Development of Portable Electronic Health Record Based Algorithms to Identify Individuals with Diabetic Retinopathy

Objectives

To develop, validate and implement algorithms to identify diabetic retinopathy (DR) cases and controls from electronic health care records (EHR)s. Methods : We developed and validated EHR-based algorithms to identify DR cases and individuals with type I or II diabetes without DR (controls) in three independent EHR systems: Vanderbilt University Medical Center Synthetic Derivative (VUMC), the VA Northeast Ohio Healthcare System (VANEOHS), and Massachusetts General Brigham (MGB). Cases were required to meet one of three criteria: 1) two or more dates with any DR ICD-9/10 code documented in the EHR, or 2) at least one affirmative health-factor or EPIC code for DR along with an ICD9/10 code for DR on a different day, or 3) at least one ICD-9/10 code for any DR occurring within 24 hours of an ophthalmology exam. Criteria for controls included affirmative evidence for diabetes as well as an ophthalmology exam.

Results

The algorithms, developed and evaluated in VUMC through manual chart review, resulted in a positive predictive value (PPV) of 0.93 for cases and negative predictive value (NPV) of 0.97 for controls. Implementation of algorithms yielded similar metrics in VANEOHS (PPV=0.94; NPV=0.86) and lower in MGB (PPV=0.84; NPV=0.76). In comparison, use of DR definition as implemented in Phenome-wide association study (PheWAS) in VUMC, yielded similar PPV (0.92) but substantially reduced NPV (0.48). Implementation of the algorithms to the Million Veteran Program identified over 62,000 DR cases with genetic data including 14,549 African Americans and 6,209 Hispanics with DR.

Conclusions/Discussion

We demonstrate the robustness of the algorithms at three separate health-care centers, with a minimum PPV of 0.84 and substantially improved NPV than existing high-throughput methods. We strongly encourage independent validation and incorporation of features unique to each EHR to enhance algorithm performance for DR cases and controls.

Palliative care for persons with late-stage Alzheimer's and related dementias and their caregivers: protocol for a randomized clinical trial

BACKGROUND

Limited access to specialized palliative care exposes persons with late-stage Alzheimer's disease and related dementias (ADRD) to burdensome treatment and unnecessary hospitalization and their caregivers to avoidable strain and financial burden. Addressing this unmet need, the purpose of this study was to conduct a randomized clinical trial (RCT) of the ADRD-Palliative Care (ADRD-PC) program.

METHODS

The study will use a multisite, RCT design and will be set in five geographically diverse US hospitals. Lead investigators and outcome assessors will be masked. The study will use 1:1 randomization of patient-caregiver dyads, and sites will enroll N = 424 dyads of hospitalized patients with late-stage ADRD with their family caregivers. Intervention dyads will receive the ADRD-PC program of (1) dementia-specific palliative care, (2) standardized caregiver education, and (3) transitional care. Control dyads will receive publicly available educational material on dementia caregiving. Outcomes will be measured at 30 days (interim) and 60 days post-discharge. The primary outcome will be 60-day hospital transfers, defined as visits to an emergency department or hospitalization ascertained from health record reviews and caregiver interviews (aim 1). Secondary patient-centered outcomes, ascertained from 30- and 60-day health record reviews and caregiver telephone interviews, will be symptom treatment, symptom control, use of community palliative care or hospice, and new nursing home transitions (aim 2). Secondary caregiver-centered outcomes will be communication about prognosis and goals of care, shared decision-making about hospitalization and other treatments, and caregiver distress (aim 3). Analyses will use intention-to-treat, and pre-specified exploratory analyses will examine the effects of sex as a biologic variable and the GDS stage.

DISCUSSION

The study results will determine the efficacy of an intervention that addresses the extraordinary public health impact of late-stage ADRD and suffering due to symptom distress, burdensome treatments, and caregiver strain. While many caregivers prioritize comfort in late-stage ADRD, shared decision-making is rare. Hospitalization creates an opportunity for dementia-specific palliative care, and the study findings will inform care redesign to advance comprehensive dementia-specific palliative care plus transitional care.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04948866. Registered on July 2, 2021.

Plasma Arginine and Citrulline are Elevated in Diabetic Retinopathy

PURPOSE

To determine if plasma levels of six arginine-related and citrulline-related metabolites (arginine, citrulline, asymmetric dimethylarginine [ADMA], ornithine, proline, and argininosuccinate) differ between patients with type 2 diabetes and diabetic retinopathy (DR) and type 2 diabetic controls or between patients with proliferative DR (PDR) and non-proliferative DR (NPDR).

DESIGN

Cross-sectional study.

METHODS

Adults with type 2 diabetes were recruited from the Vanderbilt Eye Institute. Exclusion criteria included non-diabetic retinal disease. Plasma metabolite levels were quantified in 159 diabetic controls and 156 DR patients (92 NPDR, 64 PDR) using isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS). Metabolite levels were compared using Wilcoxon Rank Sum test and logistic regressions adjusting for age, sex, hemoglobin A1c, diabetes duration, statin use, and angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker use. A secondary analysis that included creatinine in the regression model was performed for the subset of patients with available creatinine values (135 diabetic controls, 100 DR patients [58 NPDR, 42 PDR]).

RESULTS

Multivariable logistic regression analyses determined that arginine (OR = 1.20, [1.06-1.38], P = .0067) and citrulline (OR = 1.53, [1.20-1.98], P = .0025) were significantly elevated in DR patients compared to diabetic controls. While ADMA differed between NPDR and PDR patients in the primary analysis (OR = 1.56, [1.15-2.16], P = .0051), it was not significantly different when adjusting for creatinine (OR = 1.30, [0.90-1.91], P = .15).

CONCLUSIONS

Plasma arginine and citrulline were significantly elevated in type 2 diabetic patients with DR compared to diabetic controls. None of the tested metabolites significantly differed between NPDR and PDR patients in the adjusted analysis.

Arginine and Carnitine Metabolites Are Altered in Diabetic Retinopathy

Purpose

To determine plasma metabolite and metabolic pathway differences between patients with type 2 diabetes with diabetic retinopathy (DR) and without retinopathy (diabetic controls), and between patients with proliferative DR (PDR) and nonproliferative DR (NPDR).

Methods

Using high-resolution mass spectrometry with liquid chromatography, untargeted metabolomics was performed on plasma samples from 83 DR patients and 90 diabetic controls. Discriminatory metabolic features were identified through partial least squares discriminant analysis, and linear regression was used to adjust for age, sex, diabetes duration, and hemoglobin A1c. Pathway analysis was performed using Mummichog 2.0.

Results

In the adjusted analysis, 126 metabolic features differed significantly between DR patients and diabetic controls. Pathway analysis revealed alterations in the metabolism of amino acids, leukotrienes, niacin, pyrimidine, and purine. Arginine, citrulline, glutamic γ-semialdehyde, and dehydroxycarnitine were key contributors to these pathway differences. A total of 151 features distinguished PDR patients from NPDR patients, and pathway analysis revealed alterations in the β-oxidation of saturated fatty acids, fatty acid metabolism, and vitamin D3 metabolism. Carnitine was a major contributor to the pathway differences.

Conclusions

This study demonstrates that arginine and citrulline-related pathways are dysregulated in DR, and fatty acid metabolism is altered in PDR patients compared with NPDR patients.

The Carnitine Shuttle Pathway is Altered in Patients With Neovascular Age-Related Macular Degeneration

Purpose

To identify metabolites and metabolic pathways altered in neovascular age-related macular degeneration (NVAMD).

Methods

We performed metabolomics analysis using high-resolution C18 liquid chromatography-mass spectrometry on plasma samples from 100 NVAMD patients and 192 controls. Data for mass/charge ratio ranging from 85 to 850 were captured, and metabolic features were extracted using xMSanalyzer. Nested feature selection was used to identify metabolites that discriminated between NVAMD patients and controls. Pathway analysis was performed with Mummichog 2.0. Hierarchical clustering was used to examine the relationship between the discriminating metabolites and NVAMD patients and controls.

Results

Of the 10,917 metabolic features analyzed, a set of 159 was identified that distinguished NVAMD patients from controls (area under the curve of 0.83). Of these features, 39 were annotated with confidence and included multiple carnitine metabolites. Pathway analysis revealed that the carnitine shuttle pathway was significantly altered in NVAMD patients (P = 0.0001). Tandem mass spectrometry confirmed the molecular identity of five carnitine shuttle pathway acylcarnitine intermediates that were increased in NVAMD patients. Hierarchical cluster analysis revealed that 51% of the NVAMD patients had similar metabolic profiles, whereas the remaining 49% displayed greater variability in their metabolic profiles.

