Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Mais filtros

Bases de dados
Tipo de documento
Intervalo de ano de publicação
1.
Lancet Reg Health West Pac ; 45: 101020, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38380231

RESUMO

Background: Hospitals in China are classified into tiers (1, 2 or 3), with the largest (tier 3) having more equipment and specialist staff. Differential health insurance cost-sharing by hospital tier (lower deductibles and higher reimbursement rates in lower tiers) was introduced to reduce overcrowding in higher tier hospitals, promote use of lower tier hospitals, and limit escalating healthcare costs. However, little is known about the effects of differential cost-sharing in health insurance schemes on choice of hospital tiers. Methods: In a 9-year follow-up of a prospective study of 0.5 M adults from 10 areas in China, we examined the associations between differential health insurance cost-sharing and choice of hospital tiers for patients with a first hospitalisation for stroke or ischaemic heart disease (IHD) in 2009-2017. Analyses were performed separately in urban areas (stroke: n = 20,302; IHD: n = 19,283) and rural areas (stroke: n = 21,130; IHD: n = 17,890), using conditional logit models and adjusting for individual socioeconomic and health characteristics. Findings: About 64-68% of stroke and IHD cases in urban areas and 27-29% in rural areas chose tier 3 hospitals. In urban areas, higher reimbursement rates in each tier and lower tier 3 deductibles were associated with a greater likelihood of choosing their respective hospital tiers. In rural areas, the effects of cost-sharing were modest, suggesting a greater contribution of other factors. Higher socioeconomic status and greater disease severity were associated with a greater likelihood of seeking care in higher tier hospitals in urban and rural areas. Interpretation: Patient choice of hospital tiers for treatment of stroke and IHD in China was influenced by differential cost-sharing in urban areas, but not in rural areas. Further strategies are required to incentivise appropriate health seeking behaviour and promote more efficient hospital use. Funding: Wellcome Trust, Medical Research Council, British Heart Foundation, Cancer Research UK, Kadoorie Charitable Foundation, China Ministry of Science and Technology, and National Natural Science Foundation of China.

2.
Lancet Public Health ; 7(12): e1014-e1026, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36462513

RESUMO

BACKGROUND: Tobacco smoking is estimated to account for more than 1 million annual deaths in China, and the epidemic continues to increase in men. Large nationwide prospective studies linked to different health records can help to periodically assess disease burden attributed to smoking. We aimed to examine associations of smoking with incidence of and mortality from an extensive range of diseases in China. METHODS: We analysed data from the prospective China Kadoorie Biobank, which recruited 512 726 adults aged 30-79 years, of whom 210 201 were men and 302 525 were women. Participants who had no major disabilities were identified through local residential records in 100-150 administrative units, which were randomly selected by use of multistage cluster sampling, from each of the ten diverse study areas of China. They were invited and recruited between June 25, 2004, and July 15, 2008. Upon study entry, trained health workers administered a questionnaire assessing detailed smoking behaviours and other key characteristics (eg, sociodemographics, lifestyle, and medical history). Participants were followed up via electronic record linkages to death and disease registries and health insurance databases, from baseline to Jan 1, 2018. During a median 11-year follow-up (IQR 10-12), 285 542 (55·7%) participants were ever hospitalised, 48 869 (9·5%) died, and 5252 (1·0%) were lost to follow-up during the age-at-risk of 35-84 years. Cox regression yielded hazard ratios (HRs) associating smoking with disease incidence and mortality, adjusting for multiple testing. FINDINGS: At baseline, 74·3% of men and 3·2% of women (overall 32·4%) ever smoked regularly. During follow-up, 1 137 603 International Classification of Diseases, 10th revision (ICD-10)-coded incident events occurred, involving 476 distinct conditions and 85 causes of death, each with at least 100 cases. Compared with never-regular smokers, ever-regular smokers had significantly higher risks for nine of 18 ICD-10 chapters examined at age-at-risk of 35-84 years. For individual conditions, smokers had significantly higher risks of 56 diseases (50 for men and 24 for women) and 22 causes of death (17 for men and nine for women). Among men, ever-regular smokers had an HR of 1·09 (95% CI 1·08-1·11) for any disease incidence when compared with never-regular smokers, and significantly more episodes and longer duration of hospitalisation, particularly those due to cancer and respiratory diseases. For overall mortality, the HRs were greater in men from urban areas than in men from rural areas (1·50 [1·42-1·58] vs 1·25 [1·20-1·30]). Among men from urban areas who began smoking at younger than 18 years, the HRs were 2·06 (1·89-2·24) for overall mortality and 1·32 (1·27-1·37) for any disease incidence. In this population, 19·6% of male (24·3% of men residing in urban settings and 16·2% of men residing in rural settings) and 2·8% of female deaths were attributed to ever-regular smoking. INTERPRETATION: Among Chinese adults, smoking was associated with higher risks of morbidity and mortality from a wide range of diseases. Among men, the future smoking-attributed disease burden will increase further, highlighting a pressing need for reducing consumption through widespread cessation and uptake prevention. FUNDING: British Heart Foundation, Cancer Research UK, Chinese Ministry of Science and Technology, Kadoorie Charitable Foundation, UK Medical Research Council, National Natural Science Foundation of China, Wellcome Trust.


