Prevalence of Chronic Atrial Fibrillation in Dialysis Patients

Background: Atrial fibrillation (AF) is reported to be common in patients on maintenance dialysis, but estimates of prevalence vary substantially. To date, no Medicare claims-based approach has been employed to rigorously assess prevalence of chronic AF. Methods: A novel database was created to identify patients undergoing maintenance dialysis who were dually-eligible for Medicare and Medicaid for at least 3 months in 2004-05. A Medicare claims-based algorithm was used to generate a plausible range of chronic AF prevalences using four approaches. Poisson analysis was employed to determine the demographic, functional status, comorbidity, and other factors, as assessed by the Medical Evidence Form, associated with chronic AF. Results: Of 102,748 dually-eligible individuals for whom data was complete, 21,540 (21.0%) had at least one claim for non-perioperative AF. Raw percentages (irrespective of length of follow-up time) of individuals with chronic AF ranged from 9.8% (using the most inclusive strategy) to 4.6% (the most exclusive); intermediate approaches led to closely-clustered estimates of 8.1% and 6.4%. The intermediate approaches demonstrated chronic AF prevalence to range from 64.2 (95% confidence intervals, 62.9 - 65.5) to 50.4 (49.2 - 51.7) per 1000 patient-years. Age 60 years, male sex, Caucasian race, body mass index 30 kg/m2, and inability to ambulate were associated with chronic AF; hypertension as a comorbidity was inversely associated with AF. Occurrence of AF was roughly 10 times greater in the youngest patients when compared to similar individuals not on dialysis. Conclusions: A linked Medicare-Medicaid database, together with a claims-based diagnostic algorithm, was used to generate prevalence estimates for chronic AF in dually-eligible dialysis patients. As expected, AF is far more common than in the non-dialysis population

Treatment of secondary hyperparathyroidism in kidney disease: what we know and do not know about use of calcimimetics and vitamin D analogs

There is a growing understanding of the pathophysiology of secondary hyperparathyroidism (SHPT) and a recent emergence of new agents for SHPT treatment in patients with advanced kidney disease. At the same time, appreciation that mineral metabolic derangements promote vascular calcification and contribute to excess mortality, along with recognition of potentially important “non-classical” actions of vitamin D, have prompted the nephrology community to reexamine the use of various SHPT treatments, such as activated vitamin D sterols, phosphate binders, and calcimimetics. In this review, the evidence for treatment of SHPT with calcimimetics and vitamin D analogs is evaluated, with particular consideration given to recent clinical trials that have reported encouraging findings with cinacalcet use. Additionally, several controversies in the pathogenesis and treatment of SHPT are explored. The proposition that calcitriol deficiency is a true pathological state is challenged, the relative importance of the vitamin D receptor and the calcium sensing receptor in parathyroid gland function is summarized, and the potential relevance of non-classical actions of vitamin D for patients with advanced renal disease is examined. Taken collectively, the balance of evidence now supports a treatment paradigm in which calcimimetics are the most appropriate primary treatment for SHPT in the majority of end stage renal disease patients, but which nevertheless acknowledges an important role for modest doses of activated vitamin D sterols

Organizational Capacity and Progress Plateaus in the Flight Training Environment

Capacity is the ability of an organization to achieve its overall mission and satisfy stakeholder expectations. Stakeholders in a flight training organization include the owners and/or their representatives, flight school managers, instructor pilots, and the student pilots. This study was an examination of the organizational capacity of student pilots through a progress plateau theoretical lens using a mixed methodological approach and participants from a collegiate aviation program. Student pilot progress plateaus were found to have an adverse unrealized capacity consequence for the stakeholders in the organization. Recommendations to improve organizational capacity include the identification of progress plateaus utilizing flight training progress charts followed by the intervention of flight school leaders to resolve the plateau

2000 elemental analysis of lichens in Sleeping Bear Dunes National Lakeshore and George Washington Carver National Monument: Final report

1 PDF computer file (12 pages; tabular data)In the final report of the first study of the lichens and air quality in the Sleeping Bear Dunes National Lakeshore (SLBE) (Wetmore 1988) and George Washington Carver National Monument (GWCA) (Wetmore 1992) it was recommended that a restudy of the elemental analysis of lichens be done every five years. This report is on the results of a restudy done in 2000. In August; 2000, four species of lichens were collected at three of the same localities in SLBE as the previous studies. In GWCA only one species was resampled at one locality in May, 2000. The methods used were the same as in the previous studies. Statistical analyses of data from SLBE indicated that of the 15 elements measured in both years, six were significantly different for Cladina: Cd, Cr, Mn, Na, Pb and S. Chromium, Mn and Na all increased, while the other three decreased. The analysis of the GWCA data showed that twelve elements out of 23 plus ash changed significantly between 1991 and 2000, although this is based on very small sample sizes. The recommendation is made that the periodic restudy of elemental analyses of both areas be continued but on a more frequent interval in GWCA and with more samples to determine if the changes are consistent. The five-year periodic restudy in SLBE seems to be adequate.U. S. Geological Survey Biological Resources Division Purchase Order #00 MWSA 022

Impact of a modified data capture period on Liu comorbidity index scores in Medicare enrollees initiating chronic dialysis

