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BACKGROUND: Deferrals due to low hemoglobin are time-consuming and costly for blood donors and donation services. Furthermore, accepting donations from those with low hemoglobin could represent a significant safety issue. One approach to reduce them is to use hemoglobin concentration alongside donor characteristics to inform personalized inter-donation intervals. STUDY DESIGN AND METHODS: We used data from 17,308 donors to inform a discrete event simulation model comparing personalized inter-donation intervals using "post-donation" testing (i.e., estimating current hemoglobin from that measured by a hematology analyzer at last donation) versus the current approach in England (i.e., pre-donation testing with fixed intervals of 12-weeks for men and 16-weeks for women). We reported the impact on total donations, low hemoglobin deferrals, inappropriate bleeds, and blood service costs. Personalized inter-donation intervals were defined using mixed-effects modeling to estimate hemoglobin trajectories and probability of crossing hemoglobin donation thresholds. RESULTS: The model had generally good internal validation, with predicted events similar to those observed. Over 1 year, a personalized strategy requiring ≥90% probability of being over the hemoglobin threshold, minimized adverse events (low hemoglobin deferrals and inappropriate bleeds) in both sexes and costs in women. Donations per adverse event improved from 3.4 (95% uncertainty interval 2.8, 3.7) under the current strategy to 14.8 (11.6, 19.2) in women, and from 7.1 (6.1, 8.5) to 26.9 (20.8, 42.6) in men. In comparison, a strategy incorporating early returns for those with high certainty of being over the threshold maximized total donations in both men and women, but was less favorable in terms of adverse events, with 8.4 donations per adverse event in women (7.0, 10,1) and 14.8 (12.1, 21.0) in men. DISCUSSION: Personalized inter-donation intervals using post-donation testing combined with modeling of hemoglobin trajectories can help reduce deferrals, inappropriate bleeds, and costs.
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Doação de Sangue , Hemoglobinas , Masculino , Humanos , Feminino , Hemoglobinas/análise , Inglaterra , Testes Hematológicos , Doadores de SangueRESUMO
OBJECTIVE: To investigate the hypothesis that risk factors in addition to an abnormal fetal heart rate pattern (aFHRp) are independently associated with adverse neonatal outcomes of labour. DESIGN: Observational prospective cohort study. SETTING: 17 UK maternity units. SAMPLE: 585 291 pregnancies between 1988 and 2000 inclusive. METHODS: Adjusted odds ratios (OR) with 95% confidence intervals (95% CI) were estimated from multivariable logistic regression. MAIN OUTCOME MEASURES: Adverse neonatal outcome at term (5-minute Apgar score <7, and a composite measure comprising 5-minute Apgar score <7, resuscitation by intubation and/or perinatal death). RESULTS: Analysis was based on 302 137 vaginal births at 37-42 weeks inclusive. We found a higher odds of Apgar score at 5 minutes <7 with suspected fetal growth restriction (OR 1.34, 95% CI 1.16-1.53), induction of labour (OR 1.41, 95% CI 1.25-1.58), nulliparity (OR 1.48, 95% CI 1.34-1.63), booking body mass index ≥30 (OR 1.18, 95% CI 1.02-1.37), maternal age <25 (OR 1.23, 95% CI 1.10-1.39), black ethnicity (OR 1.21, 95% CI 1.03-1.43), early-term birth at 37-38 weeks (OR 1.13, 95% CI 1.02-1.25), late-term birth at 41-42 weeks (OR 1.14, 95% CI 1.01-1.28), use of oxytocin (OR 1.27, 95% CI 1.14-1.41), maternal pyrexia (OR 1.87, 95% CI 1.46-2.40), aFHRp and presence of meconium (aFHRp without meconium: OR 2.40, 95% CI 2.15-2.69; meconium without aFHRp: OR 2.20, 195% CI.94-2.49; both aFHRp and meconium: OR 4.26, 95% CI 3.74-4.87). The results were similar when the composite adverse outcome was considered. CONCLUSIONS: A range of risk factors, including suspicion of fetal growth restriction, maternal pyrexia and presence of meconium, are implicated in poor birth outcomes in addition to aFHRp. Interpretation of the fetal heart rate pattern alone is insufficient as a basis for decisions about escalation and intervention.
