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OBJECTIVE: To better understand drivers of disease progression in non-alcoholic steatohepatitis (NASH), we assessed clinical and sociodemographic markers of fibrosis progression in adults with NASH. PATIENTS AND METHODS: Physician-reported patient demographics and clinical characteristics were utilised from the real-world Global Assessment of the Impact of NASH (GAIN) study. Factors associated with likelihood of fibrosis progression since NASH diagnosis were identified using a logistic regression model. RESULTS: Overall, 2349 patients in Europe from the GAIN study were included; mean age was 54.6 years and 41% were women. Significant covariates included age, years since diagnosis, employment status, fibrosis stage at diagnosis, type 2 diabetes mellitus, hypertension, liver transplant and liver biopsy at diagnosis. Risk of progression was 1.16 (95% confidence interval 1.12-1.20; p<0.001) times higher for each additional year since NASH diagnosis and 5.43 (2.68-11.37; p<0.001) times higher when physicians proposed a liver transplant at diagnosis. Compared with full-time employed patients, risk of progression was 1.77 (1.19-2.60; p=0.004) times higher for unemployed patients and 3.16 (1.30-7.63; p=0.010) times higher for those unable to work due to NASH. CONCLUSIONS: Disease duration, NASH severity and presence of other metabolic comorbidities could help to assess risk of progression in patients with NASH.
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INTRODUCTION: Haemophilia has substantial SD effects on health-related quality of life (HRQoL), particularly for people with severe haemophilia. How certain aspects of haemophilia influence HRQoL is not well understood. AIM: To develop predictive models of variables influencing HRQoL in people with severe haemophilia A or B. METHODS: We used data from 514 participants with haemophilia A or B who provided EQ-5D-3L responses in the 2015 CHESS study. Treatment was categorized as always been on-demand (POD), previously on prophylaxis and moved to on-demand regimen (SOD), on prophylaxis from diagnosis (PX), and prophylaxis, previously on-demand (PXOD). Target joints were defined as 'locations of chronic synovitis' as reported by the treating physician. Regression models were evaluated to assess the impact of demographic and clinical covariates on HRQoL scores. RESULTS: Significant covariates were generally consistent across models, with number of target joints, number of hospital admissions, and any haemophilia treatment regimen other than PX all independently negatively impacting estimated EQ-5D score. Higher level of treatment adherence (high vs. low/medium) and use of a prophylaxis treatment regimen had positive effects on estimated EQ-5D scores. Target joints were associated with a 0.04 decrement in EQ-5D score, and high versus low/medium adherence was associated with a 0.06 increment. PXOD, POD, and SOD treatment regimens were associated with decrements in predicted scores of 0.07, 0.09, and 0.08, respectively, versus PX. CONCLUSION: This study provides a model to estimate the impact of haemophilia interventions on HRQoL, to help assess the relative impact on patient-centric outcomes for this lifelong condition.
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Hemofilia A , Sinovite , Hemofilia A/complicações , Hemofilia A/tratamento farmacológico , Humanos , Qualidade de Vida , Inquéritos e Questionários , Sinovite/complicaçõesRESUMO
INTRODUCTION: Few studies have examined the real-world impact of haemophilia on daily activities and work productivity in people with severe haemophilia A (PWSHA). AIM: To determine clinical attributes and treatment characteristics associated with impairment in daily activities and work among PWSHA using the patient-reported Work Productivity and Activity Impairment-General Health Questionnaire (WPAI-GH). METHODS: PWSHA were asked to complete the WPAI-GH as part of the Cost of Haemophilia in Europe: A Socioeconomic Survey (CHESS) study. Outcomes were determined for activity impairment (AI), absenteeism, presenteeism and overall work productivity loss (WPL). Descriptive statistics and regression analyses were used to evaluate the association between these outcomes and clinical and treatment attributes. RESULTS: Overall, 376 participants completed the AI element of WPAI-GH; 175 were employed and thus also reported on work impact. Mean ± standard deviation scores were as follows: AI = 34.2% ± 25.8%; absenteeism = 0.06% ±0.2%; presenteeism = 26.8% ± 22.4%; WPL = 28.6% ± 24.0%. Increased AI and WPL were associated with high haemophilia-related morbidity, measured both as chronic pain (p < .001 for both) and joint synovitis (AI: p <0.001; WPL: p = .017). In descriptive and multivariate analyses, lifelong prophylaxis was associated with reduced AI (p < .001 and p = .031, respectively); high therapy adherence was associated with reduced AI (p = .001 and p = .012, respectively) and with reduced WPL (p < .001 and p = .012, respectively). CONCLUSION: The WPAI-GH identified haemophilia-related morbidity and treatment characteristics, including therapy regimen and adherence, as key attributes impacting functional impairment and work contributions of PWSHA. Early prophylactic intervention and greater adherence to therapy may lead to lower AI and WPL in PWSHA.
