32 resultados para positive predictive values

em Deakin Research Online - Australia


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Introduction. A wide range of prevalence estimates of female sexual dysfunctions (FSD) have been reported.
Aim. Compare instruments used to assess FSD to determine if differences between instruments contribute to variation in reported prevalence.
Main Outcome Measures. Sexual Function Questionnaire combined with Female Sexual Distress Scale (SFQ-FSDS) was our gold standard, validated instrument for assessing FSD. Alternatives were SFQ alone and two sets of simple questions adapted from Laumann et al. 1994.
Methods. A postal survey was administered to a random sample of 356 Australian women aged 20 to 70 years.
Results. When assessed by SFQ-FSDS, prevalence estimates (95% confidence intervals) of hypoactive sexual desire disorder, sexual arousal disorder (lubrication), orgasmic disorder, and dyspareunia were 16% (12% to 20%), 7% (5% to 11%), 8% (6% to 12%), and 1% (0.5% to 3%), respectively. Prevalence estimates varied across alternative instruments for these disorders: 32% to 58%, 16% to 32%, 16% to 33%, and 3% to 23%, respectively. Compared with SFQ-FSDS alternative instruments produced higher estimates of desire, arousal and orgasm disorders and displayed a range of sensitivities (0.25 to 1.0), specificities (0.48 to 0.99), positive predictive values (0.01 to 0.56), and negative predictive values (0.95 to 1.0) across the disorders investigated. Kappa statistics comparing SFQ-FSDS and alternative instruments ranged from 0 to 0.71 but were predominantly 0.44 or less. Changing recall from previous month to 1 month or more in the previous year produced higher estimates for all disorders investigated. Including sexual distress produced lower estimates for desire, arousal, and orgasm disorders.
Conclusions. Prevalence estimates of FSD varied substantially across instruments. Relatively low positive predictive values and kappa statistics combined with a broad range of sensitivities and specificities indicated that different instruments identified different subgroups. Consequently, the instruments researchers choose when assessing FSD may affect prevalence estimates and risk factors they report.

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Introduction, objectives Despite increasing research, the true prevalence of Female Sexual Dysfunction (FSD) remains a contentious issue. Previous research suggests that aspects of study design affect the reported prevalence of FSD. We compare commonly used instruments for assessing FSD. Methods A random sample of 240 Australian women aged 20-70 participated in this population based, cross-sectional study. A questionnaire mailed to women across Australia included four instruments for assessing FSD. The Sexual Function Questionnaire combined with the Female Sexual Distress Scale (SFQ-FSDS) was employed as a standard, validated instrument. Alternative instruments were the SFQ alone and two modified versions of a set of questions originally developed by Laumann et al. Results When assessed by the SFQ-FSDS, prevalence estimates (and 95% confidence intervals) of Hypoactive Sexual Desire Disorder, Female Sexual Arousal Disorder (genital subtype), Female Orgasmic Disorder, and Dysparunia were 16%(11-20%), 8%(4-11%), 9%(6-13%), 2%(0.1-3%) respectively. The prevalence estimates of these same disorders obtained using alternative instruments were 32-55%, 17-35%, 17-33% and 3-25% respectively. The sensitivity of alternative instruments varied widely (0 to 1.0). Specificities ranged from 0.51 to 0.99. Positive predictive values ranged from 0 to 0.57. Negative predictive values were all above 0.90. Changing the time span for recalling sexual experiences in an instrument altered the prevalence estimates, sensitivity and specificity. 32% of women with low desire, 31% with low genital arousal, 36% with orgasm difficulty and 57% with sexual pain were sexually distressed. Conclusion Over a third of women who were classified as suffering FSD by alternative instruments did not have FSD when assessed by SFQ-FSDS. Alternative instruments produced substantially higher prevalence estimates of FSD and identified different groups of women. Consequently, the instruments researchers choose to assess FSD may affect both the prevalence estimates and risk factors they report.

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Erroneous patient birthdates are common in health databases. Detection of these errors usually involves manual verification, which can be resource intensive and impractical. By identifying a frequent manifestation of birthdate errors, this paper presents a principled and statistically driven procedure to identify erroneous patient birthdates.

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Background: Diagnosis of patellar tendinopathy is based primarily on clinical examination; however, it is commonplace to image the patellar tendon for diagnosis confirmation, with the imaging modalities of choice being magnetic resonance imaging (MRI) and ultrasonography (US). The comparative accuracy of these modalities has not been established.

Hypothesis: Magnetic resonance imaging and US have good (>80%) accuracy and show substantial agreement in confirming clinically diagnosed patellar tendinopathy.

Study Design: Cohort study (diagnosis); Level of evidence, 2.

Methods: Magnetic resonance imaging and US (gray scale [GS-US] and color Doppler [CD-US]) features of 30 participants with clinically diagnosed patellar tendinopathy and 33 activity-matched, asymptomatic participants were prospectively compared. Accuracy, sensitivity, specificity, positive and negative predictive values, and the likelihood of positive and negative test results were determined for each technique.

Results: The accuracy of MRI, GS-US, and CD-US was 70%, 83%, and 83%, respectively (P = .04; MRI vs GS-US). The likelihood of positive MRI, GS-US, and CD-US was 3.1, 4.8, and 11.6, respectively. The MRI and GS-US had equivalent specificity (82% vs 82%; P = 1.00); however, the sensitivity of GS-US was greater than MRI (87% vs 57%; P = .01). Sensitivity (70% vs 87%; P = .06) and specificity (94% vs 82%; P = .10) did not differ between CD-US and GS-US.

Conclusions: Ultrasonography was more accurate than MRI in confirming clinically diagnosed patellar tendinopathy. GS-US and CD-US may represent the best combination for confirming clinically diagnosed patellar tendinopathy because GS-US had the greatest sensitivity, while a positive CD-US test result indicated a strong likelihood an individual was symptomatic.

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The C282Y and H63D mutations in the HFE gene are important causes of hemochromatosis. In the elderly, these mutations might be associated with increased morbidity because of the lifelong accumulation of iron. In a population-based sample of the elderly, we determined the value of genotyping for HFE mutations to screen for subclinical hemochromatosis. HFE genotype frequencies were determined in a random group of 2095 subjects (55 years and over). In this random group, we selected within the six genotype groups a total of 342 individuals and measured their serum transferrin saturation, iron and ferritin levels. We also estimated the heritability and parameters needed to evaluate screening, including the sensitivity, specificity, positive and negative predictive values (PPV, NPV) of HFE genotypes. Iron parameters were significantly increased in subjects homozygous, heterozygous or compound heterozygous. The effect of the mutations was more pronounced in men than in women. For the H63D mutation, an allele dose effect was observed. The HFE gene explained about 5% of the variability in serum iron indices. The PPV for hemochromatosis for the C282Y homozygous was 100% in men and 67% in women. The NPV of the wild-type allele was 97% for both men and women. The sensitivity of both mutations was 70% for men and 52% for women and the specificity was 62% for men and 64% for women. Our study shows that the HFE C282Y and H63D are determinants of iron parameters in the elderly and will be effective in detecting individuals at high risk of hemochromatosis. However, when screening based on these two mutations, some individuals with subclinical hemochromatosis will be missed.

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Abstract Aims: To develop and evaluate a screening tool to identify people with diabetes at increased risk of medication problems relating to hypoglycaemia and medication non-adherence. Methods: A retrospective audit of attendances at a diabetes outpatient clinic at a public, teaching hospital over a 16-month period was conducted. Logistic regression was undertaken to examine risk factors associated with medication problems relating to hypoglycaemia and medication non-adherence and the most predictive set of factors comprise the Diabetes Medication Risk Screening Tool. Evaluating the tool involved assessing sensitivity and specificity, positive and negative predictive values, cut-off scores, inter-rater reliability, and content validity. Results: The Diabetes Medication Risk Screening Tool comprises seven predictive factors: age, living alone, English language, mental and behavioural problems, comorbidity index score, number of medications prescribed, and number of high-risk medications prescribed. The tool has 76.5% sensitivity, 59.5% specificity, and has a 65.1% positive predictive value, and a 71.8% negative predictive value. A score of 27 or more out of 62 was associated with high-risk of a medication problem. The inter-rater reliability of the tool was high (κ = 0.79, 95% CI 0.75 - 0.84) and the content validity index was 99.4%. Conclusion: The Diabetes Medication Risk Screening Tool has good psychometric properties and can proactively identify people with diabetes at greatest risk of medication problems relating to hypoglycaemia and medication non-adherence.

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Background—Palpation is an important clinical test for jumper's knee.

Objectives—To (a) test the reproducibility of palpation tenderness, (b) evaluate the sensitivity and specificity of palpation in subjects with clinical symptoms of jumper's knee, and (c) determine whether tenderness to palpation may serve as a useful screening test for patellar tendinopathy. The yardstick for diagnosis of patellar tendinopathy was ultrasonographic abnormality.

Methods—In 326 junior symptomatic and asymptomatic athletes' tendons, palpation was performed by a single examiner before ultrasonographic examination by a certified ultrasound radiologist. In 58 tendons, palpation was performed twice to test reliability. Tenderness to palpation was scored on a scale from 0 to 3 where 0 represented no pain, and 1, 2, and 3 represented mild, moderate, and severe tenderness respectively.

Results—Patellar tendon palpation was a reliable examination for a single examiner (Pearson r = 0.82). In symptomatic tendons, the positive predictive value of palpation was 68%. As a screening examination in asymptomatic subjects, the positive predictive value of tendon palpation was 36–38%. Moderate and severe palpation tenderness were better predictors of ultrasonographic tendon pathology than absent or mild tenderness (p<0.001). Tender and symptomatic tendons were more likely to have ultrasound abnormality than tenderness alone (p<0.01).

Conclusions—In this age group, palpation is a reliable test but it is not cost effective in detecting patellar tendinopathy in a preparticipation examination. In symptomatic tendons, palpation is a moderately sensitive but not specific test. Mild tenderness in the patellar tendons in asymptomatic jumping athletes should be considered normal.

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Faunal atlases are landscape-level survey collections that can be used for describing spatial and temporal patterns of distribution and densities. They can also serve as a basis for quantitative analysis of factors that may influence the distributions of species. We used a subset of Birds Australia’s Atlas of Australian Birds data (January 1998 to December 2002) to examine the spatio-temporal distribution patterns of 280 selected species in eastern Australia (17–37°S and 136–152°E). Using geographical information systems, this dataset was converted into point coverage and overlaid with a vegetation polygon layer and a half-degree grid. The exploratory data analysis involved calculating species-specific reporting rates spatially, per grid and per vegetation unit, and also temporally, by month and year. We found high spatio-temporal variability in the sampling effort. Using generalised linear models on unaggregated point data, the influences of four factors – survey method and month, geographical location and habitat type – were analysed for each species. When counts of point data were attributed to grid-cells, the total number of species correlated with the total number of surveys, while the number of records per species was highly variable. Surveys had high interannual location fidelity. The predictive values of each of the four factors were species-dependent. Location and habitat were correlated and highly predictive for species with restricted distribution and strong habitat preference. Month was only of importance for migratory species. The proportion of incidental sightings was important for extremely common or extremely rare species. In conclusion, behaviour of species differed sufficiently to require building a customized model for each species to predict distribution. Simple models were effective for habitat specialists with restricted ranges, but for generalists with wide distributions even complex models gave poor predictions.

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Aims : To assess the utility of the metabolic syndrome (MetS) and a Diabetes Predicting Model as predictors of incident diabetes.

Methods :
A longitudinal survey was conducted in Mauritius in 1987 (n = 4972; response 80%) and 1992 (n = 3685; follow-up 74.2%). Diabetes status was retrospectively determined using 1999 World Health Organization (WHO) criteria. MetS was determined according to four definitions and sensitivity, positive predictive value (PPV), specificity and the association with incident diabetes before and after adjustment for MetS components calculated.

Results : Of the 3198 at risk, 297 (9.2%) developed diabetes between 1987 and 1992. The WHO MetS definition had the highest prevalence (20.3%), sensitivity (42.1%) and PPV (26.8%) for prediction of incident diabetes, the strongest association with incident diabetes after adjustment for age and sex [odds ratio 4.6 (3.5–6.0)] and was the only definition to show a significant association after adjustment for its component parts (in men only). The low prevalence and sensitivity of the International Diabetes Federation (IDF) and ATPIII MetS definitions resulted from waist circumference cut-points that were high for this population, particularly in men, and both were not superior to a diabetes predicting model on receiver operating characteristic analysis.

Conclusions : Of the MetS definitions tested, the WHO definition best identifies those who go on to develop diabetes, but is not often used in clinical practice. If cut-points or measures of obesity appropriate for this population were used, the IDF and ATPIII MetS definitions could be recommended as useful tools for prediction of diabetes, given their relative simplicity.

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OBJECTIVE--To assess the Australian protocol for identifying undiagnosed type 2 diabetes and impaired glucose metabolism.

RESEARCH DESIGN AND METHODS--The Australian screening protocol recommends a stepped approach to detecting undiagnosed type 2 diabetes based on assessment of risk status, measurement of fasting plasma glucose (FPG) in individuals at risk, and further testing according to FPG. The performance of and variations to this protocol were assessed in a population-based sample of 10,508 Australians.

RESULTS--The protocol had a sensitivity of 79.9%, specificity of 79.9%, and a positive predictive value (PPV) of 13.7% for detecting undiagnosed type 2 diabetes and sensitivity of 51.9% and specificity of 86.7% for detecting impaired glucose tolerance (IGT) or impaired fasting glucose (IFG). To achieve these diagnostic rates, 20.7% of the Australian adult population would require an oral glucose tolerance test (OGTT). Increasing the FPG cut point to 6.1 mmol/l (110 mg/dl) or using Hb[A.sub.1c], instead of FPG to determine the need for an OGTT in people with risk factors reduced sensitivity, increased specificity and PPV, and reduced the proportion requiring an OGTT. However, each of these protocol variations substantially reduced the detection of IGT or IFG.

CONCLUSIONS--The Australian screening protocol identified one new case of diabetes for every 32 people screened, with 4 of 10 people screened requiring FPG measurement and 1 in 5 requiring an OGTT. In addition, 1 in 11 people screened had IGT or IFG. Including Hb[A.sub.1c] measurement substantially reduced both the number requiring an OGTT and the detection of IGT or IFG.

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Background: Recent evidence shows a substantial short-term risk of ischaemic stroke after transient ischaemic attack (TIA). Identification of patients with TIA with a high short-term risk of stroke is now possible through the use of the “ABCD Score”, which considers age, blood pressure, clinical features and duration of symptoms predictive of stroke.

Aim: To evaluate the ability of dichotomising the ABCD Score to predict stroke at 7 and 90 days in a population with TIA presenting to an emergency department.

Methods: A retrospective audit was conducted on all probable or definite TIAs presenting to the emergency department of a metropolitan hospital from July to December 2004. The ABCD Score was applied to 98 consecutive patients with TIA who were reviewed for subsequent strokes within 90 days. Patients obtaining an ABCD Score ≥5 were considered to be at high risk for stroke.

Results: Dichotomising the ABCD Score categorised 48 (49%) patients with TIA at high risk for stroke (ABCD Score ≥5). This high-risk group contained all four strokes that occurred within 7 days (sensitivity 100% (95% confidence interval (CI) 40% to 100%), specificity 53% (95% CI 43% to 63%), positive predictive value 8% (95% CI 3% to 21%) and negative predictive value 100% (95% CI 91% to 100%)), and six of seven occurring within 90 days (sensitivity 86% (95% CI 42% to 99%), specificity 54% (95% CI 43% to 64%), positive predictive value 12.5% (95% CI 5% to 26%) and negative predictive value 98% (95% CI 88% to 100%)). Removal of the “age” item from the ABCD Score halved the number of false-positive cases without changing its predictive value for stroke.

Conclusion: In this retrospective analysis, dichotomising the ABCD Score was overinclusive but highly predictive in identifying patients with TIA at a high short-term risk of stroke. Use of the ABCD Score in the emergency care of patients with TIA is simple, efficient and provides a unique opportunity to prevent stroke in this population of patients.

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Objective: The Mood Disorder Questionnaire (MDQ) is a widely used self-report screening instrument for the detection of bipolar disorder in clinical populations. The aim of the present study was therefore to investigate the reliability of this instrument.

Methods: Screening results using the MDQ were compared with results obtained using the Structured Clinical Interview for DSM-IV-TR Research Version, Non-patient edition (SCID) in a community-based sample of 1066 women. Trained personnel, who were blind to the results of the MDQ screen, conducted clinical interviews.

Results: Using the MDQ, 21 women screened positive for bipolar disorder, and using the SCID diagnoses, 24 women were confirmed with a diagnosis of bipolar disorder. Six women were detected on both instruments. Compared to the SCID, the sensitivity for the MDQ was 25%, specificity 99%, positive predictive value 28%, negative predictive value 98%, and a demonstrated kappa of 0.25. The MDQ failed to detect any of the 11 participants in the study with bipolar II disorder and missed seven of 13 participants with bipolar I disorder or bipolar not otherwise specified. Of the 21 women who screened positive using the MDQ, 19 had current or past psychopathologies other than bipolar disorder.

