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PURPOSE: Medicare's differential payments for services delivered in physician offices versus hospital outpatient settings incentivize hospital-physician integration (ie, vertical integration) across many specialties, but evidence for oncologists is mixed. We examined the association of Medicare site-based payment policy and physician practice characteristics, including service volume and diversity, with vertical integration among oncologists in 2013-2019. METHODS: Using the Medicare Provider Utilization and Payment Data and Medicare Data on Provider Practice and Specialty in 2013-2019, we extracted nonintegrated medical/hematologic oncologists (hereafter oncologists) in 2013 and followed them through 2019. We quantified the incentives from Medicare site-based payment policy using the hospital-office ratio-total Medicare payments if all services were delivered in the hospital outpatient department (HOPD) versus physician office. Vertical integration was defined as billing >10% of services to HOPD in a year. Multivariable linear probability regressions estimated the association between hospital-office ratio and vertical integration in 2014-2019 with and without accounting for provider characteristics. RESULTS: In 2013, the average hospital-office ratio was 1.63, which increased to 1.99 in 2018. A 25th-to-75th percentile increase in the hospital-office ratio was negatively associated with integration (-1.01 percentage points [ppts], 95% CI = -1.45 to -0.57, p < .001) not accounting for physician practice characteristics; this association was attenuated (-0.30 ppts, 95% CI = -0.67 to 0.07, p = .11) after adjusting for these characteristics. Higher baseline (ie, 2013) service volume (Quartile4 v Quartile1 = -3.00 ppts, 95% CI = -4.42 to -1.59, p < .001), more diverse services (Quartile4 v Quartile1 = -3.55 ppts, 95% CI = -4.97 to -2.13, p < .001), and urban location (-5.23 ppts, 95% CI = -6.89 to -3.57, p < .001) were more strongly associated with vertical integration. CONCLUSION: Compared to Medicare site-based payment policy, oncologists' practice characteristics emerged as more potent factors for integration and should be considered to ensure the intended impacts of site-based payment reform. Our finding raises questions about the effectiveness of ongoing movements toward site-neutral payment for drug administration services to deter vertical integration in oncology.
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European sea bass (Dicentrarchus labrax) is a species of high commercial and recreational value, but it exhibits highly variable recruitment rates and has been subject to recent declines. Emergency management measures put in place to protect spawning stocks include the annual closure of commercial and recreational fisheries over a 2-month, February-March, window. Whether this protection measure is having the desired outcome for this data-poor species remains unclear. Otolith microstructural analyses (counts and widths of daily growth rings and check marks indicative of settlement) were used to estimate (1) spawn timing, (2) pelagic larval duration and settlement timing, (3) growth rate and condition, and (4) the otolith-fish size relationship for juvenile European sea bass caught from two estuaries in Wales (Dwyryd, Y Foryd), located at the northern edge of the species range. We observed a significant mismatch between the timing of fisheries closures and the spawning, with 99.2% of recruits having been spawned after the fishery had reopened (back-calculated median spawn date = May 5 ± 17 days SD), suggesting that the closure may be too early to adequately protect this population. Further, we present the first empirically derived estimates of pelagic larval duration for sea bass recruits settling in UK habitats, which showed a strong negative relationship with spawn date. Finally, we found significant differences in fish condition between the two estuaries, suggesting local variation in habitat quality. The results suggest that the timing of current fisheries closures may not be adequately protecting the spawners supplying these northernmost estuaries, which are likely to become increasingly important as sea bass distributions shift northward in our climate future.
Subject(s)
Bass , Estuaries , Fisheries , Animals , Bass/physiology , Bass/growth & development , Reproduction , Conservation of Natural Resources , Wales , Otolithic Membrane , Body Size , Population DynamicsABSTRACT
To fully take advantage of the data provided by large-scale structure surveys, we need to quantify the potential impact of baryonic effects, such as feedback from active galactic nuclei (AGN) and star formation, on cosmological observables. In simulations, feedback processes originate on scales that remain unresolved. Therefore, they need to be sourced via subgrid models that contain free parameters. We use machine learning to calibrate the AGN and stellar feedback models for the FLAMINGO (Fullhydro Large-scale structure simulations with All-sky Mapping for the Interpretation of Next Generation Observations) cosmological hydrodynamical simulations. Using Gaussian process emulators trained on Latin hypercubes of 32 smaller volume simulations, we model how the galaxy stellar mass function (SMF) and cluster gas fractions change as a function of the subgrid parameters. The emulators are then fit to observational data, allowing for the inclusion of potential observational biases. We apply our method to the three different FLAMINGO resolutions, spanning a factor of 64 in particle mass, recovering the observed relations within the respective resolved mass ranges. We also use the emulators, which link changes in subgrid parameters to changes in observables, to find models that skirt or exceed the observationally allowed range for cluster gas fractions and the SMF. Our method enables us to define model variations in terms of the data that they are calibrated to rather than the values of specific subgrid parameters. This approach is useful, because subgrid parameters are typically not directly linked to particular observables, and predictions for a specific observable are influenced by multiple subgrid parameters.
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Specialty hospitals tend to negotiate higher commercial insurance payments, even for relatively routine procedures with comparable clinical quality across hospital types. How specialty hospitals can maintain such a price premium remains an open question. In this paper, we examine a potential (horizontal) differentiation effect in which patients perceive specialty hospitals as sufficiently distinct from other hospitals, so that specialty hospitals effectively compete in a separate market from general acute care hospitals. We estimate this effect in the context of routine pediatric procedures offered by both specialty children's hospitals as well as general acute care hospitals, and we find strong empirical evidence of a differentiation effect in which specialty children's hospitals appear largely immune to competitive forces from non-children's hospitals.
Subject(s)
Delivery of Health Care , Hospitals, Pediatric , Child , Humans , United StatesABSTRACT
During the COVID-19 pandemic, there has been considerable research on how regional and country-level forecasting can be used to anticipate required hospital resources. We add to and build on this work by focusing on ward-level forecasting and planning tools for hospital staff during the pandemic. We present an assessment, validation, and deployment of a working prototype forecasting tool used within a modified Traffic Control Bundling (TCB) protocol for resource planning during the pandemic. We compare statistical and machine learning forecasting methods and their accuracy at one of the largest hospitals (Vancouver General Hospital) in Canada against a medium-sized hospital (St. Paul's Hospital) in Vancouver, Canada through the first three waves of the COVID-19 pandemic in the province of British Columbia. Our results confirm that traditional statistical and machine learning (ML) forecasting methods can provide valuable ward-level forecasting to aid in decision-making for pandemic resource planning. Using point forecasts with upper 95% prediction intervals, such forecasting methods would have provided better accuracy in anticipating required beds on COVID-19 hospital units than ward-level capacity decisions made by hospital staff. We have integrated our methodology into a publicly available online tool that operationalizes ward-level forecasting to aid with capacity planning decisions. Importantly, hospital staff can use this tool to translate forecasts into better patient care, less burnout, and improved planning for all hospital resources during pandemics.
Subject(s)
COVID-19 , Humans , COVID-19/epidemiology , Pandemics , Hospitals , ForecastingABSTRACT
Introduction: Visual processing deficits in Alzheimer's disease are associated with diminished functional independence. While environmental adaptations have been proposed to promote independence, recent guidance gives limited consideration to such deficits and offers conflicting recommendations for people with dementia. We evaluated the effects of clutter and color contrasts on performances of everyday actions in posterior cortical atrophy and memory-led typical Alzheimer's disease. Methods: 15 patients with posterior cortical atrophy, 11 with typical Alzheimer's disease and 16 healthy controls were asked to pick up a visible target object as part of two pilot repeated-measures investigations from a standing or seated position. Participants picked up the target within a controlled real-world setting under varying environmental conditions: with/without clutter, with/without color contrast cue and far/near target position. Task completion time was recorded using a target-mounted inertial measurement unit. Results: Across both experiments, difficulties locating a target object were apparent through patient groups taking an estimated 50-90% longer to pick up targets relative to controls. There was no evidence of effects of color contrast when locating objects from standing/seated positions and of any other environmental conditions from a standing position on completion time in any participant group. Locating objects, surrounded by five distractors rather than none, from a seated position was associated with a disproportionately greater effect on completion times in the posterior cortical atrophy group relative to the control or typical Alzheimer's disease groups. Smaller, not statistically significant but directionally consistent, ratios of relative effects were seen for two distractors compared with none. Discussion: Findings are consistent with inefficient object localization in posterior cortical atrophy relative to typical Alzheimer's disease and control groups, particularly with targets presented within reaching distance among visual clutter. Findings may carry implications for considering the adverse effects of visual clutter in developing and implementing environmental modifications to promote functional independence in Alzheimer's disease.
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The study of geometric morphometrics among stocks has proven to be a valuable tool in delineating fish spatial distributions and discriminating distinct population units. Variations in fish body morphology can be linked to genetic factors or to phenotypic adaptability in response to environmental variables. The tub gurnard (Chelidonichthys lucerna) is a demersal species that usually lives in the bottom of the continental shelf, being widely distributed along the northeast Atlantic, Mediterranean and Black seas. Worldwide interest in the species has increased since 2006, when ICES recognized its potential for commercial exploitation. However, despite its broad geographic occurrence, to date, research on C. lucerna population structure at large spatial scales is still lacking. In this paper, body geometric morphometrics, using a landmark-based truss network, was applied in order to discriminate C. lucerna populations caught in three different fishery grounds areas along the northeast Atlantic: Conwy Bay (United Kingdom), Biscay Bay (Spain) and Matosinhos (Portugal). The results obtained in this study revealed a high overall relocation success (95%) of samples to their original locations, thus demonstrating the existence of significant regional differences and indicating that we are dealing with different fish population units. Moreover, the data revealed a partial overlap between individuals from Spain and United Kingdom, suggesting that in geographically distant areas these populations may inhabit similar environments. However, to corroborate these findings, future works using a holistic approach with alternative and complimentary stock assessment tools (e.g., genetic and phenotypic natural tags) are highly recommended.
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Previous studies on voting bias in competitive awards have not fully considered the role of cultural similarity. Using data for the Best FIFA Men's Player Award, we evaluate the extent of voting bias in this Award using three cultural similarity factors (cultural distance, cultural clusters, and collectivism), six established in-group factors (nationality, club, league, geography, ethnicity, religion, and language) and the impartiality of the voter's country. Using statistical and econometric methods, we find that voter-player cultural similarity is positively associated with voting bias and find no evidence of impartiality when it comes to cultural or national ties. We also find that media voters are less biased than captain voters and coach voters, and that coaches are less biased than captains.
Subject(s)
Awards and Prizes , Soccer , Humans , MaleABSTRACT
STUDY DESIGN: A training intervention study using standing dynamic load-shifting Functional Electrical Stimulation (FES) in a group of individuals with complete spinal cord injury (SCI) T2 to T10. OBJECTIVES: Investigate the effect of FES-assisted dynamic load-shifting exercises on bone mineral density (BMD). SETTING: University Lab within the Biomedical Engineering METHODS: Twelve participants with ASIA A SCI were recruited for this study. Three participants completed side-to-side load-shifting FES-assisted exercises for 29 ± 5 weeks, 2× per week for 1 h, and FES knee extension exercises on alternate days 3× per week for 1 h. Volumetric Bone Mineral density (vBMD) at the distal femur and tibia were assessed using peripheral quantitative computed tomography (pQCT) before and after the intervention study. RESULTS: Participants with acute and subacute SCI showed an absolute increase of f trabecular vBMD (vBMDTRAB) in the proximal (mean of 26.9%) and distal tibia (mean of 22.35%). Loss of vBMDTRAB in the distal femur was observed. CONCLUSION: Improvements in vBMDTRAB in the distal tibia were found in acute and subacute SCI participants, and in the proximal tibia of acute participants, when subjected to anti-gravity FES-assisted load-bearing exercises for 29 ± 5 weeks. No vBMD improvement in distal femur or tibial shaft were observed in any of the participants as was expected. However, improvements of vBMD in the proximal and distal tibia were observed in two participants. This study provides evidence of an improvement of vBMDTRAB, when combining high-intensity exercises with lower intensity exercises 5× per week for 1 h.
Subject(s)
Bone Density , Spinal Cord Injuries , Bone Density/physiology , Electric Stimulation , Humans , Pilot Projects , Posture , Spinal Cord Injuries/therapy , TibiaABSTRACT
Importance: Although children's hospitals (CH) provide a substantial proportion of highly specialized pediatric care in the United States, the value of CH compared with non-children's hospitals (NCH) for routine surgical procedures is unknown. Objective: To examine the value of CH for routine surgical procedures by assessing clinical outcomes and payment data. Design, Setting, and Participants: This retrospective cohort study examined pediatric patients undergoing 1 of 13 commonly performed surgical procedures between 2010 and 2015 with 90-day follow-up using administrative data from the Health Care Cost Institute. Data analysis was conducted from July 2019 to December 2021. Exposures: The primary exposure was tier of CH status, defined using self-reported pediatric services, affiliation with pediatric focused programs, and validated based on proportion of pediatric admissions. Main Outcomes and Measures: Payments for common surgical procedures from private insurers and overall complication and readmission rates at 30, 60, and 90 days. Results: There were 368â¯220 pediatric patients who underwent one of the surgical procedures of interest; 220â¯899 (60.0%) of the patients were male; 118â¯977 (32.3%) had their procedure at freestanding CH (CH-A), 75â¯256 (20.4%) at CH attached to an adult hospital (CH-B), and 173â¯987 (47.3%) at NCH. The mean (SD) payment for all procedures at CH-A was $6533.56 ($6399.97), $5847.50 ($4947.47) at CH-B, and $5034.25 ($4787.07) at NCH. The mean (SD) overall complication rate was 0.004 (0.06) at CH-A, 0.01 (0.07) at CH-B, and 0.003 (0.06) at NCH. Readmission rates at 30, 60, and 90 days were similar across all hospital types. After adjusting for zip code, year, surgery, surgery setting, and observable patient, hospital, and county characteristics, the estimated payments for inpatient common procedures were 39% higher at CH-A than at NCH. Payments for outpatient common procedures were 34% higher at CH-A than at NCH. Conclusions and Relevance: In this cohort study, children who underwent common surgical procedures had equivalent clinical outcomes at CH and NCH but the procedures were associated with higher payments and, thus, overall lower value care. To ensure delivery of optimal value to patients and payers, more research is needed to evaluate mechanisms to ensure access, decrease costs, and improve value at both CH and NCH.
Subject(s)
Hospitalization , Hospitals, Pediatric , Child , Cohort Studies , Female , Humans , Inpatients , Male , Retrospective Studies , United StatesABSTRACT
This study evaluated the psychometric properties of the Organizational Bullshit Perception Scale (OBPS) using two samples of employees of organizations in various sectors. The scale is designed to gauge perceptions of the extent of organizational bullshit that exists in a workplace, where bullshit is operationalized as individuals within an organization making statements with no regard for the truth. Analyses revealed three factors of organizational bullshit, termed regard for truth, the boss and bullshit language. The three factors are consistent with existing literature in the field of organizational bullshit and offer further insight into how employees view workplace bullshit. The OBPS constitutes three subscales measuring these factors. Future researchers should seek to validate the OBPS and further develop the identified factors of organizational bullshit.
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Perception , Workplace , Humans , Organizational Culture , Psychometrics , Surveys and QuestionnairesABSTRACT
Human Achilles tendon is composed of three smaller sub-tendons and exhibits non-uniform internal displacements, which decline with age and after injury, suggesting a potential role in the development of tendinopathies. Studying internal sliding behaviour is therefore important but difficult in human Achilles tendon. Here we propose the equine deep digital flexor tendon (DDFT) and its accessory ligament (AL) as a model to understand the sliding mechanism. The AL-DDFT has a comparable sub-bundle structure, is subjected to high and frequent asymmetric loads and is a natural site of injury similar to human Achilles tendons. Equine AL-DDFT were collected and underwent whole tendon level (n=7) and fascicle level (n=7) quasi-static mechanical testing. Whole tendon level testing was performed by sequentially loading through the proximal AL and subsequently through the proximal DDFT and recording regional strain in the free structures and joined DDFT and AL. Fascicle level testing was performed with focus on the inter-sub-bundle matrix between the two structures at the junction. Our results demonstrate a significant difference in the regional strain between the joined DDFT and AL and a greater transmission of force from the AL to the DDFT than vice versa. These results can be partially explained by the mechanical properties and geometry of the two structures and by differences in the properties of the interfascicular matrices. In conclusion, this tendon model successfully demonstrates that high displacement discrepancy occurs between the two structures and can be used as an easy-access model for studying intra-tendinous shear mechanics at the sub-tendon level. STATEMENT OF SIGNIFICANCE: Our study provides a naturally occurring and easily accessible equine model to study the complex behaviour of sub-tendons within the human Achilles tendon, which is likely to play a critical role in the pathogenesis of tendon disease. Our results demonstrate that the difference in material stiffness between the equine AL and DDFT stems largely from differences in the inter-fascicular matrix and furthermore that differences in strain are maintained in distal parts of the tightly joined structure. Furthermore, our results suggest that distribution of load between sub-structures is highly dependent on the morphological relationship between them; a finding that has important implications for understanding Achilles tendon mechanical behaviour, injury mechanisms and rehabilitation.
Subject(s)
Achilles Tendon , Tendinopathy , Animals , Horses , Humans , MusclesABSTRACT
The past decade has witnessed a new wave of hospital-physician integration, with the fraction of hospitals owning any office-based physician practice increasing from 28% in 2009 to 53% in 2015 nationwide. We offer one of the first hospital-level longitudinal analyses in examining how hospital-physician integration affects hospital prices in the modern healthcare environment. We find a robust 3-5% increase in hospital prices following integration. There is little indication that hospital quality is commensurately higher or that patient mix has changed following integration. Our supplementary analyses point to stronger bargaining leverage and foreclosure of rival hospitals as potential mechanisms for the estimated price effects.
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Hospitals , Physicians , Costs and Cost Analysis , Delivery of Health Care , HumansABSTRACT
We report the successful implementation of a modified Traffic Control Bundling (TCB) protocol called "Red, Yellow and Green" on the inpatient medical units at St. Paul's Hospital in Vancouver, Canada during the first wave of the coronavirus disease 2019 (COVID-19) pandemic. The modified TCB protocol demonstrates an important example on how hospitals can rapidly reorganize operational and clinical processes to reallocate existing capacity to minimize exposure, improve traffic flow and reduce nosocomial transmissions of COVID-19 to health care workers (HCWs) and other patients. Preliminary evidence demonstrates the benefits on how an existing facility can be redesigned for adjustable ward capacity to provide disease containment under a context of uncertainty of disease transmission and varying patient load. Important lessons in preparation for the evolution of the pandemic fall into categories of risk management, capacity and demand management.
Subject(s)
COVID-19/therapy , Hospital Planning , Infection Control/organization & administration , Pneumonia, Viral/therapy , Workflow , British Columbia/epidemiology , COVID-19/epidemiology , COVID-19/transmission , Cross Infection/prevention & control , Disinfection , Humans , Pandemics , Patient Isolation/organization & administration , Personal Protective Equipment , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , SARS-CoV-2 , Triage/organization & administrationABSTRACT
Background: We wished to determine whether newly available flat panel detector (FPD) c-arms were (1) associated with lower radiation dose during ureteroscopy (URS) than conventional image intensifier (CII) c-arms and (2) to compare fluoroscopic image quality between the units. Materials and Methods: We retrospectively reviewed 44 consecutive patients undergoing URS at a pediatric hospital, with c-arms assigned by availability in the operating room. We performed dosimetry experiments using the same c-arms on standard phantoms. Results: Patient and case characteristics did not differ significantly between the two groups of patients. The median dose in the FPD group was less than a quarter of the dose in the CII group, 0.48 [0.42, 0.97] mGy vs 2.2 [1.1, 3.8] mGy, p < 0.0001. The FPD dose remained at less than one-third of the CII dose accounting for any difference in fluoroscopy time, and remained significant in a multivariate model including fluoroscopy time and patient weight (ß = 2.4, p = 0.007). Phantom studies showed higher image quality for FPDs at all simulated patient sizes, even at lower radiation doses. Conclusions: This is the first report comparing radiation dose from c-arms of image intensifiers and FPDs in adults or children. Use of an FPD during URS was associated with a substantially decreased absorbed dose for patients while simultaneously improving image quality.
Subject(s)
Radiation Exposure , Ureteroscopy , Child , Fluoroscopy , Humans , Phantoms, Imaging , Radiation Dosage , Radiographic Image Enhancement , Retrospective StudiesABSTRACT
PURPOSE: Recent studies have demonstrated trends of decreasing voiding cystourethrogram utilization rates and delayed vesicoureteral reflux diagnosis in some children. It is possible that such delays could lead to more children sustaining repeated episodes of febrile urinary tract infection, and potential kidney injury, prior to diagnosis and treatment. MATERIALS AND METHODS: Using single institutional, cross-sectional cohorts of patients in 2 time periods (2005 and 2015), we compared clinical presentation and renal outcomes among patients 13 years and younger with history of febrile urinary tract infection presenting for initial voiding cystourethrogram. Outcomes included 1) recurrent urinary tract infection, 2) presence of vesicoureteral reflux, 3) grade of vesicoureteral reflux, and 4) renal scarring. Associations between year of presentation and outcomes of recurrent urinary tract infection and vesicoureteral reflux diagnosis were evaluated using multivariable logistic regression models. For the outcome of renal scarring, a logistic regression model was fitted for propensity score matched cohorts. RESULTS: Compared to children presenting in 2005, those in 2015 had 3 times the odds of recurrent urinary tract infection (OR 3.01, 95% CI 2.18-4.16, p <0.0001). Time period was not associated with the odds of vesicoureteral reflux (OR 0.98, 95% CI 0.77-1.23, p=0.85). Those in 2015 were more likely to present with vesicoureteral reflux grade >3 (OR 2.22, 95% CI 1.13-4.34, p=0.02) but not vesicoureteral reflux grade >2 (OR 1.11, 95% CI 0.74-1.67, p=0.60). Renal scarring was more common among children presenting in 2015 (OR 2.9, 95% CI 1.03-8.20, p=0.04). CONCLUSIONS: Compared to 2005, children presenting in 2015 for post-urinary tract infection voiding cystourethrogram have increased likelihood of recurrent urinary tract infection and renal scarring, despite similar likelihood of vesicoureteral reflux diagnosis.
Subject(s)
Kidney Diseases/etiology , Urinary Tract Infections/complications , Urinary Tract Infections/diagnosis , Vesico-Ureteral Reflux/complications , Child, Preschool , Cross-Sectional Studies , Cystography , Delayed Diagnosis , Female , Fever/etiology , Humans , Infant , Male , Recurrence , Retrospective Studies , Urinary Tract Infections/etiology , Vesico-Ureteral Reflux/diagnostic imagingABSTRACT
The unique structure of the Achilles tendon, combining three smaller sub-tendons, enhances movement efficiency by allowing individual control from connected muscles. This requires compliant interfaces between sub-tendons, but compliance decreases with age and may account for increased injury frequency. Current understanding of sub-tendon sliding and its role in the whole Achilles tendon function is limited. Here we show changing the degree of sliding greatly affects the tendon mechanical behaviour. Our in vitro testing discovered distinct sub-tendon mechanical properties in keeping with their mechanical demands. In silico study based on measured properties, subject-specific tendon geometry, and modified sliding capacity demonstrated age-related displacement reduction similar to our in vivo ultrasonography measurements. Peak stress magnitude and distribution within the whole Achilles tendon are affected by individual tendon geometries, the sliding capacity between sub-tendons, and different muscle loading conditions. These results suggest clinical possibilities to identify patients at risk and design personalised rehabilitation protocols.
Subject(s)
Achilles Tendon/anatomy & histology , Achilles Tendon/physiology , Achilles Tendon/diagnostic imaging , Adult , Age Factors , Aged , Aged, 80 and over , Biomechanical Phenomena , Computer Simulation , Female , Humans , Male , Middle Aged , Movement , UltrasonographyABSTRACT
Estimates of the benefits of antifraud enforcement in health care typically focus on direct monetary damages. Deterrence effects are acknowledged but unquantified. We evaluate the impact of a Department of Justice investigation of hospitals accused of billing Medicare for unnecessary implantable cardiac defibrillator (ICD) procedures on their use. Using 100 % inpatient and outpatient procedure data from Florida, we estimate that the investigation caused a 22 % decline in ICD implantations. The present value of savings nationally over a 10 year period is $2.7 billion, nearly 10 times larger than the $280 million in settlements the Department of Justice recovered from hospitals. The investigation had a large and long-lasting effect on physician behavior, indicating the utility of antifraud enforcement as a tool for reducing wasteful medical care.
Subject(s)
Medicare , Physicians , Aged , Delivery of Health Care , Florida , Fraud , Humans , United StatesABSTRACT
INTRODUCTION: Clinical reports describe patients with Alzheimer's disease (AD) exhibiting atypical adaptive walking responses to the visual environment; however, there is limited empirical investigation of such behaviors or factors modulating their expression. We aim to evaluate effects of lighting-based interventions and clinical presentation (visual- vs memory-led) on walking function in participants with posterior cortical atrophy (PCA) and typical AD (tAD). METHODS: Participants with PCA (n = 10), tAD (n = 9), and healthy controls (n = 12) walked to visible target destinations under different lighting conditions within two pilot repeated-measures design investigations (Experiment 1: 32 trials per participant; Experiment 2: 36 trials per participant). Participants walked to destinations with the floorpath interrupted by shadows varying in spatial extent (Experiment 1: no, medium, high shadow) or with different localized parts of the environment illuminated (Experiment 2: target, middle, or distractor illuminated). The primary study outcome for both experimental tasks was completion time; secondary kinematic outcomes were proportions of steps identified as outliers (Experiment 1) and walking path directness (Experiment 2). RESULTS: In Experiment 1, PCA participants overall demonstrated modest reductions in time taken to reach destinations when walking to destinations uninterrupted by shadows compared to high shadow conditions (7.1% reduction [95% confidence interval 2.5, 11.5; P = .003]). Experiment 2 found no evidence of differences in task performance for different localized lighting conditions in PCA participants overall. Neither experiment found evidence of differences in task performance between conditions in tAD or control participants overall. Completion time in both patient groups was longer relative to controls, and longer in PCA relative to tAD groups. DISCUSSION: Findings represent a quantitative characterization of a clinical phenomenon involving patients misperceiving shadows, implicating dementia-related cortico-visual impairments. Results contribute to evidence-based design guidelines for dementia-friendly environments.
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Unlike in the production of most goods, changes in capacity for labor-intensive services only affect outcomes of interest insofar as service providers change the way they allocate their time in response to those capacity changes. In this paper, we examine how public sector service providers respond to unexpected capacity constraints in the specific context of public health clinics. We exploit an exogenous reduction in public health clinic capacity to quantify the trade-off between patients treated and time spent with each patient, which we treat as a proxy for a quality versus quantity decision. We provide evidence that these small and generally insignificant effects on nurse time favor public sector employees prioritizing quality of each interaction over clearing the patient queue.