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Disease Screening (disease + screening)
Selected AbstractsMyocardial perfusion imaging and cardiac events in a cohort of asymptomatic patients with diabetes living in southern FranceDIABETIC MEDICINE, Issue 4 2006A. Sultan Abstract Aims, To assess the association between abnormal stress myocardial perfusion imaging (MPI) and cardiac events (CE) in asymptomatic patients with diabetes and with , 1 additional risk factor. Predictors of abnormal stress MPI were also evaluated. Methods, Four hundred and forty-seven consecutive patients who underwent stress MPI were prospectively followed for 2.1 [0.5,4.1] years for the subsequent occurrence of hard CE (myocardial infarction and sudden or coronary death) and soft CE (unstable angina and ischaemic heart failure requiring hospitalization). Re-vascularization procedures performed as a result of the screening protocol were not included in the analysis. Results, Follow-up was successful in 419 of 447 patients (94%), of whom 71 had abnormal MPI at baseline. Medical therapy was intensified in all subjects and especially in those with abnormal MPI. Twenty-three patients with abnormal MPI underwent a re-vascularization procedure. CEs occurred in 14 patients, including six of 71 patients (8.5%) with abnormal MPI and eight of 348 patients (2.3%) with normal MPI (P < 0.005). Only two patients developed a hard CE and 12 a soft CE. In multivariate analysis, abnormal MPI was the strongest predictor for CEs [odds ratio (OR) (95% CI) = 5.6 (1.7,18.5)]. Low-density lipoprotein cholesterol , 3.35 mmol/l [OR (95% CI) = 7.3; 1.5,34.7] and age > median [OR (95% CI) = 6.0 (1.2,28.6)] were additional independent predictors for CE. The independent predictors for abnormal MPI were male gender, plasma triglycerides , 1.70 mmol/l, creatinine clearance < 60 ml/min and HbA1c > 8%, with male gender the strongest [OR (95% CI) = 4.0 (1.8,8.8)]. Conclusions, Asymptomatic patients with diabetes in this study had a very low hard cardiac event rate over an intermediate period. This could be explained by the effects of intervention or by the low event rate in the background population. Randomized studies of cardiac heart disease screening are required in asymptomatic subjects with diabetes to determine the effectiveness of this intervention. Diabet. Med. (2006) [source] Cost effectiveness of mass screening for coeliac disease is determined by time-delay to diagnosis and quality of life on a gluten-free dietALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 8 2010T. HERSHCOVICI Aliment Pharmacol Ther,31, 901,910 Summary Background, Coeliac disease is frequently diagnosed after a long delay resulting in increased morbidity and mortality. Aims, To define the parameters which have the highest impact on the cost-effectiveness of mass screening for coeliac disease. Methods, A Markov model examined a coeliac disease screening programme of the healthy young-adult general population compared with a no-screening strategy. The main outcome measures were quality adjusted life-years (QALYs) and incremental cost-effectiveness ratio (ICER). Effects of variables were examined using sensitivity analyses. Results, The screening strategy resulted in a gain of 0.0027 QALYs. The ICER of screening vs. no-screening strategy was US$48 960/QALYs. The variables with the largest impact on cost effectiveness were: the time delay from symptom onset to diagnosis, the utility of adherence to a gluten-free diet (GFD) and the prevalence of coeliac disease. Screening would be cost-effective if the time delay to diagnosis is longer than 6 years and utility of GFD adherence is greater than 0.978. Conclusions, Our model suggests that mass screening for coeliac disease of the young-adult general population is associated with improved QALYs and is a cost effectiveness strategy. Shortening of the time-delay to diagnosis by heightened awareness of health-care professionals may be a valid alternative to screening. [source] Optometric glaucoma referrals , measures of effectiveness and implications for screening strategyOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 6 2000Jim Gilchrist Summary The effectiveness of disease screening is conventionally evaluated using the epidemiological indices of sensitivity and specificity, which measure the association between screening test results and final diagnoses of all the patients screened. The effectiveness of optometric glaucoma referrals cannot be measured using such indices because diagnoses are obtained only on patients who are referred, while the true disease status of those not referred remains unknown. Instead, glaucoma referral effectiveness has been evaluated using measures of ,detection rate', the proportion of those screened who are correctly referred, and ,referral accuracy', the proportion of those referred who are correctly referred occurrence. Examination of these operational measures shows that their obtainable values and, hence, their interpretation are influenced by the total proportions of diseased and referred patients, one or both of which will generally be unavailable in evaluating samples of referrals. On the other hand, if valid estimates of these proportions can be obtained from other sources, it is possible to rescale detection rate and referral accuracy to take account of them. This rescaling produces a pair of weighted kappa coefficients, chance-corrected measures of association between referral and diagnosis, which provide a better indication of true referral effectiveness than other measures. An important consequence of this approach is that it