897 resultados para Logistic risks
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Debris flows represent a widespread threat to villages and small towns in the Swiss Alps. For many centuries people “managed” such risks by trying to avoid hazardous areas. However, major debris flow and flood events in the last 25 years have revealed that the degree of freedom to engage in this type of risk management has substantially decreased. This became especially evident during the 1999 disasters in a number of places in Switzerland. The winter of that year was unusually wet. In February heavy snowfall triggered destructive avalanches. In May high temperatures caused heavy snowmelt, with excessive rainfall contributing more water to the already saturated soils. Landslides, debris flows and floods were triggered in many locations, including Sörenberg. Hazard prevention and disaster management have a long tradition in Switzerland, although an integrated approach to risk management is rather new. Only in recent years have methods and tools been developed to assess hazards, define protection goals, and implement disaster reduction measures. The case of Sörenberg serves as an example of how today's approaches to disaster reduction are implemented at the local level.
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BACKGROUND The benefits and risks of prolonged dual antiplatelet therapy may be different for patients with acute myocardial infarction (MI) compared with more stable presentations. OBJECTIVES This study sought to assess the benefits and risks of 30 versus 12 months of dual antiplatelet therapy among patients undergoing coronary stent implantation with and without MI. METHODS The Dual Antiplatelet Therapy Study, a randomized double-blind, placebo-controlled trial, compared 30 versus 12 months of dual antiplatelet therapy after coronary stenting. The effect of continued thienopyridine on ischemic and bleeding events among patients initially presenting with versus without MI was assessed. The coprimary endpoints were definite or probable stent thrombosis and major adverse cardiovascular and cerebrovascular events (MACCE). The primary safety endpoint was GUSTO (Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Arteries) moderate or severe bleeding. RESULTS Of 11,648 randomized patients (9,961 treated with drug-eluting stents, 1,687 with bare-metal stents), 30.7% presented with MI. Between 12 and 30 months, continued thienopyridine reduced stent thrombosis compared with placebo in patients with and without MI at presentation (MI group, 0.5% vs. 1.9%, p < 0.001; no MI group, 0.4% vs. 1.1%, p < 0.001; interaction p = 0.69). The reduction in MACCE for continued thienopyridine was greater for patients with MI (3.9% vs. 6.8%; p < 0.001) compared with those with no MI (4.4% vs. 5.3%; p = 0.08; interaction p = 0.03). In both groups, continued thienopyridine reduced MI (2.2% vs. 5.2%, p < 0.001 for MI; 2.1% vs. 3.5%, p < 0.001 for no MI; interaction p = 0.15) but increased bleeding (1.9% vs. 0.8%, p = 0.005 for MI; 2.6% vs. 1.7%, p = 0.007 for no MI; interaction p = 0.21). CONCLUSIONS Compared with 12 months of therapy, 30 months of dual antiplatelet therapy reduced the risk of stent thrombosis and MI in patients with and without MI, and increased bleeding. (The Dual Antiplatelet Therapy Study [The DAPT Study]; NCT00977938).
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BACKGROUND The long-term safety of growth hormone treatment is uncertain. Raised risks of death and certain cancers have been reported inconsistently, based on limited data or short-term follow-up by pharmaceutical companies. PATIENTS AND METHODS The SAGhE (Safety and Appropriateness of Growth Hormone Treatments in Europe) study assembled cohorts of patients treated in childhood with recombinant human growth hormone (r-hGH) in 8 European countries since the first use of this treatment in 1984 and followed them for cause-specific mortality and cancer incidence. Expected rates were obtained from national and local general population data. The cohort consisted of 24,232 patients, most commonly treated for isolated growth failure (53%), Turner syndrome (13%) and growth hormone deficiency linked to neoplasia (12%). This paper describes in detail the study design, methods and data collection and discusses the strengths, biases and weaknesses consequent on this. CONCLUSION The SAGhE cohort is the largest and longest follow-up cohort study of growth hormone-treated patients with follow-up and analysis independent of industry. It forms a major resource for investigating cancer and mortality risks in r-hGH patients. The interpretation of SAGhE results, however, will need to take account of the methods of cohort assembly and follow-up in each country.