Conclusions

Multiple long-chain acylcarnitines that are part of the carnitine shuttle pathway were significantly increased in NVAMD patients compared to controls, suggesting that fatty acid metabolism may be involved in NVAMD pathophysiology. Cluster analysis suggested that clinically indistinguishable NVAMD patients can be separated into distinct subgroups based on metabolic profiles.

Hi-MC: a novel method for high-throughput mitochondrial haplogroup classification

Effective approaches for assessing mitochondrial DNA (mtDNA) variation are important to multiple scientific disciplines. Mitochondrial haplogroups characterize branch points in the phylogeny of mtDNA. Several tools exist for mitochondrial haplogroup classification. However, most require full or partial mtDNA sequence which is often cost prohibitive for studies with large sample sizes. The purpose of this study was to develop Hi-MC, a high-throughput method for mitochondrial haplogroup classification that is cost effective and applicable to large sample sizes making mitochondrial analysis more accessible in genetic studies. Using rigorous selection criteria, we defined and validated a custom panel of mtDNA single nucleotide polymorphisms that allows for accurate classification of European, African, and Native American mitochondrial haplogroups at broad resolution with minimal genotyping and cost. We demonstrate that Hi-MC performs well in samples of European, African, and Native American ancestries, and that Hi-MC performs comparably to a commonly used classifier. Implementation as a software package in R enables users to download and run the program locally, grants greater flexibility in the number of samples that can be run, and allows for easy expansion in future revisions. Hi-MC is available in the CRAN repository and the source code is freely available at https://github.com/vserch/himc.

Mitochondrial Haplogroups Modify the Effect of Diabetes Duration and HbA1c on Proliferative Diabetic Retinopathy Risk in Patients With Type 2 Diabetes

Purpose

We previously demonstrated an association between European mitochondrial haplogroups and proliferative diabetic retinopathy (PDR). The purpose of this study was to determine how the relationship between these haplogroups and both diabetes duration and hyperglycemia, two major risk factors for diabetic retinopathy (DR), affect PDR prevalence.

Methods

Our population consisted of patients with type 2 diabetes with (n = 377) and without (n = 480) DR. A Kruskal-Wallis test was used to compare diabetes duration and hemoglobin A1c (HbA1c) among mitochondrial haplogroups. Logistic regressions were performed to investigate diabetes duration and HbA1c as risk factors for PDR in the context of European mitochondrial haplogroups.

Results

Neither diabetes duration nor HbA1c differed among mitochondrial haplogroups. Among DR patients from haplogroup H, longer diabetes duration and increasing HbA1c were significant risk factors for PDR (P = 0.0001 and P = 0.011, respectively). Neither diabetes duration nor HbA1c was a significant risk factor for PDR in DR patients from haplogroup UK.

Conclusions

European mitochondrial haplogroups modify the effects of diabetes duration and HbA1c on PDR risk in patients with type 2 diabetes. In our patient population, longer diabetes duration and higher HbA1c increased PDR risk in patients from haplogroup H, but did not affect PDR risk in patients from haplogroup UK. This relationship has not been previously demonstrated and may explain, in part, why some patients with nonproliferative DR develop PDR and others do not, despite similar diabetes duration and glycemic control.

Performance of microbial identification by MALDI-TOF MS and susceptibility testing by VITEK 2 from positive blood cultures after minimal incubation on solid media

Bloodstream infections (BSIs) are a leading cause of patient morbidity and mortality. Rapid identification of organisms from BSIs is critical for initiating targeted antimicrobial therapy. Although many methods exist for rapid identification, they do not provide detailed or definitive susceptibility information. We assessed the utility of both the VITEK MS and Bruker Biotyper MALDI-TOF mass spectrometers to identify organisms from a positive blood culture bottle after only 4 h of growth on solid media compared to identification from overnight growth using the VITEK MS. Additionally, we determined whether this limited growth could yield accurate antimicrobial susceptibility testing (AST) results compared to overnight growth using the VITEK 2 AST system. Overall, identifications using the VITEK MS and Biotyper had agreements of 127/150 (84%) and 133/150 (88%), respectively. For rapid AST, the overall categorical agreement was 1010/1017 (99.3%), where Gram-negative bacteria had concordant results for 743/750 (99.1%) organism-drug combinations and Gram-positive bacteria had concordant results for 265/267 (99.3%). Gram-negative bacteria had 4, 2, and 1 minor, major, and very major discrepancies, respectively, while Gram-positive bacteria had no minor errors, one major, and one very major discrepancy. In conclusion, organisms grown for only 4 h on solid media were accurately identified by MALDI-TOF MS and have concordant phenotypic AST profiles. This method can also be implemented using common commercial instruments, providing a way to improve upon identification and gain detailed susceptibility information without significant additional laboratory costs.

Altering the Mitochondrial Fatty Acid Synthesis (mtFASII) Pathway Modulates Cellular Metabolic States and Bioactive Lipid Profiles as Revealed by Metabolomic Profiling

Despite the presence of a cytosolic fatty acid synthesis pathway, mitochondria have retained their own means of creating fatty acids via the mitochondrial fatty acid synthesis (mtFASII) pathway. The reason for its conservation has not yet been elucidated. Therefore, to better understand the role of mtFASII in the cell, we used thin layer chromatography to characterize the contribution of the mtFASII pathway to the fatty acid composition of selected mitochondrial lipids. Next, we performed metabolomic analysis on HeLa cells in which the mtFASII pathway was either hypofunctional (through knockdown of mitochondrial acyl carrier protein, ACP) or hyperfunctional (through overexpression of mitochondrial enoyl-CoA reductase, MECR). Our results indicate that the mtFASII pathway contributes little to the fatty acid composition of mitochondrial lipid species examined. Additionally, loss of mtFASII function results in changes in biochemical pathways suggesting alterations in glucose utilization and redox state. Interestingly, levels of bioactive lipids, including lysophospholipids and sphingolipids, directly correlate with mtFASII function, indicating that mtFASII may be involved in the regulation of bioactive lipid levels. Regulation of bioactive lipid levels by mtFASII implicates the pathway as a mediator of intracellular signaling.

Mitochondrial variation and the risk of age-related macular degeneration across diverse populations

Substantial progress has been made in identifying susceptibility variants for age-related macular degeneration (AMD). The majority of research to identify genetic variants associated with AMD has focused on nuclear genetic variation. While there is some evidence that mitochondrial genetic variation contributes to AMD susceptibility, to date, these studies have been limited to populations of European descent resulting in a lack of data in diverse populations. A major goal of the Epidemiologic Architecture for Genes Linked to Environment (EAGLE) study is to describe the underlying genetic architecture of common, complex diseases across diverse populations. This present study sought to determine if mitochondrial genetic variation influences risk of AMD across diverse populations. We performed a genetic association study to investigate the contribution of mitochondrial DNA variation to AMD risk. We accessed samples from the National Health and Nutrition Examination Surveys, a U.S population-based, cross-sectional survey collected without regard to health status. AMD cases and controls were selected from the Third NHANES and NHANES 2007-2008 datasets which include non-Hispanic whites, non-Hispanic blacks, and Mexican Americans. AMD cases were defined as those > 60 years of age with early/late AMD, as determined by fundus photography. Targeted genotyping was performed for 63 mitochondrial SNPs and participants were then classified into mitochondrial haplogroups. We used logistic regression assuming a dominant genetic model adjusting for age, sex, body mass index, and smoking status (ever vs. never). Regressions and meta-analyses were performed for individual SNPs and mitochondrial haplogroups J, T, and U. We identified five SNPs associated with AMD in Mexican Americans at p < 0.05, including three located in the control region (mt16111, mt16362, and mt16319), one in MT-RNR2 (mt1736), and one in MT-ND4 (mt12007). No mitochondrial variant or haplogroup was significantly associated in non-Hispanic blacks or non- Hispanic whites in the final meta-analysis. This study provides further evidence that mitochondrial variation plays a role in susceptibility to AMD and contributes to the knowledge of the genetic architecture of AMD in Mexican Americans.

Investigating the relationship between mitochondrial genetic variation and cardiovascular-related traits to develop a framework for mitochondrial phenome-wide association studies

Background

Mitochondria play a critical role in the cell and have DNA independent of the nuclear genome. There is much evidence that mitochondrial DNA (mtDNA) variation plays a role in human health and disease, however, this area of investigation has lagged behind research into the role of nuclear genetic variation on complex traits and phenotypic outcomes. Phenome-wide association studies (PheWAS) investigate the association between a wide range of traits and genetic variation. To date, this approach has not been used to investigate the relationship between mtDNA variants and phenotypic variation. Herein, we describe the development of a PheWAS framework for mtDNA variants (mt-PheWAS). Using the Metabochip custom genotyping array, nuclear and mitochondrial DNA variants were genotyped in 11,519 African Americans from the Vanderbilt University biorepository, BioVU. We employed both polygenic modeling and association testing with mitochondrial single nucleotide polymorphisms (mtSNPs) to explore the relationship between mtDNA variants and a group of eight cardiovascular-related traits obtained from de-identified electronic medical records within BioVU.