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Cesárea , Retardo do Crescimento Fetal , Recém-Nascido , Gravidez , Feminino , Humanos , Estudos Retrospectivos , Estudos Prospectivos , Fatores de Risco , FebreRESUMO
BACKGROUND: EVAR for abdominal aortic aneurysm has an initial survival advantage over OR, but more frequent complications increase costs and long-term aneurysm-related mortality. Randomized controlled trials of EVAR versus OR have shown EVAR is not cost-effective over a patient's lifetime. However, in the EVAR-1 trial, postoperative surveillance may have been sub-optimal, as the importance of sac growth as a predictor of graft failure was overlooked. METHODS: Real-world data informed a discrete event simulation model of postoperative outcomes following EVAR. Outcomes observed EVAR-1 were compared with those from 5 alternative postoperative surveillance and re-intervention strategies. Key events, quality-adjusted life years and costs were predicted. The impact of using complication and rupture rates from more recent devices, imaging and re-intervention methods was also explored. RESULTS: Compared with observed EVAR-1 outcomes, modeling full adherence to the EVAR-1 scan protocol reduced abdominal aortic aneurysm (AAA) deaths by 3% and increased elective re-interventions by 44%. European Society re-intervention guidelines provided the most clinically effective strategy, with an 8% reduction in AAA deaths, but a 52% increase in elective re-interventions. The cheapest and most cost-effective strategy used lifetime annual ultrasound in primary care with confirmatory computed tomography if necessary, and reduced AAA-related deaths by 5%. Using contemporary rates for complications and rupture did not alter these conclusions. CONCLUSIONS: All alternative strategies improved clinical benefits compared with the EVAR-1 trial. Further work is needed regarding the cost and accuracy of primary care ultrasound, and the potential impact of these strategies in the comparison with OR.
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Aneurisma da Aorta Abdominal/cirurgia , Procedimentos Cirúrgicos Eletivos/economia , Procedimentos Endovasculares/economia , Procedimentos Endovasculares/métodos , Aneurisma da Aorta Abdominal/complicações , Ruptura Aórtica/etiologia , Simulação por Computador , Análise Custo-Benefício , Procedimentos Cirúrgicos Eletivos/efeitos adversos , Procedimentos Endovasculares/efeitos adversos , Custos Hospitalares , Humanos , Complicações Pós-Operatórias , Qualidade de Vida , ReoperaçãoRESUMO
The therapeutic benefit of self-monitoring blood pressure in stroke patients is uncertain. We investigated the effect of self-monitoring with or without guided antihypertensive management compared with usual care in patients with a recent cerebrovascular event. No between-group differences in blood pressure at outcome were found, but blood pressure self-monitoring and management was well tolerated.
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Anti-Hipertensivos/uso terapêutico , Monitorização Ambulatorial da Pressão Arterial/métodos , Pressão Sanguínea/fisiologia , Hipertensão/tratamento farmacológico , Ataque Isquêmico Transitório/fisiopatologia , Autogestão/métodos , Acidente Vascular Cerebral/fisiopatologia , Idoso , Feminino , Humanos , Hipertensão/fisiopatologia , Ataque Isquêmico Transitório/etiologia , Masculino , Pessoa de Meia-Idade , Ensaios Clínicos Controlados Aleatórios como Assunto , Acidente Vascular Cerebral/etiologiaRESUMO
Background: In the UK, primary care records are electronic and require doctors to ascribe disease codes to direct care plans and facilitate safe prescribing. We investigated factors associated with coding of chronic kidney disease (CKD) in patients with reduced kidney function and the impact this has on patient management. Methods: We identified patients meeting biochemical criteria for CKD (two estimated glomerular filtration rates <60 mL/min/1.73 m2 taken >90 days apart) from 1039 general practitioner (GP) practices in a UK audit. Clustered logistic regression was used to identify factors associated with coding for CKD and improvement in coding as a result of the audit process. We investigated the relationship between coding and five interventions recommended for CKD: achieving blood pressure targets, proteinuria testing, statin prescription and flu and pneumococcal vaccination. Results: Of 256 000 patients with biochemical CKD, 30% did not have a GP CKD code. Males, older patients, those with more severe CKD, diabetes or hypertension or those prescribed statins were more likely to have a CKD code. Among those with continued biochemical CKD following audit, these same characteristics increased the odds of improved coding. Patients without any kidney diagnosis were less likely to receive optimal care than those coded for CKD [e.g. odds ratio for meeting blood pressure target 0.78 (95% confidence interval 0.76-0.79)]. Conclusion: Older age, male sex, diabetes and hypertension are associated with coding for those with biochemical CKD. CKD coding is associated with receiving key primary care interventions recommended for CKD. Increased efforts to incentivize CKD coding may improve outcomes for CKD patients.