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Maternal thromboembolism and a spectrum of placenta-mediated complications including the pre-eclampsia syndromes, fetal growth restriction, fetal loss, and abruption manifest a shared etiopathogenesis and predisposing risk factors. Furthermore, these maternal and fetal complications are often linked to subsequent maternal health consequences that comprise the metabolic syndrome, namely, thromboembolism, chronic hypertension, and type II diabetes. Traditionally, several lines of evidence have linked vasoconstriction, excessive thrombosis and inflammation, and impaired trophoblast invasion at the uteroplacental interface as hallmark features of the placental complications. "Omic" technologies and biomarker development have been largely based upon advances in vascular biology, improved understanding of the molecular basis and biochemical pathways responsible for the clinically relevant diseases, and increasingly robust large cohort and/or registry based studies. Advances in understanding of innate and adaptive immunity appear to play an important role in several pregnancy complications. Strategies aimed at improving prediction of these pregnancy complications are often incorporating hemodynamic blood flow data using non-invasive imaging technologies of the utero-placental and maternal circulations early in pregnancy. Some evidence suggests that a multiple marker approach will yield the best performing prediction tools, which may then in turn offer the possibility of early intervention to prevent or ameliorate these pregnancy complications. Prediction of maternal cardiovascular and non-cardiovascular consequences following pregnancy represents an important area of future research, which may have significant public health consequences not only for cardiovascular disease, but also for a variety of other disorders, such as autoimmune and neurodegenerative diseases.
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Purpose: Schizophrenia is a severe mental disorder which is accompanied by an enormous individual and societal burden. Despite established efficacy of cognitive behavioral therapy (CBT) for schizophrenia, its dissemination into routine mental health care remains poor. Internet-based cognitive behavioral therapy in a self-help format helps to narrow the treatment gap in many mental disorders. Are Internet-based self-help programs, which are based on the principles of CBT, also feasible and viable for patients with schizophrenia? Methods: Mental health professionals (target N=50) as well as individuals with schizophrenia spectrum disorders (target N=50) reported their opinion regarding potential chances and risks of Internet-based self-help for schizophrenia in an online survey. Results: The preliminary data analysis of n=30 health professionals revealed a general acceptance of Internet-based programs for schizophrenia (53% acceptable, 47% acceptable after empirical evaluation) and specific contraindications (e.g., severe psychotic symptoms; 73%). People with schizophrenia highlighted the attractiveness of self-help interventions due to a wish for empowerment and for opportunities to strengthen self-efficacy. Conclusions: Risks, limitations and chances of Internet-based programs for patients with schizophrenia will be discussed.
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The ordinal logistic regression models are used to analyze the dependant variable with multiple outcomes that can be ranked, but have been underutilized. In this study, we describe four logistic regression models for analyzing the ordinal response variable. ^ In this methodological study, the four regression models are proposed. The first model uses the multinomial logistic model. The second is adjacent-category logit model. The third is the proportional odds model and the fourth model is the continuation-ratio model. We illustrate and compare the fit of these models using data from the survey designed by the University of Texas, School of Public Health research project PCCaSO (Promoting Colon Cancer Screening in people 50 and Over), to study the patient’s confidence in the completion colorectal cancer screening (CRCS). ^ The purpose of this study is two fold: first, to provide a synthesized review of models for analyzing data with ordinal response, and second, to evaluate their usefulness in epidemiological research, with particular emphasis on model formulation, interpretation of model coefficients, and their implications. Four ordinal logistic models that are used in this study include (1) Multinomial logistic model, (2) Adjacent-category logistic model [9], (3) Continuation-ratio logistic model [10], (4) Proportional logistic model [11]. We recommend that the analyst performs (1) goodness-of-fit tests, (2) sensitivity analysis by fitting and comparing different models.^
