such as bile duct injury or perioperative death. CONCLUSIONS: The information in the national registry may be accurate if the present findings can be extrapolated to the remaining departments in the country. The number of non-reported cases should be minimized by introducing a formalized procedure of handling and forwarding information to the registry. Continuous validation through external visits by registry staff to contributing departments may also be advisable.

Benchmarking↗

PubMed1997

Noninvasive measurement of distal radius instability.

Except for subjective clinical criteria, there is no formal definition of distal radius fracture instability in the literature. The purposes of this ex vivo biomechanical study were (1) to provide an objective mechanical definition of fracture instability and (2) to demonstrate a noninvasive method that allows for direct measurement of instability. The following 3 questions are addressed: (1) Can the stability of distal radius fractures be measured using computed tomography (CT)? (2) Are the stability measurements reproducible? (3) How does external fixation change stability? A CT technique is described that was used to measure displacement of fracture fragments and measure the compliance of ex vivo distal radius fractures before and after external fixation. Validation studies of the CT technique revealed a mean coefficient of variation of 0.38. There was a linear relationship between measured and known displacements for all 3 orthogonal planes (coefficient of determination 0.99; p < .01). There was significant fracture displacement with loads as small as 20 N. The slope of the load-displacement curve (structural compliance) provided a quantitative measure of fracture instability. Fracture compliance decreased up to 69% after application of an external fixator.

Biomechanical Phenomena↗

PubMed2000

Development and validation of the Self-Identity Inventory (SII): a multicultural identity development instrument.

The Self-Identity Inventory (SII) was developed using the Optimal Theory Applied to Identity Development (OTAID) model. A sample of 325 culturally diverse respondents completed the SII, the Tolerance Scale from the California Psychological Inventory, the Belief Systems Analysis Scale, and the Social Desirability and Infrequency Scales. Through confirmatory factor analysis, goodness-of-fit, and social desirability/item infrequency measures, SII items were analyzed, resulting in a 6-scale, 71-item inventory. Internal consistency for the scales ranged from .72 to .90. Test-retest reliability ranged from .72 to .92. Correlations with external construct validity measures supported predictions. Interscale correlations and other statistical tests primarily supported the OTAID model. Implications for therapy and future research are suggested.

Adolescent↗

PubMed1996

Hostility and doctor-patient interaction in chronic pelvic pain.

BACKGROUND: Interaction in medical consultations is of interest for many reasons and has long been thought an important variable in determining outcomes. Relatively few methods or instruments exist that attempt to access this phenomenon. The design, validation and possible application of a simple instrument to assess doctor-patient interaction are reported. Rapport and hostility may be related and we hypothesised that interaction between doctor and patient would be related in part to hostility. METHODS: A simple instrument to assess doctor-patient interaction was designed based on 4 areas related to interaction and perception of 'the other'. These were the areas of communication, rapport, trust and sense of ease. The instrument was compared with an external previously validated measure of hostility. Data were obtained from 74 women attending initial and follow-up consultations for chronic pelvic pain during the course of a larger study. RESULTS: The instrument had acceptable reliability and a single-factor structure. Patients' assessment of the initial consultation as unsatisfactory correlated with inwardly directed hostility (Spearman correlation coefficient, r = 0.30, p = 0.011). Patients' tendency to rate the consultation worse than the doctor was correlated with inwardly directed hostility (r = 0.42, p < 0.001). Pain outcomes were not directly related to the variables studied. CONCLUSIONS: This instrument offers a simple method of assessing some interactional aspects of a medical consultation.

Chronic Disease↗

PubMed1987

A one-step enzyme-linked immunosorbent assay to detect anti-CMV antibodies; development and clinical validation.

