Good Discriminative Capacity Research Articles

Oesophageal dysmotility in systemic sclerosis: comparison of HRCT and scintigraphy

The aim of this study was to compare oesophageal abnormalities observed in high-resolution CT with radionuclide transit in patients with systemic sclerosis. 76 patients with systemic sclerosis were evaluated by high-resolution CT and oesophageal transit scintigraphy. Residual activity > or =20% (in relation to peak activity) at 15 s after the beginning of the swallow of the labelled liquid (in supine position) was considered indicative of oesophageal dysfunction. Supra-aortic and infra-aortic oesophageal coronal diameters were measured in high-resolution CT. Oesophageal dilatation was deemed present when the diameters exceeded 10 mm. 19 patients (25%) had supra-aortic oesophageal dilatation and 48 patients (63.1%) had infra-aortic dilatation. The prevalence of radionuclide transit delay was 77.6%. All patients (19/19) with supra-aortic dilatation had oesophageal dysfunction, compared with 70.2% (40/57) of the patients with no supra-aortic dilatation (p = 0.004). Oesophageal dysfunction was present in 97.9% (47/48) of patients with infra-aortic dilatation, compared with 42.9% (12/28) in patients without it (p < 0.001). Receiver operating characteristic (ROC) curves have demonstrated that the supra-aortic and infra-aortic diameters had good discriminatory capacity for oesophageal dysfunction in systemic sclerosis (area under the curve, 95% confidence interval: 0.80, 0.70-0.89 and 0.92, 0.86-0.98, respectively). There is a clinically significant association between oesophageal dysmotility and high-resolution CT findings of oesophageal coronal dilatation. The evaluation of infra-aortic oesophageal coronal diameter can provide additional useful information about the functional and anatomic conditions of the oesophagus in systemic sclerosis.

The Portuguese language version of social phobia and Anxiety Inventory: analysis of items and internal consistency in a Brazilian sample of 1,014 undergraduate students

OBJECTIVE: Theoretical and empirical analysis of items and internal consistency of the Portuguese-language version of Social Phobia and Anxiety Inventory (SPAI-Portuguese). METHODS: Social phobia experts conducted a 45-item content analysis of the SPAI-Portuguese administered to a sample of 1,014 university students. Item discrimination was evaluated by Student's t test; interitem, mean and item-to-total correlations, by Pearson coefficient; reliability was estimated by Cronbach's alpha. RESULTS: There was 100% agreement among experts concerning the 45 items. On the SPAI-Portuguese 43 items were discriminative (p &lt; 0.05). A few inter-item correlations between both subscales were below 0.2. The mean inter-item correlations were: 0.41 on social phobia subscale; 0.32 on agoraphobia subscale and 0.32 on the SPAI-Portuguese. Item-to-total correlations were all higher then 0.3 (p &lt; 0.001). Cronbach's alphas were: 0.95 on the SPAI-Portuguese; 0.96 on social phobia subscale; 0.85 on agoraphobia subscale. CONCLUSION: The 45-item content analysis revealed appropriateness concerning the underlying construct of the SPAI-Portuguese (social phobia, agoraphobia) with good discriminative capacity on 43 items. The mean inter-item correlations and reliability coefficients demonstrated the SPAI-Portuguese and subscales internal consistency and multidimensionality. No item was suppressed in the SPAI-Portuguese but the authors suggest that a shortened SPAI, in its different versions, could be an even more useful tool for research settings in social phobia.

