Validation of a Risk Equation Predicting Hemodialysis Arteriovenous Fistula Primary Failure in Elderly

2019 ◽  
Vol 51 (1) ◽  
pp. 17-23
Author(s):  
Joyce Z. Qian ◽  
Mara A. McAdams-DeMarco ◽  
Derek Ng ◽  
Bryan Lau
Keyword(s):  
United States ◽  
Arteriovenous Fistula ◽  
The United States ◽  
Hemodialysis Patients ◽  
Calibration Plot ◽  
Good Prediction ◽  
Validation Data ◽  
Data Set ◽  
Risk Equation ◽  
Good Prediction Accuracy

Background: Choice of vascular access for older hemodialysis patients presents a special challenge since the rate of arteriovenous fistula (AVF) primary failure is high. The Lok’s risk equation predicting AVF primary failure has achieved good prediction accuracy and holds great potential for clinical use, but it has not been validated in the United States older hemodialysis patients. Methods: We assembled a validation data set of 14,892 patients aged 67 years and older who initiated hemodialysis with a central venous catheter between July 1, 2010, and June 30, 2012, and had a subsequent, incident AVF placement from the United States Renal Data System. We examined the external validity of Lok’s model by applying it to this validation data set. The discriminatory accuracy and calibration were evaluated by the concordance index (C-statistics) and calibration plot, respectively. Results: The observed frequency of AVF primary failure varied from 0.45 to 0.53 in hemodialysis patients in the validation data set. The predicted probabilities of AVF primary failure calculated by using the Lok’s risk equation ranged from 0.08 to 0.61, and 77.8, 40.5, and 51.7% of patients were categorized as having high, intermediate, and low risk of AVF primary failure, respectively. The C-statistics of the Lok’s risk equation in the validation data set was 0.53 (95% CI 0.52–0.54). The predicted probabilities of AVF primary failure corresponded poorly with the observed proportions in the calibration plot. Conclusions: When externally applied to a cohort of U.S. older hemodialysis patients, the Lok’s risk equation exhibited poor discrimination and calibration accuracy. It is invalid to use it to predict AVF primary failure. A more complex model with strong predictors is expected to better serve clinical determination for AVF placement in this population.

scholarly journals Arteriovenous Fistula Maturation in Prevalent Hemodialysis Patients in the United States: A National Study

2018 ◽  
Vol 71 (6) ◽  
pp. 793-801 ◽  
Author(s):  
Kenneth J. Woodside ◽  
Sarah Bell ◽  
Purna Mukhopadhyay ◽  
Kaitlyn J. Repeck ◽  
Ian T. Robinson ◽  
...  
Keyword(s):  
United States ◽  
Arteriovenous Fistula ◽  
The United States ◽  
Hemodialysis Patients ◽  
National Study ◽  
Fistula Maturation ◽  
Arteriovenous Fistula Maturation

scholarly journals Altitude and risk of sudden unexpected infant death in the United States

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Richard Johnston ◽  
Xiaohan Yan ◽  
Tatiana M. Anderson ◽  
Edwin A. Mitchell
Keyword(s):  
United States ◽  
Logistic Regression ◽  
Infant Death ◽  
The United States ◽  
Sudden Infant ◽  
Data Set ◽  
Live Births ◽  
Sudden Unexpected Infant Death ◽  
Increased Risk ◽  
Unexpected Infant Death

AbstractThe effect of altitude on the risk of sudden infant death syndrome (SIDS) has been reported previously, but with conflicting findings. We aimed to examine whether the risk of sudden unexpected infant death (SUID) varies with altitude in the United States. Data from the Centers for Disease Control and Prevention (CDC)’s Cohort Linked Birth/Infant Death Data Set for births between 2005 and 2010 were examined. County of birth was used to estimate altitude. Logistic regression and Generalized Additive Model (GAM) were used, adjusting for year, mother’s race, Hispanic origin, marital status, age, education and smoking, father’s age and race, number of prenatal visits, plurality, live birth order, and infant’s sex, birthweight and gestation. There were 25,305,778 live births over the 6-year study period. The total number of deaths from SUID in this period were 23,673 (rate = 0.94/1000 live births). In the logistic regression model there was a small, but statistically significant, increased risk of SUID associated with birth at > 8000 feet compared with < 6000 feet (aOR = 1.93; 95% CI 1.00–3.71). The GAM showed a similar increased risk over 8000 feet, but this was not statistically significant. Only 9245 (0.037%) of mothers gave birth at > 8000 feet during the study period and 10 deaths (0.042%) were attributed to SUID. The number of SUID deaths at this altitude in the United States is very small (10 deaths in 6 years).