A simple one-step ELISA to detect anti-CMV antibodies was developed. The test was based on the inhibition principle, and used anti-CMV coated microtitre plates, CMV nuclear antigen and anti-CMV Fab'-HRP conjugate; total assay time was 1.5 h. The use of Fab'-HRP conjugates improved discrimination between positive and negative sera as compared with IgG-HRP conjugates. In an in-house clinical study, the one-step ELISA showed a 98.4% correlation with the latex agglutination test. The test could be demonstrated to be suitable for both serum and citrate- or EDTA-plasma specimens; heparin-plasma gave somewhat higher absorbance values. In an external clinical validation, the one-step ELISA showed a 99.5% correlation with the latex agglutination test, and was found to be highly suitable for screening of blood donor specimens in a blood bank setting.

Antibodies, Viral↗

PubMed2026

A pan-cancer multi-omic SuperLearner for regulated cell death survival topologies.

INTRODUCTION: Regulated cell death (RCD) pathways influence tumor progression and immune modulation. We previously constructed a signature database mapping 25 RCD forms across seven multi-omic layers and 33 tumor types (CancerRCDShiny). Despite their ability to identify risk populations, translating these signatures into personalized clinical workflows requires a shift from cohort stratification to individualized risk mapping by modeling patient risk (survival topologies) to capture the non-linear dynamics of RCD signatures. METHODS: We engineered a pan-cancer multi-omic SuperLearner pipeline across 33 cancer types. Phase I performed zero-leakage harmonization and groupwise imputation to prevent cross-cohort amalgamation. Phase II deployed Elastic Net-regularized Cox regression as a CANARY diagnostic to map proportional hazards failures. Strata with a 35% missingness barrier entered Phase III, deploying a Quadripartite ensemble: Random Survival Forests, XGBoost, Survival-Boruta, and Multi-Task Logistic Regression, fused within an Elastic Net Multi-View Meta-Learner (MVL), with post-hoc TreeSHAP and LIME interpretability. RESULTS: The CANARY diagnostic demonstrated the structural invalidity of pan-cancer geometric proportional hazards. Across 96 admissible strata, Phase III executed algorithmic displacement: continuous multi-omic topologies suppressed static genomic mutations and copy number variations (85.7% vs. 0.0% apex retention). The MVL stabilized predictions against extreme variance; LIME surrogate validations (R 2 < 0.10) confirmed the systematic failure of linear interpretative proxies. N-dimensional TreeSHAP interaction mapping exposed synergistic and antagonistic rescue trajectories defining individualized Survival Topologies, which were invisible to additive models. The architecture was deployed as CancerRCDPredictor, a digital molecular tumor board with integrated LLM capabilities. The MVL SuperLearner achieved a median C-index of 0.749 (IQR: 0.722-0.836) across 96 modelable strata, with 95% bootstrap confidence intervals confirming precision (median width: 0.052) and permutation significance in 93.8% of strata (p < 0.001). External CPTAC validation across ten cancer types demonstrated significant cross-cohort generalizability in clear cell renal carcinoma (KIRC; C-index 0.675, p = 0.017) and modest performance across the remaining adequately powered cancers (median 0.582), underscoring the need for larger multi-institutional validation cohorts. CONCLUSION: This pan-cancer multi-omic SuperLearner bypasses linear topological failures, advancing beyond generalized stratification to establish a deterministically mapped architecture for predicting RCD-related survival topologies. Through the CancerRCDPredictor interface, multi-omic insights translate into individualized survival topology exploration, providing a foundation for future precision oncology validation.

SuperLearner↗

PubMed2001

Improved prognostication of renal cell carcinoma using an integrated staging system.