Conclusion: The MDQ has substantial limitations for detection of bipolar disorder, in particular bipolar II disorder, in non-clinical populations.

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Background The diagnosis of displacement in scaphoid fractures is notorious for poor interobserver reliability.

Questions/purposes We tested whether training can improve interobserver reliability and sensitivity, specificity, and accuracy for the diagnosis of scaphoid fracture displacement on radiographs and CT scans.

Methods Sixty-four orthopaedic surgeons rated a set of radiographs and CT scans of 10 displaced and 10 nondisplaced scaphoid fractures for the presence of displacement, using a web-based rating application. Before rating, observers were randomized to a training group (34 observers) and a nontraining group (30 observers). The training group received an online training module before the rating session, and the nontraining group did not. Interobserver reliability for training and nontraining was assessed by Siegel’s multirater kappa and the Z-test was used to test for significance.

Results There was a small, but significant difference in the interobserver reliability for displacement ratings in favor of the training group compared with the nontraining group. Ratings of radiographs and CT scans combined resulted in moderate agreement for both groups. The average sensitivity, specificity, and accuracy of diagnosing displacement of scaphoid fractures were, respectively, 83%, 85%, and 84% for the nontraining group and 87%, 86%, and 87% for the training group. Assuming a 5% prevalence of fracture displacement, the positive predictive value was 0.23 in the nontraining group and 0.25 in the training group. The negative predictive value was 0.99 in both groups.

Conclusions Our results suggest training can improve interobserver reliability and sensitivity, specificity and accuracy for the diagnosis of scaphoid fracture displacement, but the improvements are slight. These findings are encouraging for future research regarding interobserver variation and how to reduce it further.

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Purpose : To determine the interobserver agreement and diagnostic performance characteristics of computed tomography (CT) for determining union of scaphoid waist fractures.

Methods : A total of 59 orthopedic and trauma surgeons rated for union a set of 30 sagittal CT scans of 30 scaphoid waist fractures. Of these fractures, 20 were treated nonoperatively, were imaged between 6 and 10 weeks after injury, and were known to have eventually achieved union. Ten were operatively confirmed to be ununited. We rated each scan as united or ununited using a Web-based rating application. We assessed interobserver reliability using Siegel's multirater Kappa. We calculated diagnostic performance characteristics using Bayesian formulas.

Results : The interobserver agreement among 59 raters was substantial. The average sensitivity, specificity, and accuracy of diagnosing union of scaphoid waist fractures on sagittal CT scans were 78%, 96%, and 84%, respectively. Assuming a 90% prevalence of fracture union of the scaphoid, the positive predictive value of a diagnosis of union on sagittal CT scan was 0.99 and the negative predictive value was 0.41.

Conclusions : Our results suggest that CT scans are accurate and reliable for diagnosis of union but inadequate for ruling out nonunion of scaphoid waist fractures between 6 and 10 weeks after injury.

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There is mounting evidence that current food production, transport, land use and urban design negatively impact both climate change and obesity outcomes. Recommendations to prevent climate change provide an opportunity to improve environmental outcomes and alter our food and physical activity environments in favour of a ‘healthier’ energy balance. Hence, setting goals to achieve a more sustainable society offers a unique opportunity to reduce levels of obesity. In the case of children, this approach is supported with evidence that even from a young age they show emerging understandings of complex environmental issues and are capable of both internalizing positive environmental values and influencing their own environmental outcomes. Given young children's high levels of environmental awareness, it is easy to see how environmental sustainability messages may help educate and motivate children to make ‘healthier’ choices. The purpose of this paper is to highlight a new approach to tackling childhood obesity by tapping into existing social movements, such as environmental sustainability, in order to increase children's motivation for healthy eating and physical activity behaviours and thus foster more wholesome communities. We contend that a social marketing framework may be a particularly useful tool to foster behaviour change beneficial to both personal and environmental health by increasing perceived benefits and reducing perceived costs of behaviour change. Consequently, we propose a new framework which highlights suggested pathways for helping children initiate and sustain ‘healthier’ behaviours in order to inform future research and potentially childhood obesity intervention strategies.