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Auditoria Clínica/métodos , Gerenciamento Clínico , Médicos de Atenção Primária , Atenção Primária à Saúde/métodos , Encaminhamento e Consulta , Insuficiência Renal Crônica/terapia , Idoso , Idoso de 80 Anos ou mais , Inglaterra/epidemiologia , Feminino , Taxa de Filtração Glomerular/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Insuficiência Renal Crônica/epidemiologia , Insuficiência Renal Crônica/fisiopatologia , Fatores de Risco , País de Gales/epidemiologiaRESUMO
Background: Early diagnosis of chronic kidney disease (CKD) facilitates best management in primary care. Testing coverage of those at risk and translation into subsequent diagnostic coding will impact on observed CKD prevalence. Using initial data from 915 general practitioner (GP) practices taking part in a UK national audit, we seek to apply appropriate methods to identify outlying practices in terms of CKD stages 3-5 prevalence and diagnostic coding. Methods: We estimate expected numbers of CKD stages 3-5 cases in each practice, adjusted for key practice characteristics, and further inflate the control limits to account for overdispersion related to unobserved factors (including unobserved risk factors for CKD, and between-practice differences in coding and testing). Results: GP practice prevalence of coded CKD stages 3-5 ranges from 0.04 to 7.8%. Practices differ considerably in coding of CKD in individuals where CKD is indicated following testing (ranging from 0 to 97% of those with and glomerular filtration rate <60 mL/min/1.73 m 2 ). After adjusting for risk factors and overdispersion, the number of 'extreme' practices is reduced from 29 to 2.6% for the low-coded CKD prevalence outcome, from 21 to 1% for high-uncoded CKD stage and from 22 to 2.4% for low total (coded and uncoded) CKD prevalence. Thirty-one practices are identified as outliers for at least one of these outcomes. These can then be categorized into practices needing to address testing, coding or data storage/transfer issues. Conclusions: GP practice prevalence of coded CKD shows wide variation. Accounting for overdispersion is crucial in providing useful information about outlying practices for CKD prevalence.
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Insuficiência Renal Crônica/diagnóstico , Adulto , Diagnóstico Precoce , Feminino , Taxa de Filtração Glomerular , Humanos , Masculino , Distribuição Normal , Prevalência , Atenção Primária à Saúde , Insuficiência Renal Crônica/epidemiologia , Insuficiência Renal Crônica/fisiopatologia , Fatores de RiscoRESUMO
Combining information from multiple GWASs for a disease and its risk factors has proven a powerful approach for development of polygenic risk scores (PRSs). This may be particularly useful for type 2 diabetes (T2D), a highly polygenic and heterogeneous disease where the additional predictive value of a PRS is unclear. Here, we use a meta-scoring approach to develop a metaPRS for T2D that incorporated genome-wide associations from both European and non-European genetic ancestries and T2D risk factors. We evaluated the performance of this metaPRS and benchmarked it against existing genome-wide PRS in 620,059 participants and 50,572 T2D cases amongst six diverse genetic ancestries from UK Biobank, INTERVAL, the All of Us Research Program, and the Singapore Multi-Ethnic Cohort. We show that our metaPRS was the most powerful PRS for predicting T2D in European population-based cohorts and had comparable performance to the top ancestry-specific PRS, highlighting its transferability. In UK Biobank, we show the metaPRS had stronger predictive power for 10-year risk than all individual risk factors apart from BMI and biomarkers of dysglycemia. The metaPRS modestly improved T2D risk stratification of QDiabetes risk scores for 10-year risk prediction, particularly when prioritising individuals for blood tests of dysglycemia. Overall, we present a highly predictive and transferrable PRS for T2D and demonstrate that the potential for PRS to incrementally improve T2D risk prediction when incorporated into UK guideline-recommended screening and risk prediction with a clinical risk score.
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Parsing of sound sources in the auditory environment or 'auditory scene analysis' is a computationally demanding cognitive operation that is likely to be vulnerable to the neurodegenerative process in Alzheimer's disease. However, little information is available concerning auditory scene analysis in Alzheimer's disease. Here we undertook a detailed neuropsychological and neuroanatomical characterization of auditory scene analysis in a cohort of 21 patients with clinically typical Alzheimer's disease versus age-matched healthy control subjects. We designed a novel auditory dual stream paradigm based on synthetic sound sequences to assess two key generic operations in auditory scene analysis (object segregation and grouping) in relation to simpler auditory perceptual, task and general neuropsychological factors. In order to assess neuroanatomical associations of performance on auditory scene analysis tasks, structural brain magnetic resonance imaging data from the patient cohort were analysed using voxel-based morphometry. Compared with healthy controls, patients with Alzheimer's disease had impairments of auditory scene analysis, and segregation and grouping operations were comparably affected. Auditory scene analysis impairments in Alzheimer's disease were not wholly attributable to simple auditory perceptual or task factors; however, the between-group difference relative to healthy controls was attenuated after accounting for non-verbal (visuospatial) working memory capacity. These findings demonstrate that clinically typical Alzheimer's disease is associated with a generic deficit of auditory scene analysis. Neuroanatomical associations of auditory scene analysis performance were identified in posterior cortical areas including the posterior superior temporal lobes and posterior cingulate. This work suggests a basis for understanding a class of clinical symptoms in Alzheimer's disease and for delineating cognitive mechanisms that mediate auditory scene analysis both in health and in neurodegenerative disease.