Results

Using polygenic modeling we found evidence for an effect of mtDNA variation on total cholesterol and type 2 diabetes (T2D). After performing comprehensive mitochondrial single SNP associations, we identified an increased number of single mtSNP associations with total cholesterol and T2D compared to the other phenotypes examined, which did not have more significantly associated SNPs than would be expected by chance. Among the mtSNPs significantly associated with T2D we identified variant mt16189, an association previously reported only in Asian and European-descent populations.

Conclusions

Our replication of previous findings and identification of novel associations from this initial study suggest that our mt-PheWAS approach is robust for investigating the relationship between mitochondrial genetic variation and a range of phenotypes, providing a framework for future mt-PheWAS.

Characterization of mitochondrial haplogroups in a large population-based sample from the United States

Mitochondrial DNA (mtDNA) haplogroups are valuable for investigations in forensic science, molecular anthropology, and human genetics. In this study, we developed a custom panel of 61 mtDNA markers for high-throughput classification of European, African, and Native American/Asian mitochondrial haplogroup lineages. Using these mtDNA markers, we constructed a mitochondrial haplogroup classification tree and classified 18,832 participants from the National Health and Nutrition Examination Surveys (NHANES). To our knowledge, this is the largest study to date characterizing mitochondrial haplogroups in a population-based sample from the United States, and the first study characterizing mitochondrial haplogroup distributions in self-identified Mexican Americans separately from Hispanic Americans of other descent. We observed clear differences in the distribution of maternal genetic ancestry consistent with proposed admixture models for these subpopulations, underscoring the genetic heterogeneity of the United States Hispanic population. The mitochondrial haplogroup distributions in the other self-identified racial/ethnic groups within NHANES were largely comparable to previous studies. Mitochondrial haplogroup classification was highly concordant with self-identified race/ethnicity (SIRE) in non-Hispanic whites (94.8 %), but was considerably lower in admixed populations including non-Hispanic blacks (88.3 %), Mexican Americans (81.8 %), and other Hispanics (61.6 %), suggesting SIRE does not accurately reflect maternal genetic ancestry, particularly in populations with greater proportions of admixture. Thus, it is important to consider inconsistencies between SIRE and genetic ancestry when performing genetic association studies. The mitochondrial haplogroup data that we have generated, coupled with the epidemiologic variables in NHANES, is a valuable resource for future studies investigating the contribution of mtDNA variation to human health and disease.

KIAA1462, a coronary artery disease associated gene, is a candidate gene for late onset Alzheimer disease in APOE carriers

Alzheimer disease (AD) is a devastating neurodegenerative disease affecting more than five million Americans. In this study, we have used updated genetic linkage data from chromosome 10 in combination with expression data from serial analysis of gene expression to choose a new set of thirteen candidate genes for genetic analysis in late onset Alzheimer disease (LOAD). Results in this study identify the KIAA1462 locus as a candidate locus for LOAD in APOE4 carriers. Two genes exist at this locus, KIAA1462, a gene associated with coronary artery disease, and "rokimi", encoding an untranslated spliced RNA The genetic architecture at this locus suggests that the gene product important in this association is either "rokimi", or a different isoform of KIAA1462 than the isoform that is important in cardiovascular disease. Expression data suggests that isoform f of KIAA1462 is a more attractive candidate for association with LOAD in APOE4 carriers than "rokimi" which had no detectable expression in brain.

Medical student appraisal: electronic resources for inpatient pre-rounding

BACKGROUND

Pre-rounding is essential to preparing for morning rounds. Despite its importance, pre-rounding is rarely formally taught within the medical school curriculum and more often informally learned by modeling residents. The evolution of mobile applications provides opportunities to optimize this process.

OBJECTIVES

To evaluate three options available to medical students while pre-rounding and promote adoption of mobile resources in clinical care.

METHODS

Six medical students formed the evaluation cohort. Students were surveyed to assess pre-rounding practices. Participants utilized paper-based pre-rounding templates for two weeks followed by two weeks of the electronic note-taking service Evernote. A review of mobile applications on the iTunes and Google Play stores was performed, with each application informally reviewed by a single student. The application Scutsheet was selected for formal review by all students. Data was collected from narrative responses supplied by students throughout the evaluation periods and aggregated to assess strengths and limitations of each application.

RESULTS

Pre-study responses demonstrated two consistent processes: verbal sign-out of overnight events and template use to organize patient information. The paper-based template was praised for its organization and familiarity amongst residents, but perceived as limited by the requirement of re-copying data into the hospital's electronic medical record (EMR). Evernote excelled due to compatibility across multiple operating systems, including accessibility from clinical workstations and ability to copy notes into the hospital's EMR. Scutsheet allowed for retention of data across multiple hospital days, but was limited by inability to export data or modify the electronic template. Aggregated user feedback identified the abilities to customize templates and copy information into the EMR as two prevailing characteristics that enhanced the efficiency of pre-rounding.

DISCUSSION

Mobile devices offer the potential to enhance pre-rounding efficiency for medical students and residents. A customizable Evernote-based system is described in sufficient detail for reproduction by interested students.

Medical student appraisal: applications for bedside patient education

BACKGROUND

Medical students are often afforded the privilege of counselling patients. In the past resources were limited to pen and paper or anatomic models. The evolution of mobile applications allows for limitless access to resources that facilitate bedside patient education.

OBJECTIVES

To evaluate the utility of six applications in patient education and promote awareness of implementing mobile resources in clinical care.

METHODS

Six medical students rotating on various clerkships evaluated a total of six mobile applications. Strengths, limitations, and suggested uses in clinical care were identified. Applications included Meditoons™, VisiblePatient™, DrawMD™, CardioTeach™, Visual Anatomy™, and 360° Patient Education Suite™. Data was generated from narrative responses supplied by each student during their evaluation period.

RESULTS

Bedside teaching was enhanced by professional illustrations and animations depicting anatomy and pathophysiology. Impromptu teaching was facilitated, as resources were conveniently available on a student's smartphone or tablet. The ability to annotate and modify images and subsequently email to patients was an extraordinary improvement in provider-patient communication. Universal limitations included small smartphone screens and the novelty of new technology.

DISCUSSION

Mobile applications have the potential to greatly enhance patient education and simultaneously build rapport. Endless opportunities exist for their integration in clinical practice, particularly for new diagnoses, consent for procedures, and at time of discharge. Providers should be encouraged to try new applications and utilize them with patients.

Trans-ethnic fine-mapping of lipid loci identifies population-specific signals and allelic heterogeneity that increases the trait variance explained

Genome-wide association studies (GWAS) have identified ∼100 loci associated with blood lipid levels, but much of the trait heritability remains unexplained, and at most loci the identities of the trait-influencing variants remain unknown. We conducted a trans-ethnic fine-mapping study at 18, 22, and 18 GWAS loci on the Metabochip for their association with triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), respectively, in individuals of African American (n = 6,832), East Asian (n = 9,449), and European (n = 10,829) ancestry. We aimed to identify the variants with strongest association at each locus, identify additional and population-specific signals, refine association signals, and assess the relative significance of previously described functional variants. Among the 58 loci, 33 exhibited evidence of association at P<1×10⁻⁴ in at least one ancestry group. Sequential conditional analyses revealed that ten, nine, and four loci in African Americans, Europeans, and East Asians, respectively, exhibited two or more signals. At these loci, accounting for all signals led to a 1.3- to 1.8-fold increase in the explained phenotypic variance compared to the strongest signals. Distinct signals across ancestry groups were identified at PCSK9 and APOA5. Trans-ethnic analyses narrowed the signals to smaller sets of variants at GCKR, PPP1R3B, ABO, LCAT, and ABCA1. Of 27 variants reported previously to have functional effects, 74% exhibited the strongest association at the respective signal. In conclusion, trans-ethnic high-density genotyping and analysis confirm the presence of allelic heterogeneity, allow the identification of population-specific variants, and limit the number of candidate SNPs for functional studies.

Lipid traits are heritable, but many of the DNA variants that influence lipid levels remain unknown. In a genomic region, more than one variant may affect gene expression or function, and the frequencies of these variants can differ across populations. Genotyping densely spaced variants in individuals with different ancestries may increase the chance of identifying variants that affect gene expression or function. We analyzed high-density genotyped variants for association with TG, HDL-C, and LDL-C in African Americans, East Asians, and Europeans. At several genomic regions, we provide evidence that two or more variants can influence lipid traits; across loci, these additional signals increase the proportion of trait variation that can be explained by genes. At some association signals shared across populations, combining data from individuals of different ancestries narrowed the set of likely functional variants. At PCSK9 and APOA5, the data suggest that different variants influence trait levels in different populations. Variants previously reported to alter gene expression or function frequently exhibited the strongest association at those signals. The multiple signals and population-specific characteristics of the loci described here may be shared by genetic loci for other complex traits.