PURPOSE: To integrate stage, grade, and Eastern Cooperative Oncology Group (ECOG) performance status (PS) into a clinically useful tool capable of stratifying the survival of renal cell carcinoma (RCC) patients. PATIENTS AND METHODS: The medical records of 661 patients undergoing nephrectomy at University of California Los Angeles between 1989 and 1999 were evaluated. Median age was 61 years, male-to-female ratio was 2.2:1, and median follow-up was 37 months. Survival time was the primary end point assessed. Sixty-four possible combinations of stage, grade, and ECOG PS were analyzed and collapsed into distinct groups. The internal validity of the categorized was challenged by a univariate analysis and a multivariate analysis testing for the accountability of each UCLA Integrated Staging System (UISS) category against independent variables shown to have impact on survival. RESULTS: Combining and stratifying 1997 tumor-node-metastasis stage, Fuhrman's grade and ECOG PS resulted in five survival stratification groups designated UISS, and numbered I to V. The projected 2- and 5-year survival for the UISS groups are as follows for the groups: I, 96% and 94%; II, 89% and 67%; III, 66% and 39%; IV, 42% and 23%; and V, 9% and 0%, respectively. UISS accounted for the significant variables in the variate analysis. CONCLUSION: A novel system for staging and predicting survival for RCC integrating clinical variables is offered. UISS is simple to use and is superior to stage alone in differentiating patients' survival. Our data suggests that UISS is an important prognostic tool for counseling patients with various stages of kidney cancer. Further prospective large-scale validation with external data is awaited.

Adult↗

PubMed2002

Quality assessment of sputum transportation, smear preparation and AFB microscopy in a rural district in Malawi.

SETTING: Ntcheu District, Central Region of Malawi. OBJECTIVES: To assess 1) the feasibility of introducing simple internal quality control procedures for acid-fast bacilli (AFB) microscopy, and 2) the quality of the district sputum smear microscopy service. DESIGN: A simple internal quality control system was piloted in which district laboratory staff assessed: 1) specimen suitability, 2) time between sputum submission and smear examination, 3) smear preparation and staining, and 4) microscopy. Actual times for processing specimens were compared with recommended times. External quality validation was carried out. RESULTS: Of 4805 sputum specimens: 1) documentation was complete in 95%, 2) 93% reached the laboratory within 7 days of collection, 3) 96% of smears were well prepared and stained, and 4) 97% concordance (96.4% smear-positive and 97.6% smear-negative) was demonstrated when 208 smears were re-examined by a second technician. The aggregate index of reliability was 86%. The mean time spent on microscopic examination was 3.8 minutes, compared with the recommended time of 10 minutes. When all smears from 164 patients were assessed externally, 98.2% concordance (98.1% smear-positive and 98.2% smear-negative) was demonstrated. False smear-negative and smear-positive rates were less than 2% each. CONCLUSION: District laboratory staff were able to incorporate simple quality control procedures for AFB microscopy into their routine practice, resulting in a reliable service. The lessons learnt are widely relevant and potentially useful for implementation of a national quality assurance scheme.

Chi-Square Distribution↗

PubMed2005

Measurement properties of a new quality of life measure for patients with work disability associated with musculoskeletal pain.

INTRODUCTION: The Quality of Life Systemic Inventory (QLSI) measures patients' goal attainment based on the system control theory. It quantifies the perceived impact of the disorder and the gap between the present and aspired states. PURPOSE: To evaluate concurrent validity and responsiveness of the QLSI among workers on sick leave due to musculoskeletal disorders (MSDs). METHODS: Participants (10 women; 29 men) were recruited at a work rehabilitation centre and had more than 4 weeks of absence from work due to MSDs compensated by the Workers' Compensation Board. Concurrent validity and external responsiveness were based on baseline and post-treatment measures of external criteria. Criteria and related instruments were the following: perception of disability (Roland-Morris Disability Questionnaire); health-related quality of life (SF-12); stress (Psychological Stress Measure) and distress (Psychological Distress Index). RESULTS: Regression analyses revealed significant correlations between QLSI scores and the Psychological Distress Index (r2 = .11 to .19 and .66; p < .001), with either the SF-12 mental component scale (r2 = .18 and .11; p < .01) or the Roland-Morris Disability Questionnaire (r2 = .04 and .10; p < .05). All measures showed highly significant change over time. CONCLUSION: Results support the concurrent validity and responsiveness of the QLSI, with an MSD population. SIGNIFICANCE: This instrument could serve in future research as an outcome measurement instrument in the evaluation of more long-term effects of rehabilitation programs.