Assuntos
Fumar , Fumar Tabaco , Adulto , Feminino , Masculino , Humanos , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Estudos Prospectivos , China/epidemiologia , Efeitos Psicossociais da Doença
3.
Sci Rep ; 12(1): 1067, 2022 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-35058491

RESUMO

Missing values are a major issue in quantitative proteomics analysis. While many methods have been developed for imputing missing values in high-throughput proteomics data, a comparative assessment of imputation accuracy remains inconclusive, mainly because mechanisms contributing to true missing values are complex and existing evaluation methodologies are imperfect. Moreover, few studies have provided an outlook of future methodological development. We first re-evaluate the performance of eight representative methods targeting three typical missing mechanisms. These methods are compared on both simulated and masked missing values embedded within real proteomics datasets, and performance is evaluated using three quantitative measures. We then introduce fused regularization matrix factorization, a low-rank global matrix factorization framework, capable of integrating local similarity derived from additional data types. We also explore a biologically-inspired latent variable modeling strategy-convex analysis of mixtures-for missing value imputation and present preliminary experimental results. While some winners emerged from our comparative assessment, the evaluation is intrinsically imperfect because performance is evaluated indirectly on artificial missing or masked values not authentic missing values. Nevertheless, we show that our fused regularization matrix factorization provides a novel incorporation of external and local information, and the exploratory implementation of convex analysis of mixtures presents a biologically plausible new approach.


Assuntos
Interpretação Estatística de Dados , Proteômica/estatística & dados numéricos , Algoritmos , Proteômica/métodos
4.
Lancet Glob Health ; 8(4): e591-e602, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32199125

RESUMO

BACKGROUND: China initiated major health-care reforms in 2009 aiming to provide universal health care for all by 2020. However, little is known about trends in health-care use and health outcomes across different socioeconomic groups in the past decade. METHODS: We used data from the China Kadoorie Biobank (CKB), a nationwide prospective cohort study of adults aged 30-79 years in 2004-08, in ten regions (five urban, five rural) in China. Individuals who were alive in 2009 were included in the present study. Data for all admissions were obtained by linkage to electronic hospital records from the health insurance system, and to region-specific disease and death registers. Generalised linear models were used to estimate trends in annual hospital admission rates, 28-day case fatality rates, and mean length of stay for stroke, ischaemic heart disease, and any cause in all relevant individuals. FINDINGS: 512 715 participants were recruited to the CKB between June 25, 2004, and July 15, 2008, 505 995 of whom were still alive on Jan 1, 2009, and contributed to the present study. Among them, we recorded 794 824 hospital admissions (74 313 for stroke, 69 446 for ischaemic heart disease) between 2009 and 2016. After adjustment for demographic, socioeconomic, lifestyle, and morbidity factors, hospitalisation rates increased annually by 3·6% for stroke, 5·4% for ischaemic heart disease, and 4·2% for any cause, between 2009 and 2016. Higher socioeconomic groups had higher hospitalisation rates, but the annual proportional increases were higher in those with lower education or income levels, those enrolled in the urban or rural resident health insurance scheme, and for those in rural areas. Lower socioeconomic groups had higher case fatality rates for stroke and ischaemic heart disease, but greater reductions in case fatality rates than higher socioeconomic groups. By contrast, mean length of stay decreased by around 2% annually for stroke, ischaemic heart disease, and any cause, but decreased to a greater extent in higher than lower socioeconomic groups for stroke and ischaemic heart disease. INTERPRETATION: Between 2009 and 2016, lower socioeconomic groups in China had greater increases in hospital admission rates and greater reductions in case fatality rates for stroke and ischaemic heart disease. Additional strategies are needed to further reduce socioeconomic differences in health-care use and disease outcomes. FUNDING: Wellcome Trust, Medical Research Council, British Heart Foundation, Cancer Research UK, Kadoorie Charitable Foundation, China Ministry of Science and Technology, and Chinese National Natural Science Foundation.