provides a clear quantitative illustration of the need for a dual strategy to improve the overall quality of optometric glaucoma screening; widespread adoption of more comprehensive modes of screening to improve accuracy, together with a significant increase in the total numbers of patients screened to improve detection. In order for detection rates to reach desirable levels, the total number of referrals in any sub-population of patients must match or exceed the number of patients with disease. This analysis confirms quantitatively that which is intuitively obvious; not only that glaucoma awareness and uptake of screening opportunities must be encouraged in all patients over 40 years of age, but also that the older and/or more at risk patients are, the greater is their need to take advantage of glaucoma screening. [source] Estimation methods for time-dependent AUC models with survival dataTHE CANADIAN JOURNAL OF STATISTICS, Issue 1 2010Hung Hung Abstract The performance of clinical tests for disease screening is often evaluated using the area under the receiver-operating characteristic (ROC) curve (AUC). Recent developments have extended the traditional setting to the AUC with binary time-varying failure status. Without considering covariates, our first theme is to propose a simple and easily computed nonparametric estimator for the time-dependent AUC. Moreover, we use generalized linear models with time-varying coefficients to characterize the time-dependent AUC as a function of covariate values. The corresponding estimation procedures are proposed to estimate the parameter functions of interest. The derived limiting Gaussian processes and the estimated asymptotic variances enable us to construct the approximated confidence regions for the AUCs. The finite sample properties of our proposed estimators and inference procedures are examined through extensive simulations. An analysis of the AIDS Clinical Trials Group (ACTG) 175 data is further presented to show the applicability of the proposed methods. The Canadian Journal of Statistics 38:8,26; 2010 © 2009 Statistical Society of Canada La performance des tests cliniques pour le dépistage de maladie est souvent évaluée en utilisant l'aire sous la courbe caractéristique de fonctionnements du récepteur (, ROC , ), notée , AUC , . Des développements récents ont généralisé le cadre traditionnel à l'AUC avec un statut de panne binaire variant dans le temps. Sans considérer les covariables, nous commençons par proposer un estimateur non paramétrique pour l'AUC simple et facile à calculer. De plus, nous utilisons des modèles linéaires généralisés avec des coefficients dépendant du temps pour caractériser les AUC, dépendant du temps, comme fonction des covariables. Les procédures d'estimation asociées correspondantes sont proposées afin d'estimer les fonctions paramètres d'intérêt. Les processus gaussiens limites sont obtenus ainsi que les variances asymptotiques estimées afin de construire des régions de confiance approximatives pour les AUC. À l'aide de nombreuses simulations, les propriétés pour de petits échantillons des estimateurs proposés et des procédures d'inférence sont étudiées. Une analyse du groupe d'essais cliniques sur le sida 175 (ACTG 175) est aussi présentée afin de montrer l'applicabilité des méthodes proposées. La revue canadienne de statistique 38: 8,26; 2010 © 2009 Société statistique du Canada [source] Community-based multiple screening model,,§¶CANCER, Issue 8 2004387 participants Taiwan community-based integrated screening group, Design, analysis of 4, implementation Abstract BACKGROUND Multiple disease screening may have several advantages over single disease screening because of the economics of scale, with the high yield of detecting asymptomatic diseases, the identification of multiple diseases or risk factors simultaneously, the enhancement of the attendance rate, and the efficiency of follow-up. METHODS An integrated model of community-based multiple screening was designed and conducted between 1999 and 2001 in Keelung, Taiwan. The authors used a Papanicolaou (Pap) smear screening program as a base to integrate other screening regimens encompassing four other neoplastic diseases and three nonneoplastic chronic diseases. Screening methods, the interscreening interval, and the follow-up for each screening regimen were designed based on evidence-based literature and current national screening policy. RESULTS A total of 42,387 subjects participated in the screening activities. A 25% increase in the attendance rate for Pap smear screening was demonstrated after the introduction of multiple disease screening programs. At the first screen, this program yielded a total of 677 asymptomatic neoplasms (16.0 per 1000), including a large proportion of precancerous lesions and small presymptomatic tumors without lymph node involvement. The association between the occurrence of neoplasm and the presence of comorbid nonneoplastic chronic disease was found to be statistically significant (odds ratio, 1.64; 95% confidence interval, 1.38,1.94 [P < 0.05]). The authors also identified 5314 subjects with metabolic syndrome who were at a greater risk for colorectal and oral neoplasias. CONCLUSIONS The results of the current study demonstrate that an outreach and community-based multiple screening program not only enhances attendance rates but also has a high yield of early cases of various diseases simultaneously, and provides a natural opportunity to elucidate the correlation between neoplastic disease and nonneoplastic chronic disease. Cancer 2004. © 2004 American Cancer Society. [source] | ||||||||||