Effects of meals high in carbohydrate, protein, and fat on ghrelin and peptide YY secretion in prepubertal children

CONTEXT

Ghrelin and peptide YY (PYY) are two hormones produced by the gastrointestinal tract that have effects on appetite. However, little is known about their secretion in response to meals high in individual macronutrients in prepubertal children.

OBJECTIVE

We sought to understand how meals high in carbohydrate, protein, and fat affect serum concentrations of total ghrelin and total PYY, hypothesizing that these macronutrients would exert differential effects on their secretion.

DESIGN AND SETTING

This was a cross-sectional study at one tertiary care center.

SUBJECTS

Subjects were 7- to 11-yr-old healthy normal-weight (NW) and obese (OB) volunteers recruited from local advertisements.

INTERVENTIONS

After an overnight fast, the subjects were given a breakfast high in carbohydrate, protein, or fat at 0800 h. Blood samples for total ghrelin and total PYY were taken at baseline, 30 min, and hourly from 0900 to 1200 h.

MAIN OUTCOME MEASURE

We assessed postprandial ghrelin suppression and PYY elevation, as well as changes in reported hunger and satiety, after the three test meals.

RESULTS

After the high-protein meal, ghrelin declined gradually in both groups over the study period without subsequent increase, whereas ghrelin suppressed more rapidly to a nadir at 60 min after the high-carbohydrate meal in both NW and OB children, followed by rebound in ghrelin levels. Similarly, after the high-protein meal, PYY concentrations increased steadily over the course of the morning in both groups without decline, whereas PYY levels peaked 30 min after the high-carbohydrate meal in both NW and OB subjects with significant decline thereafter. Ghrelin and PYY responses to the high-fat meal were somewhat intermediate between that observed with high carbohydrate and high protein. The OB children reported higher hunger and lower satiety after the high-carbohydrate meal compared to the NW subjects, whereas appetite ratings were similar between the groups after the high-protein and high-fat meals. Additionally, within the OB group, area under the curve (AUC) analysis revealed significantly greater PYY response, as well as lower AUC hunger and higher AUC satiety, to the high-protein meal than the high-carbohydrate and high-fat meals.

CONCLUSIONS

The patterns of secretion of ghrelin and PYY in our study of prepubertal children suggest that they may play a role in the effectiveness of high-protein/low-carbohydrate diets in promoting weight loss.

Defining parkinsonism in the Canadian Study of Health and Aging

This study sought an operational definition of parkinsonism in elderly people (n = 2,914) who underwent a clinical examination in the Canadian Study of Health and Aging (CSHA). Parkinsonism was defined as having two of the following features: (1) bradykinesia of face or limbs, (2) resting tremor, (3) rigidity, and (4) abnormality of gait and posture. The association of parkinsonism with other parkinsonian-related features (prior diagnosis of Parkinson's disease, use of drugs with extrapyramidal side effects, and use of antiparkinsonian medications) and variables not expected to be related to parkinsonism (stroke and Hachinski score > 5) was determined. Parkinsonism was identified in 337 people (11.6%). It was significantly more likely with other parkinsonian-related characteristics, and was not associated with a history of stroke, but was slightly higher among those subjects with a Hachinski score > 5. Posture and gait abnormalities were significantly associated with other parkinsonian-related variables, but were also more common among subjects with stroke-related features. When the gait and posture disturbance category was excluded as a parkinsonian sign, the narrower definition was more specific but less sensitive in detecting cases with a clinical diagnosis of Parkinson's disease. Despite limitations, the approach presented in this article is a valid method to operationalize parkinsonism from the dataset.

Racial and state differences in the designation of advance directives in nursing home residents

OBJECTIVES

To examine racial and state differences in the use of advance directives and surrogate decision-making in a nursing home population.

DESIGN

A retrospective cohort study.

SETTING

Nursing homes in the states of California (CA), Massachusetts (MA), New York (NY), and Ohio (OH).

PARTICIPANTS

Nursing home residents: 130,308 in CA, 59,691 in MA, 112,080 in NY, and 98,954 in OH.

MEASUREMENTS

Minimum Data Set information concerning resident race and whether or not residents have a living will (LW), a do not resuscitate (DNR) order, or a surrogate decision-maker (SDM).

RESULTS

The proportion of LWs, DNR orders, and SDMs varied significantly (P < .0001) by racial categories in each state. In general, whites were distinctly different from other racial categories. Whites were significantly more likely to have a LW (odds ratio (OR) = 1.9 (CA), OR = 2.2 (NY), OR = 4.9 (OH)), a DNR order (OR = 2.4 (CA), OR = 2.4 (MA), OR = 3.3 (NY), OR = 3.2 (OH)), and a SDM (OR = 1.1 (CA), OR = 1.2 (NY), OR = 1.6 (OH)) than were nonwhites, after adjusting for potentially confounding factors. Significant state differences (P < .0001) were observed in LWs, DNR orders, and SDMs and were most pronounced in residents of Ohio, who were significantly more likely to have a LW than were residents in other states (OR = 9.3).

CONCLUSIONS

Various resident characteristics explain some of the racial differences, although whites are still more likely to have a LW, a DNR order, or an SDM independent of various resident characteristics included in the adjusted analyses. This pattern is observed in all states, although the ORs varied by state. Some of these differences may be due to distinct cultural approaches to end-of-life care and lack of knowledge and understanding of advance directives. The distinctly higher rates of LWs among all racial groups in Ohio than in other states suggest that states can potentially increase the use of advance directives through intervention.

The hierarchy of functional loss associated with cognitive decline in older persons

OBJECTIVES

We studied a representative cohort of community-dwelling elderly persons to (i) examine the relationship between the loss of specific functional activities and cognitive status at the time of these losses, (ii) compare the cognitive status of participants who have and have not lost independence in these functional activities, and (iii) determine whether a hierarchical scale of functional loss is associated with declining cognitive status.

METHODS

A cohort of 5874 community-dwelling persons aged 65 years and older from the Canadian Study of Health and Aging I and II were analyzed. At baseline and 5 years later, cognitive status with the Modified Mini-Mental State Examination (3MS) and functional status with 14 Older American Resources and Services (OARS) items were measured. For each OARS functional item, the mean 3MS scores for persons who lost independence during the 5-year period versus those who did not were compared.

RESULTS

For each functional item, the 5-year decline in 3MS scores of persons who lost independence were significantly greater than those who remained independent (e.g., ability to do finances), with an 18-point decline for those who lost independence and a 2-point decline for those who retained independence. A hierarchy of functional items existed, with instrumental activities of daily living (ADLs) (e.g., shopping, banking, and cooking) being lost at higher cognitive scores than basic ADL items (e.g., eating, dressing, and walking), although there was some overlap.

CONCLUSIONS

This is the first prospective study using a large representative cohort of elderly persons to demonstrate that progressive cognitive decline is associated with a specific pattern of loss of functional tasks. Clear cognitive thresholds at which development of dependency in OARS functional items occurred. By providing estimates of the cognitive status of persons at the time at which they developed dependency in specific functional items, a natural hierarchy of functional loss associated with cognitive decline emerged. For caregivers, clinicians, and health policy makers, this information can help anticipate the pattern of functional decline and the subsequent care needs of persons with declining cognition, potentially improving the quality of life of these persons and their caregivers and playing an important part in health care planning.

Compressive properties of cancellous bone defects in a rabbit model treated with particles of natural bone mineral and synthetic hydroxyapatite

A rabbit model was developed to evaluate the compressive mechanical properties of cancellous bone defects treated with particles of selected bone graft substitute materials. A novel feature of the model was the precise retrieval of the site of implantation. A notable finding was a 9-fold increase in the modulus of elasticity of the defect implanted with a synthetic hydroxyapatite material after 26 weeks when compared to the modulus of the trabecular bone normally at the site. The compressive modulus of lesions treated with particles of a natural bovine bone mineral (anorganic bovine bone) was closer to the normal modulus of the cancellous bone at the site. While the compressive strength of the anorganic bone particles was less than that of normal bone, the site implanted with the bone mineral particles achieved compressive strength greater than normal after 6 weeks. Moreover, the anorganic bone particles accelerated the increase in strength of the lesion, at 6 weeks exceeding the strength achieved by the untreated defect after 26 weeks. The potential problem associated with the disparity in the compressive modulus between sites implanted with the synthetic HA particles and surrounding bone is discussed.

Randomized controlled trial of quadriceps training after proximal femoral fracture

OBJECTIVE

To determine whether systematic progressive high-intensity quadriceps training increases leg extensor power and reduces disability in patients rehabilitating after proximal femoral fracture.

