David Weitzenkamp

Performance of 3-Dimensional Echocardiography in Measuring Left Ventricular Volumes and Ejection Fraction : A Systematic Review and Meta-Analysis

OBJECTIVES The primary aim of this systematic review is to objectively evaluate the test performance characteristics of three-dimensional echocardiography (3DE) in measuring left ventricular (LV) volumes and ejection fraction (EF). BACKGROUND Despite its growing use in clinical laboratories, the accuracy of 3DE has not been studied on a large scale. It is unclear if this technology offers an advantage over traditional two-dimensional (2D) methods. METHODS We searched for studies that compared LV volumes and EF measured by 3DE and cardiac magnetic resonance (CMR) imaging. A subset of those also compared standard 2D methods with CMR. We used meta-analyses to determine the overall bias and limits of agreement of LV end-diastolic volume (EDV), end-systolic volume (ESV), and EF measured by 3DE and 2D echocardiography (2DE). RESULTS Twenty-three studies (1,638 echocardiograms) were included. The pooled biases ± 2 SDs for 3DE were -19.1 ± 34.2 ml, -10.1 ± 29.7 ml, and - 0.6 ± 11.8% for EDV, ESV, and EF, respectively. Nine studies also included data from 2DE, where the pooled biases were -48.2 ± 55.9 ml, -27.7 ± 45.7 ml, and 0.1 ± 13.9% for EDV, ESV, and EF, respectively. In this subset, the difference in bias between 3DE and 2D volumes was statistically significant (p = 0.01 for both EDV and ESV). The difference in variance was statistically significant (p < 0.001) for all 3 measurements. CONCLUSIONS Three-dimensional echocardiography underestimates volumes and has wide limits of agreement, but compared with traditional 2D methods in these carefully performed studies, 3DE is more accurate for volumes and more precise in all 3 measurements.

Patterns of growth in ambulatory males with Duchenne muscular dystrophy.

OBJECTIVE To provide weight-for-age, height-for-age, and body mass index-for-age growth reference standards for ambulatory, steroid-naïve males, ages 2-12 years, with Duchenne muscular dystrophy (DMD) and to compare these growth curves to the 2000 Centers for Disease Control and Prevention growth charts for boys, which serve as references of physical size and growth for the general male pediatric population in the US. STUDY DESIGN Through a multi-state population-based surveillance of individuals with muscular dystrophy, a total of 1877 weight and 1544 height measurements ascertained during 1985-2010 from 513 males with DMD were obtained retrospectively from medical record review. Cases were classified as DMD if loss of ambulation occurred before the 12th birthday or, if younger than 12 years and still ambulating, the earliest symptoms of dystrophinopathy occurred before the 6th birthday. Each growth chart was constructed using 5 percentiles: 10th, 25th, 50th, 75th, and 90th. Smoothing procedures were applied in 2 stages to the irregular plots of the empirical percentile values. RESULTS A set of growth curves, derived from a large cohort of male youth with DMD, are presented. These curves demonstrate that DMD males are shorter and tend to the extremes of weight and body mass index compared with the general male pediatric population in the US. CONCLUSION Charts representing the pattern of growth in ambulatory, steroid-naïve males with DMD can facilitate monitoring of growth and early detection of unusual growth patterns. Use of these growth standards also will assist in monitoring responses to corticosteroid treatment.

Factors predicting weight-bearing asymmetry 1 month after unilateral total knee arthroplasty: A cross-sectional study

UNLABELLED Factors predicting weight-bearing asymmetry (WBA) after unilateral total knee arthroplasty (TKA) are not known. However, identifying modifiable and non-modifiable predictors of WBA is needed to optimize rehabilitation, especially since WBA is negatively correlated to poor functional performance. The purpose of this study was to identify factors predictive of WBA during sit-stand transitions for people 1month following unilateral TKA. METHODS Fifty-nine people were tested preoperatively and 1month following unilateral TKA for WBA using average vertical ground reaction force under each foot during the Five Times Sit-to-Stand Test. Candidate variables tested in the regression analysis represented physical impairments (strength, muscle activation, pain, and motion), demographics, anthropometrics, and movement compensations. RESULTS WBA, measured as the ratio of surgical/non-surgical limb vertical ground reaction force, was 0.69 (0.18) (mean (SD)) 1month after TKA. Regression analysis identified preoperative WBA (β=0.40), quadriceps strength ratio (β=0.31), and hamstrings strength ratio (β=0.19) as factors predictive of WBA 1month after TKA (R(2)=0.30). CONCLUSION Greater amounts of WBA 1month after TKA are predicted by modifiable factors including habitual movement pattern and asymmetry in quadriceps and hamstrings strength.

Small Business Total Worker Health: a Conceptual and Methodological Approach to Facilitating Organizational Change

Nearly half of Americans are employed by small businesses, and future projections suggest that the number of those employed by small businesses will rise. Despite this, there is relatively little small business intervention research on the integration of health protection and health promotion, known as Total Worker Health® (TWH). We first discuss the importance of studying small businesses in TWH research and practice. Second, we describe an example of a small business TWH intervention, Health Links™ plus TWH owner/senior manager leadership training, that we are evaluating via the Small+Safe+Well (SSWell) study. Key features of the intervention and the SSWell study include attention to multi-level influences on worker health, safety and well-being; organizational change; and dissemination and implementation science strategies via the RE-AIM model. We offer several considerations for future small business TWH research and practice both in terms of the small business context as well as intervention development and evaluation. Our goal is to provide TWH researchers and practitioners with a framework and an example of how to approach small business TWH interventions. Ultimately, through the SSWell study, we aim to provide small businesses with strong evidence to support the use of TWH strategies that are practical, effective and sustainable.

