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True Prevalence (true + prevalence)
Selected AbstractsOriginal article: The prevalence of Barrett's esophagus in the US: estimates from a simulation model confirmed by SEER dataDISEASES OF THE ESOPHAGUS, Issue 6 2010T. J. Hayeck SUMMARY Barrett's esophagus (BE) is the precursor and the biggest risk factor for esophageal adenocarcinoma (EAC), the solid cancer with the fastest rising incidence in the US and western world. Current strategies to decrease morbidity and mortality from EAC have focused on identifying and surveying patients with BE using upper endoscopy. An accurate estimate of the number of patients with BE in the population is important to inform public health policy and to prioritize resources for potential screening and management programs. However, the true prevalence of BE is difficult to ascertain because the condition frequently is symptomatically silent, and the numerous clinical studies that have analyzed BE prevalence have produced a wide range of estimates. The aim of this study was to use a computer simulation disease model of EAC to determine the estimates for BE prevalence that best align with US Surveillance Epidemiology and End Results (SEER) cancer registry data. A previously developed mathematical model of EAC was modified to perform this analysis. The model consists of six health states: normal, gastroesophageal reflux disease (GERD), BE, undetected cancer, detected cancer, and death. Published literature regarding the transition rates between these states were used to provide boundaries. During the one million computer simulations that were performed, these transition rates were systematically varied, producing differing prevalences for the numerous health states. Two filters were sequentially applied to select out superior simulations that were most consistent with clinical data. First, among these million simulations, the 1000 that best reproduced SEER cancer incidence data were selected. Next, of those 1000 best simulations, the 100 with an overall calculated BE to Detected Cancer rates closest to published estimates were selected. Finally, the prevalence of BE in the final set of best 100 simulations was analyzed. We present histogram data depicting BE prevalences for all one million simulations, the 1000 simulations that best approximate SEER data, and the final set of 100 simulations. Using the best 100 simulations, we estimate the prevalence of BE to be 5.6% (5.49,5.70%). Using our model, an estimated prevalence for BE in the general population of 5.6% (5.49,5.70%) accurately predicts incidence rates for EAC reported to the US SEER cancer registry. Future clinical studies are needed to confirm our estimate. [source] A Bayesian model for estimating the effects of drug use when drug use may be under-reportedADDICTION, Issue 11 2009Garnett P. McMillan ABSTRACT Aims We present a statistical model for evaluating the effects of substance use when substance use might be under-reported. The model is a special case of the Bayesian formulation of the ,classical' measurement error model, requiring that the analyst quantify prior beliefs about rates of under-reporting and the true prevalence of substance use in the study population. Design Prospective study. Setting A diversion program for youths on probation for drug-related crimes. Participants A total of 257 youths at risk for re-incarceration. Measurements The effects of true cocaine use on recidivism risks while accounting for possible under-reporting. Findings The proposed model showed a 60% lower mean time to re-incarceration among actual cocaine users. This effect size is about 75% larger than that estimated in the analysis that relies only on self-reported cocaine use. Sensitivity analysis comparing different prior beliefs about prevalence of cocaine use and rates of under-reporting universally indicate larger effects than the analysis that assumes that everyone tells the truth about their drug use. Conclusion The proposed Bayesian model allows one to estimate the effect of actual drug use on study outcome measures. [source] A PCR-DGGE method for detection and identification of Campylobacter, Helicobacter, Arcobacter and related Epsilobacteria and its application to saliva samples from humans and domestic petsJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2007R.F. Petersen Abstract Aims:, To develop a PCR-denaturing gradient gel electrophoresis (PCR-DGGE) method for the detection and identification of Campylobacter, Helicobacter and Arcobacter species (Epsilobacteria) in clinical samples and evaluate its efficacy on saliva samples from humans and domestic pets. Methods and Results:, A semi-nested PCR was developed to allow sensitive detection of all Epsilobacteria, with species separation undertaken by DGGE. A database was constructed in BioNumerics using 145 strains covering 51 Campylobacter, Arcobacter and Helicobacter taxa; Nineteen distinct DGGE profile-groups were distinguished. This approach detected Epsilobacteria in all saliva samples collected from humans, cats and dogs, and identified Campylobacter concisus and/or Campylobacter gracilis in the human samples. The pet animal samples were taken from individuals with oral/dental diseases; PCR-DGGE identified up to four different species in each sample. The most common species detected included Wolinella succinogenes, Arcobacter butzleri and two hitherto uncultured campylobacters. The enteropathogen Campylobacter lari was also found. Conclusions:, PCR combined with DGGE is a useful tool for direct detection and preliminary identification of Epsilobacteria in the oral cavity of humans and small animals. Significance and Impact of the Study:, The PCR-DGGE method should allow determination of the true prevalence and diversity of Epsilobacteria in clinical and other samples. Contact with the oral cavity of domestic pets may represent a route of transmission for epsilobacterial enteric diseases. [source] Identification of operationally tolerant liver transplant recipients,LIVER TRANSPLANTATION, Issue S2 2010Alberto Sánchez-Fueyo KEY POINTS: (1) Liver allografts exhibit intrinsic tolerogenic properties that result in their spontaneous acceptance