Assuntos
Disparidades nos Níveis de Saúde , Isquemia Miocárdica/terapia , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Acidente Vascular Cerebral/terapia , Adulto , Idoso , China , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores Socioeconômicos , Resultado do Tratamento
5.
JAMA Netw Open ; 2(5): e194873, 2019 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-31150080

RESUMO

Importance: A better understanding of the role of atherosclerosis in the development of ischemic stroke subtypes could help to improve strategies for prevention of stroke worldwide. Objective: To assess the role of carotid atherosclerosis in the association between major cardiovascular risk factors and ischemic stroke subtypes. Design, Setting, and Participants: The prospective China Kadoorie Biobank cohort study was conducted in the general population of 5 urban and 5 rural areas in China, with a baseline survey obtained between June 2004 and July 2008. A random sample of 23 973 participants with no history of cardiovascular disease at enrollment who had carotid artery ultrasonographic measurements recorded at a resurvey from September 2013 to June 2014 were included. Data analysis was performed from July 1, 2016, to April 10, 2019. Exposures: Major cardiovascular risk factors (ie, blood pressure [BP], blood lipid levels, smoking, and diabetes). Main Outcomes and Measures: Carotid ultrasonographic measures of plaque burden (derived from number and maximum size of carotid artery plaques at resurvey) and first ischemic stroke during follow-up (n = 952), with subtyping (data release, August 2018) as lacunar (n = 263), probable large artery (n = 193), probable cardioembolic (n = 66), or unconfirmed (n = 430). Associations between cardiovascular risk factors, carotid plaque burden, and ischemic stroke subtypes were adjusted for age, sex, and geographic area. Results: The 23 973 participants in the study had a mean (SD) age of 50.6 (10.0) years, and 14 833 (61.9%) were women. Systolic BP had a stronger association (odds ratio [OR] per SD, 1.51; 95% CI, 1.42-1.61) than plaque burden (OR per SD, 1.34; 95% CI, 1.26-1.44) with ischemic stroke, and the associations of systolic BP with each subtype of ischemic stroke were modestly attenuated by adjustment for plaque burden. After adjustment for BP, plaque burden had a stronger association with probable large artery stroke (OR, 1.43; 95% CI, 1.24-1.63) than with lacunar stroke (OR, 1.25; 95% CI, 1.10-1.43) but was not associated with probable cardioembolic stroke (OR, 1.06; 95% CI, 0.83-1.36). Conclusions and Relevance: Although BP was an important risk factor for all ischemic stroke subtypes, carotid atherosclerosis was an important risk factor only for large artery and lacunar strokes, suggesting that drug treatments targeting atherosclerosis may reduce the risk of stroke subtypes to different extents.


Assuntos
Pressão Sanguínea/fisiologia , Doenças das Artérias Carótidas/patologia , Estenose das Carótidas/patologia , Acidente Vascular Cerebral/etiologia , Adulto , Doenças das Artérias Carótidas/diagnóstico por imagem , Doenças das Artérias Carótidas/epidemiologia , Estenose das Carótidas/diagnóstico por imagem , Estudos de Casos e Controles , Comorbidade , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Acidente Vascular Cerebral/classificação , Acidente Vascular Cerebral/epidemiologia , Ultrassonografia
6.
JAMA Netw Open ; 2(3): e190223, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30821829

RESUMO

Importance: Acquisition of reliable randomized clinical trial evidence of the effects of cardiovascular interventions on cognitive decline is a priority. Objectives: To estimate the association of cognitive aging with the avoidance of vascular events in cardiovascular intervention trials and understand whether reports of nonsignificant results exclude worthwhile benefit. Design, Setting, and Participants: This secondary analysis of 3 randomized clinical trials in participants with preexisting occlusive vascular disease or diabetes included survivors to final in-trial follow-up in the Heart Protection Study (HPS), Study of the Effectiveness of Additional Reductions in Cholesterol and Homocysteine (SEARCH), and Treatment of HDL (High-Density Lipoprotein) to Reduce the Incidence of Vascular Events (HPS2-THRIVE) trials of lipid modification for prevention of cardiovascular events. Data were collected from February 1994 through January 2013 and analyzed from January 2015 through December 2018. Exposures: Incident vascular events and diabetes and statin therapy. Main Outcomes and Measures: Cognitive function was assessed at the end of a mean (SD) of 4.9 (1.5) years of follow-up using a 14-item verbal test. Associations of the incidence of vascular events and new-onset diabetes during the trials, with cognitive function at final in-trial follow-up were estimated and expressed as years of cognitive aging (using the association of the score with age >60 years). The benefit on cognitive aging mediated through the effects of lowering low-density lipoprotein cholesterol levels on events was estimated by applying these findings to nonfatal event differences observed with statin therapy in the HPS trial. Results: Among 45 029 participants undergoing cognitive assessment, mean (SD) age was 67.9 (8.0) years; 80.7% were men. Incident stroke (n = 1197) was associated with 7.1 (95% CI, 5.7-8.5) years of cognitive aging; incident transient ischemic attack, myocardial infarction, heart failure, and new-onset diabetes were associated with 1 to 2 years of cognitive aging. In HPS, randomization to statin therapy for 5 years resulted in 2.0% of survivors avoiding a nonfatal stroke or transient ischemic attack and 2.4% avoiding a nonfatal cardiac event, which yielded an expected reduction in cognitive aging of 0.15 (95% CI, 0.11-0.19) years. With 15 926 participants undergoing cognitive assessment, HPS had 80% power to detect a 1-year (ie, 20% during the 5 years) difference in cognitive aging. Conclusions and Relevance: The expected cognitive benefits of the effects of preventive therapies on cardiovascular events during even the largest randomized clinical trials may have been too small to be detectable. Hence, nonsignificant findings may not provide good evidence of a lack of worthwhile benefit on cognitive function with prolonged use of such therapies. Trial Registration: isrctn.com and ClinicalTrials.gov Identifiers: ISRCTN48489393, ISRCTN74348595, and NCT00461630.