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Doença de Alzheimer/fisiopatologia , Percepção Auditiva/fisiologia , Encéfalo/fisiopatologia , Estimulação Acústica , Idoso , Doença de Alzheimer/psicologia , Sinais (Psicologia) , Feminino , Humanos , Masculino , Memória de Curto Prazo/fisiologia , Pessoa de Meia-Idade , Testes NeuropsicológicosRESUMO
BACKGROUND: many chronic conditions have their roots in modifiable health-related behaviours. METHODS: a total of 4,286 women aged 60-79 in the British Women's Heart and Health Study are followed up for incident cardiovascular disease (CVD), arthritis and locomotor disability over 7 years. Self-reported smoking, alcohol consumption, exercise and fruit intake at baseline is also available. Associations between these and each outcome, plus a composite outcome, are investigated in those without prevalent disease at baseline using logistic regression with multiple imputation. RESULTS: ex-smokers and current smokers showed increased odds of locomotor disability, CVD and the combined outcome. Less regular exercisers had increased odds of all outcomes, particularly locomotor disability. There was no evidence that alcohol or fruit intake was associated with any outcome. Population attributable fractions (PAFs) suggest in addition to the influence of smoking and alcohol, exercise accounts for 9% of incident locomotor disability, 5% of CVD and 4% of arthritis. All four lifestyle factors combined account for 17% of incident locomotor disability and 9% of incident conditions combined. CONCLUSIONS: never smokers and regular exercisers had substantially reduced odds of 7-year disability onset. Low PAFs suggest changes in health-related behaviours in older women would result in only modest reductions in common chronic conditions.
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Envelhecimento , Artrite/epidemiologia , Doenças Cardiovasculares/epidemiologia , Comportamento de Escolha , Comportamentos Relacionados com a Saúde , Estilo de Vida , Atividade Motora , Fatores Etários , Idoso , Consumo de Bebidas Alcoólicas , Artrite/prevenção & controle , Doenças Cardiovasculares/prevenção & controle , Deambulação com Auxílio , Dieta , Avaliação da Deficiência , Exercício Físico , Feminino , Frutas , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Incidência , Modelos Lineares , Modelos Logísticos , Pessoa de Meia-Idade , Limitação da Mobilidade , Razão de Chances , Estudos Prospectivos , Fatores de Risco , Comportamento de Redução do Risco , Fatores Sexuais , Fumar/efeitos adversos , Fumar/epidemiologia , Abandono do Hábito de Fumar , Prevenção do Hábito de Fumar , Fatores de Tempo , Reino Unido/epidemiologiaRESUMO
OBJECTIVE: To provide quantitative evidence for systematically prioritising individuals for full formal cardiovascular disease (CVD) risk assessment using primary care records with a novel tool (eHEART) with age- and sex- specific risk thresholds. METHODS AND ANALYSIS: eHEART was derived using landmark Cox models for incident CVD with repeated measures of conventional CVD risk predictors in 1,642,498 individuals from the Clinical Practice Research Datalink. Using 119,137 individuals from UK Biobank, we modelled the implications of initiating guideline-recommended statin therapy using eHEART with age- and sex-specific prioritisation thresholds corresponding to 5% false negative rates to prioritise adults aged 40-69 years in a population in England for invitation to a formal CVD risk assessment. RESULTS: Formal CVD risk assessment on all adults would identify 76% and 49% of future CVD events amongst men and women respectively, and 93 (95% CI: 90, 95) men and 279 (95% CI: 259, 297) women would need to be screened (NNS) to prevent one CVD event. In contrast, if eHEART was first used to prioritise individuals for formal CVD risk assessment, we would identify 73% and 47% of future events amongst men and women respectively, and a NNS of 75 (95% CI: 72, 77) men and 162 (95% CI: 150, 172) women. Replacing the age- and sex-specific prioritisation thresholds with a 10% threshold identify around 10% less events. CONCLUSIONS: The use of prioritisation tools with age- and sex-specific thresholds could lead to more efficient CVD assessment programmes with only small reductions in effectiveness at preventing new CVD events.