Evaluation of the CONSUME and FOFEM fuel consumption models in pine and mixed hardwood forests of the eastern United States

2014 ◽  
Vol 44 (7) ◽  
pp. 784-795 ◽  
Author(s):  
Susan J. Prichard ◽  
Eva C. Karau ◽  
Roger D. Ottmar ◽  
Maureen C. Kennedy ◽  
James B. Cronan ◽  
...  
Keyword(s):  
United States ◽  
Fuel Consumption ◽  
Prescribed Burning ◽  
Forest Type ◽  
Fire Effects ◽  
Eastern United States ◽  
Validation Data ◽  
Data Set ◽  
Predicted Values ◽  
Fine Fuels

Reliable predictions of fuel consumption are critical in the eastern United States (US), where prescribed burning is frequently applied to forests and air quality is of increasing concern. CONSUME and the First Order Fire Effects Model (FOFEM), predictive models developed to estimate fuel consumption and emissions from wildland fires, have not been systematically evaluated for application in the eastern US using the same validation data set. In this study, we compiled a fuel consumption data set from 54 operational prescribed fires (43 pine and 11 mixed hardwood sites) to assess each model’s uncertainties and application limits. Regions of indifference between measured and predicted values by fuel category and forest type represent the potential error that modelers could incur in estimating fuel consumption by category. Overall, FOFEM predictions have narrower regions of indifference than CONSUME and suggest better correspondence between measured and predicted consumption. However, both models offer reliable predictions of live fuel (shrubs and herbaceous vegetation) and 1 h fine fuels. Results suggest that CONSUME and FOFEM can be improved in their predictive capability for woody fuel, litter, and duff consumption for eastern US forests. Because of their high biomass and potential smoke management problems, refining estimates of litter and duff consumption is of particular importance.

scholarly journals Development of a semi-parametric PAR (Photosynthetically Active Radiation) partitioning model for the United States, version 1.0

2014 ◽  
Vol 7 (5) ◽  
pp. 2477-2484 ◽  
Author(s):  
J. C. Kathilankal ◽  
T. L. O'Halloran ◽  
A. Schmidt ◽  
C. V. Hanson ◽  
B. E. Law
Keyword(s):  
United States ◽  
Elevation Angle ◽  
Model Performance ◽  
Diffuse Radiation ◽  
The United States ◽  
Polynomial Model ◽  
Coefficient Of Determination ◽  
Data Set ◽  
Cubic Polynomial ◽  
Solar Elevation Angle

Abstract. A semi-parametric PAR diffuse radiation model was developed using commonly measured climatic variables from 108 site-years of data from 17 AmeriFlux sites. The model has a logistic form and improves upon previous efforts using a larger data set and physically viable climate variables as predictors, including relative humidity, clearness index, surface albedo and solar elevation angle. Model performance was evaluated by comparison with a simple cubic polynomial model developed for the PAR spectral range. The logistic model outperformed the polynomial model with an improved coefficient of determination and slope relative to measured data (logistic: R2 = 0.76; slope = 0.76; cubic: R2 = 0.73; slope = 0.72), making this the most robust PAR-partitioning model for the United States currently available.

Racial Sentiment and Public Support for Arming Teachers with Guns in the United States

2021 ◽  
pp. 215336872110389
Author(s):  
Andrew J. Baranauskas
Keyword(s):  
United States ◽  
African Americans ◽  
Minority Groups ◽  
Public Support ◽  
The United States ◽  
Data Set ◽  
Racial Issue ◽  
Racial Resentment ◽  
Nationally Representative ◽  
Negative Feelings

In the effort to prevent school shootings in the United States, policies that aim to arm teachers with guns have received considerable attention. Recent research on public support for these policies finds that African Americans are substantially less likely to support them, indicating that support for arming teachers is a racial issue. Given the racialized nature of support for punitive crime policies in the United States, it is possible that racial sentiment shapes support for arming teachers as well. This study aims to determine the association between two types of racial sentiment—explicit negative feelings toward racial/ethnic minority groups and racial resentment—and support for arming teachers using a nationally representative data set. While explicit negative feelings toward African Americans and Hispanics are not associated with support for arming teachers, those with racial resentments are significantly more likely to support arming teachers. Racial resentment also weakens the effect of other variables found to be associated with support for arming teachers, including conservative ideology and economic pessimism. Implications for policy and research are discussed.

