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The genome sequence of the pied hoverfly, Scaeva pyrastri (Linnaeus, 1758). Wellcome Open Res 2023. [DOI: 10.12688/wellcomeopenres.18892.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
We present a genome assembly from an individual female Scaeva pyrastri (the pied hoverfly; Arthropoda; Insecta; Diptera; Syrphidae). The genome sequence is 320 megabases in span. Most of the assembly is scaffolded into four chromosomal pseudomolecules, including the assembled X chromosome. The mitochondrial genome has also been assembled and is 17.3 kilobases in length. Gene annotation of this assembly on Ensembl identified 11,352 protein coding genes.
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Regulation of cardiomyocyte adhesion and mechanosignalling through distinct nanoscale behaviour of integrin ligands mimicking healthy or fibrotic extracellular matrix. Philos Trans R Soc Lond B Biol Sci 2022; 377:20220021. [PMID: 36189804 PMCID: PMC9527911 DOI: 10.1098/rstb.2022.0021] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 04/12/2022] [Indexed: 12/21/2022] Open
Abstract
The stiffness of the cardiovascular environment changes during ageing and in disease and contributes to disease incidence and progression. Changing collagen expression and cross-linking regulate the rigidity of the cardiac extracellular matrix (ECM). Additionally, basal lamina glycoproteins, especially laminin and fibronectin regulate cardiomyocyte adhesion formation, mechanics and mechanosignalling. Laminin is abundant in the healthy heart, but fibronectin is increasingly expressed in the fibrotic heart. ECM receptors are co-regulated with the changing ECM. Owing to differences in integrin dynamics, clustering and downstream adhesion formation this is expected to ultimately influence cardiomyocyte mechanosignalling; however, details remain elusive. Here, we sought to investigate how different cardiomyocyte integrin/ligand combinations affect adhesion formation, traction forces and mechanosignalling, using a combination of uniformly coated surfaces with defined stiffness, polydimethylsiloxane nanopillars, micropatterning and specifically designed bionanoarrays for precise ligand presentation. Thereby we found that the adhesion nanoscale organization, signalling and traction force generation of neonatal rat cardiomyocytes (which express both laminin and fibronectin binding integrins) are strongly dependent on the integrin/ligand combination. Together our data indicate that the presence of fibronectin in combination with the enhanced stiffness in fibrotic areas will strongly impact on the cardiomyocyte behaviour and influence disease progression. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'.
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Left ventricular assessment with artificial intelligence increases the diagnostic accuracy of stress echocardiography. EUROPEAN HEART JOURNAL OPEN 2022; 2:oeac059. [PMID: 36284642 PMCID: PMC9580364 DOI: 10.1093/ehjopen/oeac059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 08/26/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
AIMS To evaluate whether left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS), automatically calculated by artificial intelligence (AI), increases the diagnostic performance of stress echocardiography (SE) for coronary artery disease (CAD) detection. METHODS AND RESULTS SEs from 512 participants who underwent a clinically indicated SE (with or without contrast) for the evaluation of CAD from seven hospitals in the UK and US were studied. Visual wall motion scoring (WMS) was performed to identify inducible ischaemia. In addition, SE images at rest and stress underwent AI contouring for automated calculation of AI-LVEF and AI-GLS (apical two and four chamber images only) with Ultromics EchoGo Core 1.0. Receiver operator characteristic curves and multivariable risk models were used to assess accuracy for identification of participants subsequently found to have CAD on angiography. Participants with significant CAD were more likely to have abnormal WMS, AI-LVEF, and AI-GLS values at rest and stress (all P < 0.001). The areas under the receiver operating characteristics for WMS index, AI-LVEF, and AI-GLS at peak stress were 0.92, 0.86, and 0.82, respectively, with cut-offs of 1.12, 64%, and -17.2%, respectively. Multivariable analysis demonstrated that addition of peak AI-LVEF or peak AI-GLS to WMS significantly improved model discrimination of CAD [C-statistic (bootstrapping 2.5th, 97.5th percentile)] from 0.78 (0.69-0.87) to 0.83 (0.74-0.91) or 0.84 (0.75-0.92), respectively. CONCLUSION AI calculation of LVEF and GLS by contouring of contrast-enhanced and unenhanced SEs at rest and stress is feasible and independently improves the identification of obstructive CAD beyond conventional WMSI.
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Automated analysis of limited echocardiograms: Feasibility and relationship to outcomes in COVID-19. Front Cardiovasc Med 2022; 9:937068. [PMID: 35935624 PMCID: PMC9353267 DOI: 10.3389/fcvm.2022.937068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 06/27/2022] [Indexed: 11/19/2022] Open
Abstract
Background As automated echocardiographic analysis is increasingly utilized, continued evaluation within hospital settings is important to further understand its potential value. The importance of cardiac involvement in patients hospitalized with COVID-19 provides an opportunity to evaluate the feasibility and clinical relevance of automated analysis applied to limited echocardiograms. Methods In this multisite US cohort, the feasibility of automated AI analysis was evaluated on 558 limited echocardiograms in patients hospitalized with COVID-19. Reliability of automated assessment of left ventricular (LV) volumes, ejection fraction (EF), and LV longitudinal strain (LS) was assessed against clinically obtained measures and echocardiographic findings. Automated measures were evaluated against patient outcomes using ROC analysis, survival modeling, and logistic regression for the outcomes of 30-day mortality and in-hospital sequelae. Results Feasibility of automated analysis for both LVEF and LS was 87.5% (488/558 patients). AI analysis was performed with biplane method in 300 (61.5%) and single plane apical 4- or 2-chamber analysis in 136 (27.9%) and 52 (10.7%) studies, respectively. Clinical LVEF was assessed using visual estimation in 192 (39.3%), biplane in 163 (33.4%), and single plane or linear methods in 104 (21.2%) of the 488 studies; 29 (5.9%) studies did not have clinically reported LVEF. LV LS was clinically reported in 80 (16.4%). Consistency between automated and clinical values demonstrated Pearson's R, root mean square error (RMSE) and intraclass correlation coefficient (ICC) of 0.61, 11.3% and 0.72, respectively, for LVEF; 0.73, 3.9% and 0.74, respectively for LS; 0.76, 24.4ml and 0.87, respectively, for end-diastolic volume; and 0.82, 12.8 ml, and 0.91, respectively, for end-systolic volume. Abnormal automated measures of LVEF and LS were associated with LV wall motion abnormalities, left atrial enlargement, and right ventricular dysfunction. Automated analysis was associated with outcomes, including survival. Conclusion Automated analysis was highly feasible on limited echocardiograms using abbreviated protocols, consistent with equivalent clinically obtained metrics, and associated with echocardiographic abnormalities and patient outcomes.
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The genome sequence of the plain-faced dronefly, Eristalis arbustorum (Linnaeus, 1758). Wellcome Open Res 2022; 7:61. [PMID: 38779419 PMCID: PMC11109569 DOI: 10.12688/wellcomeopenres.17580.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/11/2022] [Indexed: 05/25/2024] Open
Abstract
We present a genome assembly from an individual female Eristalis arbustorum (the plain-faced dronefly; Arthropoda; Insecta; Diptera; Syriphidae). The genome sequence is 451 megabases in span. The majority of the assembly (94.71%) is scaffolded into 6 chromosomal pseudomolecules, with the X sex chromosome assembled. The complete mitochondrial genome was also assembled and is 16.0 kilobases in length.
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The genome sequence of the dumpy grass hoverfly, Melanostoma mellinum (Linnaeus, 1758). Wellcome Open Res 2022; 7:59. [PMID: 36874577 PMCID: PMC9975431 DOI: 10.12688/wellcomeopenres.17615.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2022] [Indexed: 11/20/2022] Open
Abstract
We present a genome assembly from an individual male Melanostoma mellinum (the dumpy grass hoverfly; Arthropoda; Insecta; Diptera; Syriphidae). The genome sequence is 731 megabases in span. The majority of the assembly (99.67%) is scaffolded into five chromosomal pseudomolecules, with the X and Y sex chromosomes assembled. The complete mitochondrial genome was also assembled and is 16.1 kilobases in length.