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Purpose. To examine the association between living in proximity to Toxics Release Inventory (TRI) facilities and the incidence of childhood cancer in the State of Texas. ^ Design. This is a secondary data analysis utilizing the publicly available Toxics release inventory (TRI), maintained by the U.S. Environmental protection agency that lists the facilities that release any of the 650 TRI chemicals. Total childhood cancer cases and childhood cancer rate (age 0-14 years) by county, for the years 1995-2003 were used from the Texas cancer registry, available at the Texas department of State Health Services website. Setting: This study was limited to the children population of the State of Texas. ^ Method. Analysis was done using Stata version 9 and SPSS version 15.0. Satscan was used for geographical spatial clustering of childhood cancer cases based on county centroids using the Poisson clustering algorithm which adjusts for population density. Pictorial maps were created using MapInfo professional version 8.0. ^ Results. One hundred and twenty five counties had no TRI facilities in their region, while 129 facilities had at least one TRI facility. An increasing trend for number of facilities and total disposal was observed except for the highest category based on cancer rate quartiles. Linear regression analysis using log transformation for number of facilities and total disposal in predicting cancer rates was computed, however both these variables were not found to be significant predictors. Seven significant geographical spatial clusters of counties for high childhood cancer rates (p<0.05) were indicated. Binomial logistic regression by categorizing the cancer rate in to two groups (<=150 and >150) indicated an odds ratio of 1.58 (CI 1.127, 2.222) for the natural log of number of facilities. ^ Conclusion. We have used a unique methodology by combining GIS and spatial clustering techniques with existing statistical approaches in examining the association between living in proximity to TRI facilities and the incidence of childhood cancer in the State of Texas. Although a concrete association was not indicated, further studies are required examining specific TRI chemicals. Use of this information can enable the researchers and public to identify potential concerns, gain a better understanding of potential risks, and work with industry and government to reduce toxic chemical use, disposal or other releases and the risks associated with them. TRI data, in conjunction with other information, can be used as a starting point in evaluating exposures and risks. ^
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It is estimated that 50% of all lung cancer patients continue to smoke after diagnosis. Many of these lung cancer patients who are current smokers often experience tremendous guilt and responsibility for their disease, and feel it might be too late for them to quit smoking. In addition, many oncologists may be heard to say that it is 'too late', 'it doesn't matter', 'it is too difficult', 'it is too stressful' for their patients to stop smoking, or they never identify the smoking status of the patient. Many oncologists feel unprepared to address smoking cessation as part of their clinical practice. In reality, physicians can have tremendous effects on motivating patients, particularly when patients are initially being diagnosed with cancer. More information is needed to convince patients to quit smoking and to encourage clinicians to assist patients with their smoking cessation. ^ In this current study, smoking status at time of lung cancer diagnosis was assessed to examine its impact on complications and survival, after exploring the reliability of smoking data that is self-reported. Logistic Regression was used to determine the risks of smoking prior to lung resection. In addition, survival analysis was performed to examine the impact of smoking on survival. ^ The reliability of how patients report their smoking status was high, but there was some discordance between current smokers and recent quitters. In addition, we found that cigarette pack-year history and duration of smoking cessation were directly related to the rate of a pulmonary complication. In regards to survival, we found that current smoking at time of lung cancer diagnosis was an independent predictor of early stage lung cancer. This evidence supports the idea that it is "never too late" for patients to quit smoking and health care providers should incorporate smoking status regularly into their clinical practice.^