Calibration Of The Biotrainer Pro Activity Monitor In Youth Using Receiver Operator Characteristic (roc) Curves

To facilitate the application of accelerometry-based monitors for field research with children, monitors must be calibrated with age-appropriate activities and with a criterion measure that is sensitive to intermittent changes in the intensity and duration of physical activity. PURPOSE The purpose of this study was to develop calibration equations for the Biotrainer Pro that capture children's intermittent activity patterns. METHODS The participants in this study included 9 boys and 13 girls (ages 7 to 12) that were participating in a youth sport camp. Participants wore a HR monitor and a Biotrainer while completing 2 testing protocols 1) a structured protocol involving 7 intermittent movement tasks (2 min each) and 2) a free play situation (∼15 minutes) in which the child participated in a group activity. Both protocols were videotaped and coded using an adapted version of the Children's Activity Record System. Coding was done with a computerized observation tool (BEST) that allows “real time” coding of data. The outcome measure, computed as the mean observation code across each minute (1=sit, 2=stand, 3=walk, and 4=run), was temporally merged with corresponding HR and Biotrainer data. Receiver operator characteristic (ROC) curves were used to determine the cutpoint defining the threshold for moderate to vigorous activity in youth (operationalized as a code of 2.5). This approach offers considerable advantages for selecting cutpoints for accelerometry-based activity monitors since it can empirically determine the appropriate balance between sensitivity and specificity. RESULTS A two-way ANOVA yielded non significant gender and age group effects so combined data were used. Observation codes ranged from 1.0 (HR ∼ 100) to 3.99 (HR ∼ 182) for the structured calibration while the mean code for the free-play activities was 2.3 (HR ∼ 140). ROC curves yielded cutpoints of 3.0 using both the structured protocol and the free play protocol. The curves demonstrated good discrimination characteristics with sensitivities and specificity both exceeding .78. This indicates that the cutpoint can classify periods of physical activity while maintaining good discriminatory capacity to exclude non-active moments. CONCLUSIONS The results support the use of the Biotrainer Pro calibration cutpoint for youth ages 7–12.

Calibration Of The Biotrainer Pro Activity Monitor In Youth Using Receiver Operator Characteristic (roc) Curves

To facilitate the application of accelerometry-based monitors for field research with children, monitors must be calibrated with age-appropriate activities and with a criterion measure that is sensitive to intermittent changes in the intensity and duration of physical activity. PURPOSE The purpose of this study was to develop calibration equations for the Biotrainer Pro that capture children's intermittent activity patterns. METHODS The participants in this study included 9 boys and 13 girls (ages 7 to 12) that were participating in a youth sport camp. Participants wore a HR monitor and a Biotrainer while completing 2 testing protocols 1) a structured protocol involving 7 intermittent movement tasks (2 min each) and 2) a free play situation (∼15 minutes) in which the child participated in a group activity. Both protocols were videotaped and coded using an adapted version of the Children's Activity Record System. Coding was done with a computerized observation tool (BEST) that allows “real time” coding of data. The outcome measure, computed as the mean observation code across each minute (1=sit, 2=stand, 3=walk, and 4=run), was temporally merged with corresponding HR and Biotrainer data. Receiver operator characteristic (ROC) curves were used to determine the cutpoint defining the threshold for moderate to vigorous activity in youth (operationalized as a code of 2.5). This approach offers considerable advantages for selecting cutpoints for accelerometry-based activity monitors since it can empirically determine the appropriate balance between sensitivity and specificity. RESULTS A two-way ANOVA yielded non significant gender and age group effects so combined data were used. Observation codes ranged from 1.0 (HR ∼ 100) to 3.99 (HR ∼ 182) for the structured calibration while the mean code for the free-play activities was 2.3 (HR ∼ 140). ROC curves yielded cutpoints of 3.0 using both the structured protocol and the free play protocol. The curves demonstrated good discrimination characteristics with sensitivities and specificity both exceeding .78. This indicates that the cutpoint can classify periods of physical activity while maintaining good discriminatory capacity to exclude non-active moments. CONCLUSIONS The results support the use of the Biotrainer Pro calibration cutpoint for youth ages 7–12.