Assuntos
Cognição/efeitos dos fármacos , Envelhecimento Cognitivo , Diabetes Mellitus/epidemiologia , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Infarto do Miocárdio/prevenção & controle , Acidente Vascular Cerebral/prevenção & controle , Idoso , Feminino , Avaliação Geriátrica/métodos , Humanos , Incidência , Testes de Inteligência , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Doenças Vasculares/complicações , Doenças Vasculares/epidemiologia
7.
Age Ageing ; 48(2): 247-253, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30624572

RESUMO

AIMS AND OBJECTIVES: to examine the hypothesis that obesity is protective for dementia, we compared the associations of death from dementia with body weight and body mass index (BMI) in both middle and old age. DESIGN: height and weight were measured in a prospective study of 19,019 middle-aged men in the Whitehall study in 1967-70 and in 6,158 surviving participants at resurvey in 1997. Cox regression was used to examine the associations of death from dementia over a 40-year period with weight or BMI measured by health professionals in middle and old age adjusting for age, smoking habits, employment grade and marital status. SETTING: central government employees in London, UK. MAIN OUTCOMES MEASURE: death due to dementia in 320 participants. RESULTS: body weight measured in middle age was weakly inversely associated with death from dementia (hazard ratio 0.98 [95%CI: 0.97-0.99] per kg), but neither height nor BMI were related to risk of dementia. In contrast, body weight in old age was more strongly inversely related to deaths from dementia (0.96; [0.95-0.98] per kg) as was BMI (0.92 [0.86-0.97] per kg/m2). Weight loss over the 30 years between baseline and resurvey was associated with a higher risk of death from dementia, with an adjusted HR per kg/30 years of 1.04 [95%CI: 1.02-1.08] and the association with loss of BMI was even stronger (adjusted HR of 1.10 [1.03-1.19]) per kg/m2 decrease. CONCLUSIONS: the stronger inverse associations of deaths from dementia with BMI in old age, compared with middle age, together with strong positive associations of loss of BMI or body weight between middle and old age casts doubt on previous suggestions that obesity protects against death from dementia.


Assuntos
Adiposidade , Demência/mortalidade , Fatores Etários , Idoso , Estatura , Índice de Massa Corporal , Peso Corporal , Demência/etiologia , Emprego/economia , Emprego/estatística & dados numéricos , Humanos , Londres/epidemiologia , Masculino , Estado Civil , Pessoa de Meia-Idade , Obesidade/complicações , Modelos de Riscos Proporcionais , Estudos Prospectivos , Fatores de Risco , Fumar/efeitos adversos , Fumar/epidemiologia
8.
Age Ageing ; 47(5): 714-720, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29796607

RESUMO

Objective: to examine the associations of cardiovascular disease (CVD) and cardiovascular risk factors with frailty. Design: a cross-sectional study. Setting: the Irish Longitudinal Study on Ageing (TILDA). Participants: frailty measures were obtained on 5,618 participants and a subset of 4,330 participants with no prior history of CVD. Exposures for observational study: cardiovascular risk factors were combined in three composite CVD risk scores (Systematic Coronary Risk Evaluation [SCORE], Ideal Cardiovascular Health [ICH] and Cardiovascular Health Metrics [CHM]). Main outcome measures: a frailty index (40-items) was used to screen for frailty. Methods: the associations of CVD risk factors with frailty were examined using logistic regression. Results: overall, 16.4% of participants had frailty (7.6% at 50-59 years to 42.5% at 80+ years), and the prevalence was higher in those with versus those without prior CVD (43.0% vs. 10.7%). Among those without prior CVD, mean levels of CVD risk factors were closely correlated with higher frailty index scores. Combined CVD risk factors, assessed using SCORE, were linearly and positively associated with frailty. Compared to low-to-moderate SCOREs, the odds ratio (OR) (95% confidence interval, CI) of frailty for those with very high risk was 3.18 (2.38-4.25). Conversely, ICH was linearly and inversely associated with frailty, with an OR for optimal health of 0.29 (0.21-0.40) compared with inadequate health. Conclusions: the concordant positive associations of SCORE and inverse associations of ICH and CHM with frailty highlight the potential importance of optimum levels of CVD risk factors for prevention of disability in frail older people.