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Automated contouring of non-contrast echocardiograms result in similar estimates of left ventricular function to manually contoured contrast-enhanced images in chemotherapy patients. Eur Heart J Cardiovasc Imaging 2022. [DOI: 10.1093/ehjci/jeab289.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: Private company. Main funding source(s): Ultromics Ltd
Introduction
Transthoracic echocardiography (TTE) assessment of left ventricular (LV) function has a central role in early detection and treatment of cancer-therapy related cardiac dysfunction (CTRCD). Contrast TTE is recommended to aid accurate and reproducible LV contouring , but contrast agents are underused and high variability remains. Using machine learning (ML) to automatically contour the LV reduces variability, and may provide comparable clinical benefit to contrast-enhanced TTE.
Purpose
Retrospective single site study evaluating agreement between LV volumes and function from manually contoured contrast-enhanced TTE and automated contouring of non-contrast enhanced images.
Methods
Adults at risk of developing CTRCD who underwent TTE were recruited. LV volumes (end-diastolic and systolic; EDV and ESV, respectively) and function (ejection fraction; EF) were measured from contrast-enhanced images using manual contouring (MAN-CONT), and non-contrast enhanced images using automation (AUTO-NON). Method comparisons were summarised based on: (i) statistical equivalence (two one-sided t-tests), (ii) systematic difference between methods, via root mean-squared error (RMSE; Deming regression), and (iii) average bias (Bland-Altman). Statistical equivalence bounds were conservatively determined from reproducibility estimates in a similar cohort (EDV, 20 mL; ESV, 15 mL; EF, 5%; REF1), and used to interpret RMSE and bias.
Results
The cohort comprised of patients undergoing treatment for breast cancer, lymphoma, and myeloma. Similar body mass indices were seen between groups (median [IQR]: 26.5 [6.7] kg/m2; Kruskall-Wallace test, p = 0.320), but breast cancer patients were younger (55.0 [14.5], 58.5 [23], 60 [9], respectively; p = 0.034). For estimates of LV volumes and function, statistical equivalence, RMSE, and bias are presented in Table1. Average estimates (mean [SD]) of EDV, ESV, and EF were 121 [33] vs. 112 [33] mL, 50 [23] vs. 44 [19] mL, and 60 [9] vs. 61 [8]%, for MAN-CON and AUTO-NON respectively. Comparing between MAN-CON and AUTO-NON in breast cancer patients, all variables were statistically equivalent (Figure1), and while bias was lower than equivalence bounds, RMSE was only lower for EDV and ESV, not EF. For lymphoma patients, estimates of EDV were statistically equivalent, but not EF and ESV. Bias was lower than equivalence bounds for all variables, whereas RMSE was lower for ESV, but not EDV or EF. For myeloma patients, estimates of ESV and EF were statistically equivalent, but not EDV. While bias was lower than equivalence bounds for all variables, RMSE was not lower for any variable. Conclusions: Estimates of LV function from automated contouring of non-contrast TTE are similar to contrast-enhanced TTE (manually contoured), despite poorer image quality. Automated contouring using ML reduces variability, therefore increasing TTE sensitivity, which is critical when clinical management relies on accurate assessment of LV function. Abstract Table1 Abstract Figure1
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Fully automated quantification of LV regional wall motion from echocardiograms to detect myocardial infarction. Eur Heart J Cardiovasc Imaging 2022. [DOI: 10.1093/ehjci/jeab289.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: Private company. Main funding source(s): Ultromics Ltd
Background
Myocardial wall motion analysis from echocardiography allows precise assessment of cardiac contractile function. Strain, which assesses myocardial deformation, has been shown to enable earlier detection of myocardial disease [1]. Current analysis software packages [2] use semi-automated methods to compute strain, which frequently require manual endocardial delineation and iterative contour adjustment based on tracking results, respectively, causing significant variability.
Purpose
We present a fully automated pipeline for tracking left ventricular (LV) wall motion to quantify global and segmental longitudinal strain from 2D echocardiograms, and go on to validate the pipeline with an openly available myocardial infarction (MI) dataset.
Methods
We applied our existing deep learning-based automated contouring method [3] to delineate the endocardial border in the A4C, A2C and A3C views and combined this with spline-based elastic image registration to track LV motion through time. We sampled points from a region of interest initiated from the endocardial border at the end-diastolic (ED) frame, and tracked subsequent motion by recomputing updated positions of all sample points based on each frame‘s displacement field, enabling us to both track the myocardium throughout the cardiac cycle and calculate longitudinal strain relative to the ED frame. The automated endocardial contour was used to regularise the process. The pipeline was independently tested on the HMC-QU dataset [4] which was downloaded from Kaggle and consists of a single cardiac cycle from the A4C view from 160 patients who were diagnosed with an acute MI and underwent echocardiography either prior to percutaneous coronary intervention or within 24 hours of undergoing the procedure; the dataset includes the labels of ED and end-systolic (ES) frames, as well as the presence of an MI in 6 segments excluding the apical cap (Fig 1a), as determined by the consensus of cardiologists from HMC Hospital in Qatar. The Wilcoxon signed-rank test was used to compare peak strain between the MI and non-MI segments; ROC curves were computed to compare the performance of the automatically derived peak longitudinal strain against the MI labels.
Results
Fig 1b shows ROC curves of peak segmental longitudinal strain for detecting MI, with the best performance in the mid-anterolateral segment (AUC 0.84), and a lower performance for basal segments than mid and apical segments, consistent with known variation in clinical practice [5]. Fig 2 shows that peak longitudinal strain computed from our pipeline was statistically significantly more positive in segments with an MI.
Conclusions
We present a fully automated pipeline for calculating segmental strain across a cardiac cycle to identify infarcted segments without any observer variability. Clinical application of this method has the potential to identify and monitor regional myocardial function and benefit patient management. Abstract Figure. Fig1. ROC of peak longitudinal strains Abstract Figure. Fig2.Boxplot of peak longitudinal strain
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The genome sequence of the tapered dronefly, Eristalis pertinax (Scopoli, 1763). Wellcome Open Res 2021; 6:292. [PMID: 36873714 PMCID: PMC9975435 DOI: 10.12688/wellcomeopenres.17267.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2021] [Indexed: 11/20/2022] Open
Abstract
We present a genome assembly from an individual male Eristalis pertinax (the tapered dronefly; Arthropoda; Insecta; Diptera; Syriphidae). The genome sequence is 487 megabases in span. The majority of the assembly (95.23%) is scaffolded into seven chromosomal pseudomolecules, with the X and Y sex chromosomes assembled. The complete mitochondrial genome was also assembled and is 17.2 kilobases in length.
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Automated Echocardiographic Detection of Severe Coronary Artery Disease Using Artificial Intelligence. JACC Cardiovasc Imaging 2021; 15:715-727. [PMID: 34922865 DOI: 10.1016/j.jcmg.2021.10.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 10/01/2021] [Accepted: 10/21/2021] [Indexed: 01/27/2023]
Abstract
OBJECTIVES The purpose of this study was to establish whether an artificially intelligent (AI) system can be developed to automate stress echocardiography analysis and support clinician interpretation. BACKGROUND Coronary artery disease is the leading global cause of mortality and morbidity and stress echocardiography remains one of the most commonly used diagnostic imaging tests. METHODS An automated image processing pipeline was developed to extract novel geometric and kinematic features from stress echocardiograms collected as part of a large, United Kingdom-based prospective, multicenter, multivendor study. An ensemble machine learning classifier was trained, using the extracted features, to identify patients with severe coronary artery disease on invasive coronary angiography. The model was tested in an independent U.S. STUDY How availability of an AI classification might impact clinical interpretation of stress echocardiograms was evaluated in a randomized crossover reader study. RESULTS Acceptable classification accuracy for identification of patients with severe coronary artery disease in the training data set was achieved on cross-fold validation based on 31 unique geometric and kinematic features, with a specificity of 92.7% and a sensitivity of 84.4%. This accuracy was maintained in the independent validation data set. The use of the AI classification tool by clinicians increased inter-reader agreement and confidence as well as sensitivity for detection of disease by 10% to achieve an area under the receiver-operating characteristic curve of 0.93. CONCLUSION Automated analysis of stress echocardiograms is possible using AI and provision of automated classifications to clinicians when reading stress echocardiograms could improve accuracy, inter-reader agreement, and reader confidence.
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The genome sequence of the two-banded wasp hoverfly, Chrysotoxum bicinctum (Linnaeus, 1758). Wellcome Open Res 2021; 6:321. [PMID: 36866282 PMCID: PMC9971694 DOI: 10.12688/wellcomeopenres.17382.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2021] [Indexed: 11/20/2022] Open
Abstract
We present a genome assembly from an individual female Chrysotoxum bicinctum (the two-banded wasp hoverfly; Arthropoda; Insecta; Diptera; Syriphidae). The genome sequence is 913 megabases in span. The majority of the assembly (98.81%) is scaffolded into five chromosomal pseudomolecules, with the X sex chromosome assembled.