Septic shock and systemic inflammatory response syndrome patients' CD15+ granulocytes were subjected to global transcriptional profiling (SIRS)

2021 ◽  
Author(s):  
Marni Mack ◽  
Argo Easston
Keyword(s):  
Gene Expression ◽  
United States ◽  
Septic Shock ◽  
Immune Cells ◽  
Transcriptional Profiling ◽  
The United States ◽  
Transcriptional Level ◽  
Data Set ◽  
Transcriptional Alterations ◽  
Level I

In the United States, sepsis, the body's response to infection in a typically sterile circulation, is a leading causeof death (1). To assess the primary transcriptional alterations associated with each illness state, I utilized amicroarray data set from a cohort of thirtyone individuals with septic shock or systemic inflammatory responsesyndrome (2). At the transcriptional level, I discovered that the granulocytes of patients with SIRS weresimilar to those of patients with septic shock. SIRS showed a “intermediate” gene expression state betweenthat of control patients and that of septic shock patients for numerous genes expressed in the granulocyte. Thediscovery of the most differentially expressed genes in the granulocytic immune cells of patients with septicshock might aid the development of new therapies or diagnostics for an illness with a 14.7 percent to 29.9% inhospitaldeath rate despite decades of study (1).

scholarly journals Gender Disparities in Vascular Access Surgical Outcomes in Elderly Hemodialysis Patients

2018 ◽  
Vol 49 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Timmy Lee ◽  
Joyce Qian ◽  
Mae Thamer ◽  
Michael Allon
Keyword(s):  
United States ◽  
Vascular Access ◽  
Surgical Outcomes ◽  
Relative Rate ◽  
Venous Catheter ◽  
The United States ◽  
Hemodialysis Patients ◽  
Elderly Male ◽  
Female Patients ◽  
Arteriovenous Fistulas

Background: Despite national vascular access guidelines promoting the use of arteriovenous fistulas (AVF) over arteriovenous grafts (AVGs) for dialysis, AVF use is substantially lower in females. We assessed clinically relevant AVF and AVG surgical outcomes in elderly male and female patients initiating hemodialysis with a central venous catheter (CVC). Methods: Using the United States Renal Data System standard analytic files linked with Medicare claims, we assessed incident hemodialysis patients in the United States, 9,458 elderly patients (≥67 years; 4,927 males and 4,531 females) initiating hemodialysis from July 2010 to June 2011 with a catheter and had an AVF or AVG placed within 6 months. We evaluated vascular access placement, successful use for dialysis, assisted use (requiring an intervention before successful use), abandonment after successful use, and rate of interventions after successful use. Results: Females were less likely than males to receive an AVF (adjusted likelihood 0.57, 95% CI 0.52–0.63). Among patients receiving an AVF, females had higher adjusted likelihoods of unsuccessful AVF use (hazard ratio [HR] 1.46, 95% CI 1.36–1.56), assisted AVF use (OR 1.34, 95% CI 1.17–1.54), and AVF abandonment (HR 1.28, 95% CI 1.10–1.50), but similar relative rate of AVF interventions after successful use (relative risk [RR] 1.01, 95% CI 0.94–1.08). Among patients receiving an AVG, females had a lower likelihood of unsuccessful AVG use (HR 0.83, 95% CI 0.73–0.94), similar rates of assisted AVG use (OR 1.05, 95% CI 0.78–1.40) and AVG abandonment, and greater relative rate of interventions after successful AVG use (RR 1.16, 95% CI 1.01–1.33). Conclusions: While AVFs should be considered the preferred vascular access in most circumstances, clinical AVF surgical outcomes are uniformly worse in females. Clinicians should also consider AVGs as a viable alternative in elderly female patients initiating hemodialysis with a CVC to avoid extended CVC dependence.

Legislative Accomplishment and Policy Issue Substance

2013 ◽  
Author(s):  
John S. Lapinski
Keyword(s):  
United States ◽  
Substance P ◽  
Political Behavior ◽  
Policy Issue ◽  
The United States ◽  
Legislative Behavior ◽  
Aggregate Level ◽  
Data Set ◽  
Proper Understanding ◽  
Specific Policy

This chapter introduces a new measure of legislative accomplishment. To understand lawmaking requires that one move beyond studying political behavior in Congress alone and beyond a complete empirical reliance on roll call votes. Moreover, legislative behavior and legislative outputs must be studied in tandem to gain a proper understanding of the lawmaking process in the United States. Although the idea of studying important lawmaking across time is not controversial, constructing an appropriate measure is not a trivial exercise. The chapter constructs a comprehensive lawmaking data set that provides measures of legislative accomplishment at the aggregate level as well as by specific policy issue areas for a 118-year period. It also explains the construction of Congress-by-Congress measures of legislative accomplishment, including measures broken down by the policy-coding schema.

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