in many experimental animal models. (2) In clinical transplantation, liver allografts require milder immunosuppression (IS) regimens than other organs, are remarkably resistant to antibody-mediated rejection, and only very rarely are lost because of immunological insults. (3) A fraction of stable liver transplant recipients can withdraw from all IS therapy and then maintain normal graft function and not experience rejection. This phenomenon is known as spontaneous operational tolerance. (4) The intentional discontinuation of IS in stable liver transplant recipients has led to successful weaning in almost 20% of recipients, but the true prevalence of spontaneous operational tolerance in unselected recipients is still unknown. (5) The prevalence could be higher in pediatric recipients undergoing transplantation before 1 year of age and in adult recipients with more than 10 years of posttransplant follow-up. (6) Rejection occurring during medically supervised IS weaning trials tends to be mild and, in the overwhelming majority of cases, can be easily resolved without the administration of high-dose IS. (7) Tolerant liver recipients exhibit specific transcriptional patterns in peripheral blood and in liver tissue that may constitute future diagnostic markers of tolerance. (8) There is still no formal proof that the discontinuation of low-dose IS in long-term surviving liver recipients improves the morbidity and mortality rates associated with IS therapy. Liver Transpl 16:S82-S86, 2010. © 2010 AASLD. [source] A Review of Sympathetically Maintained Pain Syndromes in the Cancer Pain Population:PAIN PRACTICE, Issue 4 2001The spectrum of ambiguous entities of RSD, other pain states related to the sympathetic nervous system Abstract: Accepted wisdom contends that sympathetically maintained pain is rare in cancer pain syndromes. But this may be more of an artifact of how we diagnose this condition than a reflection of its true prevalence. One area in which one might suspect this to be true is in postsurgical states. While there are case reports of sympathetically maintained pain occurring after radical neck dissection, orbital and maxillary exenteration, it has not been reported in the more common areas of postsurgical pain. For instance, although one should suspect that the nerve damage that accompanies post-thoracotomy and postmastectomy pain syndromes would bring into being a certain incidence of sympathetically maintained pain, it is difficult to find collaborative reports. This may have more to do with the difficulty inherent in diagnosing sympathetically maintained pain than its actual contribution to these persistent cancer pain syndromes. The reason that it is more commonly reported in limb amputation is less comprehensible since blocking the sympathetic fibers that travel to an extremity is easier than those going to the thoracic cavity. In addition to surgically induced sympathetically maintained pain, medical patients with lymphoma and leukemia may have an element of sympathetically maintained pain when they develop postherpetic neuralgia. While the contribution of sympathetically maintained pain in these cases is not totally ignored, its involvement, as in the surgical patients mentioned above, is worthy of another analysis. This paper will discuss the topics introduced above and suggest diagnostic and therapeutic options available for this condition. [source] Identification of children with the same level of impairment as children on the autistic spectrum, and analysis of their service useTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 6 2010Ginny Russell Background:, Data from epidemiology have consistently highlighted a disparity between the true prevalence of childhood psychiatric disorders and their recognition as defined by receiving a clinical diagnosis. Few studies have looked specifically at the level of unidentified autistic spectrum disorder (ASD) in the population. Method:, Logistic regression was used to determine the behavioural traits associated with receiving a diagnosis of ASD using data from the Avon Longitudinal Study of Parents and Children (ALSPAC). A composite score was derived to measure levels of autistic traits; undiagnosed children with scores matching those diagnosed with ASD were identified. Levels of educational provision beyond that provided by standard schooling were examined. Results:, Fifty-five percent of children with autistic traits at the same levels as those who had an autism diagnosis had not been identified as needing extra support from education or specialised health services. Of those who were identified as having special needs, 37.5% had been formally diagnosed with an ASD. For children with impairment at the same level as that associated with Asperger's syndrome, 57% had no special provision at school, and were not accessing specialised health services. Twenty-six percent of those who did have special provision at school had an ASD diagnosis. Conclusions:, The results suggest that there may be a substantial proportion of children on the autistic spectrum who are never identified by services. [source] IDENTIFYING MUSCULOSKELETAL CONDITIONS AMONG RURAL INDIGENOUS PEOPLESAUSTRALIAN JOURNAL OF RURAL HEALTH, Issue 4 2003Dein Vindigni ABSTRACT Objective: To critically review the methodological properties of previous musculoskeletal studies among Indigenous populations. In particular, non-rheumatic, musculoskeletal conditions of mechanical origin are examined as these appear to be commonly related to syndromes of pain and disability. Design: Systematic review. Setting: Rural, Indigenous communities throughout the world. Subjects: Indigenous peoples aged 16 and over living in rural communities. Main outcome measure: Minimum requirements for methodologically sound musculoskeletal health research according to previously published criteria. Results: Due to methodological limitations in the 14 studies reviewed, only five methodologically acceptable studies were found. Conclusion: Given the paucity of methodologically sound musculoskeletal studies among Indigenous populations, the true prevalence of musculoskeletal conditions in these communities remains largely unknown. [source] | ||||||||||