Assuntos
Doenças Cardiovasculares/economia , Doenças Cardiovasculares/terapia , Prestação Integrada de Cuidados de Saúde , Idoso Fragilizado , Fragilidade/terapia , Medicina Geral , Atenção Primária à Saúde , Atividades Cotidianas , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/epidemiologia , Ensaios Clínicos Controlados como Assunto , Análise Custo-Benefício , Estudos Transversais , Prestação Integrada de Cuidados de Saúde/economia , Feminino , Fragilidade/diagnóstico , Fragilidade/economia , Fragilidade/epidemiologia , Medicina Geral/economia , Custos de Cuidados de Saúde , Humanos , Masculino , Países Baixos/epidemiologia , Atenção Primária à Saúde/economia , Prognóstico , Qualidade de Vida , Medição de Risco , Fatores de Risco , Comportamento Social
9.
Ann Med Surg (Lond) ; 23: 28-31, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29098077

RESUMO

BACKGROUND: There is increasing pressure on emergency services within the NHS requiring efficient, rapid assessment and management of patients. A subsequent reduction in hospital admissions reduces overall costs with an aim to improve quality of care. At the Royal Shrewsbury Hospital we run a one stop emergency surgical clinic. With strict criteria for admission to this clinic we have established a care pathway for those patients requiring urgent surgical review but not necessarily hospital admission. MATERIALS AND METHODS: We reviewed our initial referral pathway to the emergency surgical assessment clinic. New guidelines were distributed to the local Care Coordination Centre (CCC) through which GP referrals to the clinic were made. A re-audit carried out 6 weeks later assessed change in clinical practice. RESULTS: With the introduction of guidelines for referral we significantly increased the percentage of appropriate referrals to the one stop emergency surgical clinic (42.9%-79.4%, p = 0.000017). The majority (75.8%) of appropriate referrals can be successfully managed on an urgent outpatient basis. Appropriate referrals unsuitable for discharge from clinic had genuine reasons for admission such as abnormal results on assessment, or a need for surgery. 97.8% of referrals not deemed appropriate for the clinic were admitted for inpatient management. CONCLUSION: By providing suitable guidance for referring practitioners we have optimised our clinic use significantly and improved our acute ambulatory surgical care. We have reduced admissions, provided rapid treatment and have established a service that helps address the ever increasing demand on acute services within the NHS.

10.
Artigo em Inglês | MEDLINE | ID: mdl-27042034

RESUMO

BACKGROUND: COPD is the fourth leading cause of death worldwide, with particularly high rates in the People's Republic of China, even among never smokers. Large population-based cohort studies should allow for reliable assessment of the determinants of diseases, which is dependent on the quality of disease diagnoses. We assessed the validity of COPD diagnoses collected through electronic health records in the People's Republic of China. METHODS: The CKB study recruited 0.5 million adults aged 30-79 years from ten diverse regions in the People's Republic of China during the period 2004-2008. During 7 years of follow-up, 11,800 COPD cases were identified by linkage with mortality registries and the national health insurance system. We randomly selected ~10% of the reported COPD cases and then undertook an independent adjudication of retrieved hospital medical records in 1,069 cases. RESULTS: Overall, these 1,069 cases were accrued over a 9-year period (2004-2013) involving 153 hospitals across ten regions. A diagnosis of COPD was confirmed in 911 (85%) cases, corresponding to a positive predictive value of 85% (95% confidence interval [CI]: 83%-87%), even though spirometry testing was not widely used (14%) in routine hospital care. The positive predictive value for COPD did not vary significantly by hospital ranking or calendar period, but was higher in men than women (89% vs 79%), at age ≥70 years than in younger people (88%, 95% CI: 85%-91%), and when the cases were reported from both death registry and health insurance systems (97%, 95% CI: 94%-100%). Among the remaining cases, 87 (8.1%) had other respiratory diseases (chiefly pneumonia and asthma; n=85) and 71 (6.6%) cases showed no evidence of any respiratory disease on their clinical records. CONCLUSION: In the People's Republic of China, COPD diagnoses obtained from electronic health records are of good quality and suitable for large population-based studies and do not warrant systematic adjudication of all the reported cases.