Prognostic Assessment of Patients With Acute Myocardial Infarction Treated With Primary Angioplasty

The aim of this study was to create a practical score for risk stratification in patients with ST-segment elevation myocardial infarction (STEMI) treated with primary angioplasty and to assess the feasibility of early discharge in low-risk patients. A prognostic score was built according to 30-day mortality rates in 1791 patients undergoing primary angioplasty for STEMI. For the identified low-risk patients without any contraindication to early discharge, we estimated and compared the costs of conventional care (prolonged 24-hour hospitalization) with the costs of shifting the care from inpatient to outpatient setting (early discharge) between 48 and 72 hours. Independent predictors of 30-day mortality included in the score were age, anterior infarction, Killip class, ischemic time, postprocedural Thrombolysis In Myocardial Infarction (TIMI) flow, and multivessel disease. This score was able to identify a large cohort (73.4%) of low-risk (score < or =3) patients, with a good discriminatory capacity (c statistic=0.907). The mortality rate was 0.1% at 2 days and 0.2% between 2 and 10 days in patients with a score < or =3. The incremental cost-effectiveness ratio for late discharge in low-risk patients was estimated at 1949.33. Therefore, this policy would save 1 life per 1097 low-risk patients, at additional costs of 194 933.33, in comparison with an early discharge policy. This score is a practical and useful index for risk stratification after primary angioplasty for STEMI, with a significant impact on clinical decision-making and the related costs. It reliably identifies a large group of patients at very low risk, who may safely be discharged early after primary angioplasty.

Analysis of Self-Concept in Older Adults in Different Contexts

Summary: Self-concept is a construct consisting of a group of specific self-perceptions that are hierarchically organized. Age-associated changes of self-concept are related to the individual's perception of the changes occurring throughout the aging process. The authors examined external validity and internal consistency of an instrument that has been developed to assess self-concept in older adults and examined self-concept's characteristics in two different contexts. Results confirm the multidimensionality of the scale and show a satisfactory external validity, indicating good discriminatory capacity. Findings support the hypothesis that older people who live in a nursing home have a poor self-esteem, self-concept, and psychological well-being and have a greater presence of depressive symptoms than people who live in their own home.

Can generic paediatric mortality scores calculated 4 hours after admission be used as inclusion criteria for clinical trials?

IntroductionTwo generic paediatric mortality scoring systems have been validated in the paediatric intensive care unit (PICU). Paediatric RISk of Mortality (PRISM) requires an observation period of 24 hours, and PRISM III measures severity at two time points (at 12 hours and 24 hours) after admission, which represents a limitation for clinical trials that require earlier inclusion. The Paediatric Index of Mortality (PIM) is calculated 1 hour after admission but does not take into account the stabilization period following admission. To avoid these limitations, we chose to conduct assessments 4 hours after PICU admission. The aim of the present study was to validate PRISM, PRISM III and PIM at the time points for which they were developed, and to compare their accuracy in predicting mortality at those times with their accuracy at 4 hours.MethodsAll children admitted from June 1998 to May 2000 in one tertiary PICU were prospectively included. Data were collected to generate scores and predictions using PRISM, PRISM III and PIM.ResultsThere were 802 consecutive admissions with 80 deaths. For the time points for which the scores were developed, observed and predicted mortality rates were significantly different for the three scores (P < 0.01) whereas all exhibited good discrimination (area under the receiver operating characteristic curve ≥0.83). At 4 hours after admission only the PIM had good calibration (P = 0.44), but all three scores exhibited good discrimination (area under the receiver operating characteristic curve ≥0.82).ConclusionsAmong the three scores calculated at 4 hours after admission, all had good discriminatory capacity but only the PIM score was well calibrated. Further studies are required before the PIM score at 4 hours can be used as an inclusion criterion in clinical trials.