DESIGN

Open parallel group randomized controlled trial comparing the addition of six weeks quadriceps training (40 patients) with standard physiotherapy alone (40 patients). The training group exercised twice weekly, with six sets of 12 repetitions of knee extension (both legs), progressing up to 80% of their one-repetition maximum.

SETTING

Orthogeriatric unit, and community follow-up.

SUBJECTS

Eighty patients rehabilitating after proximal femoral fracture.

MAIN OUTCOME MEASURES

Measurements of leg extensor power (Nottingham Power Rig), functional mobility (elderly mobility score), disability (Barthel Index) and quality of life (Nottingham Health Profile) were made at baseline, after six weeks (at the end of the intervention) and at 16 weeks.

RESULTS

Leg extensor power increased significantly in the quadriceps training group (fractured leg mean improvement at six weeks 157% (standard error 16), nonfractured leg 80% (12)) compared with the control group (63% (11) and 26% (8) respectively, unpaired Student's t-test p = 0.007 and p = 0.01 for between-group comparisons). Significant benefits were maintained at 16 weeks. Quadriceps training resulted in a greater increase in elderly mobility scale score compared with standard rehabilitation (between-group difference of 2.5 (95% CI 1.1,3.8) at week 6 and 1.9 (0.4,3.4) at week 16). Barthel score increased significantly from week 0 to 6 in the quadriceps training group compared with controls (Mann-Whitney U-test p = 0.05). Patients in the quadriceps training group scored significantly better in the energy subscore of the Nottingham Health Profile at the end of follow-up (Mann-Whitney U-test p = 0.0185).

CONCLUSIONS

Progressive high-intensity quadriceps training in elderly proximal femoral fracture patients increased leg extensor power and reduced disability. This was accompanied by an increase in energy as measured by the Nottingham Health Profile. This intervention may provide a simple practical way of improving outcome in these patients.

Movement and sound generation by the toadfish swimbladder

Although sound-producing (sonic) muscles attached to fish swimbladders are the fastest known vertebrate muscles, the functional requirement for such extreme speed has never been addressed. We measured movement of the swimbladder caused by sonic muscle stimulation in the oyster toadfish Opsanus tau and related it to major features of the sound waveform. The movement pattern is complex and produces sound inefficiently because the sides and bottom of the bladder move in opposite in and out directions, and both movement and sound decay rapidly. Sound amplitude is related to speed of swimbladder movement, and slow movements do not produce perceptible sound. Peak sound amplitude overlaps fundamental frequencies of the male's mating call because of muscle mechanics and not the natural frequency of the bladder. These findings suggest that rapid muscle speed evolved to generate sound from an inefficient highly damped system.

A comparison of mobility assessments in a geriatric day hospital

OBJECTIVE

To assess the sensitivity of the Elderly Mobility Scale (EMS) to detect improvements in mobility after physiotherapy in comparison with the Barthel Index (BI) and Functional Ambulation Category (FAC) in routine clinical day hospital practice.

SUBJECTS

Eighty-three patients who completed a course of physiotherapy were studied.

METHODS

Each was assessed by an independent physiotherapist before and after a programme of physiotherapy, using the EMS, BI and FAC.

RESULTS

The mean age was 79 years (SD 7.7). Fifty-three out of 83 (64%) patients were female and 92% were community dwelling. The median number of physiotherapy sessions undergone by each patient was 9 (range 3-51). All three scales detected an improvement in mobility with physiotherapy (p < 0.001). However, using the EMS, 68 out of 82 (83%) patients had a detectable improvement in mobility compared with only 34 out of 80 (42%) using the BI and 28 out of 81 (35%) using the FAC. Using a matched-pairs comparison, the EMS was significantly more likely to detect an improvement in mobility following physiotherapy within the study group than the BI (p < 0.001) or the FAC (p < 0.001).

CONCLUSION

Although all three scales detected improvements in mobility, the EMS detected mobility improvements in a significantly greater number of patients.

The association between antiulcer medication and initiation of cobalamin replacement in older persons

As chronic use of antiulcer medications might predispose older persons to cobalamin deficiency, we studied participants (> 65 years) in the clinical examination of the Canadian Study of Health and Aging to test the association between the use of an antiulcer medication (histamine-2 blocker or proton pump inhibitor) at baseline with initiation of cobalamin replacement during the 5 year follow-up period. Of 1054 eligible subjects, 125 (11.7%) were taking an antiulcer medication at baseline. At follow-up, 49 (4.6%) had started cobalamin replacement. Antiulcer medication use at baseline was significantly associated with the initiation of cobalamin therapy (odds ratio 2.56, 95% confidence interval 1.30-5.05), even after adjusting for age, gender and institutional residence (odds ratio 2.61, 95% confidence interval 1.31-5.23). There is an independent association between the use of antiulcer medication and initiation of cobalamin therapy. While the relationship is not unambiguously causal, this finding underscores the need for judicious prescribing of antiulcer medications for older persons.

Influence of bone densitometry results on the treatment of osteoporosis

BACKGROUND

Measurement of bone mineral density is widely used to diagnose osteoporosis. The objectives of this study are to determine how bone densitometry affects subsequent treatment of osteopenia and osteoporosis with either hormone replacement therapy or bisphosphonates and to examine clinical factors associated with starting either therapy after bone densitometry.

METHODS

We conducted a prospective study involving women over 50 years of age who were referred to a tertiary care hospital for the first time to undergo bone density measurement using dual-energy x-ray absorptiometry (DXA). Baseline clinical data were collected through face-to-face interviews before the test. Subsequently, the scans were reviewed and categorized as showing no bone loss, osteopenia or osteoporosis, based on World Health Organization criteria. Three months after DXA, subjects were contacted by telephone to determine their understanding of the test results and any new treatments started or recommended since the scan.

RESULTS

Of 383 women recruited at the time of their DXA, 335 (87.5%) completed the 3-month follow-up. Among those reached at follow-up, DXA results showed no bone loss in 119 (35.5%), osteopenia in 137 (40.9%) and osteoporosis in 79 (23.6%). The proportion of subjects with osteoporosis receiving either hormone replacement therapy or bisphosphonate therapy was 15.2% before the test, increasing to 63.3% after the scan. The following factors were independently associated with the initiation of either therapy: actual DXA result showing osteoporosis (odds ratio [OR] 7.2; 95% confidence interval [CI] 1.7-30.3), compared with a normal scan; subjects' perception that their scan showed bone loss (osteopenia, or osteoporosis) (OR 13.5; 95% CI 4.0-45.5) or that they were unclear about the results (OR 5.4; 95% CI 1.6-18.8), compared with the perception that the results were normal; and discussion of the DXA results with a physician (OR 5.5; 95% CI 1.9-16.0).

INTERPRETATION

The proportion of women with osteoporosis receiving hormone replacement therapy or bisphosphonate therapy increases after diagnosis with densitometry. However, communication by physicians so that patients understand their test results is a critical component in the initiation of therapy after bone densitometry.

A decision aid for long-term tube feeding in cognitively impaired older persons

OBJECTIVE

To describe the development and evaluation of a decision aid for long-term tube feeding in cognitively impaired older people.

DESIGN

Before-and-after study.

SETTING

Acute care hospitals in Ottawa, Canada.

PARTICIPANTS

Substitute decision makers for 15 cognitively impaired inpatients 65 years and older being considered for placement of a percutaneous endoscopic gastrostomy tube.

MEASUREMENTS

Questionnaires were used to compare the substitute decision makers' knowledge, decisional conflict, and predisposition regarding feeding tube placement before and after exposure to the decision aid. The acceptability of the decision aid was also assessed.

RESULTS

Substitute decision makers significantly increased their knowledge (P = .004) and decreased their decisional conflict (P = .004) regarding long-term tube feeding after using the decision aid. The impact of the decision aid on predisposition toward the intervention was greatest for those who were unsure of their preferences at baseline. All substitute decision makers found the decision aid helpful and acceptable despite very difficult and emotional circumstances.

CONCLUSIONS

A decision aid improves the decision-making process for long-term tube feeding in cognitively impaired older patients by decreasing decisional conflict and by promoting decisions that are informed and consistent with personal values. There are particular challenges for developing and evaluating these tools in the context of end-of-life decisions.

A cross-national comparison of institutionalized tube-fed older persons: the influence of contrasting healthcare systems

OBJECTIVE

Different health care settings may influence the type of patients selected for long-term tube-feeding. Clinical characteristics of older, tube-fed institutionalized subjects living in Ontario, Canada were compared with those in the United States (US).

DESIGN

A cross-sectional cohort study Setting: Nursing homes in the states of Mississippi, Texas, and Vermont (US) and chronic care facilities in Ontario.

PARTICIPANTS

Tube-fed residents older than age 65 living in facilities in the US between January 1, 1996, and March 31, 1997 (n = 859), and in institutions in Ontario between January 1, 1996, and December 31, 1997 (n = 913).

MEASUREMENTS

Data were obtained from Minimum Dataset assessments at both sites. Demographic and clinical characteristics were compared between tube-fed subjects living in the US and those in Canadian facilities.

RESULTS

In a logistic regression model, the following characteristics were significantly more likely to be found among tube-fed subjects in the US than in those in Ontario: greater impairment of cognitive performance, cardiopulmonary disease, a diagnosis of dementia, female, and age greater than 80 years. Characteristics that were significantly less likely to be present among the US tube-fed subjects included: recurrent lung aspirations, a chewing or swallowing problem, do not resuscitate status, restraint use, weight loss, and stroke.

CONCLUSIONS

Clinical characteristics differ between older, institutionalized tube-fed subjects in Ontario and in US nursing homes. In order to put these differences into context, consideration must be given to how the contrasting healthcare systems in these two countries may drive decision-making for long-term tube-feeding.

Survival after percutaneous endoscopic gastrostomy placement in older persons

BACKGROUND

The prolongation of life is an important consideration in the decision to initiate long-term tube feeding. This report critically synthesizes the evidence regarding the impact of percutaneous endoscopic gastrostomy (PEG) tube placement on survival in older persons.

METHODS

A systematic search was conducted using MEDLINE from January 1980 until January 1999. Articles reporting survival data in older persons (mean or median age >65 years) after PEG tube placement were identified. The number and age of subjects, length of follow-up, setting, and survival data were extracted from all eligible studies. Mortality data at 1, 2, 6, and 12 months after PEG placement were quantitatively synthesized. Clinical characteristics associated with decreased survival among subjects with PEG tubes were identified.

RESULTS

Five cohort studies compared survival in patients with and without feeding tubes in nursing homes, but none demonstrated a survival benefit. Another cohort study reported increased survival for tube-fed patients with amyotrophic lateral sclerosis. The pooled proportion of all subjects surviving after PEG placement was as follows: 1 month = 0.81 (95% confidence interval [CI], 0.74-0.88), 2 months = 0.70 (95% CI, 0.65-0.74), 6 months = 0.56 (95% CI, 0.20-0.92), and 12 months = 0.38 (95% CI, 0.26-0.49). Advanced age and malignancy were the factors most often reported to be associated with poorer survival among subjects with PEG tubes.

CONCLUSIONS

The impact of PEG placement on survival is not known because the level of evidence is limited. PEG tubes may prolong life in selected populations. However, the majority of older patients selected for PEG placement will not survive 1 year after the procedure. Certain factors may identify those patients more likely to derive a survival benefit from long-term tube feeding. This information may offer some guidance to decision makers for whom prolongation of life is an important factor in the tube-feeding decision.

A retrospective comparison of abdominal muscle strength following breast reconstruction with a free TRAM or DIEP flap

Abdominal weakness is a known potential complication of breast reconstruction with a pedicled or free TRAM flap. It has been presumed that the DIEP flap, which involves no muscle resection, does not compromise abdominal muscle strength but little objective research exists to substantiate this. The aims of this retrospective study were to compare abdominal muscle strength following free TRAM flap and DIEP flap, to compare both groups with a control group and to establish the effect of both procedures on functional activities. Fifty women (23 with a DIEP flap, 27 with a free TRAM flap) plus 32 non-operated controls underwent assessment of their abdominal and back extensor muscle strength on a KIN COM isokinetic dynamometer. Two questionnaires were used to establish the impact on function. The TRAM flap group had significant weakness of the abdominal and back extensor muscles compared with the DIEP flap group and the control group. The trend was for the DIEP flap group to have weaker abdominal muscles than the control group. There was a higher level of abdominal pain and a greater number of reported functional difficulties in the TRAM flap group than in the DIEP flap group. This study demonstrates that whilst the DIEP flap can reduce the strength deficit caused by the free TRAM flap, abdominal weakness can still result from the DIEP flap. A randomised controlled trial is currently underway to investigate the effect of preoperative abdominal exercises in preventing/minimising postoperative abdominal muscle weakness in this group.

Migration of polyethylene particles around stable implants in an animal model

The aim of this study was to test the hypothesis that a tight seal between bone and implant will eliminate the avenue of particle migration around stable implants. Three types of implants were used in rabbits (polished press-fit Ti-6Al-4V or plasma-sprayed hydroxyapatite [HA]-coated Ti-6Al-4V) or doughy stage polymethyl methacrylate (PMMA). Implants were placed in the condylar notch. Each animal received an intra-articular injection of high density polyethylene (PE) particles (10(8) in 0.4 mL; mean size 4.7 microns) at 4 and 6 weeks postoperatively. Eight weeks postoperatively, peri-implant tissues were examined for PE particles and osteolysis. In all cases, intracellular PE particles were seen at the bone-implant interface and within marrow. No osteolysis was observed. Bone apposition was determined by computerized image analysis. There was no significant difference in the percentage of bone apposition (+/- SD) among the three groups of implants: Ti-6Al-4V (68% +/- 19%), HA-coated Ti-6Al-4V (70% +/- 10%), and PMMA (59% +/- 12%). These results indicate that a polished Ti-6Al-4V surface is as effective as PMMA or HA coating in limiting migration of PE particles around stable osseointegrated implants in rabbits.

Tracheal rupture associated with intubation in cats: 20 cases (1996-1998)

OBJECTIVE

To characterize clinical features of tracheal rupture associated with endotracheal intubation in cats and to evaluate the most appropriate treatment for this condition.

DESIGN

Retrospective study.

ANIMALS

20 cats with a history of endotracheal intubation that subsequently developed dyspnea or subcutaneous emphysema.

PROCEDURE

Medical records of cats with a presumptive diagnosis of tracheal rupture associated with intubation were reviewed. Clinical and clinicopathologic data were retrieved.

RESULTS

Cats were evaluated 5 hours to 12 days after a surgical or medical procedure requiring general anesthesia with intubation had been performed. Fourteen (70%) cats were evaluated after dental prophylaxis. All cats radiographed had pneumomediastinum and subcutaneous emphysema. Eighteen of 19 cats were initially treated medically. Duration of medical treatment for cats that did not have surgery ranged from 12 to 72 hours. Cats that had surgery received medical treatment 3 to 24 hours prior to the surgical procedure. Medical treatment alone was administered to 15 cats that had moderate dyspnea, whereas surgical treatment was chosen for 4 cats that had severe dyspnea (open-mouth breathing despite treatment with oxygen) or worsening subcutaneous emphysema. Eighteen cats had improvement of clinical signs, 1 cat died after surgery, and 1 cat died before medical or surgical intervention.

CONCLUSIONS AND CLINICAL RELEVANCE

Most cats with tracheal rupture associated with intubation can be treated medically. Cats with worsening clinical signs (severe dyspnea, suspected pneumothorax, or worsening subcutaneous emphysema) should have surgery performed immediately to correct the defect.

The association between parkinsonism, Alzheimer's disease, and mortality: a comprehensive approach

BACKGROUND

The impact of parkinsonism on survival in older persons independent of dementia is not well understood.

METHODS

Participants in the clinical examination of the Canadian Study of Health and Aging who had parkinsonism and were older than age 65 were identified. The impact of parkinsonism on 5-year survival was determined for a combined cohort with and without dementia, and a stratified analysis was then conducted for the subgroups with Alzheimer's disease (AD) and those without dementia. Subjects with a previous diagnosis of Parkinson's disease and those prescribed drugs causing extrapyramidal side effects were excluded.

FINDINGS

A total of 721 subjects with AD and 1705 subjects without dementia were examined. After adjusting for age and residential status (community vs institution), parkinsonism was associated with poorer survival in the combined cohort (risk ratio 1.51; 95% CI, 1.22-1.85), in those with AD (risk ratio 1.34; 95% CI, 1.02-1.76), and those without dementia (risk ratio 1.54; 95% CI, 1.11-2.15). In the combined cohort, parkinsonism remained independently associated with higher mortality after adjusting for AD status (risk ratio 1.39; 95% CI, 1.13-1.72). In the subgroup with AD, parkinsonism remained associated with poorer survival after adjusting for severity of cognitive impairment (risk ratio 1.33; 95% CI. 1.04-1.74).

INTERPRETATION

Parkinsonism is significantly associated with poorer survival in older persons, regardless of whether they have dementia.

A cross-national survey of tube-feeding decisions in cognitively impaired older persons

OBJECTIVES

Many factors affect the decision to institute long-term tube-feeding in older persons. The objectives of this cross-national survey are to examine the tube-feeding decision-making process for cognitively impaired older persons from the perspective of the substitute decision-makers (SDM) and to contrast this process in US and Canadian healthcare settings.

DESIGN

Survey.

SETTING

Chronic care facilities in Ottawa and nursing homes in Boston.