Assuntos
Doença Pulmonar Obstrutiva Crônica/diagnóstico , Adulto , Idoso , China , Feminino , Humanos , Seguro Saúde , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes
11.
BMC Genomics ; 16 Suppl 7: S10, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26099273

RESUMO

BACKGROUND: Identification of protein interaction network is a very important step for understanding the molecular mechanisms in cancer. Several methods have been developed to integrate protein-protein interaction (PPI) data with gene expression data for network identification. However, they often fail to model the dependency between genes in the network, which makes many important genes, especially the upstream genes, unidentified. It is necessary to develop a method to improve the network identification performance by incorporating the dependency between genes. RESULTS: We proposed an approach for identifying protein interaction network by incorporating mutual information (MI) into a Markov random field (MRF) based framework to model the dependency between genes. MI is widely used in information theory to measure the uncertainty between random variables. Different from traditional Pearson correlation test, MI is capable of capturing both linear and non-linear relationship between random variables. Among all the existing MI estimators, we choose to use k-nearest neighbor MI (kNN-MI) estimator which is proved to have minimum bias. The estimated MI is integrated with an MRF framework to model the gene dependency in the context of network. The maximum a posterior (MAP) estimation is applied on the MRF-based model to estimate the network score. In order to reduce the computational complexity of finding the optimal network, a probabilistic searching algorithm is implemented. We further increase the robustness and reproducibility of the results by applying a non-parametric bootstrapping method to measure the confidence level of the identified genes. To evaluate the performance of the proposed method, we test the method on simulation data under different conditions. The experimental results show an improved accuracy in terms of subnetwork identification compared to existing methods. Furthermore, we applied our method onto real breast cancer patient data; the identified protein interaction network shows a close association with the recurrence of breast cancer, which is supported by functional annotation. We also show that the identified subnetworks can be used to predict the recurrence status of cancer patients by survival analysis. CONCLUSIONS: We have developed an integrated approach for protein interaction network identification, which combines Markov random field framework and mutual information to model the gene dependency in PPI network. Improvements in subnetwork identification have been demonstrated with simulation datasets compared to existing methods. We then apply our method onto breast cancer patient data to identify recurrence related subnetworks. The experiment results show that the identified genes are enriched in the pathway and functional categories relevant to progression and recurrence of breast cancer. Finally, the survival analysis based on identified subnetworks achieves a good result of classifying the recurrence status of cancer patients.


Assuntos
Biologia Computacional/métodos , Neoplasias/genética , Mapas de Interação de Proteínas , Algoritmos , Perfilação da Expressão Gênica/métodos , Redes Reguladoras de Genes , Humanos , Cadeias de Markov , Modelos Genéticos , Neoplasias/metabolismo , Mapeamento de Interação de Proteínas/métodos
12.
Bioinformatics ; 31(14): 2412-4, 2015 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-25755273

RESUMO

UNLABELLED: Identification of protein interaction subnetworks is an important step to help us understand complex molecular mechanisms in cancer. In this paper, we develop a BMRF-Net package, implemented in Java and C++, to identify protein interaction subnetworks based on a bagging Markov random field (BMRF) framework. By integrating gene expression data and protein-protein interaction data, this software tool can be used to identify biologically meaningful subnetworks. A user friendly graphic user interface is developed as a Cytoscape plugin for the BMRF-Net software to deal with the input/output interface. The detailed structure of the identified networks can be visualized in Cytoscape conveniently. The BMRF-Net package has been applied to breast cancer data to identify significant subnetworks related to breast cancer recurrence. AVAILABILITY AND IMPLEMENTATION: The BMRF-Net package is available at http://sourceforge.net/projects/bmrfcjava/. The package is tested under Ubuntu 12.04 (64-bit), Java 7, glibc 2.15 and Cytoscape 3.1.0.


Assuntos
Mapeamento de Interação de Proteínas/métodos , Software , Algoritmos , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Feminino , Expressão Gênica , Humanos , Cadeias de Markov
13.
Nucleic Acids Res ; 41(2): e42, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23161673

RESUMO

Identification of differentially expressed subnetworks from protein-protein interaction (PPI) networks has become increasingly important to our global understanding of the molecular mechanisms that drive cancer. Several methods have been proposed for PPI subnetwork identification, but the dependency among network member genes is not explicitly considered, leaving many important hub genes largely unidentified. We present a new method, based on a bagging Markov random field (BMRF) framework, to improve subnetwork identification for mechanistic studies of breast cancer. The method follows a maximum a posteriori principle to form a novel network score that explicitly considers pairwise gene interactions in PPI networks, and it searches for subnetworks with maximal network scores. To improve their robustness across data sets, a bagging scheme based on bootstrapping samples is implemented to statistically select high confidence subnetworks. We first compared the BMRF-based method with existing methods on simulation data to demonstrate its improved performance. We then applied our method to breast cancer data to identify PPI subnetworks associated with breast cancer progression and/or tamoxifen resistance. The experimental results show that not only an improved prediction performance can be achieved by the BMRF approach when tested on independent data sets, but biologically meaningful subnetworks can also be revealed that are relevant to breast cancer and tamoxifen resistance.