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author’s publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.Background: The Liu Comorbidity Index uses the United States Renal Data System (USRDS) to quantify comorbidity in chronic dialysis patients, capturing baseline comorbidities from days 91 through 270 after dialysis initiation. The 270 day survival requirement results in sample size reductions and potential survivor bias. An earlier and shorter time-frame for data capture could be beneficial, if sufficiently similar comorbidity information could be ascertained. Methods: USRDS data were used in a retrospective observational study of 70,114 Medicare- and Medicaid-eligible persons who initiated chronic dialysis during the years 2000–2005. The Liu index was modified by changing the baseline comorbidity capture period to days 1–90 after dialysis initiation for persons continuously enrolled in Medicare. The scores resulting from the original and the modified comorbidity indices were compared, and the impact on sample size was calculated. Results: The original Liu comorbidity index could be calculated for 75% of the sample, but the remaining 25% did not survive to 270 days. Among 52,937 individuals for whom both scores could be calculated, the mean scores for the original and the modified index were 7.4 ± 4.0 and 6.4 ± 3.6 points, respectively, on a 24-point scale. The most commonly calculated difference between scores was zero, occurring in 44% of patients. Greater comorbidity was found in those who died before 270 days. Conclusions: A modified version of the Liu comorbidity index captures the majority of comorbidity in persons who are Medicare-enrolled at the time of chronic dialysis initiation. This modification reduces sample size losses and facilitates inclusion of a sicker portion of the population in whom early mortality is common. Keywords: Comorbidity, Kidney failure, Chronic, Renal dialysis, Epidemiologic research desig

Combined Spectroscopic and Photometric Analysis of Flares in the Dwarf M Star EV Lacertae

We report results of an observing campaign to study the dwarf M flare star EV Lacertae. Between October 2021 and January 2022 we obtained concurrent B band photometry and low resolution spectroscopy of EV Lac on 39 occasions during 10 of which we observed flares with amplitude greater than 0.1 magnitude. Spectra were calibrated in absolute flux using concurrent photometry and flare-only spectra obtained by subtracting mean quiescent spectra. We measured B band flare energies between Log E = 30.8 and 32.6 erg. In the brightest flares we measured temporal development of flare flux in H I and He I emission lines and in the adjacent continuum and found that flux in the continuum subsided more rapidly than in the emission lines. Although our time resolution was limited, in our brightest flare we saw flux in the continuum clearly peaking before flux in the emission lines. We observed a progressive decrease in flare energy from H\b{eta} to H{\delta}. On average we found 37% of B band flare energy appeared in the H\b{eta} to H{\epsilon} emission lines with the remainder contributing to a rise in continuum flux. We measured black-body temperatures for the brightest flares between 10,500 +- 700 K and 19,500 +- 500 K and found a linear relationship between flare temperature and continuum flux at 4170 {\AA}. Balmer lines in flare-only spectra were well fitted by Gaussian profiles with some evidence of additional short-lived blue-shifted emission at the flare peak.Comment: 12 pages, 13 figures, accepted for publication in the Journal of the AAVS

Association of polygenic scores with chronic kidney disease phenotypes in a longitudinal study of older adults

Risk of chronic kidney disease (CKD) is influenced by environmental and genetic factors and increases sharply in individuals 70 years and older. Polygenic scores (PGS) for kidney disease-related traits have shown promise but require validation in well-characterized cohorts. Here, we assessed the performance of recently developed PGSs for CKD-related traits in a longitudinal cohort of healthy older individuals enrolled in the Australian ASPREE randomized controlled trial of daily low-dose aspirin with CKD risk at baseline and longitudinally. Among 11,813 genotyped participants aged 70 years or more with baseline eGFR measures, we tested associations between PGSs and measured eGFR at baseline, clinical phenotype of CKD, and longitudinal rate of eGFR decline spanning up to six years of follow-up per participant. A PGS for eGFR was associated with baseline eGFR, with a significant decrease of 3.9 mL/min/1.73m2 (95% confidence interval -4.17 to -3.68) per standard deviation (SD) increase of the PGS. This PGS, as well as a PGS for CKD stage 3 were both associated with higher risk of baseline CKD stage 3 in cross-sectional analysis (Odds Ratio 1.75 per SD, 95% confidence interval 1.66-1.85, and Odds Ratio 1.51 per SD, 95% confidence interval 1.43-1.59, respectively). Longitudinally, two separate PGSs for eGFR slope were associated with significant kidney function decline during follow-up. Thus, our study demonstrates that kidney function has a considerable genetic component in older adults, and that new PGSs for kidney disease-related phenotypes may have potential utility for CKD risk prediction in advanced age

Toxicokinetic Triage for Environmental Chemicals

Toxicokinetic (TK) models link administered doses to plasma, blood, and tissue concentrations. High-throughput TK (HTTK) performs in vitro to in vivo extrapolation to predict TK from rapid in vitro measurements and chemical structure-based properties. A significant toxicological application of HTTK has been “reverse dosimetry,” in which bioactive concentrations from in vitro screening studies are converted into in vivo doses (mg/kg BW/day). These doses are predicted to produce steady-state plasma concentrations that are equivalent to in vitro bioactive concentrations. In this study, we evaluate the impact of the approximations and assumptions necessary for reverse dosimetry and develop methods to determine whether HTTK tools are appropriate or may lead to false conclusions for a particular chemical. Based on literature in vivo data for 87 chemicals, we identified specific properties (eg, in vitro HTTK data, physico-chemical descriptors, and predicted transporter affinities) that correlate with poor HTTK predictive ability. For 271 chemicals we developed a generic HT physiologically based TK (HTPBTK) model that predicts non-steady-state chemical concentration time-courses for a variety of exposure scenarios. We used this HTPBTK model to find that assumptions previously used for reverse dosimetry are usually appropriate, except most notably for highly bioaccumulative compounds. For the thousands of man-made chemicals in the environment that currently have no TK data, we propose a 4-element framework for chemical TK triage that can group chemicals into 7 different categories associated with varying levels of confidence in HTTK predictions. For 349 chemicals with literature HTTK data, we differentiated those chemicals for which HTTK approaches are likely to be sufficient, from those that may require additional data