Unadjusted point of care creatinine results overestimate acute kidney injury incidence during field testing in Guatemala

Objective Acute kidney injury (AKI) occurs at high rates among agricultural workers (12–33%) in tropical environments. Because of the remote locations affected, traditional laboratory services are often unavailable. In this study we compare point of care (POC) creatinine values to standardized laboratory values, and examine the effect of POC testing on the interpretation of AKI rates under tropical field conditions. Methods Blood samples were collected from 104 sugarcane workers from two time points in January 2018 as a derivation cohort, and from 105 workers from February to April 2017 as a validation cohort. Finger stick and venipuncture samples were drawn at the end of a worker’s shift to measure creatinine. Laboratory samples were tested in Guatemala City, Guatemala, in duplicate using the Jaffe Generation 2 method. An adjustment factor to improve agreement with serum creatinine was statistically derived and validated, and then used to determine impact on observed rates of acute kidney injury based on across shift changes in creatinine. Results POC creatinine and serum creatinine measures showed that POC consistently overestimated the creatinine by an average of 22% (95% CI: 19.8%, 24.7%) and the disagreement appeared greater at higher values of serum creatinine. An adjustment factor of 0.7775 was applied, which led to significantly greater agreement between the two measures. Rates of AKI in the two combined groups fell from 72% before adjustment to 57% afterwards. Conclusions POC testing under tropical field conditions routinely overestimates creatinine compared to laboratory testing, which leads to overestimation of rates of acute kidney injury. The application of an adjustment factor significantly improved the accuracy of the POC value.

The impact of heat and impaired kidney function on productivity of Guatemalan sugarcane workers

Background Climate change has implications for human health and productivity. Models suggest that heat extremes affect worker health, reduce labor capacity, and commodity supply. Chronic health conditions are on the rise internationally. However there is a paucity of direct empirical evidence relating increasing temperatures to both agricultural worker health and productivity. Methods and findings We evaluated the relationship between temperature exposure, kidney function, and two measures of productivity—tons of commodity produced and job attrition, of 4,095 Guatemalan sugarcane cutters over a 6-month harvest. We used distributed lag non-linear models to evaluate associations between wet bulb globe temperature (WBGT) and productivity of workers with normal or impaired kidney function. The cumulative effect of exposure to a max WBGT of 34°C was 1.16 tons (95% CI: -2.87, 0.54) less sugarcane cut over the next five days by workers with impaired kidney function, compared to exposure to 29°C. Impaired kidney function was associated with premature workforce attrition. Workers starting the harvest season with impaired kidney function were more than twice as likely to leave employment (HR: 2.92, 95% CI: 1.88, 4.32). Conclusions Heat extremes may be associated with loss of agricultural worker productivity and employment, especially among those with impaired kidney function. Agricultural workers who develop health conditions, such as kidney disease, are particularly vulnerable in the face of climate change and increasing heat extremes. The resultant loss of employment and productivity has significant implications for global commodity supplies.

Time Course of C-Reactive Protein and Procalcitonin Levels During the Treatment of Acute Bacterial Skin Infections

Abstract In a pilot study of 22 patients with an acute bacterial skin infection, serum levels of C-reactive protein and procalcitonin tended to be elevated at presentation and declined within 3–5 days of treatment. Further study of a biomarker-guided treatment strategy to reduce antibiotic overuse in skin infections is warranted.

Reoccurring Injury, Chronic Health Conditions, and Behavioral Health: Gender Differences in the Causes of Workers’ Compensation Claims

Objective: The aim of this study was o examine how work and nonwork health-related factors contribute to workers’ compensation (WC) claims by gender. Methods: Workers (N = 16,926) were enrolled in the Pinnacol Assurance Health Risk Management study, a multiyear, longitudinal research program assessing small and medium-sized enterprises in Colorado. Hypotheses were tested using gender-stratified logistic regression models. Results: For both women and men, having incurred a prior WC claim increased the odds of a future claim. The combination of incurring a prior claim and having metabolic health conditions resulted in lower odds of a future claim. Behavioral health risk factors increased the odds of having a claim more so among women than among men. Conclusion: This study provides data to support multifactorial injury theories, and the need for injury prevention efforts that consider workplace conditions as well as worker health.

The Impact of Worksite Wellness Programs by Size of Business: A 3-Year Longitudinal Study of Participation, Health Benefits, Absenteeism, and Presenteeism

Objective Worksite wellness programs (WWP) may positively impact employee health, medical expenditures, absenteeism, and presenteeism. However, there has been little research to assess the benefits of WWP in small businesses. The purpose of this study is to prospectively evaluate changes in health, absenteeism, and presenteeism for employees who participated in a WWP. Methods We conducted an observational, 3-year cohort study of 5766 employees from 314 businesses of differing sizes. We followed two cohorts of employees, who completed at least two annual health risk assessments (HRA) between May 2010 and December 2014. Changes from baseline to the first and second follow-up periods were assessed for chronic and non-chronic health conditions, absenteeism, and presenteeism. Results Small business employees were more likely to participate in the WWP than were employees from large businesses. Changes in chronic and non-chronic health conditions varied by size of business, with small business employees showing improvements in stress, overall health, depression, smoking status, vegetable and fruit consumption, and physical activity, and in their perceptions of job health culture. In contrast, large business employees experienced improvements in stress, vegetable consumption, and alcohol use. No changes in absenteeism or presenteeism were observed. Conclusions Small businesses achieve higher employee participation rates and more health improvements when compared to employees from large employers. Findings suggest that small businesses may gain the most from a WWP.