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External beam radiation therapy is used to treat nearly half of the more than 200,000 new cases of prostate cancer diagnosed in the United States each year. During a radiation therapy treatment, healthy tissues in the path of the therapeutic beam are exposed to high doses. In addition, the whole body is exposed to a low-dose bath of unwanted scatter radiation from the pelvis and leakage radiation from the treatment unit. As a result, survivors of radiation therapy for prostate cancer face an elevated risk of developing a radiogenic second cancer. Recently, proton therapy has been shown to reduce the dose delivered by the therapeutic beam to normal tissues during treatment compared to intensity modulated x-ray therapy (IMXT, the current standard of care). However, the magnitude of stray radiation doses from proton therapy, and their impact on this incidence of radiogenic second cancers, was not known. ^ The risk of a radiogenic second cancer following proton therapy for prostate cancer relative to IMXT was determined for 3 patients of large, median, and small anatomical stature. Doses delivered to healthy tissues from the therapeutic beam were obtained from treatment planning system calculations. Stray doses from IMXT were taken from the literature, while stray doses from proton therapy were simulated using a Monte Carlo model of a passive scattering treatment unit and an anthropomorphic phantom. Baseline risk models were taken from the Biological Effects of Ionizing Radiation VII report. A sensitivity analysis was conducted to characterize the uncertainty of risk calculations to uncertainties in the risk model, the relative biological effectiveness (RBE) of neutrons for carcinogenesis, and inter-patient anatomical variations. ^ The risk projections revealed that proton therapy carries a lower risk for radiogenic second cancer incidence following prostate irradiation compared to IMXT. The sensitivity analysis revealed that the results of the risk analysis depended only weakly on uncertainties in the risk model and inter-patient variations. Second cancer risks were sensitive to changes in the RBE of neutrons. However, the findings of the study were qualitatively consistent for all patient sizes and risk models considered, and for all neutron RBE values less than 100. ^
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This retrospective cohort study examined the association between nativity status and very preterm birth, preterm birth, and small-for-gestational-age (SGA) among Asian subgroups using Texas birth certificate data with no personal identifiers. A total of 877,322 birth certificates of Asian and US-born white women with a singleton birth in Texas from 2001-2004 were analyzed. Birth certificate records of US-born white, Chinese, Japanese, Korean, Vietnamese, Filipino, and Asian Indian women with a singleton birth were included in the analysis. Logistic regressions models were used to explore and understand the differences of the effect of nativity status on birth outcomes in Asian subgroups with US-born whites as the reference group. Most of the Asian subgroups had a lower risk of preterm births compared with US born whites, with reductions in risk ranging from 19% to 49% and the lowest risk of preterm birth observed among foreign-born Chinese mothers. Only Filipino mothers had a higher risk of preterm birth compared to US-born whites. Overall, foreign-born Asians had lower risks for very preterm birth and preterm birth than US-born Asians and US-born whites. US-born Asians were at higher risk for preterm birth than US-born whites. For SGA, all Asian subgroups and Asian subgroups by nativity status were at higher risk of SGA than US-born whites. Asian Indians and Japanese were at highest risk for SGA infants with 2.5 to 3 times the risk of SGA present in US-born whites. Foreign-born Asian women were at higher risk for SGA than their US-born counterparts. This study showed that health disparities among Asian subgroups are hidden by classifying Asians into a single group. By examining Asian subgroups separately and looking at nativity status, the differences in risk of SGA and preterm birth can be revealed so prevention efforts can focus on high risk groups. ^
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Ordinal outcomes are frequently employed in diagnosis and clinical trials. Clinical trials of Alzheimer's disease (AD) treatments are a case in point using the status of mild, moderate or severe disease as outcome measures. As in many other outcome oriented studies, the disease status may be misclassified. This study estimates the extent of misclassification in an ordinal outcome such as disease status. Also, this study estimates the extent of misclassification of a predictor variable such as genotype status. An ordinal logistic regression model is commonly used to model the relationship between disease status, the effect of treatment, and other predictive factors. A simulation study was done. First, data based on a set of hypothetical parameters and hypothetical rates of misclassification was created. Next, the maximum likelihood method was employed to generate likelihood equations accounting for misclassification. The Nelder-Mead Simplex method was used to solve for the misclassification and model parameters. Finally, this method was applied to an AD dataset to detect the amount of misclassification present. The estimates of the ordinal regression model parameters were close to the hypothetical parameters. β1 was hypothesized at 0.50 and the mean estimate was 0.488, β2 was hypothesized at 0.04 and the mean of the estimates was 0.04. Although the estimates for the rates of misclassification of X1 were not as close as β1 and β2, they validate this method. X 1 0-1 misclassification was hypothesized as 2.98% and the mean of the simulated estimates was 1.54% and, in the best case, the misclassification of k from high to medium was hypothesized at 4.87% and had a sample mean of 3.62%. In the AD dataset, the estimate for the odds ratio of X 1 of having both copies of the APOE 4 allele changed from an estimate of 1.377 to an estimate 1.418, demonstrating that the estimates of the odds ratio changed when the analysis includes adjustment for misclassification. ^