Adolescent↗

PubMed2006

Lack of validity of a French adaptation of a scale measuring attitudes towards clinical practice guidelines.

BACKGROUND: Valid instruments to measure practitioners' attitudes towards clinical practice guidelines need to be developed. However, few of the available instruments have been thoroughly validated. OBJECTIVE: To adapt into French and to test the reliability and validity of a scale for measurement of attitudes towards guidelines developed by Elovainio et al. METHODS: A 27-item scale (divided into six dimensions) measuring attitudes towards guidelines was translated into French by two English native translators, reviewed and finalized by expert committee and administered to 314 practitioners who agreed to participate. Main practitioners' characteristics were collected. Item and dimension reproducibility were assessed for 62 practitioners by calculation of intraclass correlation coefficients. Internal construct validity was assessed by principal components analyses. Convergent and discriminant validity were analysed. RESULTS: Item response rates ranged from 82 to 100%. In the test-retest procedure, intraclass correlation coefficients for separate items ranged from 0.1 to 0.7 and those for dimensions were 0.7 [95% confidence interval (CI): 0.5-0.8] for usefulness, 0.5 (0.3-0.6) for reliability, 0.4 (0.2-0.5) for individual competence, 0.5 (0.3-0.6) for organizational competence, 0.7 (0.5-0.8) for impracticality and 0.4 (0.3-0.6) for availability. The factorial structure after Varimax rotation showed that none of the different solutions obtained had a strictly comparable structure to that of the original scale. External construct validity was satisfactory. CONCLUSION: This scale does not have satisfactory psychometric properties and therefore cannot confidently be used in future research assessing whether attitudes towards guidelines are a determining factor in physicians' compliance with guidelines. More research is needed to develop valid scales in a more rigorous procedure, involving qualitative and quantitative steps.

Attitude of Health Personnel↗

PubMed1985

Is the Jarman underprivileged area score valid?

A recently published validation of an underprivileged area score, which is intended to reflect factors that increase general practice workload or pressure on their services, was incomplete; a validation based on criteria other than the opinion of general practitioners is also required. Areas with higher mortality from diseases where general practitioner intervention can reduce mortality substantially are likely to have a greater need for general practice services. Similarly, the need for general practitioner services should be higher where the incidence of such treatable conditions is higher. This paper describes the association between Jarman's score and (a) mortality from causes that are amenable to general practice intervention and (b) incidence of two diseases where general practice intervention is important. Using these data the score appears to have external criterion validity and thus is likely to reflect, at least crudely, the need for general practitioner services.

Catchment Area, Health↗

PubMed2005

A gene expression signature that predicts the future onset of drug-induced renal tubular toxicity.

One application of genomics in drug safety assessment is the identification of biomarkers to predict compound toxicity before it is detected using traditional approaches, such as histopathology. However, many genomic approaches have failed to demonstrate superiority to traditional methods, have not been appropriately validated on external samples, or have been derived using small data sets, thus raising concerns of their general applicability. Using kidney gene expression profiles from male SD rats treated with 64 nephrotoxic or non-nephrotoxic compound treatments, a gene signature consisting of only 35 genes was derived to predict the future development of renal tubular degeneration weeks before it appears histologically following short-term test compound administration. By comparison, histopathology or clinical chemistry fails to predict the future development of tubular degeneration, thus demonstrating the enhanced sensitivity of gene expression relative to traditional approaches. In addition, the performance of the signature was validated on 21 independent compound treatments structurally distinct from the training set. The signature correctly predicted the ability of test compounds to induce tubular degeneration 76% of the time, far better than traditional approaches. This study demonstrates that genomic data can be more sensitive than traditional methods for the early prediction of compound-induced pathology in the kidney.

Animals↗