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Abstract
We present a genome assembly from an individual female Eristalis tenax (the drone fly; Arthropoda; Insecta; Diptera; Syriphidae). The genome sequence is 487 megabases in span. The majority of the assembly (96.50%) is scaffolded into six chromosomal pseudomolecules, with the X sex chromosome assembled.
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The genome sequence of the tapered dronefly, Eristalis pertinax (Scopoli, 1763). Wellcome Open Res 2021; 6:292. [PMID: 36873714 PMCID: PMC9975435 DOI: 10.12688/wellcomeopenres.17267.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2021] [Indexed: 11/20/2022] Open
Abstract
We present a genome assembly from an individual male Eristalis tenax (the tapered dronefly; Arthropoda; Insecta; Diptera; Syriphidae). The genome sequence is 487 megabases in span. The majority of the assembly (95.23%) is scaffolded into seven chromosomal pseudomolecules, with the X and Y sex chromosomes assembled. The complete mitochondrial genome was also assembled and is 17.2 kilobases in length.
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Fully automated left ventricular ejection fraction and global longitudinal strain predicts obstructive coronary artery disease in patients undergoing stress echocardiography: a multi-centre study. Eur Heart J 2021. [DOI: 10.1093/eurheartj/ehab724.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Assessment of LVEF and myocardial deformation with GLS has shown promise in predicting CAD, which may add prognostic information for patients undergoing SE. However, selection bias precludes an accurate assessment of routine clinical SE workflow due to the exclusion of poor image quality and contrast enhanced studies. We hypothesise that an artificial intelligence (AI) pipeline capable of fully automated contouring of the left ventricle and GLS analysis of both non-contrast and contrast SE images is feasible and can predict CAD.
Purpose
The aim of this study was to evaluate the prediction of obstructive coronary artery disease (CAD) from fully automated left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) measures in a large multicentre population of patients undergoing stress echocardiography (SE).
Methods
500 patients from five medical centres undergoing SE for the clinical evaluation of ischaemic heart disease were included in this study. LVEF and GLS was automatically calculated using AI in non-contrast and contrast images at rest and peak stress. The primary endpoint was CAD assessed using invasive coronary angiography.
Results
Patients with significant CAD demonstrated significantly reduced LVEF and GLS at rest and peak stress (all p<0.001) compared to those without CAD. Of the 130 patients who exhibited myocardial ischaemia at peak stress, patients without significant CAD (37%) had significantly reduced LVEF and GLS when compared to those who did. Multivariate analysis demonstrated that a peak LVEF (0.93; 95% CI 0.9–0.96) and peak GLS (1.15; 95% CI 1.07–1.24) were significant independent predictors of CAD. The addition of automated LVEF and GLS to basic models significantly improved the C statistic from 0.78 to 0.83 and 0.85 (both p<0.001), respectively.
Conclusions
Fully automated LVEF and GLS in non-contrast and contrast SE images is feasible and independently augment the prediction of obstructive CAD above and beyond traditional SE indexes.
Funding Acknowledgement
Type of funding sources: None.
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Using deep learning to extract novel and quantitative imaging features from perfluoropropane contrast, sulphur hexafluoride contrast and non-contrast stress echocardiography images. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.0005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Stress echocardiography has become established as the most widely applied non-invasive imaging test for diagnosis of coronary artery disease within the UK. However, stress echocardiography has been substantially qualitative, rather than quantitative, based on visual wall motion assessment. For the first time, we have identified and validated quantitative descriptors of cardiac geometry and motion, extracted from ultrasound images acquired using contrast agents in an automated way.
Purpose
To establish whether these novel imaging features can be generated in an automated, quantifiable and reproducible way from images acquired with perfluoropropane contrast, as well as investigating how these extracted measures compare to those extracted from sulphur hexafluoride contrast and non-contrast studies.
Methods
100 patients who received perfluoropropane contrast during their stress echocardiogram were recruited. Their stress echocardiography images were processed through a deep learning algorithm. Novel feature values were recorded and a subset of 10 studies were repeated. The automated measures of global longitudinal strain (GLS) and ejection fraction (EF) extracted from these images were compared to values previously extracted from sulphur hexafluoride contrast and non-contrast images using the same software.
Results
A full set of 31 novel imaging features were successfully extracted from 79 studies acquired using the perfluoropropane contrast agent with a dropout rate of 14% (n=92, 8 incomplete image sets). Repeated analysis in a subset of 10 perfluoropropane cases demonstrated excellent reproducibility of the extracted feature values (R2=1). Automated values of GLS and EF, at both rest (GLS = −16.4±4.8%, EF = 63±13%) and stress stages (GLS = −17.7±5.8%, EF = 68±11%), were extracted from 83 perfluoropropane studies, with a dropout rate of 16% (n=99, fewer incomplete sets as short axis view not required). The ranges of GLS and EF measures extracted from the perfluoropropane images were comparable to the other contrast studies (n=222) (Rest GLS = −16.8±5.8%, Rest EF = 63±10%; Stress GLS = −19.1±6.7%, Stress EF = 71±9%) and non-contrast studies (n=86) (Rest GLS = −15.7±5.3%, Rest EF = 57±10%; Stress GLS = −17.3±6.4%, Stress EF = 61±14%).
Conclusions
Novel features and clinically relevant measures were extracted from images acquired using perfluoropropane contrast for the first time in a fully automated and reproducible way using a deep learning algorithm. The analysis failure rate and generated measures are comparable to those extracted from images using other commonly used sulphur hexafluoride contrast agents and non-contrast stress echocardiography studies. These findings demonstrate that deep learning algorithms can be used for automated quantitative analysis of stress echocardiograms acquired using various contrast agents and in non-contrast studies to improve stress echocardiography practice.
Funding Acknowledgement
Type of funding source: Private company. Main funding source(s): Lantheus Medical Imaging, Inc.
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Probing the nanoscale organisation and multivalency of cell surface receptors: DNA origami nanoarrays for cellular studies with single-molecule control. Faraday Discuss 2020; 219:203-219. [PMID: 31314021 DOI: 10.1039/c9fd00023b] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nanoscale organisation of receptor ligands has become an important approach to study the clustering behaviour of cell-surface receptors. Biomimetic substrates fabricated via different nanopatterning strategies have so far been applied to investigate specific integrins and cell types, but without multivalent control. Here we use DNA origami to surpass the limits of current approaches and fabricate nanoarrays to study different cell adhesion processes, with nanoscale spatial resolution and single-molecule control. Notably, DNA nanostructures enable the display of receptor ligands in a highly customisable manner, with modifiable parameters including ligand number, ligand spacing and most importantly, multivalency. To test the adaptability and robustness of the system we combined it with focused ion beam and electron-beam lithography nanopatterning to additionally control the distance between the origami structures (i.e. receptor clusters). Moreover, we demonstrate how the platform can be used to interrogate two different biological questions: (1) the cooperative effect of integrin and growth factor receptor in cancer cell spreading, and (2) the role of integrin clustering in cardiomyocyte adhesion and maturation. Thereby we find previously unknown clustering behaviour of different integrins, further outlining the importance for such customisable platforms for future investigations of specific receptor organisation at the nanoscale.
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Calponin-3 is critical for coordinated contractility of actin stress fibers. Sci Rep 2018; 8:17670. [PMID: 30518778 PMCID: PMC6281606 DOI: 10.1038/s41598-018-35948-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/05/2018] [Indexed: 01/05/2023] Open
Abstract
Contractile actomyosin bundles, stress fibers, contribute to morphogenesis, migration, and mechanosensing of non-muscle cells. In addition to actin and non-muscle myosin II (NMII), stress fibers contain a large array of proteins that control their assembly, turnover, and contractility. Calponin-3 (Cnn3) is an actin-binding protein that associates with stress fibers. However, whether Cnn3 promotes stress fiber assembly, or serves as either a positive or negative regulator of their contractility has remained obscure. Here, we applied U2OS osteosarcoma cells as a model system to study the function of Cnn3. We show that Cnn3 localizes to both NMII-containing contractile ventral stress fibers and transverse arcs, as well as to non-contractile dorsal stress fibers that do not contain NMII. Fluorescence-recovery-after-photobleaching experiments revealed that Cnn3 is a dynamic component of stress fibers. Importantly, CRISPR/Cas9 knockout and RNAi knockdown studies demonstrated that Cnn3 is not essential for stress fiber assembly. However, Cnn3 depletion resulted in increased and uncoordinated contractility of stress fibers that often led to breakage of individual actomyosin bundles within the stress fiber network. Collectively these results provide evidence that Cnn3 is dispensable for the assembly of actomyosin bundles, but that it is required for controlling proper contractility of the stress fiber network.
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Cardiomyocytes Sense Matrix Rigidity through a Combination of Muscle and Non-muscle Myosin Contractions. Dev Cell 2018; 45:661. [PMID: 29870723 PMCID: PMC5988560 DOI: 10.1016/j.devcel.2018.05.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Synchrony of anterior cingulate cortex and insular-striatal activation predicts ambiguity aversion in individuals with low impulsivity. Cereb Cortex 2013; 24:1397-408. [PMID: 23355606 DOI: 10.1093/cercor/bht008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Personal attitude toward ambiguity contributes to individual differences in decision making in uncertain situations. Operationally, these attitudes reflect the various coping strategies elected to overcome the limited information. A key brain region involved in cognitive control for performance adjustments is the dorsal anterior cingulate cortex (dACC). To test how dACC functional network connectivity would be modulated by uncertainty and differ between individuals, 24 healthy participants underwent functional MRI in 3 sequential runs: 1 resting-state and 2 decision-making task runs. Individuals with lower nonplanning impulsiveness made greater use of a Pass option and avoided uncertain ambiguous situations. Seed-based functional connectivity analysis during the task runs revealed that stronger activation synchrony between the left dACC and the right anterior insula correlated with greater use of a Pass response option. During the resting-state, stronger resting-state functional connectivity between the left dACC and the ventral striatum predicted the adoption of Pass as a behavioral strategy and correlated with stronger task-activated synchrony between the dACC and the right anterior insula. Our findings indicate that that the synchrony between the dACC and insula-striatal circuitry was greater in individuals with low compared with high nonplanning impulsiveness and contributed to adopting Pass as a useful behavioral strategy.
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The association between body mass index, weight loss and physical function in the year following a hip fracture. J Nutr Health Aging 2013; 17:91-5. [PMID: 23299386 PMCID: PMC3569623 DOI: 10.1007/s12603-012-0073-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVES To determine whether body mass index (BMI) at the time of hospitalization or weight change in the period immediately following hospitalization predict physical function in the year after hip fracture. DESIGN Prospective observational study. SETTING Two hospitals in Baltimore, Maryland. PARTICIPANTS Female hip fracture patients age 65 years or older (N=136 for BMI analysis, N=41 for analysis of weight change). MEASUREMENTS Body mass index was calculated based on weight and height from the medical chart. Weight change was based on DXA scans at 3 and 10 days post fracture. Physical function was assessed at 2, 6 and 12 months following fracture using the lower extremity gain scale (LEGS), walking speed and grip strength. RESULTS LEGS score and walking speed did not differ across BMI tertiles. However, grip strength differed significantly across BMI tertiles (p=0.029), with underweight women having lower grip strength than normal weight women at all time points. Women experiencing the most weight loss (>4.8%) had significantly lower LEGS scores at all time points, slower walking speed at 6 months, and weaker grip strength at 12 months post-fracture relative to women with more modest weight loss. In adjusted models, overall differences in function and functional change across all time points were not significant. However, at 12 months post fracture,women with the most weight loss had an average grip strength 7.0 kg lower than women with modest weight loss (p=0.030). CONCLUSIONS Adjustment for confounders accounts for much of the relationships between BMI and function and weight change and function in the year after fracture. However, weight loss is associated with weakness during hip fracture recovery. Weight loss during and immediately after hospitalization appears to identify women at risk of poor function and may represent an important target for future interventions.
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Abstract
OBJECTIVE Celiac disease is associated with decreased bone density; however, the risk of fractures in celiac disease patients is unclear. We compared the prevalence of celiac disease between a group of women with hip fractures and a group of women undergoing elective joint replacement surgery and the association between celiac disease and vitamin D levels. METHODS Two hundred eight community dwelling and postmenopausal women were recruited from Boston, MA (n=81) and Baltimore, MD (n=127). We measured tissue transglutaminase IgA by ELISA to diagnose celiac disease and 25-hydroxyvitamin D (25(OH)D) levels by radioimmunoassay in both women with hip fractures (n=157) and a control group (n=51) of total hip replacement subjects from Boston. Subjects were excluded if they took any medications or had medical conditions that might affect bone. RESULTS Median serum 25(OH)D levels were significantly lower (p< 0.0001) in the hip fracture cohorts compared to the elective joint replacement cohort (14.1 ng/ml vs. 21.3 ng/ml, respectively). There were no differences in the percentage of subjects with a positive tissue transglutaminase in the women with hip fractures versus the control group (1.91% vs. 1.96%, respectively). CONCLUSION Vitamin D levels are markedly reduced in women with hip fractures, however hip fracture patients did not show a higher percentage of positive tissue transglutaminase levels compared with controls. These data suggest that routine testing for celiac disease among hip fracture patients may not be necessary in the absence of clinical signs and symptoms, although data from larger studies among hip fracture subjects are needed.
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Abstract
OBJECTIVES To estimate meaningful improvements in gait speed observed during recovery from hip fracture and to evaluate the sensitivity and specificity of gait speed changes in detecting change in self-reported mobility. DESIGN Secondary longitudinal data analysis from two randomized controlled trials SETTING Twelve hospitals in the Baltimore, Maryland, area. PARTICIPANTS Two hundred seventeen women admitted with hip fracture. MEASUREMENTS Usual gait speed and self-reported mobility (ability to walk 1 block and climb 1 flight of stairs) measured 2 and 12 months after fracture. RESULTS Effect size-based estimates of meaningful differences were 0.03 for small differences and 0.09 for substantial differences. Depending on the anchor (stairs vs walking) and method (mean difference vs regression), anchor-based estimates ranged from 0.10 to 0.17 m/s for small meaningful improvements and 0.17 to 0.26 m/s for substantial meaningful improvement. Optimal gait speed cutpoints yielded low sensitivity (0.39-0.62) and specificity (0.57-0.76) for improvements in self-reported mobility. CONCLUSION Results from this sample of women recovering from hip fracture provide only limited support for the 0.10-m/s cut point for substantial meaningful change previously identified in community-dwelling older adults experiencing declines in walking abilities. Anchor-based estimates and cut points derived from receiver operating characteristic curve analysis suggest that greater improvements in gait speed may be required for substantial perceived mobility improvement in female hip fracture patients. Furthermore, gait speed change performed poorly in discriminating change in self-reported mobility. Estimates of meaningful change in gait speed may differ based on the direction of change (improvement vs decline) or between patient populations.
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Use of pressure-redistributing support surfaces among elderly hip fracture patients across the continuum of care: adherence to pressure ulcer prevention guidelines. THE GERONTOLOGIST 2009; 50:253-62. [PMID: 19587108 DOI: 10.1093/geront/gnp101] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
PURPOSE To estimate the frequency of use of pressure-redistributing support surfaces (PRSS) among hip fracture patients and to determine whether higher pressure ulcer risk is associated with greater PRSS use. DESIGN AND METHODS Patients (n = 658) aged >or=65 years who had surgery for hip fracture were examined by research nurses at baseline and on alternating days for 21 days. Information on PRSS use and pressure ulcer risk factors was recorded at each assessment visit. Other information was obtained by interview and chart review. RESULTS A PRSS was observed at 36.4% of the 5,940 study visits. The odds of PRSS use were lower in the rehabilitation setting (adjusted odds ratio [OR] 0.4, 95% confidence interval [CI] 0.3-0.6), in the nursing home (adjusted OR 0.2, 95% CI 0.1-0.3), and during readmission to the acute setting (adjusted OR 0.6, 95% CI 0.4-0.9) than in the initial acute setting. There was wide variation in frequency of PRSS use by admission hospital, even after adjusting for pressure ulcer risk factors. The relationships between PRSS use and pressure ulcer risk factors were not strong. IMPLICATIONS In this study of hip fracture patients, adherence to guidelines for PRSS use was low and was based more on facility-related factors than on patient risk. There is an urgent need for health care providers to improve strategies for the prevention of pressure ulcers in high-risk patients.
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Association of serotonin-1A and 2A receptor promoter polymorphisms with depressive symptoms and functional recovery in elderly persons after hip fracture. J Affect Disord 2008; 111:61-6. [PMID: 18334271 PMCID: PMC2610462 DOI: 10.1016/j.jad.2008.02.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Revised: 02/04/2008] [Accepted: 02/06/2008] [Indexed: 10/22/2022]
Abstract
BACKGROUND Depression is common after hip fracture and is associated with poorer functional recovery. Polymorphisms of the serotonin 1a (5HTR1A) and 2a receptors (5HTR2A) are associated with depression; therefore, we examined their association with depressive symptoms and functional recovery after hip fracture. METHODS 145 elderly women were followed for 12 months after hip fracture. Depressive symptoms were measured with the 15-item Geriatric Depression Scale (GDS). Functional status was measured by Lower Extremity Physical and Instrumental Activity of Daily Living scales (LPADLs and IADLs). Time-adjusted general linear regression models compared mean GDS between those with and without risk alleles for 5HTR1A and 5HTR2A. RESULTS Women with 1-2 copies of the 5HTR1A (-1019) G allele had higher GDS scores (Adjusted Mean Difference=0.59; 95% CI, 0.12-1.06), and poorer IADL scores (Adjusted Mean Difference=0.24; 95%CI -0.002 to 0.49), compared to those without this allele, controlling for potential confounders and 5HTR2A. Depressive symptoms partly accounted for poorer IADL recovery. Women with 1-2 copies of the 5HTR2A (-1438) C allele did not have significantly higher GDS scores (Adjusted Mean Difference=0.34; 95%CI, -0.20 to 0.87) and had better IADL scores (Adjusted Mean Difference=-0.40; 95%CI -0.74 to 0.06) than those with A/A genotype. LIMITATIONS The findings are limited by small sample size and the use of a screening scale to measure depression. CONCLUSIONS The 5HTR1A (-1019) G allele is associated with increased depressive symptoms after hip fracture, which in turn accounts for poorer functional recovery. These results suggest a role for serotonergic genetic variation in elderly persons' resilience and recovery from medical events.
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Adherence to an Exercise Intervention Among Older Women Post Hip Fracture. JOURNAL OF CLINICAL SPORT PSYCHOLOGY 2008; 2:41-56. [PMID: 20428489 PMCID: PMC2859720 DOI: 10.1123/jcsp.2.1.41] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
The purpose of this study was to evaluate adherence to home-based exercise interventions among older women post hip fracture that were randomized to one of three exercise intervention groups or a routine care group. A total of 157 female hip fracture patients provided data for the intervention analysis. Factors evaluated baseline, 2, 6, and 12 months post hip fracture included demographic variables, adherence to treatment visits, self-efficacy, outcome expectations, stage of change for exercise, social support for exercise, mood, health status, pain, and fear of falling. The hypothesized model tested the direct and indirect impact of all study variables on adherence to exercise intervention sessions. Different factors appeared to influence adherence to visits across the recovery trajectory.
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Abstract
BACKGROUND Exercise is an important strategy with potential to improve recovery in older adults following a hip fracture. PURPOSE The purpose of this study was to test the impact of a self-efficacy based intervention, the Exercise Plus Program, and the different components of the intervention, on self-efficacy, outcome expectations, and exercise behavior among older women post-hip fracture. METHODS Participants were randomized to one of four groups: exercise plus, exercise only, plus only (i.e., motivation), or routine care. Data collection was done at baseline (within 22 days of fracture), 2, 6, and 12 months post-hip fracture. RESULTS A total of 209 women were recruited with an average age of 81.0 years (SD=6.9). The majority was White (97.1%), was widowed (57.2%), and had a high school education (66.7%). Generalized Estimating Equations were used to perform repeated measures analyses. No differences in trajectories of recovery were observed for self-efficacy or outcome expectations. A statistically significant difference in the overall trajectory of time in exercise was seen (p<.001), with more time spent exercising in all three treatment groups. CONCLUSIONS The study demonstrated that it was possible to engage these women in a home-based exercise program and that the plus only, exercise only, and the exercise plus groups all increased exercise.
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Abstract
Despite the potential benefits associated with exercise after hip fracture, those who have sustained hip fractures are among the least likely to engage in regular exercise (resistive or aerobic). This article describes the psychosocial state, specifically the self-efficacy expectations and outcome expectations related to exercise, mood, fear of falling, pain, and health status of older women who enrolled in either of two Baltimore Hip Studies (BHS), BHS-4 and BHS-5, and to test a self-efficacy-based model to explain exercise behavior after hip fracture. A total of 389 older women with hip fractures participated in these studies. The participants reported moderate confidence in their ability to exercise and a general belief in the benefits of exercise, high perceived health status, limited depressive symptoms, and some pain and fear of falling. Consistently across these two samples, age and mental status or depressive symptoms influenced outcome expectations, such that older women with more depressive symptoms or lower mental health status had weaker outcome expectations for exercise. Self-efficacy expectations consistently influenced exercise behavior across both samples. It was also consistent across both models that age, cognitive status, physical and mental health status, pain, fear, outcome expectations, and depressive symptoms did not directly influence exercise behavior.
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Factors that influence exercise activity among women post hip fracture participating in the Exercise Plus Program. Clin Interv Aging 2007; 2:413-27. [PMID: 18044192 PMCID: PMC2685262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Using a social ecological model, this paper describes selected intra- and interpersonal factors that influence exercise behavior in women post hip fracture who participated in the Exercise Plus Program. Model testing of factors that influence exercise behavior at 2, 6 and 12 months post hip fracture was done. The full model hypothesized that demographic variables; cognitive, affective, physical and functional status; pain; fear of falling; social support for exercise, and exposure to the Exercise Plus Program would influence self-efficacy, outcome expectations, and stage of change both directly and indirectly influencing total time spent exercising. Two hundred and nine female hip fracture patients (age 81.0 +/- 6.9), the majority of whom were Caucasian (97%), participated in this study. The three predictive models tested across the 12 month recovery trajectory suggest that somewhat different factors may influence exercise over the recovery period and the models explained 8 to 21% of the variance in time spent exercising. To optimize exercise activity post hip fracture, older adults should be helped to realistically assess their self-efficacy and outcome expectations related to exercise, health care providers and friends/peers should be encouraged to reinforce the positive benefits of exercise post hip fracture, and fear of falling should be addressed throughout the entire hip fracture recovery trajectory.
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Abstract
The purpose of this study was to test the reliability and validity of the Self-Efficacy for Exercise (SEE) and the Outcome Expectations for Exercise (OEE) scales in a sample of 166 older women post-hip fracture. There was some evidence of validity of the SEE and OEE based on confirmatory factor analysis and Rasch model testing, criterion based and convergent validity, and evidence of internal consistency based on alpha coefficients and separation indices and reliability based on R2 estimates. Rasch model testing demonstrated that some items had high variability. Based on these findings suggestions are made for how items could be revised and the scales improved for future use.
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Female hip fracture patients had poorer performance-based functioning than community-dwelling peers over 2-year follow-up period. J Clin Epidemiol 2005; 58:1289-98. [PMID: 16291474 DOI: 10.1016/j.jclinepi.2004.04.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2004] [Revised: 03/13/2004] [Accepted: 04/20/2005] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND OBJECTIVES Compare performance-based functioning over 2 years among elderly women hip fracture patients vs. community-dwelling older women. METHODS AND SETTING 268 hip fracture patients from eight hospitals in Baltimore, MD, in 1990-1991, and 486 respondents from the Women's Health and Aging Study I (WHAS I) were assessed prospectively at 6-month intervals for 2 years. Usual and rapid walking speeds, and chair rise time, were calculated and standardized to the baseline distribution of the WHAS subsample. RESULTS At baseline, all respondents were aged 65+ years, White, cognitively intact, and could walk across a room independently. Hip fracture patients had significantly poorer functioning than WHAS respondents at each follow-up interview through 24 months postfracture. The difference was greatest at 6 months: mean walking speed for hip fracture patients was approximately one standard deviation lower than for WHAS respondents for usual pace (adjusted difference = -1.06, 95% confidence interval (CI) = -1.22, -0.89) and rapid pace (adjusted difference = -0.95, 95% CI = -1.13, -0.79). These differences were most pronounced among respondents who were aged 80+ years or had comorbid conditions. CONCLUSION Elderly women had poorer performance-based functioning over 2 years following hip fracture than would be expected by normal aging in same-aged women.