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Asthma is the most common chronic disorder in childhood, affecting an estimated 6.2 million children under 18 years (1). The purpose of this study was to look at individual- and community-level characteristics simultaneously to examine and explain the factors that contribute to the use of emergency department services by children 18 years old or less and to determine if there was an association between air quality and ED visits in the same population, from 2005-2007 in Houston/Harris County. Data were collected from the Houston Safety Net Hospital Emergency Department Use Study and the 2000 US Census. Bivariate and multivariate logistic regression models and mixed effects models were used to analyze data that was collected during the study period.^ There were 704,902 ED visits made by children 18 and younger, who were living in Houston from January 1, 2005 to December 31, 2007. Of those, 19,098 had a primary discharge diagnosis of asthma. Asthma ED visits varied by season, with proportions of ED visits for asthma highest from September-December. African-American children were 2.6 (95% CI, 2.43-2.66) times more likely to have an ED visit for asthma compared to White children. Poverty, single parent headed households, and younger age all a greater likelihood of having gone to the ED for asthma treatment. Compared to Whites living in lightly-monitored pollution areas, African-Americans and Hispanics living in heavily monitored areas were 1.15 (95% CI, 1.04-1.28) times more likely to have an ED visit for asthma.^ Race and poverty seem to account for a large portion of the disparities in ED use found among children. This was true even after accounting for multiple individual- and community-level variables. These results suggest that racial disparities in asthma continue to pose risks for African American children, and they point to the need for additional research into potential explanations and remedies. Programs to reduce inappropriate ED use must be sensitive to an array of complex socioeconomic issues within minority and income populations. ^
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Acute kidney Injury (AKI) in hospitalized pediatric patients can be a significant event that can result in increased patient morbidity and mortality. The incidence of medication associated AKI is increasing in the pediatric population. Currently, there are no data to quantify the risks of developing AKI for various potentially nephrotoxic medications. The primary objective of this study was to determine the odds of nephrotoxic medication exposure in hospitalized pediatric patients with AKI as defined by the pediatric modified pRIFLE criteria. A retrospective case-control study was performed with patients that developed AKI, as defined by the pediatric pRIFLE criteria, as cases, and patients without AKI as controls that were matched by age category, gender, and disease state. Patients between 1 day and 18 years of age, admitted to a non-intensive care unit at Texas Children's Hospital for at least 3 days, and had at least 2 serum creatinine values drawn were included. Patient data was analyzed with Student's t test, Mann-Whitney U test, Chi square analysis, ANOVA, and conditional logistic regression. ^ Out of 1,660 patients identified for inclusion, 561 (33.8%) patients had AKI, and 357 cases were matched with 357 controls to become pairs. Of the cases, 441 were category 'R', 117 category 'I', 3 patients were category 'F', and no patient died. Cases with AKI were significantly younger than controls (p < 0.05). Significantly longer hospital length of stays, increased hospital costs, and exposure to more nephrotoxic medications for a longer period of time were characteristics of patients with AKI compared to patient without AKI. Patients with AKI had greater odds of exposure to one or more nephrotoxic medication than patients without AKI (OR 1.3, 95% CI 1.1–1.4, p < 0.05). Percent changes in estimated creatinine clearance (eCCl) from baseline were greatest with increased number of nephrotoxic medication exposures. ^ Exposure to potentially nephrotoxic medications may place pediatric patients at greater risk of acute kidney injury. Multiple nephrotoxic medication exposure may confer a greater risk of development of acute kidney injury, and result in increased hospital costs and patient morbidity. Due to the high percentage of patients that were exposed to potentially nephrotoxic medications, monitoring and medication selection strategies may need to be altered to prevent or minimize risk.^