Assuntos
Neoplasias da Mama/metabolismo , Perfilação da Expressão Gênica/métodos , Mapeamento de Interação de Proteínas/métodos , Antineoplásicos Hormonais/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos , Feminino , Redes Reguladoras de Genes , Humanos , Cadeias de Markov , Mapas de Interação de Proteínas , Tamoxifeno/uso terapêutico
14.
Trustee ; 63(6): 26-8, 30-1, 1, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20632646

RESUMO

If your hospital approaches the zone of insolvency, it's time to try some innovative remedies.


Assuntos
Eficiência Organizacional/economia , Administração Financeira de Hospitais/métodos , Administração Financeira de Hospitais/normas , Estados Unidos
16.
Lancet Neurol ; 7(8): 683-9, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18614402

RESUMO

BACKGROUND: Observational epidemiological studies have shown a positive association between hypertension and risk of incident dementia; however, the effects of antihypertensive therapy on cognitive function in controlled trials have been conflicting, and meta-analyses of the trials have not provided clear evidence of whether antihypertensive treatment reduces dementia incidence. The Hypertension in the Very Elderly trial (HYVET) was designed to assess the risks and benefits of treatment of hypertension in elderly patients and included an assessment of cognitive function. METHODS: Patients with hypertension (systolic pressure 160-200 mm Hg; diastolic pressure <110 mm Hg) who were aged 80 years or older were enrolled in this double-blind, placebo-controlled trial. Participants were randomly assigned to receive 1.5 mg slow release indapamide, with the option of 2-4 mg perindopril, or placebo. The target systolic blood pressure was 150 mm Hg; the target diastolic blood pressure was 80 mm Hg. Participants had no clinical diagnosis of dementia at baseline, and cognitive function was assessed at baseline and annually with the mini-mental state examination (MMSE). Possible cases of incident dementia (a fall in the MMSE score to <24 points or a drop of three points in 1 year) were assessed by standard diagnostic criteria and expert review. The trial was stopped in 2007 at the second interim analysis after treatment resulted in a reduction in stroke and total mortality. Analysis was by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00122811. FINDINGS: 3336 HYVET participants had at least one follow-up assessment (mean 2.2 years) and were included: 1687 participants were randomly assigned to the treatment group and 1649 to the placebo group. Only five reports of adverse effects were attributed to the medication: three in the placebo group and two in the treatment group. The mean decrease in systolic blood pressure between the treatment and placebo groups at 2 years was systolic -15 mm Hg, p<0.0001; and diastolic -5.9 mm Hg, p<0.0001. There were 263 incident cases of dementia. The rates of incident dementia were 38 per 1000 patient-years in the placebo group and 33 per 1000 patient-years in the treatment group. There was no significant difference between treatment and placebo groups (hazard ratio [HR] 0.86, 95% CI 0.67-1.09); however, when these data were combined in a meta-analysis with other placebo-controlled trials of antihypertensive treatment, the combined risk ratio favoured treatment (HR 0.87, 0.76-1.00, p=0.045). INTERPRETATION: Antihypertensive treatment in elderly patients does not statistically reduce incidence of dementia. This negative finding might have been due to the short follow-up, owing to the early termination of the trial, or the modest effect of treatment. Nevertheless, the HYVET findings, when included in a meta-analysis, might support antihypertensive treatment to reduce incident dementia.


Assuntos
Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Demência/prevenção & controle , Avaliação Geriátrica , Indapamida/uso terapêutico , Perindopril/uso terapêutico , Idoso de 80 Anos ou mais , Cognição/efeitos dos fármacos , Demência/epidemiologia , Método Duplo-Cego , Feminino , Humanos , Hipertensão/tratamento farmacológico , Hipertensão/epidemiologia , Incidência , Estudos Longitudinais , Masculino , Entrevista Psiquiátrica Padronizada , Testes Neuropsicológicos
17.
Nat Genet ; 40(2): 161-9, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18193043

RESUMO

To identify genetic variants influencing plasma lipid concentrations, we first used genotype imputation and meta-analysis to combine three genome-wide scans totaling 8,816 individuals and comprising 6,068 individuals specific to our study (1,874 individuals from the FUSION study of type 2 diabetes and 4,184 individuals from the SardiNIA study of aging-associated variables) and 2,758 individuals from the Diabetes Genetics Initiative, reported in a companion study in this issue. We subsequently examined promising signals in 11,569 additional individuals. Overall, we identify strongly associated variants in eleven loci previously implicated in lipid metabolism (ABCA1, the APOA5-APOA4-APOC3-APOA1 and APOE-APOC clusters, APOB, CETP, GCKR, LDLR, LPL, LIPC, LIPG and PCSK9) and also in several newly identified loci (near MVK-MMAB and GALNT2, with variants primarily associated with high-density lipoprotein (HDL) cholesterol; near SORT1, with variants primarily associated with low-density lipoprotein (LDL) cholesterol; near TRIB1, MLXIPL and ANGPTL3, with variants primarily associated with triglycerides; and a locus encompassing several genes near NCAN, with variants strongly associated with both triglycerides and LDL cholesterol). Notably, the 11 independent variants associated with increased LDL cholesterol concentrations in our study also showed increased frequency in a sample of coronary artery disease cases versus controls.