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Doenças Cardiovasculares , Adulto , Masculino , Humanos , Feminino , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/prevenção & controle , Inglaterra/epidemiologia , Medição de Risco , Atenção Primária à Saúde , Fatores de RiscoRESUMO
Background The aim of this study was to provide quantitative evidence of the use of polygenic risk scores for systematically identifying individuals for invitation for full formal cardiovascular disease (CVD) risk assessment. Methods and Results A total of 108 685 participants aged 40 to 69 years, with measured biomarkers, linked primary care records, and genetic data in UK Biobank were used for model derivation and population health modeling. Prioritization tools using age, polygenic risk scores for coronary artery disease and stroke, and conventional risk factors for CVD available within longitudinal primary care records were derived using sex-specific Cox models. We modeled the implications of initiating guideline-recommended statin therapy after prioritizing individuals for invitation to a formal CVD risk assessment. If primary care records were used to prioritize individuals for formal risk assessment using age- and sex-specific thresholds corresponding to 5% false-negative rates, then the numbers of men and women needed to be screened to prevent 1 CVD event are 149 and 280, respectively. In contrast, adding polygenic risk scores to both prioritization and formal assessments, and selecting thresholds to capture the same number of events, resulted in a number needed to screen of 116 for men and 180 for women. Conclusions Using both polygenic risk scores and primary care records to prioritize individuals at highest risk of a CVD event for a formal CVD risk assessment can efficiently prioritize those who need interventions the most than using primary care records alone. This could lead to better allocation of resources by reducing the number of risk assessments in primary care while still preventing the same number of CVD events.
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Doenças Cardiovasculares , Doença da Artéria Coronariana , Acidente Vascular Cerebral , Masculino , Humanos , Feminino , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/genética , Fatores de Risco , Doença da Artéria Coronariana/complicações , Medição de Risco/métodos , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/genética , Acidente Vascular Cerebral/prevenção & controleRESUMO
Cost-effectiveness analysis is usually based on life-years gained estimated from all-cause mortality. When an intervention affects only a few causes of death accounting for a small fraction of all deaths, this approach may lack precision. We develop a novel technique for cost-effectiveness analysis when life-years gained are estimated from cause-specific mortality, allowing for competing causes of death. In the context of randomised trial data, we adjust for other-cause mortality combined across randomised groups. This method yields a greater precision than analysis based on total mortality, and we show application to life-years gained, quality-adjusted life-years gained, incremental costs, and cost effectiveness. In multi-state health economic models, however, mortality from competing causes is commonly derived from national statistics and is assumed to be known and equal across intervention groups. In such models, our method based on cause-specific mortality and standard methods using total mortality give essentially identical estimates and precision. The methods are applied to a randomised trial and a health economic model, both of screening for abdominal aortic aneurysm. A gain in precision for cost-effectiveness estimates is clearly helpful for decision making, but it is important to ensure that 'cause-specific mortality' is defined to include all causes of death potentially affected by the intervention.
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Aneurisma da Aorta Abdominal/diagnóstico , Programas de Rastreamento/economia , Anos de Vida Ajustados por Qualidade de Vida , Aneurisma da Aorta Abdominal/economia , Aneurisma da Aorta Abdominal/mortalidade , Aneurisma da Aorta Abdominal/cirurgia , Causas de Morte , Análise Custo-Benefício , Humanos , Estimativa de Kaplan-Meier , Cadeias de Markov , Modelos Econômicos , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
BACKGROUND: The National Health Service (NHS) abdominal aortic aneurysm (AAA) screening programme (NAAASP) in England screens 65-year-old men. The programme monitors those with an aneurysm, and early intervention for large aneurysms reduces ruptures and AAA-related mortality. AAA screening services have been disrupted following COVID-19 but it is not known how this may impact AAA-related mortality, or where efforts should be focussed as services resume. METHODS: We repurposed a previously validated discrete event simulation model to investigate the impact of COVID-19-related service disruption on key outcomes. This model was used to explore the impact of delayed invitation and reduced attendance in men invited to screening. Additionally, we investigated the impact of temporarily suspending scans, increasing the threshold for elective surgery to 7cm and increasing drop-out in the AAA cohort under surveillance, using data from NAAASP to inform the population. FINDINGS: Delaying invitation to primary screening up to two years had little impact on key outcomes whereas a 10% reduction in attendance could lead to a 2% lifetime increase in AAA-related deaths. In surveillance patients, a 1-year suspension of surveillance or increase in the elective threshold resulted in a 0.4% increase in excess AAA-related deaths (8% in those 5-5.4cm at the start). Longer suspensions or a doubling of drop-out from surveillance would have a pronounced impact on outcomes. INTERPRETATION: Efforts should be directed towards encouraging men to attend AAA screening service appointments post-COVID-19. Those with AAAs on surveillance should be prioritised as the screening programme resumes, as changes to these services beyond one year are likely to have a larger impact on surgical burden and AAA-related mortality.
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Aneurisma da Aorta Abdominal/diagnóstico , Ruptura Aórtica/prevenção & controle , COVID-19/prevenção & controle , Programas de Rastreamento/estatística & dados numéricos , Modelos Estatísticos , Fatores Etários , Idoso , Aneurisma da Aorta Abdominal/complicações , Aneurisma da Aorta Abdominal/mortalidade , Aneurisma da Aorta Abdominal/cirurgia , Ruptura Aórtica/etiologia , Ruptura Aórtica/mortalidade , COVID-19/epidemiologia , COVID-19/transmissão , Controle de Doenças Transmissíveis/normas , Simulação por Computador , Efeitos Psicossociais da Doença , Procedimentos Cirúrgicos Eletivos/normas , Procedimentos Cirúrgicos Eletivos/estatística & dados numéricos , Inglaterra/epidemiologia , Política de Saúde , Humanos , Masculino , Programas de Rastreamento/organização & administração , Programas de Rastreamento/normas , Pandemias/prevenção & controle , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Medição de Risco/estatística & dados numéricos , Fatores de Risco , Índice de Gravidade de Doença , Medicina Estatal/normas , Medicina Estatal/estatística & dados numéricos , Tempo para o Tratamento , Ultrassonografia/normas , Ultrassonografia/estatística & dados numéricosRESUMO
Alzheimer's disease (AD) and semantic dementia (SD) are characterized by different patterns of global and temporal lobe atrophy which can be studied using magnetic resonance imaging (MRI). Manual delineation of regions of interest is time-consuming. FreeSurfer is a freely available automated technique which has a facility to label cortical and subcortical brain regions automatically. As with all automated techniques comparison with existing methods is important. Eight temporal lobe structures in each hemisphere were delineated using FreeSurfer and compared with manual segmentations in 10 control, 10 AD, and 10 SD subjects. The reproducibility errors for the manual segmentations ranged from 3% to 6%. Differences in protocols between the two methods led to differences in absolute volumes with the greatest differences between methods found bilaterally in the hippocampus, entorhinal cortex and fusiform gyrus (p<0.005). However, good correlations between the methods were found for most regions, with the highest correlations shown for the ventricles, whole brain and left medial-inferior temporal gyrus (r>0.9), followed by the bilateral amygdala and hippocampus, left superior temporal gyrus, right medial-inferior temporal gyrus and left temporal lobe (r>0.8). Overlap ratios differed between methods bilaterally in the amygdala, superior temporal gyrus, temporal lobe, left fusiform gyrus and right parahippocampal gyrus (p<0.01). Despite differences in protocol and volumes, both methods showed similar atrophy patterns in the patient groups compared with controls, and similar right-left differences, suggesting that both methods accurately distinguish between the three groups.
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Doença de Alzheimer/patologia , Encéfalo/patologia , Degeneração Lobar Frontotemporal/patologia , Interpretação de Imagem Assistida por Computador/métodos , Atrofia/patologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-IdadeRESUMO
OBJECTIVE: To assess the relationship between MRI-derived changes in whole-brain and ventricular volume with change in cognitive scores in Alzheimer's disease (AD), mild cognitive impairment (MCI) and control subjects. MATERIAL AND METHODS: In total 131 control, 231 MCI and 99 AD subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort with T1-weighted volumetric MRIs from baseline and 12-month follow-up were used to derive volume changes. Mini mental state examination (MMSE), Alzheimer's disease assessment scale (ADAS)-cog and trails test changes were calculated over the same period. RESULTS: Brain atrophy rates and ventricular enlargement differed between subject groups (p < 0.0005) and in MCI and AD were associated with MMSE changes. Both measures were additionally associated with ADAS-cog and trails-B in MCI patients, and ventricular expansion was associated with ADAS-cog in AD patients. Brain atrophy (p < 0.0005) and ventricular expansion rates (p = 0.001) were higher in MCI subjects who progressed to AD within 12 months of follow-up compared with MCI subjects who remained stable. MCI subjects who progressed to AD within 12 months had similar atrophy rates to AD subjects. CONCLUSION: Whole-brain atrophy rates and ventricular enlargement differed between patient groups and healthy controls, and tracked disease progression and psychological decline, demonstrating their relevance as biomarkers.
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Doença de Alzheimer/complicações , Doença de Alzheimer/patologia , Encéfalo/patologia , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/etiologia , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Idoso , Feminino , Humanos , Masculino , Tamanho do Órgão , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Health economic decision models are based on specific assumptions relating to model structure and parameter estimation. Validation of these models is recommended as an indicator of reliability, but is not commonly reported. Furthermore, models derived from different data and employing different assumptions may produce a variety of results.A Markov model for evaluating the long-term cost-effectiveness of screening for abdominal aortic aneurysm is described. Internal, prospective and external validations are carried out using individual participant data from two randomised trials. Validation is assessed in terms of total numbers and timings of key events, and total costs and life-years. Since the initial model validates well only internally, two further models are developed that better fit the prospective and external validation data. All three models are then extrapolated to a life-time horizon, producing cost-effectiveness estimates ranging from pound1600 to pound4200 per life-year gained.Parameter uncertainty is now commonly addressed in health economic decision modelling. However, the derivation of models from different data sources adds another level of uncertainty. This extra uncertainty should be recognised in practical decision-making and, where possible, specifically investigated through independent model validation.
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Técnicas de Apoio para a Decisão , Modelos Econométricos , Aneurisma da Aorta Abdominal/economia , Aneurisma da Aorta Abdominal/prevenção & controle , Análise Custo-Benefício , Humanos , Cadeias de Markov , Programas de Rastreamento/economia , Reprodutibilidade dos Testes , Fatores de Risco , Análise de Sobrevida , Fatores de Tempo , IncertezaRESUMO
BACKGROUND: Prevalence of cardiovascular disease (CVD) in women shows regional variations not explained by common risk factors. Analysis of CVD incidence will provide insight into whether there is further divergence between regions with increasing age. METHODS: Seven-year follow-up data on 2685 women aged 59-80 (mean 69) at baseline from 23 towns in the UK were available from the British Women's Heart and Health Study. Time to fatal or non-fatal CVD was analyzed using Cox regression with adjustment for risk factors, using multiple imputation for missing values. RESULTS: Compared to South England, CVD incidence is similar in North England (HR 1.05 (95% CI 0.84, 1.31)) and Scotland (0.93 (0.68, 1.27)), but lower in Midlands/Wales (0.85 (0.64, 1.12)). Event severity influenced regional variation, with South England showing lower fatal incident CVD than other regions, but higher non-fatal incident CVD. Kaplan-Meier plots suggested that regional divergence in CVD occurred before baseline (before mean baseline age of 69). CONCLUSIONS: In women, regional differences in CVD early in adult life do not further diverge in later life. This may be due to regional differences in early detection, survivorship of women entering the study, or event severity. Targeting health care resources for CVD by geographic variation may not be appropriate for older age-groups.
Assuntos
Doenças Cardiovasculares/epidemiologia , Geografia , Idoso , Idoso de 80 Anos ou mais , Doenças Cardiovasculares/mortalidade , Feminino , Inquéritos Epidemiológicos , Humanos , Estimativa de Kaplan-Meier , Pessoa de Meia-Idade , Prevalência , Modelos de Riscos Proporcionais , Fatores de Risco , Reino Unido/epidemiologia , Saúde da MulherRESUMO
BACKGROUND: Prevention of secondary stroke following initial ictus is an important focus of after-stroke care. Blood pressure (BP) is a key risk factor, so usual care following stroke or transient ischaemic attack includes regular BP checks and monitoring of anti-hypertensive medication. This is traditionally carried out in primary care, but the evidence supporting self-monitoring and self-guided management of BP in the general population with hypertension is growing. OBJECTIVE: Our objective was to estimate the cost effectiveness of treatment as usual (TAU) versus (1) self-monitoring of BP (S-MON) and (2) self-monitoring and guided self-management of anti-hypertensive medication (S-MAN). METHODS: This was a within-trial economic evaluation of a randomised controlled trial estimating the incremental cost per 1 mmHg BP reduction and per quality-adjusted life-year (QALY) gained over a 6-month time horizon from the perspective of the UK National Health Service (NHS). RESULTS: Data were evaluable for 140 participants. Costs per patient were £473, £853 and £1035; mean reduction in systolic BP (SBP) was 3.6, 6.7 and 6.1 mmHg, and QALYs accrued were 0.427, 0.422 and 0.423 for TAU, S-MON and S-MAN, respectively. No statistically significant differences in incremental costs or outcomes were detected. On average, S-MAN was dominated or extended dominated. The incremental cost per 1 mmHg BP reduction from S-MON versus TAU was £137. CONCLUSION: On average, S-MAN is an inefficient intervention. S-MON may be cost effective, depending on the willingness to pay for a 1 mmHg BP reduction, although it yielded fewer QALYs over the within-trial time horizon. Decision modelling is required to explore the longer-term costs and outcomes.
RESUMO
BACKGROUND: Longer-term mortality benefit and cost-effectiveness for abdominal aortic aneurysm (AAA) screening are uncertain. OBJECTIVE: To estimate the benefits, in terms of AAA-related and all-cause mortality, and cost-effectiveness of ultrasonography screening for AAA in a group that was invited to screening compared with a group that was not invited at a mean 7-year follow-up. DESIGN: Randomized trial. SETTING: 4 centers in the United Kingdom. PATIENTS: Population-based sample of 67,770 men age 65 to 74 years. INTERVENTION: Patients with an AAA detected at screening had surveillance and were offered surgery after predefined criteria were met. MEASUREMENTS: Mortality data were obtained after flagging on the national database. Unit costs obtained from large samples were applied to individual event data for the cost analysis. RESULTS: The hazard ratio was 0.53 (95% CI, 0.42 to 0.68) for AAA-related mortality in the group invited for screening. The rupture rate in men with normal results on initial ultrasonography has remained low: 0.54 rupture (CI, 0.25 to 1.02 ruptures) per 10 000 person-years. In terms of all-cause mortality, the observed hazard ratio was 0.96 (CI, 0.93 to 1.00). At the 7-year follow-up, cost-effectiveness was estimated at $19 500 (CI, $12,400 to $39,800) per life-year gained based on AAA-related mortality and $7600 (CI, $3300 to infinity) per life-year gained based on all-cause death. (All values are reported in U.S. dollars [U.K. 1 pound sterling = U.S. $1.58]). LIMITATION: Inclusion of deaths from aortic aneurysm at an unspecified site, which may include some thoracic aortic aneurysms, may have underestimated the treatment effect. CONCLUSIONS: These results from a large, pragmatic randomized trial show that the early mortality benefit of screening ultrasonography for AAA is maintained in the longer term and that the cost-effectiveness of screening improves over time. International Standard Randomized Controlled Trial registration number: ISRCTN37381646.
Assuntos
Aneurisma da Aorta Abdominal/mortalidade , Programas de Rastreamento/economia , Idoso , Aneurisma da Aorta Abdominal/diagnóstico por imagem , Aneurisma da Aorta Abdominal/cirurgia , Ruptura Aórtica/diagnóstico por imagem , Ruptura Aórtica/mortalidade , Ruptura Aórtica/cirurgia , Análise Custo-Benefício , Seguimentos , Humanos , Masculino , Ultrassonografia/economia , Estados Unidos/epidemiologiaRESUMO
BACKGROUND: The MRC Multicentre trial for Early Epilepsy and Single Seizures (MESS) showed a reduced risk of further seizures in patients, for whom treatment with antiepileptic drugs was uncertain, who were randomly assigned immediate treatment compared with delayed treatment. However, there was no evidence of an effect on [corrected] long-term remission rates. This study was undertaken to assess the role of patient characteristics and treatment in the prediction of seizure recurrence. This will enable decision-making on the basis of the perceived risk of treatment compared with the benefit of reducing the risk of further seizures in the initial years after diagnosis. METHODS: A prognostic model was developed based on individual patient data from MESS to enable identification of patients at low, medium, or high risk of seizure recurrence. A split-sample approach was used in which the model was developed on a subsample of the full data and validated on the remainder of the sample. Distinction of the prognostic groups and predictive accuracy of the model were assessed. FINDINGS: Number of seizures of all types at presentation, presence of a neurological disorder, and an abnormal electroencephalogram (EEG) were significant factors in indicating future seizures. Individuals with two or three seizures, a neurological disorder, or an abnormal EEG were identified as the medium-risk group, those with two of these features or more than three seizures as the high-risk group, and those with a single seizure only as the low-risk group. INTERPRETATION: The model shows that there is little benefit to immediate treatment in patients at low risk of seizure recurrence, but potentially worthwhile benefits are seen in those at medium and high risk.