Intérêt du dosage de la progestérone sérique dans la prise en charge des grossesses anormales (grossesse extra-utérine, fausses couches spontanées) au cours du premier trimestre

Low serum progesterone measurement, described in ectopic pregnancy (GEU), has been advocated as a diagnostic tool, with hCG measurement, in the non-invasive diagnosis of GEU. To access the accuracy of this test in the diagnosis of GEU, progesterone measurements were obtained from 67 pregnancies with outcome defined as GEU or spontaneous abortion. The diagnostic accuracy of the test was analysed by generating “receiver operating characteristics” (Roc) curves. The Roc curve for the diagnostic of pregnancy failure vs viable intra-uterine pregnancy showed a good discriminative capacity. Yet, single progesterone measurement could not discriminate between ectopic pregnancy and non-ectopic pregnancy. In conclusion, a threshold progesterone value of 5 ng/ml is proposed as a safe value for identification of patients with first trimester pregnancy failure, including GEU, but is insufficient for establishing a definite diagnosis.

Ecotoxicological study of Lithuanian and Estonian wastewaters: selection of the biotests, and correspondence between toxicity and chemical-based indices

The toxicity of industrial and urban wastewater (WW) samples collected in Lithuania and Estonia was evaluated by using a suite of biological tests comprising the Algaltoxkit F™ with Selenastrum capricornutum, the Charatox with Nitellopsis obtusa, Daphtoxkit F™ with Daphnia magna, Thamnotoxkit F™ with Thamnocephalus platyurus, Protoxkit F™ with Tetrahymena thermophila and the Microtox® with Vibrio fischeri. The Charatox and Thamnotoxkit F™ tests showed highest relative sensitivity, responding to 80–90% of samples, respectively, and both expressed good discrimination capacity between samples. Principal Component and pairwise correlation analysis allowed to select test-battery consisting of Charatox, Thamnotoxkit™ and Microtox®. The WW toxicity was evaluated by means of cumulative indices such as average toxicity (AvTx) and two indices derived from the PEEP-index (Environ. Toxicol. Water Qual. 8 (1993) 115). In addition to these integrated evaluations of test-battery response, WW toxicity was evaluated according to the most sensitive test (MST) in the battery. The linear regression analysis between cumulative toxicity indices and chemical-based indices (derived from comparison of WW chemical concentrations and their respective maximum allowable concentration) revealed positive linear relationships ( r 2=0.7–0.8), while toxicity evaluation based on the MST was less positively related with chemical analysis data ( r 2=0.5–0.6). Although better coincidence between the toxicity and chemical-based assessments was achieved when information from all tests in the battery was assembled, the prediction of toxicity from chemical data was still limited. In search of suitable test-battery for the screening of certain type of WWs, a preliminary study comprising excessive suite of tests might be useful.

The accuracy of single serum progesterone measurement in the diagnosis of ectopic pregnancy: a meta-analysis

Serum progesterone measurement has been advocated as a diagnostic tool in the non-invasive diagnosis of ectopic pregnancy. To assess the accuracy of a single serum progesterone measurement in the diagnosis of ectopic pregnancy, a meta-analysis was performed incorporating 26 studies evaluating the performance of single serum progesterone measurement in the diagnosis of ectopic pregnancy. A distinction was made in the diagnosis of pregnancy failure of any type versus viable intrauterine pregnancy and the diagnosis of ectopic pregnancy versus non-ectopic pregnancy. The reported sensitivity and specificity differed between the studies. Since there was a clear negative correlation between sensitivity and specificity, summary receiver-operating characteristic (ROC) curves could be estimated. The ROC curve for the diagnosis of pregnancy failure versus viable intrauterine pregnancy showed a good discriminative capacity. Single serum progesterone measurement could not discriminate between ectopic pregnancy and non-ectopic pregnancy. It is concluded that serum progesterone measurement can identify patients at risk for ectopic pregnancy, who need further evaluation, but its discriminative capacity is insufficient to diagnose ectopic pregnancy with certainty.