Assuntos
HDL-Colesterol/genética , LDL-Colesterol/genética , Doença da Artéria Coronariana/genética , Lipídeos/genética , Triglicerídeos/genética , Alelos , Estudos de Casos e Controles , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Estudos de Coortes , Simulação por Computador , Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/patologia , Frequência do Gene , Variação Genética , Genoma Humano , Haplótipos , Humanos , Funções Verossimilhança , Lipídeos/sangue , Cadeias de Markov , Polimorfismo de Nucleotídeo Único , Probabilidade , Fatores de Risco , Triglicerídeos/sangue
18.
Breast Cancer Res ; 8(5): 214, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17076877

RESUMO

Gene expression profiling is a relatively new technology for the study of breast cancers, but within the past few years there has been a rapid rise in interest in its potential to improve the clinical management of breast cancer. This technology has contributed to our knowledge of the molecular pathology of breast tumours and shows promise as a tool to predict response to therapy and outcome, such as risk of metastasis. Microarray technology is continually developing and it is becoming apparent that, despite the various platforms available, robust conclusions can still be drawn that apply across the different array types. Gene expression profiling is beginning to appear in the breast cancer clinic but it is not yet fully evaluated. This review explores the questions that must be addressed before this technology can become an everyday clinical tool.


Assuntos
Neoplasias da Mama/genética , Perfilação da Expressão Gênica , Transferência de Tecnologia , Ensaios Clínicos como Assunto , Análise Custo-Benefício , Feminino , Perfilação da Expressão Gênica/economia , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , Prognóstico
19.
Biosecur Bioterror ; 3(4): 316-30, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16366841

RESUMO

Evidence in the disaster mental health literature indicates that psychosocial consequences of terrorism are a critical component of chemical, biological, radiological, and nuclear (CBRN) events, both at the clinical level and the normal behavioral and emotional levels. Planning for such psychosocial aspects should be an integral part of emergency preparedness. As Canada and other countries build the capacity to prevent, mitigate, and manage CBRN threats and events, it is important to recognize the range of social, psychological, emotional, spiritual, behavioral, and cognitive factors that may affect victims and their families, communities, children, the elderly, responders, decision makers, and others at all phases of terrorism, from threat to post-impact recovery. A structured process to assist CBRN emergency planners, decision makers, and responders in identifying psychosocial risks, vulnerable populations, resources, and interventions at various phases of a CBRN event to limit negative psychosocial impacts and promote resilience and adaptive responses is the essence of our psychosocial risk assessment and management (P-RAM) framework. This article presents the evidence base and conceptual underpinnings of the framework, the principles underlying its design, its key elements, and its use in the development of decision tools for responders, planners, decision makers, and the general public to better assess and manage psychosocial aspects of CBRN threats or attacks.


Assuntos
Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Medição de Risco/métodos , Terrorismo/psicologia , Canadá , Comunicação , Planejamento em Desastres/organização & administração , Humanos , Gestão de Riscos , Comportamento Social
20.
Int J Geriatr Psychiatry ; 18(4): 318-24, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12673608

RESUMO

BACKGROUND: Routine screening of high-risk elderly people for early cognitive impairment is constrained by the limitations of currently available cognitive function tests. The Telephone Interview of Cognitive Status is a novel instrument for assessment of cognitive function that can be administered in person or by telephone. OBJECTIVE: To evaluate the determinants and utility of TICS-M (13-item modified version) for assessment of cognitive function in healthy elderly people. METHODS: The utility of TICS-M was compared with more widely used MMSE and CAMCOG in a cross-sectional survey of 120 older (62 to 89 years) UK adults. RESULTS: The TICS-M cognitive test scores (27.97, SD 4.15) were normally distributed in contrast with those for MMSE and CAMCOG that had a negatively skewed distribution. TICS-M scores were inversely correlated with age (r = -0.21) and with the NART fullscale IQ (r = -0.35), but were independent of years of education in this cohort. TICS-M was highly correlated with MMSE (r = 0.57) and with CAMCOG (r = 0.62) scores. The time required to complete the test is comparable to MMSE and substantially less than CAMCOG. CONCLUSIONS: The normal distribution of TICS-M test scores suggest that this test is less constrained by the ceiling effect which limits the utility of MMSE and CAMCOG test scores in detecting early cognitive impairment. TICS-M is an appropriate instrument to assess cognitive function in both research and in clinical practice.


Assuntos
Transtornos Cognitivos/diagnóstico , Escalas de Graduação Psiquiátrica , Consulta Remota/métodos , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Demência/diagnóstico , Humanos , Entrevista Psicológica , Programas de Rastreamento/métodos , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Telefone
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA