An Analysis of a Biometric Screening and Premium Incentive-Based Employee Wellness Program: Enrollment Patterns, Cost, and Outcome.

Since 2012, a large health care system has offered an employee wellness program providing premium discounts for those who voluntarily undergo biometric screenings and meet goals. This study evaluates the program impact on care utilization and total cost of care, taking into account employee self-selection into the program. A retrospective claims data analysis of 6453 employees between 2011 and 2015 was conducted, categorizing the sample into 3 mutually exclusive subgroups: Subgroup 1 enrolled and met goals in all years, Subgroup 2 enrolled or met goals in some years but not all, and Subgroup 3 never enrolled. Each subgroup was compared to a cohort of employees in other employer groups (N = 24,061). Using a difference-in-difference method, significant reductions in total medical cost (14.2%; P = 0.014) and emergency department (ED) visits (11.2%; P = 0.058) were observed only among Subgroup 2 in 2015. No significant impact was detected among those in Subgroup 1. Those in Subgroup 1 were less likely to have chronic conditions at baseline. The results indicate that the wellness program enrollment was characterized by self-selection of healthier employees, among whom the program appeared to have no significant impact. Yet, cost savings and reductions in ED visits were observed among the subset of employees who enrolled or met goal in some years but not all, suggesting a potential link between the wellness program and positive behavior changes among certain subsets of the employee population.

Environmentally-controlled microtensile testing of mechanically-adaptive polymer nanocomposites for ex vivo characterization.

Implantable microdevices are gaining significant attention for several biomedical applications. Such devices have been made from a range of materials, each offering its own advantages and shortcomings. Most prominently, due to the microscale device dimensions, a high modulus is required to facilitate implantation into living tissue. Conversely, the stiffness of the device should match the surrounding tissue to minimize induced local strain. Therefore, we recently developed a new class of bio-inspired materials to meet these requirements by responding to environmental stimuli with a change in mechanical properties. Specifically, our poly(vinyl acetate)-based nanocomposite (PVAc-NC) displays a reduction in stiffness when exposed to water and elevated temperatures (e.g. body temperature). Unfortunately, few methods exist to quantify the stiffness of materials in vivo, and mechanical testing outside of the physiological environment often requires large samples inappropriate for implantation. Further, stimuli-responsive materials may quickly recover their initial stiffness after explantation. Therefore, we have developed a method by which the mechanical properties of implanted microsamples can be measured ex vivo, with simulated physiological conditions maintained using moisture and temperature control. To this end, a custom microtensile tester was designed to accommodate microscale samples with widely-varying Young's moduli (range of 10 MPa to 5 GPa). As our interests are in the application of PVAc-NC as a biologically-adaptable neural probe substrate, a tool capable of mechanical characterization of samples at the microscale was necessary. This tool was adapted to provide humidity and temperature control, which minimized sample drying and cooling. As a result, the mechanical characteristics of the explanted sample closely reflect those of the sample just prior to explantation. The overall goal of this method is to quantitatively assess the in vivo mechanical properties, specifically the Young's modulus, of stimuli-responsive, mechanically-adaptive polymer-based materials. This is accomplished by first establishing the environmental conditions that will minimize a change in sample mechanical properties after explantation without contributing to a reduction in stiffness independent of that resulting from implantation. Samples are then prepared for implantation, handling, and testing (Figure 1A). Each sample is implanted into the cerebral cortex of rats, which is represented here as an explanted rat brain, for a specified duration (Figure 1B). At this point, the sample is explanted and immediately loaded into the microtensile tester, and then subjected to tensile testing (Figure 1C). Subsequent data analysis provides insight into the mechanical behavior of these innovative materials in the environment of the cerebral cortex.