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Abstract
BACKGROUND Treatment fidelity refers to the methodological strategies used to monitor and enhance the reliability and validity of behavioral interventions. Assuring optimal treatment fidelity also may decrease the costs of a study and help the research team explain findings. APPROACH The Behavioral Change Consortium developed a comprehensive model of treatment fidelity that incorporates 5 areas: (a) study design, (b) training providers, (c) delivery of treatment, (d) receipt of treatment, and (e) enactment of treatment skills. The definitions of these areas and a case example (Testing the Effectiveness of the Exercise Plus Program) are provided. RESULTS There was evidence of treatment fidelity related to delivery based on careful monitoring of the study implementation. A comprehensive plan for training of the interventionists was provided, although evidence of treatment fidelity to training was not quantified. There were evidence based on observations of treatment sessions of delivery and receipt of the intervention and evidence of enactments based on evaluation of exercise calendars. DISCUSSION The development and implementation of a treatment fidelity plan requires a careful conceptualization of what is relevant to treatment fidelity in any given study. Monitoring of treatment fidelity ideally requires direct or indirect observations of sessions, which can be built into the study design so that costs are minimal in terms of time and resources. Monitoring treatment fidelity allows research teams to truly test interventions and to develop and implement interventions that ultimately improve the overall health and well-being of individuals.
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Abstract
The purpose of this study was to explore the impact of health-related quality of life (HRQOL) measured with the Short Form Health Survey (SF-36) on Functional Recovery Status (physical and psychosocial recovery status) at base-line, 2 months, 6 months, and 12 months following total hip replacement (THR). A secondary analysis was performed using data gathered from a sample of 271 older adults post THR. Four empirically based hypothesized models were tested. None of the models fit the data, with each having significant chi2 values and chi2 /df ratios greater than 3. Different dimensions of HRQOL at baseline, 2, 6, and 12 months were related to physical recovery status, and none of the 8 dimensions of the SF-36 was significantly related to psychosocial recovery status. Overall, the results of this study do not support the hypothesis that HRQOL, as measured by the SF-36, comprehensively explains functional recovery status following THR. Clinically, these findings may be applicable to individuals at risk for poor recovery. They also may prompt practitioners to consider alternative factors that influence psychosocial recovery.
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The contribution of hip fracture to risk of subsequent fractures: data from two longitudinal studies. Osteoporos Int 2003; 14:879-83. [PMID: 14530910 DOI: 10.1007/s00198-003-1460-x] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2002] [Accepted: 05/14/2003] [Indexed: 10/26/2022]
Abstract
BACKGROUND The contribution of hip fracture to the risk of subsequent fractures is unclear. METHODS Data from the Baltimore Hip Studies and the Established Populations for Epidemiologic Studies of the Elderly (EPESE) were used. Baltimore subjects enrolled at the time of hip fracture ( n=549) and EPESE subjects without previous fractures at baseline ( n=10,680) were followed for 2-10 years. Self-reported nonhip skeletal fracture was the outcome, and hip fracture was a time-varying covariate in a survival analysis stratified by study site. The model was adjusted for race, sex, age, BMI, stroke, cancer, difficulty walking across a room, dependence in grooming, dependence in transferring, and cognitive impairment. RESULTS The rate of all subsequent self-reported fractures after hip fracture was 10.4 fractures/100 person-years. The unadjusted hazard of nonhip skeletal fracture was 2.52 (95% confidence interval 2.05 to 3.12) for subjects with hip fracture compared with subjects without; when adjusted for other known fracture risk factors the hazard ratio was 1.62 (1.30 to 2.02). Men and women had a similar relative risk increase. The increased risk of secondary fracture after hip fracture persisted over time. CONCLUSIONS A hip fracture is associated with a 2.5-fold increased risk of subsequent fracture, which is not entirely explained by prefracture risk factors. Careful attention to secondary prevention is warranted in these patients.
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Abstract
OBJECTIVES To examine the prevalence, incidence, persistence, predictors, and outcomes of cognitive impairment after hip fracture. DESIGN Longitudinal cohort study. SETTING Eight hospitals in Baltimore, Maryland. PARTICIPANTS Six hundred seventy-four hip fracture patients aged 65 and older living in the community before fracture. MEASUREMENT Delirium at admission and postsurgery, Mini-Mental State Examination (MMSE) scores postsurgery, and prefracture proxy ratings of MMSE and dementia. Follow-up measures at 2 and 12 months postfracture included mortality, MMSE, physical activities of daily living (PADLs), instrumental activities of daily living (IADLs), social functioning, and the Center for Epidemiologic Studies-Depression Scale. RESULTS Overall, 28% had prefracture dementia or MMSE impairment, 8% had cognitive impairment first detected presurgery, 14% had impairment first detected postsurgery, and 50% were not impaired before or during hospitalization. Incident cognitive impairment was more likely in patients who were older, male, and less educated and had more prefracture PADL impairment, intertrochanteric fractures, and higher anesthesia risk ratings. Presurgery incident cases did not differ significantly from those detected postsurgery in functional outcomes or in persistence of cognitive impairment. Cognitive impairment first noted in the hospital persisted through 2 and 12 months in more than 40% of patients. Those with cognitive impairment persisting through 2 months had poorer 12-month PADLs and social functioning. CONCLUSION Prefracture cognitive impairment and incident cognitive impairment during hospitalization are risk factors for poor functional outcomes. Many incident cognitive problems persisted over 2 to 12 months, and per-sistence predicted later functional and social impairment.
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Changes in functional status attributable to hip fracture: a comparison of hip fracture patients to community-dwelling aged. Am J Epidemiol 2003; 157:1023-31. [PMID: 12777366 DOI: 10.1093/aje/kwg081] [Citation(s) in RCA: 189] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Disability attributable to hip fracture regarding activities of daily living was evaluated by comparing 594 hip fracture patients entering eight hospitals in Baltimore, Maryland, in 1990-1991 with community-dwelling aged from the Established Populations for Epidemiologic Studies of the Elderly (EPESE) cohort matched on age, sex, and walking ability. Subjects were assessed at baseline (prefracture report for patients), 12 months, and 24 months. At baseline, 26% of both groups had walking disability, 12-14% had transferring disability, and 6-8% evidenced grooming disability. At 12 and 24 months, about 50% of hip fracture patients were walking disabled compared with 21-29% of EPESE respondents after the authors controlled for age, sex, comorbidities, and functional status (excess disability attributable to hip fracture, i.e., attributable disability, of 26 additional cases of disability per 100 persons in the hip fracture cohort during follow-up). Likewise, hip fracture patients experienced more disability regarding transferring (38-39% vs. 10-18%; attributable disability, approximately 22 cases per 100 persons) and grooming (17-19% vs. 7-15%; attributable disability, approximately six cases per 100 persons). Thus, results showed that hip fracture patients had substantially more activities of daily living disability than that explained by aging over 24 months.
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Abstract
OBJECTIVES To investigate cross-validated methods of identifying patients at increased risk of fracture in nursing homes using readily available data. DESIGN Prospective cohort study with 18 months of follow-up. SETTING Forty-seven randomly selected nursing homes in Maryland. PARTICIPANTS One thousand four hundred twenty-seven white female nursing home residents aged 65 and older were followed for fracture for 18 months after baseline assessment. MEASUREMENTS Fracture ascertained by physician note or x-ray from chart abstraction; demographic and baseline data extracted from the Minimum Data Set (MDS). RESULTS Exploratory analyses on a random subset (67%) of the data (development sample) identified variables that might be important in predicting subsequent fracture and included variables for how the resident moved between locations in her room or adjacent corridor (mobility), age, weight, height, independence in eating and dressing, urinary incontinence, resistance to care, falls in the previous 6 months, a dementia score, and other activities of daily living. A simple scoring algorithm derived from a subset of these MDS variables showed good sensitivity (.70) but low specificity (.39) in the random validation sample. CONCLUSION A scoring algorithm developed in more than 1,400 white females from 47 nursing homes in the state of Maryland shows high sensitivity for identifying women at increased risk for fracture and may be useful in targeting fracture prevention programs.