PARTICIPANTS

Patients more than age 65 who were tube-fed for at least 2 months and who were unable to make their own healthcare decisions at the time of tube placement were identified at both sites. The SDMs of 46 patients in Ottawa and 48 patients in Boston were surveyed.

MEASUREMENTS

The survey asked questions relating to the following categories: health status of the patient, advance directives, communication with the healthcare team, perceived goals of tube-feeding, decision satisfaction, and sociodemographic data.

RESULTS

Tube-fed patients in Boston were more likely to have a diagnosis of dementia than those in Ottawa (60.4% vs 10.9%, P < .001) and were less likely to have had an acute neurological event (35.4% vs 71.7%, P < .001). There was a greater likelihood in Boston than in Ottawa (68.7% vs 6.5%, P < .001) for tube-feeding decisions to be made in a nursing home (vs an acute hospital). In the combined cohort, 19.1% of patients had a living will, and only 47.9% of SDMs felt confident that the patients would want to have a feeding tube. The majority of SDMs at both sites felt they understood the benefits (83.0%), but not the risks (48.9%), of tube-feeding. The most commonly perceived reasons for tube-feeding were to "prolong life" (84.0%) and to "prevent aspiration" (67.0%). Approximately half of all SDMs felt they had received adequate support from the healthcare team. A minority of SDMs (38.3%) at both sites stated that they would want a feeding tube for themselves, and only 40% of SDMs felt the feeding tube had improved the patients' quality of life.

CONCLUSIONS

A greater proportion of patients have feedings tubes inserted because of a degenerative dementia in Boston compared with an acute neurological event in Ottawa. Despite the difference in diagnostic indication for tube-feeding, the substitute decision-making process was seriously limited at both sites by poor implementation of the principle of substituted judgement, a need for broader advance directives, and improved transfer of knowledge between clinicians and decision-makers.

Patterns of outcome measurement in Parkinson's disease clinical trials

The study examines the pattern of use and clinimetric properties of clinical endpoints used in randomized trials for Parkinson's disease (PD). Randomized drug trials for PD were identified through a Medline search conducted from January 1966 until August 1998. The endpoints used in these trials were abstracted. Reports examining the clinimetric properties of the disease-specific scales used in these trials were also abstracted. Data regarding the consistency, accuracy, discrimination and feasibility of scales used in at least 10% of trials were determined. One hundred and thirty-seven articles met the inclusion criteria; 70.8% of trials used some clinical scale for PD as an endpoint. The Unified Parkinson's Disease Rating Scale (UPDRS) was the most commonly used scale (32.8%). Factors independently associated with the use of the UPDRS included: the study location in the US, mean age of subjects over 62.7 years and publication after 1994. The UPDRS was more thoroughly studied and superior in most clinimetric domains compared to scales developed earlier. Few studies included generic health status (2.9%) or cognitive measures (16.8%) as secondary endpoints. There have been definite improvements in the area of disease-specific measurement in PD trials since the introduction of the UPDRS. The results of studies that used instruments with poor or unreported clinimetric properties should be critically interpreted.

Assessing the quality of newspaper medical advice columns for elderly readers

BACKGROUND

Medical advice columns in newspapers can provide a valuable service by educating the general public about important health-related issues. However, these columns may be harmful if the advice or information given in them is incomplete, inappropriate or misleading. The objective of this study was to assess the safety and appropriateness of advice given to elderly readers of newspapers in medical advice columns.

METHODS

Medical advice columns published in Canadian newspapers in 1995 were identified from a CD-ROM database. The articles that were selected were published in English and contained medical advice pertinent to elderly people about topics that could be found in a textbook of geriatric medicine. Fifty articles, randomly selected from the 109 articles that met these criteria, were independently assessed by 5 geriatricians. A scoring system was used to rate the ability to determine to which population the article applied, how well fact was distinguished from opinion, the degree to which critical issues were addressed, the safety and the appropriateness of the advice. When the kappa statistic for inter-rater agreement was 0.74 or less, a 2-stage Delphi process was used in an attempt to reach consensus.

RESULTS

Agreement (kappa > 0.74) was eventually achieved for 232 (92.8%) of the 250 ratings. In 4 (8%) of the articles there was a high probability that the advice given could be applied to the wrong patient population; in 7 (14%) there was a high probability that opinion might be interpreted as fact; and in 11 (22%) the major critical issues were not identified. Of greatest concern, however, the advice in 25 (50%) of the articles was judged to be inappropriate, and in 14 (28%) advice may have been dangerous and potentially life-threatening.

INTERPRETATION

Although medical advice columns have the potential to improve the health of elderly readers, a significant percentage of these articles contain inappropriate or even potentially dangerous advice.

Decision-making for long-term tube-feeding in cognitively impaired elderly people

BACKGROUND

The decision to start long-term tube-feeding in elderly people is complex. The process by which such decisions are made is not well understood. The authors examined the factors involved in the decision to start long-term tube-feeding in cognitively impaired older people from the perspective of the substitute decision-maker.

METHODS

A telephone survey was administered to the substitute decision-makers of tube-fed patients over 65 years old in chronic care facilities in Ottawa. Subjects were recruited from September 1997 to March 1998. Patients were incapable of making their own decisions about tube-feeding. Data were collected on sociodemographic factors, patients' health status, advance directives, communication between the substitute decision-maker and the health care team, and the decision-maker's perceived goals of tube-feeding and satisfaction with the decision regarding tube-feeding.

RESULTS

Among the 57 cases in which the patient was eligible for inclusion in the study, 46 substitute decision-makers agreed to participate. Most of the patients had not given advance directives, and only 26 substitute decision-makers (56.5%) were confident that the patient would want to be tube-fed. A physician spoke with the substitute decision-maker about tube-feeding for 15 minutes or less in 17 cases (37.0%) and not at all in 13 cases (28.3%). Most of the substitute decision-makers (39 [84.8%]) felt that they understood the benefits of tube-feeding, but less than half (21 [45.7%]) felt that they understood the risks. The prevention of aspiration and the prolongation of life were the medical benefits most often cited as reasons for tube-feeding. Just over half (24 [52.2%]) of the substitute decision-makers felt that they had received adequate support from the health care team in making the decision. Substitute decision-makers of patients less than 75 years old were more likely than those of older patients to feel supported (odds ratio [OR] 4.2, 95% confidence interval [CI] 1.0-17.9). Compared with the physician's making the decision independently, substitute decision-makers felt more supported if they primarily made the decision (OR 16.5, 95% CI 2.7-101.4) or if they made the decision together with the physician (OR 5.3, 95% CI 1.0-27.9). Most (20 [43.5%]) of the substitute decision-makers did not feel that tube-feeding improved the patient's quality of life, and less than half (21 [45.7%]) indicated that they would choose the intervention for themselves.

INTERPRETATION

The substitute decision-making process for tube-feeding in cognitively impaired elderly people is limited by a need for advance directives, lack of confidence in substituted judgement and poor communication of information to the substitute decision-maker by the health care team.

Assessing muscle stiffness from quiet stance in Parkinson's disease

In previous studies, we developed a postural stiffness measure that is extracted from foot center-of-pressure (COP) trajectories from quietly standing individuals and is based on an analytical mechanical model of posture control. Here we apply this measure to patients with Parkinson's disease (PD). We correlated the postural stiffness measure with different clinical rating scales, obtained from patients. Kendall's rank correlation was highly significant between the stiffness measure and rigidity, bradykinesia, posture impairment, gait, and leg agility, respectively, as rated by the Unified Parkinson's Disease Rating Scale. These results provide further evidence that a higher intrinsic muscle stiffness may contribute to the aforementioned clinically defined symptoms. From a clinical standpoint, this work indicates that the proposed postural stiffness measure may be useful as an assessment tool for the evaluation of PD patients subsequent to pharmacological and surgical treatment.

Radiologic diagnosis and staging of head and neck squamous cell carcinoma

The predominant extracranial head and neck cancer in adults is squamous cell carcinoma. The purpose of this article is to discuss the radiographic evaluation of these patients with CT scans or MR imaging before therapeutic intervention. Specific focus is given to the efficacy of CT scans and MR imaging, as an adjunct to clinical staging for evaluation of the primary tumor, and metastatic adenopathy. MR imaging, because of its improved soft tissue contrast and multiplanar capability, is probably superior to CT scans for evaluation of the primary tumor in patients with squamous cell carcinoma. CT scans, however, remain the gold standard for identifying metastatic adenopathy and in most institutions remain the study of choice for evaluating this patient population.

Does artificial enteral nutrition prolong the survival of institutionalized elders with chewing and swallowing problems?

BACKGROUND

There is a lack of prognostic data regarding tube feeding of institutionalized elderly people. The objective of this study was to determine the impact of feeding tubes on the survival of nursing home residents with chewing and swallowing problems, and to follow the course of the tube-fed residents over one year.