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Hemofilia A , Absenteísmo , Eficiência , Hemofilia A/complicações , Humanos , Presenteísmo , Qualidade de Vida , Inquéritos e QuestionáriosRESUMO
BACKGROUND: Ulcerative colitis (UC) is an inflammatory bowel disease with increasing prevalence worldwide. Current treatment strategies place considerable economic and humanistic burdens on patients. The aim of this study was to determine the socioeconomic burden of UC in adult patients in European countries in a real-world setting. METHODS: In this retrospective, cross-sectional and observational pan-European study, patients with moderate or severe UC were assigned to ARM 1 and patients who had moderate or severe UC but achieved mild or remission status 12 months before index date (or clinical consultation date), were assigned to ARM 2. Clinical and medical resource use data were collected via electronic case report forms, and data on non-medical and indirect costs, and health-related quality of life (HRQoL) were collected via patient and public involvement and engagement (PPIE) questionnaires. Per-patient annual total costs per ARM and per country were calculated using the collated resource use in the last 12 months (between the start of the documentation period and patient consultation or index date) and country specific unit costs. Quality of life was described by arm and by country. RESULTS: In the physician-reported eCRF population (n = 2966), the mean annual direct medical cost was 4065 in ARM 1 (n = 1835) and 2935 in ARM 2 (n = 1131). In the PPIE population (ARM 1, n = 1001; ARM 2, n = 647), mean annual direct cost was 4526 in ARM 1 and 3057 in ARM 2, mean annual direct non-medical cost was 1162 in ARM 1 and 1002 in ARM 2, mean annual indirect cost was 3098 in ARM 1 and 2309 ARM 2, and mean annual total cost was in 8787 in ARM 1 and 6368 in ARM 2. HRQoL scores showed moderate to high burden of UC in both groups. CONCLUSIONS: The cost and HRQoL burden were high in patients in both ARM 1 and ARM 2 indicating unmet needs in the UC active population.
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Colite Ulcerativa , Adulto , Colite Ulcerativa/epidemiologia , Colite Ulcerativa/terapia , Estudos Transversais , Europa (Continente) , Humanos , Qualidade de Vida , Estudos Retrospectivos , Fatores SocioeconômicosRESUMO
INTRODUCTION: The benefits of physical activity (PA) for people with haemophilia (PWH) may include improvements in joint, bone and muscle health. However, the factor VIII activity level required to avoid a bleeding episode associated with PA is unknown. AIM: To elicit the opinion of clinical experts on the minimum level and ideal factor VIII activity ('level') required to avoid a bleeding episode during participation in different types of PA for PWH. METHODS: Based on the 2017 National Hemophilia Foundation PA descriptions, clinical experts estimated a minimally acceptable and an ideal factor level at which a bleed could be avoided. The uncertainty around estimates was quantified using an approach to construct a probability distribution to represent expert opinion. RESULTS: Minimum and ideal factor level increased with higher risk PA, whether or not joint morbidity was present, as did the experts' uncertainty in their estimates (ie the range between lowest and highest estimates for minimum and ideal levels). Mean minimum levels ranged from 4% to 48% for low to high risk for people without joint morbidity, and from 7% to 47% for those with joint morbidity. For ideal factor levels, corresponding figures were 9%-52% and 12%-64%, respectively. CONCLUSION: To support a patient-centric outcome, expert opinion indicates that the clinical norm of 0.01 IU/mL (1%) trough level is insufficient. It is anticipated that introducing a more targeted approach to meet the needs of patients who are increasingly physically active will benefit patients further in addition to recent treatment advances.
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Exercício Físico/fisiologia , Hemartrose/prevenção & controle , Hemofilia A/terapia , Hemorragia/prevenção & controle , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Conferências de Consenso como Assunto , Fator VIII/análise , Hemartrose/diagnóstico , Hemartrose/etiologia , Hemofilia A/sangue , Hemofilia A/complicações , Hemorragia/etiologia , Humanos , Lactente , Artropatias/sangue , Artropatias/diagnóstico , Artropatias/patologia , Pessoa de Meia-Idade , Medição de Risco , Adulto JovemRESUMO
Leptospira interrogans is the etiological agent of leptospirosis, a globally distributed zoonotic disease. Human infection usually occurs through skin exposure with water and soil contaminated with the urine of chronically infected animals. In this study, we aimed to quantitatively characterize the survival of Leptospira interrogans serovar Copenhageni in environmental matrices. We constructed laboratory microcosms to simulate natural conditions and determined the persistence of DNA markers in soil, mud, spring water and sewage using a quantitative PCR (qPCR) and a propidium monoazide (PMA)-qPCR assay. We found that L. interrogans does not survive at high concentrations in the tested matrices. No net growth was detected in any of the experimental conditions and in all cases the concentration of the DNA markers targeted decreased from the beginning of the experiment following an exponential decay with a decreasing decay rate over time. After 12 and 21 days of incubation the spiked concentration of 106L. interrogans cells/ml or g decreased to approximately 100 cells/ml or g in soil and spring water microcosms, respectively. Furthermore, culturable L. interrogans persisted at concentrations under the limit of detection by PMA-qPCR or qPCR for at least 16 days in soil and 28 days in spring water. Altogether, our findings suggest that the environment is not a multiplication reservoir but a temporary carrier of L. interrogans Copenhageni, although the observed prolonged persistence at low concentrations may still enable the transmission of the disease.IMPORTANCE Leptospirosis is a zoonotic disease caused by spirochetes of the genus Leptospira that primarily affects impoverished populations worldwide. Although leptospirosis is transmitted by contact with water and soil, little is known about the ability of the pathogen to survive in the environment. In this study, we quantitatively characterized the survival of L. interrogans in environmental microcosms and found that although it cannot multiply in water, soil or sewage, it survives for extended time periods (days to weeks depending on the matrix). The survival parameters obtained here may help to better understand the distribution of pathogenic Leptospira in the environment and improve the predictions of human infection risks in areas where such infections are endemic.
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Leptospira interrogans/crescimento & desenvolvimento , Leptospira interrogans/isolamento & purificação , Viabilidade Microbiana , Microbiologia do Solo , Microbiologia da Água , Animais , DNA Bacteriano/análise , Marcadores Genéticos , Humanos , Leptospira , Leptospira interrogans/genética , Leptospira interrogans/patogenicidade , Leptospirose/microbiologia , Leptospirose/transmissão , Reação em Cadeia da Polimerase em Tempo Real , Esgotos/microbiologia , Solo , Fatores de Tempo , Urina , Água , Doenças Transmitidas pela Água/microbiologia , Doenças Transmitidas pela Água/transmissão , ZoonosesRESUMO
Urban slums provide suitable conditions for infestation by rats, which harbour and shed a wide diversity of zoonotic pathogens including helminths. We aimed to identify risk factors associated with the probability and intensity of infection of helminths of the digestive tract in an urban slum population of Rattus norvegicus. Among 299 rats, eleven species/groups of helminths were identified, of which Strongyloides sp., Nippostrongylus brasiliensis and, the human pathogen, Angiostrongylus cantonensis were the most frequent (97, 41 and 39%, respectively). Sex interactions highlighted behavioural differences between males and females, as eg males were more likely to be infected with N. brasiliensis where rat signs were present, and males presented more intense infections of Strongyloides sp. Moreover, rats in poor body condition had higher intensities of N. brasiliensis. We describe a high global richness of parasites in R. norvegicus, including five species known to cause disease in humans. Among these, A. cantonensis was found in high prevalence and it was ubiquitous in the study area - knowledge which is of public health importance. A variety of environmental, demographic and body condition variables were associated with helminth species infection of rats, suggesting a comparable variety of risk factors for humans.
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Helmintíase Animal/epidemiologia , Áreas de Pobreza , Ratos/parasitologia , Doenças dos Roedores/epidemiologia , Zoonoses/epidemiologia , Angiostrongylus cantonensis/isolamento & purificação , Animais , Brasil/epidemiologia , Feminino , Helmintíase Animal/parasitologia , Helmintíase Animal/transmissão , Humanos , Masculino , Saúde Pública , Fatores de Risco , Doenças dos Roedores/parasitologia , Doenças dos Roedores/transmissão , Reforma Urbana , Zoonoses/parasitologia , Zoonoses/transmissãoRESUMO
BACKGROUND: The presence of synanthropic rodents, such as Rattus norvegicus, in urban environments generates high costs of prophylaxis and control, in large part due to the environmental transmission of the pathogenic spirochete Leptospira interrogans, which causes leptospirosis. In Salvador, Brazil, The Center for Control of Zoonosis (CCZ) is responsible for planning and implementing Rodent Control Programs (RCP) which are based on chemical rodenticide. However, these strategies have not been standardized for use in developing countries. AIM: This study aimed to identify the effect of a chemical control campaign on the demographic variables of urban R. norvegicus, analyzing relative abundance, sex structure, body mass, and age of the population, as well as the characterization of spatial distribution among households, rodent capture campaigns and interventions. METHODS: This study was carried out during 2015 in three valleys of an urban poor community in Salvador. Individuals of R. norvegicus were systematically captured before (Pre-intervention) and three months (1st post-intervention) and six months (2nd post-intervention) after a chemical control intervention conducted by the CCZ in two valleys of the study area while the third valley was not included in the intervention campaign and was used as a non-intervention reference. We used analysis of variance to determine if intervention affected demographic variables and chi-square to compare proportions of infested households (Rodent infestation index-PII). RESULTS: During the chemical intervention, 939 households were visited. In the pre-intervention campaign, an effort of 310 trap nights resulted in 43 rodents captured, and in the 1st and 2nd, post-intervention campaigns resulted in 47 rodents captured over 312 trap nights and 36 rodents captured over 324 traps-nights, respectively. The rodent infestation index (PII) points did not show a reduction between the period before the intervention and the two periods after the chemical intervention (70%, 72%, and 65%, respectively). Regarding relative abundances, there was no difference between valleys and period before and two periods after chemical intervention (trap success valley 1: 0,18; 0,19; 0,18 / Valley 3 0,15; 0,17; 0,13/ P>0,05). Other demographic results showed that there was no difference in demographic characteristics of the rodent population before and after the intervention, as well as there being no influence of the application of rodenticide on the areas of concentration of capture of rodents between the campaigns. CONCLUSION: Our study indicates that the chemical control was not effective in controlling the population of R. norvegicus and provides evidence of the need for re-evaluation of rodent control practices in urban poor community settings.
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Leptospira interrogans , Leptospirose , Doenças dos Roedores , Rodenticidas , Animais , Brasil/epidemiologia , Leptospirose/epidemiologia , Ratos , Doenças dos Roedores/epidemiologia , RoedoresRESUMO
ABSTRACT: One fifth of patients with nonalcoholic fatty liver disease (NAFLD) may progress to nonalcoholic steatohepatitis (NASH), which can increase the risk of cirrhosis, cancer, and death. To date, reported predictors of NASH progression have been heterogeneous.We identified determinants of fibrosis progression in patients with NASH in the United States using physician-reported data from the real-world Global Assessment of the Impact of NASH (GAIN) study, including demographics and clinical characteristics, NASH diagnostic information, fibrosis stage, comorbidities, and treatment. We developed a logistic regression model to assess the likelihood of fibrosis progression since diagnosis, controlling for sociodemographic and clinical variables. An iterative nested model selection approach using likelihood ratio test determined the final model.A total of 989 patients from the GAIN US cohort were included; 46% were women, 58% had biopsy-proven NAFLD, and 74% had fibrosis stage F0-F2 at diagnosis. The final multivariable model included age, years since diagnosis, sex, employment status, smoking status, obesity, fibrosis stage, diagnostic biopsy, Vitamin E, and liver transplant proposed at diagnosis. Odds of progression were 17% higher (odds ratio, 1.17 [95% CI: 1.11-1.23]; Pâ<â.001) with each year since NASH diagnosis, 41% lower (0.59 [0.38-0.90]; Pâ=â.016) for women than men, 131% higher (2.31 [1.30-4.03]; Pâ=â.004) for smokers versus non-smokers, and 89% higher (1.89 [1.26-2.86]; Pâ=â.002) with obesity. Odds of progression were also higher with part-time, retired, unemployed, and unable to work due to NASH status versus full-time employment, and when a liver transplant was proposed at diagnosis.Disease duration and severity, obesity, smoking, and lack of full-time employment were significant determinants of fibrosis progression. These findings can support clinical and health-policy decisions to improve NASH management in the US.
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Cirrose Hepática/patologia , Hepatopatia Gordurosa não Alcoólica/patologia , Determinantes Sociais da Saúde , Idoso , Biópsia , Progressão da Doença , Feminino , Fibrose , Humanos , Fígado/patologia , Cirrose Hepática/epidemiologia , Cirrose Hepática/etiologia , Masculino , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/complicações , Hepatopatia Gordurosa não Alcoólica/epidemiologia , Obesidade/complicações , Obesidade/epidemiologia , Estados Unidos/epidemiologiaRESUMO
BACKGROUND & AIMS: Non-alcoholic steatohepatitis (NASH) leads to cirrhosis and is associated with a substantial socioeconomic burden, which, coupled with rising prevalence, is a growing public health challenge. However, there are few real-world data available describing the impact of NASH. METHODS: The Global Assessment of the Impact of NASH (GAIN) study is a prevalence-based burden of illness study across Europe (France, Germany, Italy, Spain, and the UK) and the USA. Physicians provided demographic, clinical, and economic patient information via an online survey. In total, 3,754 patients found to have NASH on liver biopsy were stratified by fibrosis score and by biomarkers as either early or advanced fibrosis. Per-patient costs were estimated using national unit price data and extrapolated to the population level to calculate the economic burden. Of the patients, 767 (20%) provided information on indirect costs and health-related quality of life using the EuroQOL 5-D (EQ-5D; n = 749) and Chronic Liver Disease Questionnaire - Non-Alcoholic Fatty Liver Disease (CLDQ-NAFLD) (n = 723). RESULTS: Mean EQ-5D and CLDQ-NAFLD index scores were 0.75 and 4.9, respectively. For 2018, the mean total annual per patient cost of NASH was 2,763, 4,917, and 5,509 for direct medical, direct non-medical, and indirect costs, respectively. National per-patient cost was highest in the USA and lowest in France. Costs increased with fibrosis and decompensation, driven by hospitalisation and comorbidities. Indirect costs were driven by work loss. CONCLUSIONS: The GAIN study provides real-world data on the direct medical, direct non-medical, and indirect costs associated with NASH, including patient-reported outcomes in Europe and the USA, showing a substantial burden on health services and individuals. LAY SUMMARY: There has been little research into the socioeconomic burden associated with non-alcoholic steatohepatitis (NASH). The GAIN study provides real-world data on the direct medical, direct non-medical, and indirect costs associated with NASH, including patient-reported outcomes in five European countries (UK, France, Germany, Spain, and Italy) and the USA. Mean total annual per patient cost of NASH was estimated at 2,763, 4,917, and 5,509 for the direct medical, direct non-medical, and indirect cost categories, respectively.
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BRCA testing received much publicity following Angelina Jolie's editorial "My Medical Choice" in May 2013 and updated NICE clinical guidance (CG164) in June 2013. We assessed the effect of these two concurrent events on BRCA testing in one UK catchment area and relate this to socioeconomic deprivation. A database of 1393 patients who received BRCA testing was collated. This included individuals with breast/ovarian cancer, and those unaffected by cancer, where a relative has a ≥10% probability of carrying a BRCA variant which affects function. A segmented regression was conducted to estimate changes in testing. To examine the relative distribution of testing by deprivation, the deprivation status of patients who received testing was examined. Between April 2010 and March 2017, testing increased 11-fold and there was an 84% increase (P = 0.006) in BRCA1/2 testing in the month following both publications. In the pre-publication period, there was no statistically significant difference in testing between advantaged and disadvantaged areas (OR 1.21, 95% CI 0.99-1.48; P = 0.06). In the post-publication period helped by a larger sample size, the difference was statistically significant (OR 1.18, 95% CI 1.08-1.29; P = 0.0002) and of a similar magnitude to the pre-publication period. Testing increased following Jolie's editorial and NICE guidance update. However, further research is needed to examine differences in testing by the deprivation group which adjusts for confounders.
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Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Genes BRCA1 , Genes BRCA2 , Testes Genéticos/tendências , Neoplasias Ovarianas/epidemiologia , Neoplasias Ovarianas/genética , Neoplasias da Mama/diagnóstico , Estudos de Casos e Controles , Feminino , Testes Genéticos/métodos , Geografia , Mutação em Linhagem Germinativa , Humanos , Razão de Chances , Neoplasias Ovarianas/diagnóstico , Vigilância da População , Fatores Socioeconômicos , Reino Unido/epidemiologiaRESUMO
Objective To better understand drivers of disease progression in non-alcoholic steatohepatitis (NASH), we assessed clinical and sociodemographic markers of fibrosis progression in adults with NASH.Patients and methodsPhysician-reported patient demographics and clinical characteristics were utilised from the real-world Global Assessment of the Impact of NASH (GAIN) study. Factors associated with likelihood of fibrosis progression since NASH diagnosis were identified using a logistic regression model.ResultsOverall, 2349 patients in Europe from the GAIN study were included; mean age was 54.6 years and 41% were women. Significant covariates included age, years since diagnosis, employment status, fibrosis stage at diagnosis, type 2 diabetes mellitus, hypertension, liver transplant and liver biopsy at diagnosis. Risk of progression was 1.16 (95% confidence interval 1.121.20; p<0.001) times higher for each additional year since NASH diagnosis and 5.43 (2.6811.37; p<0.001) times higher when physicians proposed a liver transplant at diagnosis. Compared with full-time employed patients, risk of progression was 1.77 (1.192.60; p=0.004) times higher for unemployed patients and 3.16 (1.307.63; p=0.010) times higher for those unable to work due to NASH.ConclusionsDisease duration, NASH severity and presence of other metabolic comorbidities could help to assess risk of progression in patients with NASH. (AU)
Objetivo Para comprender mejor los factores que impulsan la progresión de la enfermedad en la esteatohepatitis no alcohólica (NASH), evaluamos los marcadores clínicos y sociodemográficos de la progresión de la fibrosis en adultos con NASH.Pacientes y métodosSe utilizaron las características demográficas y clínicas de los pacientes informadas por los médicos del estudio de Evaluación Global del Impacto de NASH (GAIN) del mundo real. Los factores asociados con la probabilidad de progresión de la fibrosis desde el diagnóstico de EHNA se identificaron mediante un modelo de regresión logística.ResultadosEn total, se incluyeron 2.349 pacientes en Europa del estudio GAIN; la edad media fue 54,6 años y el 41% eran mujeres. Las covariables significativas incluyeron edad, años desde el diagnóstico, situación laboral, estadio de fibrosis en el momento del diagnóstico, diabetes mellitus tipo 2, hipertensión, trasplante de hígado y biopsia de hígado en el momento del diagnóstico. El riesgo de progresión fue 1,16 (intervalo de confianza del 95% 1,12-1,20; p < 0,001) veces mayor por cada año adicional desde el diagnóstico de EHNA y 5,43 (2,68-11,37; p < 0,001) veces mayor cuando los médicos propusieron un trasplante de hígado. en el momento del diagnóstico. En comparación con los pacientes empleados a tiempo completo, el riesgo de progresión fue 1,77 (1,19-2,60; p = 0,004) veces mayor para los pacientes desempleados y 3,16 (1,30-7,63; p = 0,010) veces mayor para aquellos que no podían trabajar debido a a NASH.ConclusionesLa duración de la enfermedad, la gravedad de NASH y la presencia de otras comorbilidades metabólicas podrían ayudar a evaluar el riesgo de progresión en pacientes con NASH. (AU)
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Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/prevenção & controle , Hepatopatias/prevenção & controle , Cirrose Hepática/prevenção & controle , Cirrose Hepática/terapia , Biópsia , Fatores de RiscoRESUMO
The Norway rat (Rattus norvegicus) is a key pest species globally and responsible for seasonal outbreaks of the zoonotic bacterial disease leptospirosis in the tropics. The city of Salvador, Brazil, has seen recent and dramatic increases in human population residing in slums, where conditions foster high rat density and increasing leptospirosis infection rates. Intervention campaigns have been used to drastically reduce rat numbers. In planning these interventions, it is important to define the eradication units - the spatial scale at which rats constitute continuous populations and from where rats are likely recolonizing, post-intervention. To provide this information, we applied spatial genetic analyses to 706 rats collected across Salvador and genotyped at 16 microsatellite loci. We performed spatially explicit analyses and estimated migration levels to identify distinct genetic units and landscape features associated with genetic divergence at different spatial scales, ranging from valleys within a slum community to city-wide analyses. Clear genetic breaks exist between rats not only across Salvador but also between valleys of slums separated by <100 m-well within the dispersal capacity of rats. The genetic data indicate that valleys may be considered separate units and identified high-traffic roads as strong impediments to rat movement. Migration data suggest that most (71-90%) movement is contained within valleys, with no clear source population contributing to migrant rats. We use these data to recommend eradication units and discuss the importance of carrying out individual-based analyses at different spatial scales in urban landscapes.
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The Norway or brown rat (Rattus norvegicus) is among the most ubiquitous of rodents. However, the lack of studies describing Norway rat populations from tropical areas have limited our understanding regarding their demography and seasonal dynamics. In this study, we describe seasonal pattern in the abundance, reproductive parameters, and morphometrics of Norway rat populations in Salvador, Brazil. Rodents were trapped over four seasonal trapping periods (2013-2014) from three valleys. A total of 802 Norway rats were trapped over the course of the study over 7653 trap-nights. Norway rat abundance was high, but there was no significant differences between seasons. The reproductive parameters (e.g. frequency of pregnant and lactating females) did not show statistical differences between seasons. Female rats collected in the rainy season were heavier and older than females from the dry season. Salvador rats had a high incidence of pregnancy and birth rate (estimated birth rate of 79 young per year) compared to previous studies. The information generated is critical for the understanding of the ecology of Norway rat, the main reservoir of Leptospira in Salvador. However, future studies examining the effect of rodent control programs aimed at reducing populations, and determining rates of recovery, will further clarify our understanding of population dynamics.