Renal biopsy collagen I mRNA predicts scarring in rabbit anti-GBM disease: Comparison with conventional measures

Progressive loss of normal structure associated with scarring is the hallmark of chronic diseases of most organs. To test the hypothesis that measurement of interstitial collagen mRNA levels would be a useful index to predict future scarring, we developed an assay to quantitate alpha 1(I) procollagen mRNA factored for GAPDH mRNA using RT-PCR (the "CI:G ratio"). We first defined conditions under which the assay could be used for analysis of renal biopsy samples. The CI:G ratio was then used to determine whether mRNA measurements performed at an early stage of inflammation (day 7) in a model of anti-GBM disease in the rabbit would predict outcome at day 30 as measured by interstitial and glomerular scarring and renal cortical hydroxyproline accumulation. The predictive value of this assay was compared to functional (serum creatinine and urine protein:creatinine ratio) and histologic (glomerular and interstitial scoring) parameters also measured at day 7. We found that the CI:G ratio alone provided a sensitive and discriminating assay over a wide range of renal injury that predicted various parameters of scarring with an average coefficient of determination (r2) of 0.69. This predictive power was higher than that found for conventional measures, which tended to have good discriminatory capacity over limited ranges of renal injury. The CI:G ratio provided significant additional predictive power over and above that available from combinations of conventional functional or histologic parameters. We conclude that measurement of the CI:G ratio in biopsy samples deserves further assessment as a potentially useful quantitative predictor of outcome that could lead to improved clinical decision-making.

Development and validation of a clinical scale for the diagnosis of drug-induced hepatitis.

The objective of this study is to present and validate a clinical scale for the diagnosis of drug-induced liver injury (DILI). Five components were selected to be included in the scale: temporal relationship between drug intake and the onset of clinical picture, exclusion of alternative causes, extrahepatic manifestations, rechallenge or accidental re-exposure, and previous report in medical literature. The relative importance of each component was weighed, and arbitrary scores were attributed. The probability of the diagnosis of DILI was expressed as a final score, which could vary from -6 to 20. Content validity, criterion validity, construct validity, and inter-rater reliability were studied. To analyze validity and reliability, a random sample of 50 cases of suspected DILI was drawn from a series of 120 cases reported to our unit. The classification of the 50 cases by three experts in DILI was used as the external standard in the study of criterion validity. Agreement between the scale and the standard, and agreement between two independent raters (inter-rater reliability) was analyzed by weighted kappa coefficient. There was agreement between the scale and the standard in 42 cases (84%) with a weighted kappa coefficient of 0.90. A good discriminatory capacity of the scale was found when construct validity was studied. Agreement between raters was observed in 86% of the cases, corresponding to the weighted kappa of 0.93. In conclusion, the clinical scale was shown to have a high-level of validity and inter-rater reliability as well as a good discriminatory capacity between different levels of probability. These data suggest that the scale is suitable for use in clinical practice and may contribute to overcome the difficulties in the process of causality assessment in DILI.

Development and validation of a clinical scale for the diagnosis of drug-induced hepatitis

The objective of this study is to present and validate a clinical scale for the diagnosis of drug-induced liver injury (DILI). Five components were selected to be included in the scale: temporal relationship between drug intake and the onset of clinical picture, exclusion of alternative causes, extrahepatic manifestations, rechallenge or accidental re-exposure, and previous report in medical literature. The relative importance of each component was weighed, and arbitrary scores were attributed. The probability of the diagnosis of DILI was expressed as a final score, which could vary from -6 to 20. Content validity, criterion validity, construct validity, and inter-rater reliability were studied. To analyze validity and reliability, a random sample of 50 cases of suspected DILI was drawn from a series of 120 cases reported to our unit. The classification of the 50 cases by three experts in DILI was used as the external standard in the study of criterion validity. Agreement between the scale and the standard, and agreement between two independent raters (inter-rater reliability) was analyzed by weighted kappa coefficient. There was agreement between the scale and the standard in 42 cases (84%) with a weighted kappa coefficient of 0.90. A good discriminatory capacity of the scale was found when construct validity was studied. Agreement between raters was observed in 86% of the cases, corresponding to the weighted kappa of 0.93. In conclusion, the clinical scale was shown to have a high-level of validity and inter-rater reliability as well as a good discriminatory capacity between different levels of probability. These data suggest that the scale is suitable for use in clinical practice and may contribute to overcome the difficulties in the process of causality assessment in DILI. (Hepatology 1997 Sep;26(3):664-9)

Italian version of the Perceived Physical Ability Scale.