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Abstract
BACKGROUND Osteoporotic fractures result in increased health care use. Care following fracture has been characterized for community dwellers but not for nursing home residents, whose fracture rates are as much as 11 times higher than those of age-matched community dwellers. Knowing the amount of care following fracture may help determine the effects of fracture prevention on use and costs in this population. METHODS A prospective cohort study was conducted, with 18 months of follow-up, of 1427 randomly selected white, female nursing home residents 65 years and older from 47 randomly selected nursing homes in Maryland. RESULTS After controlling for age, comorbidities, and mobility, nursing home residents who experienced a fracture were hospitalized more than 15 times as often as those who did not in the month following the fracture (relative rate, 15.35; 95% confidence interval, 12.27-19.21) and at a higher rate from 3 through 12 months postfracture. Rates in the first month were higher for persons with a hip fracture (relative rate, 31.01; 95% confidence interval, 26.52-36.24). Rates of emergency department use and contacts with physicians and therapists were increased, the latter two for 12 months following fracture. Also, before the fracture, patients who experienced a fracture visited the emergency department and had more physician contacts; for those with a hip fracture, there were fewer prefracture hospitalizations. CONCLUSIONS Health care use remained elevated through 1 year postfracture. Comparisons with community patients suggest that this care may be less than what would be provided in other settings. For patients who fractured a hip, higher use decreased after 6 months, similar to community cohorts. Nursing home residents who visit the emergency department may warrant special screening for a fracture.
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Correlates of bone mineral density in nursing home residents. J Nutr Health Aging 2001; 3:140-5. [PMID: 10823980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
PURPOSE To explore correlates of bone mineral density (BMD) in nursing home residents, examining factors associated with BMD in community cohorts and factors prevalent among nursing home residents. METHODS A cross sectional study of 2156 elderly residents from a representative state-wide sample of 47 nursing homes in Maryland. Data consisted of BMD scans of the distal radius and ulna; information on comorbidities, activities, behavior and medications abstracted from medical charts and interviews; and observation of cognitive and neuromuscular performance. RESULTS Forty-two percent of the variance in BMD was explained by age, gender, race and weight. Fracture, use of steroids and seizure medications, and alcohol use were also related to low BMD. Other factors prevalent in nursing home populations, such as cognitive impairment and depressive symptomatology, were not strongly associated with low BMD. CONCLUSIONS Despite the diversity of the nursing home population, their older age and greater dependency and comorbidity, the factors most closely related to low BMD in nursing home residents were comparable to those in community-dwellers. Demographic information, along with other clinical factors such as fracture and use of steroid and seizure medications, may aid health care providers in identifying high risk individuals in nursing homes.
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Extending gerontological research through linking investigators' studies to public-use datasets. THE GERONTOLOGIST 2001; 41:15-22. [PMID: 11220810 DOI: 10.1093/geront/41.1.15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
PURPOSE Public-use datasets can extend data collected by individual investigators in various ways: making external comparisons, providing additional data on individual respondents, and creating internal comparison groups. The authors describe the advantages and limitations of these methods and practical and conceptual issues in combining investigator-initiated and public-use datasets. DESIGN AND METHODS These issues are illustrated with a study of functional decline among 674 patients following hospitalization for hip fracture that was augmented with data from a public-use dataset, the Established Populations for Epidemiologic Studies of the Elderly (EPESE). RESULTS By creating an internal comparison group of EPESE respondents, frequency matched to hip fracture patients on age, sex, and baseline functional limitations, the authors formed a single dataset and performed multivariable analyses of factors associated with functional decline. IMPLICATIONS Gerontological research may benefit by applying these methods to program evaluations and longitudinal analyses of health outcomes with numerous public-use datasets.
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Responding to Meyer et al. Factors associated with mortality after hip fracture. Osteoporos Int 2000; 11:228-32. Osteoporos Int 2001; 12:516-7. [PMID: 11446569 DOI: 10.1007/s001980170098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
BACKGROUND This report describes changes in eight areas of functioning after a hip fracture, identifies the point at which maximal levels of recovery are reached in each area, and evaluates the sequence of recuperation across multiple functional domains. METHODS. Community-residing hip fracture patients (n = 674) admitted to eight hospitals in Baltimore, Maryland, 1990-1991 were followed prospectively for 2 years from the time of hospitalization. Eight areas of function (i.e., upper and lower extremity physical and instrumental activities of daily living; gait and balance; social, cognitive, and affective function) were measured by personal interview and direct observation during hospitalization at 2, 6, 12, 18, and 24 months. Levels of recovery are described in each area, and time to reach maximal recovery was estimated using Generalized Estimating Equations and longitudinal data. RESULTS Most areas of functioning showed progressive lessening of dependence over the first postfracture year, with different levels of recovery and time to maximum levels observed for each area. New dependency in physical and instrumental tasks for those not requiring equipment or human assistance prefracture ranged from as low as 20.3% for putting on pants to as high as 89.9% for climbing five stairs. Recuperation times were specific to area of function, ranging from approximately 4 months for depressive symptoms (3.9 months), upper extremity function (4.3 months), and cognition (4.4 months) to almost a year for lower extremity function (11.2 months). CONCLUSIONS Functional disability following hip fracture is significant, patterns of recovery differ by area of function, and there appears to be an orderly sequence by which areas of function reach their maximal levels.
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Abstract
CONTEXT Low bone mineral density (BMD) is a strong risk factor for fracture in community-dwelling white women, but the relationship in white female nursing home residents, for whom fracture rates are highest, is less clear. OBJECTIVE To assess the relative contribution of low BMD to fracture risk in nursing home residents. DESIGN Prospective cohort study with baseline data collected April 1995 to June 1997, with 18 months of follow-up. SETTING Forty-seven randomly selected nursing homes in Maryland. PATIENTS A total of 1427 white female nursing home residents aged 65 years or older. MAIN OUTCOME MEASURE Documented osteoporotic fracture occurring during follow-up as a function of baseline BMD measurements higher vs lower than the median, and after controlling for demographic, functional, cognitive, psychosocial, and medical factors. RESULTS A total of 223 osteoporotic fractures occurred among 180 women. Low BMD and transfer independence were significant independent risk factors for fracture in this nursing home sample (P<.001) and the 2 factors acted synergistically (P =.06) to further increase fracture risk. Compared with women whose BMD was higher than the median (0. 296 g/cm(2)), those whose BMD was lower than the median had an unadjusted hazard ratio for risk of fracture of 2.1 (95% confidence interval [CI], 1.5-2.8); women who were independent in transfer had a hazard ratio of 1.6 (95% CI, 1.2-2.2) compared with women dependent in transfer. Among residents independent in transfer, those with BMD below the median had a more than 3-fold increase in fracture risk compared with those with higher BMD (unadjusted hazard ratio, 3.1; 95% CI, 2.2-4.4). Among residents dependent in transfer, those with BMD below the median had a 60% increase in fracture risk (unadjusted hazard ratio, 1.6; 95% CI, 1.1-2.3). Adjustment for covariates did not alter the BMD-fracture relationship. CONCLUSIONS Our data indicate that low BMD and independence in transfer are significant predictors of osteoporotic fracture in white female nursing home residents. JAMA. 2000;284:972-977
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Change in muscle mass and muscle strength after a hip fracture: relationship to mobility recovery. J Gerontol A Biol Sci Med Sci 2000; 55:M434-40. [PMID: 10952365 DOI: 10.1093/gerona/55.8.m434] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Hip fracture in elderly persons has a serious impact on long-term physical function. This study determines the change in muscle strength and muscle mass after a hip fracture, and the associations between these changes and mobility recovery. METHODS Ninety community-dwelling women aged 65 years and older who had recently experienced a fracture of the proximal femur were included in the study. At 2 to 10 days after hospital admission, the women's grip strength, ankle dorsiflexion strength, and regional muscle mass (by dual-energy x-ray absorptiometry) were measured, and the prefracture level of independence for five mobility function items was assessed. All measurements were repeated at 12 months. RESULTS At follow-up, only 17.8% of the women had returned to their prefracture level of mobility function for all five items. Mobility function recovery was not related to change in skeletal muscle mass of the nonfractured leg or the arms. However, women who lost grip strength (mean loss of -28.7%, SD = 16.9%), or who lost ankle strength of the nonfractured leg (mean loss of -21.5%, SD = 14.7%), had a worse mobility recovery compared with those who gained strength (p = .04 and p = .09, respectively). In addition, chronic disease (p = .03), days hospitalized (p = .04), and self-reported hip pain (p = .07) were independent predictors of decline in mobility function. CONCLUSIONS The results suggest that loss of muscle strength, but not loss of muscle mass, is an independent predictor of poorer mobility recovery 12 months after a hip fracture. When confirmed by other studies, these findings may have implications for rehabilitation strategies after a hip fracture.
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Serum concentrations of steroids, parathyroid hormone, and calcitonin in postmenopausal women during the year following hip fracture: effect of location of fracture and age. J Gerontol A Biol Sci Med Sci 1999; 54:M467-73. [PMID: 10536650 DOI: 10.1093/gerona/54.9.m467] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Hip fracture in the aged is a major health problem, especially considering the increasing proportion of the elderly in the population. This study examines changes in circulating levels of hormones, which are purported to affect bone metabolism, in response to hip fracture in postmenopausal women. METHODS Patients consisted of women ages 65 and older who had surgery within 2 days of fracture. Serum samples were obtained at 3, 10, 60, 180, and 360 days postfracture. Healthy women without hip fractures from the same age range served as a control group (n = 17). Hormones were determined by radioimmunoassay. Subjects with fractures in the neck region of the femur (n = 78) were compared to subjects with fractures in the trochanteric region (n = 88). RESULTS Estrone concentration (47.6 +/- 5.7 pg/mL; mean +/- SEM) at 3 days postfracture was elevated (p < .001) compared to control levels of 20.7 +/- 4.6 pg/mL. By 2 months, levels had declined to control levels. Androstenedione and the adrenal hormones, DHEAS and cortisol, displayed similar responses. Parathyroid hormone (PTH) levels were not significantly different from the control concentration at 3 days following fracture, but increased (p < .001) during the year following fracture. Calcitonin concentrations were much higher (p < .001) 3 days postfracture (42.1 +/- 3.7 pg/mL) compared to controls without fracture (9.8 +/- 3 pg/mL). Except for testosterone, no differences could be attributed to fracture location. Only PTH, with concentrations higher in the older age groups (p < .001), showed an age-related response. CONCLUSIONS Following hip fracture, there are some dramatic responses in hormones that purportedly are mechanistically important in bone metabolism. These changes include transient increases in steroid hormones, chronic elevations in calcitonin, and rising levels of PTH during the year after fracture.
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Abstract
Many different forearm sites have been used for the measurement of bone mineral density (BMD) and prediction of risk of future fracture among community dwelling populations. In populations where bone densitometry of peripheral sites may be the most cost effective and practical means of measuring BMD, such as the nursing home population, knowing the characteristics of forearm BMD measures would be beneficial. The purpose of this study was to assess the relationship of four common commercially available measures to each other and to estimate the inter- and intrarater reliability of the measures in a sample of nursing home residents as a first step toward identifying appropriate forearm measurement sites. These sites were the distal radius, the distal ulna, a composite of the distal radius and distal ulna, and the ultra distal radius. BMD measurements on 48 nursing home patients were obtained using single X-ray absorptiometry. Inter- and intrarater reliability was excellent at all four sites (interclass correlation coefficients > 0. 85). Moderate to high correlations (0.84-0.91) between the distal radius and ultra distal radius sites of the forearm suggest that these measures may be interchangeable. Although not directly assessed here, differences in bone composition among forearm sites may partially explain moderate rather than high correlations between sites and may affect the ability of each site to predict future fractures. Thus, different forearm sites may be used interchangeably for diagnostic purposes; however, the prognostic value of each site remains unknown.
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Abstract
This study describes the prevalence of osteoporosis in a statewide sample of nursing home residents. Composite forearm bone mineral density (BMD) (including the distal radius and the distal ulna) of 1475 residents aged 65 years and older from 34 randomly selected, stratified nursing homes was assessed. BMD was expressed with reference to World Health Organization diagnostic criteria. Trends with age, gender and race were consistent with other populations. However, prevalence estimates were higher than community-based age-specific rates. The prevalence of osteoporosis for white female residents increased from 63.5% for women aged 65-74 years to 85.8% for women over 85 years of age. Only 3% had composite forearm BMD within 1 standard deviation of the young adult mean. The significance of the high prevalence of low BMD in nursing home residents is the increased fracture risk it may confer. In community cohorts of white women, the risk of hip fracture increases approximately 50% for every 1 standard deviation decrease in bone mass. However, the degree to which BMD contributes to fracture risk in this population has not been well established.
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Depressive symptoms and 6-year mortality among elderly community-dwelling women. Epidemiology 1999; 10:54-9. [PMID: 9888280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Depression is associated with an increased risk of mortality in studies that included adults of all ages, but results of studies restricted to older adults are less consistent. This study evaluated the association between depressive symptoms and mortality among 764 white women aged 65+ years in Baltimore, Maryland, and examined methodologic and conceptual issues regarding this association. The Center for Epidemiologic Studies-Depression Scale (CES-D) was administered in face-to-face interviews in 1984. Mortality data were collected through 1990. The 6-year risk of death was 14.5% among women with CES-D scores of 0-1, 24% to 28% among women with scores of 2-24, and 47% among those with scores over 24. The adjusted hazards ratio (RR) comparing women with the highest (25-58) vs lowest (0-1) scores was 1.77 (95% confidence interval (CI) = 0.91-3.42). Depressive symptoms were only weakly associated with mortality when using the CES-D scale dichotomized at the traditional cutpoint of 16 (RR = 1.10, CI = 0.73-1.66), or when the follow-up period was 2 years. Furthermore, depressive symptoms were associated with mortality only among women in poor health. The association between depressive symptoms and mortality risk appeared to be affected by baseline physical health, length of follow-up, and measurement of depression.
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Outcome after hemiarthroplasty for femoral neck fractures in the elderly. Clin Orthop Relat Res 1998:51-8. [PMID: 9553533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A prospective outcome study was performed on 270 patients, 65 years of age and older, who sustained a femoral neck fracture and underwent hemiarthroplasty. The treatment compared was the use of a noncemented unipolar versus either a cemented or a press fit bipolar prosthesis. The outcome variables assessed included the occurrence of a postoperative complication, length and cost of hospitalization, and function in various quality of life measurements. Patients who underwent bipolar hemiarthroplasty with either a cemented or a press fit prosthesis had better pain relief and function than patients who had a noncemented unipolar prosthesis at a minimum of 24 months after surgery. However, the mean hospitalization cost for patients who had a bipolar prosthesis was $12,290 compared with $8876 for a unipolar prosthesis.
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Abstract
OBJECTIVE The purpose of this study was to estimate the excess mortality attributable to hip fracture. METHODS The 6-year survival rate of community-dwelling White female hip fracture patients aged 70 years and older entering one of seven hospitals from 1984 to 1986 (n = 578) was compared with that of White female respondents aged 70 years and older interviewed in 1984 for the Longitudinal Study on Aging (n = 3773). RESULTS After age, education, comorbidity, and functional impairment were controlled, the mortality differential between the two groups accumulated to an excess among hip fracture patients of 9 deaths per 100 women 5 years postfracture. Among those with three or more functional impairments or one or more comorbidities, the excess was 7 deaths per 100: the effect of the fracture had disappeared in these groups by 4 years. In contrast, those with two or fewer impairments and those with no comorbidities had a continuing trend of increased mortality, with an excess of 14 deaths per 100 by 5 years. CONCLUSIONS There is an immediate increase in mortality following a hip fracture in medically ill and functionally impaired patients, whereas among those with no comorbidities and few impairments, there is a gradual increase in mortality that continues for 5 years postfracture.
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Relation of social network characteristics to 5-year mortality among young-old versus old-old white women in an urban community. Am J Epidemiol 1997; 145:516-23. [PMID: 9063341 DOI: 10.1093/oxfordjournals.aje.a009139] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
This study examines age-related differences in the association between social network characteristics and mortality for aged white women. Subjects include a community-dwelling sample of white women aged > or = 65 years (n = 806), who lived in northeast Baltimore, Maryland, in 1984. Three characteristics of social networks were measured: availability of network resources; contact with network resources; and integration into the neighborhood. The association of social network with 5-year mortality was examined with a proportional hazards model adjusting for perceived health status, impairment in physical activities of daily living, number of chronic conditions, and years of education. Analyses were stratified by age (65-74 years, > or = 75 years). Elements of social network contact and neighborhood integration were associated with reduced mortality among women aged > or = 75 years, but not among women aged 65-74 years. In the > or = 75 years group, women who had no contact with children, friends, and group organizations showed hazard ratios (95% confidence intervals (CI)) of 3.1 (1.2-7.5), 2.2 (1.0-4.9), and 2.8 (1.2-6.5), respectively. Women who had lived < or = 10 years in the neighborhood and women who had no interaction with local merchants showed hazard ratios of 2.5 (95% CI 1.3-4.8) and 2.2 (95% CI 1.2-3.9), respectively. Thus, both age and specific aspects of network structure were found to influence the association between social networks and mortality in elderly women.
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