METHODS

We conducted a cohort study with 12-month follow-up using Minimum Data Set resident assessments from 1991. Participants included 5,266 nursing home residents over the age of 65 with chewing and swallowing problems living in 272 Washington state nursing homes. Residents who had a feeding tube were identified. Baseline clinical characteristics and 12-month survival were compared for residents with and without feeding tubes. The proportion of tube-fed residents who became tube-free during the follow-up period was determined, and clinical features that predicted this outcome were examined.

RESULTS

Among the residents with chewing and swallowing problems, 10.5% had a feeding tube. After adjusting for potential confounding covariates, tube-fed residents had a significantly higher one-year mortality rate than those without feeding tubes (risk ratio, 1.44; 95% CI, 1.17-1.76). Of the 430 residents with feeding tubes who survived the follow-up period, 25.1% became free of a feeding tube. Age less than 87 years was associated with a significantly greater likelihood of becoming tube-free (odds ratio, 1.66; 95% CI, 1.03-2.6).

CONCLUSIONS

Residents selected for feeding tube placement have poorer survival after one year than residents who are not tube-fed. However, the feeding tubes are removed in a significant proportion of residents who survive one year. Residents with a potentially reversible condition, for whom the feeding tubes are a temporary intervention, need to be identified.

Interaction of stress, smoking, and dietary restraint in women

Smoking cessation often results in weight gain but certain subtypes of smokers may be more likely than others to gain weight. Women high in dietary restraint ("restrainers") increase food intake and gain more weight than nonrestrainers during smoking cessation. Restrainers have also been reported to increase food intake following laboratory stressors. Therefore, the present study was designed to measure the influence of stress on food intake and subjective distress during acute smoking abstinence in restrained and nonrestrained women. Participants were 48 women, 18-40 years old, comprising six groups (n = 8 per group) in a 2 x 3 x 2 design. Groups consisted of two levels of restraint (restrained and nonrestrained) and three levels of smoking (ad lib. smokers, abstinent smokers, and nonsmokers), whereas the within-participant manipulation involved two sessions differing in stress (stress and control). Snack foods were available for consumption. Results showed that distress, measured by the Stress-Arousal Checklist and visual analogue measures of tension and anxiety, was higher in the stress session for all groups except for restrainers who smoked ad lib. Furthermore, distress was significantly higher in smoke-abstinent restrainers during the stress session than all other conditions. However, despite differences in distress, no effect was observed for food intake. Desire for a cigarette showed a sharper increase over the stress session for restrainers compared with nonrestrainers but did not differ in the control session. These data suggest that restrainers may use smoking to reduce distress and may increase smoking, but not eating, during stress.

Exclusion of elderly subjects from clinical trials for Parkinson disease

OBJECTIVES

To determine whether subjects older than 75 years are included in the randomized controlled trials of antiparkinsonian medications conducted during the last 30 years and to identify study characteristics that are associated with the exclusion of patients of advanced age.

METHODS

A systematic search was conducted on MEDLINE from January 1966 until September 1996 of all randomized controlled trials of drugs used to treat the motor symptoms of Parkinson disease. Articles were abstracted for the age of subjects date of publication, geographic location, drug class studied, stage of Parkinson disease of subjects, and the number of subjects in each trial.

RESULTS

One hundred twelve articles met the inclusion criteria. The weighted mean (+/- SD) age for subjects in all trials was 62.2 +/- 3.9 years. Forty-two studies (37.5%) included subjects older than 75 years. However, in 31 articles (27.7%) it could not be determined if subjects older than 75 years were included. Among the 8 studies that provided the actual number of subjects within specific age groups, only 8 (5.5%) of 145 subjects were older than 75 years. Publication in the last decade was significantly associated with a decreased likelihood of including subjects older than 75 years (odds ratio, 0.19; 95% confidence interval, 0.06-0.62).

CONCLUSIONS

The relatively small number of subjects older than 75 years included in controlled trials of antiparkinsonian drugs seriously impedes our understanding of the efficacy and safety of these drugs in a large subgroup of frail patients for whom these products are prescribed. The tendency to exclude subjects of advanced age is highest in the most recently published articles that study new advances in pharmacotherapy. There is inadequate reporting of the age characteristics of subjects in clinical trials. This limitation hinders the synthesis of data regarding drug efficacy and toxicity relevant to older age groups.

Increased gait unsteadiness in community-dwelling elderly fallers

OBJECTIVE

To test the hypothesis that quantitative measures of gait unsteadiness are increased in community-dwelling elderly fallers.

STUDY DESIGN

Retrospective, case-control study.

SETTING

General community.

PARTICIPANTS

Thirty-five community-dwelling elderly subjects older than 70 years of age who were capable of ambulating independently for 6 minutes were categorized as fallers (age, 82.2 +/- 4.9 yrs [mean +/- SD]; n = 18) and nonfallers (age, 76.5 +/- 4.0 yrs; n = 17) based on history; 22 young (age, 24.6 +/- 1.9 yrs), healthy subjects also participated as a second reference group.

MAIN OUTCOME MEASURES

Stride-to-stride variability (standard deviation and coefficient of variation) of stride time, stance time, swing time, and percent stance time measured during a 6-minute walk.

RESULTS

All measures of gait variability were significantly greater in the elderly fallers compared with both the elderly nonfallers and the young subjects (p < .0002). In contrast, walking speed of the elderly fallers was similar to that of the nonfallers. There were little or no differences in the variability measures of the elderly nonfallers compared with the young subjects.

CONCLUSIONS

Stride-to-stride temporal variations of gait are relatively unchanged in community-dwelling elderly nonfallers, but are significantly increased in elderly fallers. Quantitative measurement of gait unsteadiness may be useful in assessing fall risk in the elderly.

The risk factors and impact on survival of feeding tube placement in nursing home residents with severe cognitive impairment

BACKGROUND

The provision of artificial enteral nutrition to an aged person with severe cognitive impairment is a complex dilemma in the long-term care setting.

OBJECTIVE

To determine the risk factors and impact on survival of feeding tubes in nursing home residents with advanced cognitive impairment.

METHODS

We conducted a cohort study with 24-month follow-up using Minimum Data Set resident assessments on 1386 nursing home residents older than 65 years with recent progression to severe cognitive impairment in the state of Washington. Residents within this population who underwent feeding tube placement were identified. Clinical characteristics and survival for a period of 24 months were compared for residents who were and were not tube fed.

RESULTS

Among the residents with recent progression to severe cognitive impairment, 9.7% underwent placement of a feeding tube. Factors independently associated with feeding tube placement included age younger than 87 years (odds ratio [OR], 1.85; 95% confidence interval [CI], 1.25-2.78), aspiration (OR, 5.46; 95% CI, 2.66-11.20), swallowing problems (OR, 3.00; 95% CI, 1.81-4.97), pressure ulcer (OR, 1.64; 95% CI, 1.23-2.95), stroke (OR, 2.12; 95% CI, 1.17-2.62), less baseline functional impairment (OR, 2.07; 95% CI, 1.27-3.36), no do-not-resuscitate order (OR, 3.03; 95% CI, 1.92-4.85), and no dementia (OR, 2.17; 95% CI, 1.43-3.22). Survival did not differ between groups of residents with and without feeding tubes even after adjusting for independent risk factors for feeding tube placement.

CONCLUSIONS

There are specific risk factors associated with feeding tube placement in nursing home residents with severe cognitive impairment. However, there is no survival benefit compared with similar residents who are not tube fed. These prognostic data are important for health care providers, families, and patients making decisions regarding enteral nutritional support in long-term care.

Altered fractal dynamics of gait: reduced stride-interval correlations with aging and Huntington's disease

Fluctuations in the duration of the gait cycle (the stride interval) display fractal dynamics and long-range correlations in healthy young adults. We hypothesized that these stride-interval correlations would be altered by changes in neurological function associated with aging and certain disease states. To test this hypothesis, we compared the stride-interval time series of 1) healthy elderly subjects and young controls and of 2) subjects with Huntington's disease and healthy controls. Using detrended fluctuation analysis we computed alpha, a measure of the degree to which one stride interval is correlated with previous and subsequent intervals over different time scales. The scaling exponent alpha was significantly lower in elderly subjects compared with young subjects (elderly: 0.68 +/- 0.14; young: 0.87 +/- 0.15; P < 0.003). The scaling exponent alpha was also smaller in the subjects with Huntington's disease compared with disease-free controls (Huntington's disease: 0.60 +/- 0.24; controls: 0.88 +/-0.17; P < 0.005). Moreover, alpha was linearly related to degree of functional impairment in subjects with Huntington's disease (r = 0.78, P < 0.0005). These findings demonstrate that strike-interval fluctuations are more random (i.e., less correlated) in elderly subjects and in subjects with Huntington's disease. Abnormal alterations in the fractal properties of gait dynamics are apparently associated with changes in central nervous system control.