The Perceived Physical Ability scale developed by Ryckman, Robbins, Thornton, and Cantrell in 1982 was translated into the Italian language and modified to be applicable to children and youth. The scale was administered to 2,546 subjects, 1,269 females and 1,277 males, aged 10 to 20 years. Composed of 10 items, the scale assesses an individual's perception of his physical ability and motor performance. The scale showed good reliability and discriminative capacity. From factor analysis, two factors linked to perceptions of physical efficiency and difficulties with movements emerged. Findings with this scale showed that higher scores on Perceived Physical Ability were reported for males than for females, and for subjects with sport experience than for subjects without. Further, high scores on Perceived Physical Ability tended to be associated with high scores on Self-perception, Confidence with own body, and Positive Attitude when facing motor tasks.

ITALIAN VERSION OF THE PERCEIVED PHYSICAL ABILITY SCALE

The Perceived Physical Ability scale developed by Ryckman, Robbins, Thornton, and Cantrell in 1982 was translated into the Italian language and modified to be applicable to children and youth. The scale was administered to 2,546 subjects, 1,269 females and 1,277 males, aged 10 to 20 years. Composed of 10 items, the scale assesses an individual's perception of his physical ability and motor performance. The scale showed good reliability and discriminative capacity. From factor analysis, two factors linked to perceptions of physical efficiency and difficulties with movements emerged. Findings with this scale showed that higher scores on Perceived Physical Ability were reported for males than for females, and for subjects with sport experience than for subjects without. Further, high scores on Perceived Physical Ability tended to be associated with high scores on Self-perception, Confidence with own body, and Positive Attitude when facing motor tasks.

Respiratory resistance and transcutaneous PO2 during histamine provocation in children with bronchial asthma.

Bronchial reactivity was assessed in 66 children with bronchial asthma (aged 8-15 years) by provocation with histamine-HCl during a symptom-free period. A significant bronchial reaction to histamine was defined as a 50% increase in the resistance of the respiratory system (Rrs) determined by the forced oscillation technique. The provocative dose causing a 50% increase in the Rrs (PD50Rrs) was interpolated from the log dose-response curve. The mean PD50Rrs was significantly lower in children with asthma (0.22 mg/mL) compared with a group of healthy children in the same age range (1.55 mg/mL) (P < 0.001). In children with clinically severe asthma, the mean PD50Rrs was lower (0.13 mg/mL) than in children with mild asthma (0.34 mg/mL) (P < 0.001). Transcutaneous PO2 (PtcO2) was monitored in 25 of the children with asthma. In this group the proportion of mild and severe asthma, the baseline lung function variables, and the PD50Rrs were not significantly different from those of the whole group of children. During the reaction, the PtcO2 fell on average by 29% of the baseline value (P < 0.001); in 88% of the children, the fall in PtcO2 was 20% or more of the baseline value. We conclude that histamine provocation tests using the forced oscillation technique and transcutaneous PO2 to assess a bronchial reaction have a good discriminatory capacity for different degrees of clinical severity of asthma in children.

A comparative validation of the Foulds and Bedford hierarchy of psychiatric symptomatology.

This study investigated the validity of the Fould & Bedford hierarchical model of psychiatric illness, as compared to hierarchical models based upon prevalence and severity of disorder. The DSSI was administered to 52 American psychiatric in-patients with severe disturbances. The reports of symptoms in this sample conformed to the Foulds hierarchy in 90% of cases, while 94% of cases conformed to a model based upon prevalence. When a cross-method validation was investigated, the Foulds & Bedford classification demonstrated good discriminative capacity, while models based upon prevalence and severity failed to achieve significance. These results suggest that the Foulds & Bedford model is a useful taxonomy of symptomatology in psychiatric illness.