Cementless total knee arthroplasty in young patients using tantalum trabecular implants results in significantly lower rates of aseptic loosening.

Aims: The mean age of patients undergoing total knee arthroplasty (TKA) has reduced with time. Younger patients have increased expectations following TKA. Aseptic loosening of the tibial component is the most common cause of failure of TKA in the UK. Interest in cementless TKA has re-emerged due to its encouraging results in the younger patient population. We review a large series of tantalum trabecular metal cementless implants in patients who are at the highest risk of revision surgery. Methods: A total of 454 consecutive patients who underwent cementless TKA between August 2004 and December 2021 were reviewed. The mean follow-up was ten years. Plain radiographs were analyzed for radiolucent lines. Patients who underwent revision TKA were recorded, and the cause for revision was determined. Data from the National Joint Registry for England, Wales, Northern Island, the Isle of Man and the States of Guernsey (NJR) were compared with our series. Results: No patients in our series had evidence of radiolucent lines on their latest radiological assessment. Only eight patients out of 454 required revision arthroplasty, and none of these revisions were indicated for aseptic loosening of the tibial baseplate. When compared to data from the NJR annual report, Kaplan-Meier estimates from our series (2.94 (95% confidence interval (CI) 1.24 to 5.87)) show a significant reduction in cumulative estimates of revision compared to all cemented (4.82 (95% CI 4.69 to 4.96)) or cementless TKA (5.65 (95% CI 5.23 to 6.10)). Our data (2.94 (95% CI 1.24 to 5.87)) also show lower cumulative revision rates compared to the most popular implant (PFC Sigma Cemented Knee implant fixation, 4.03 (95% CI 3.75 to 4.33)). The prosthesis time revision rate (PTIR) estimates for our series (2.07 (95% CI 0.95 to 3.83)) were lower than those of cemented cases (4.53 (95% CI 4.49 to 4.57)) from NJR. Conclusion: The NexGen trabecular (tantalum) cementless implant has lower revision rates in our series compared to all cemented implants and other types of cementless implants, and its use in younger patients should be encouraged.

Safe Insertion of Arterial Catheters (SIA): An ultrasound-guided protocol to minimize complications for arterial cannulation.

Direct puncture and cannulation of peripheral arteries is frequently performed in critical care and in emergency settings, mainly for hemodynamic monitoring and blood sampling. While there is abundant literature on peripheral arterial cannulation in children and adults, there is still scope for clinical improvements which may impact on patient safety. Although the radial artery is the most frequently utilized access site today, due to its superficial proximity, ease of access, and low risk of adverse events, other sites are sometimes chosen. The authors propose the Safe Insertion of Arterial Catheters (SIA) protocol, an ultrasound-guided insertion bundle applying a systematic approach to arterial cannulation, with a focus on improving insertion practices, reducing procedural complications, increasing the patient safety profile, and improving device performance.

The predictive value of vascular calcification on plain radiographs of the ankle to diagnose diabetes mellitus.

INTRODUCTION: There are nearly 500,000 people with undiagnosed diabetes mellitus in the UK. A common complication of diabetes is vascular calcification. The incidental finding of vascular calcification on plain radiographs in patients with undiagnosed diabetes has the potential to alter patient management. We hypothesised that the presence of vascular calcification on plain radiographs of the foot may predict the diagnosis of diabetes and aimed to determine the positive predictive value of vascular calcification to diagnose diabetes. METHODS: A retrospective case control study compared 130 diabetic patients to 130 non-diabetic patients that were matched for age and gender. The presence of vascular calcification in anterior, posterior or plantar vessels was measured on plain radiographs. McNemar's Chi-squared test and positive predictive values were calculated. Conditional logistic regression models estimated the association between calcification and diabetes RESULTS: The overall mean age was 58.0 % and 31.5 % were females. 89.2 % of those with diabetes had calcification present, and 23.1 % in those who did not have diabetes had calcification. McNemar's test for independence gives p < 0.001. Calcification in both anterior and posterior vessels predicts diabetes with a positive predictive value of 91.2 % (95 % CI 76.9-97.0 %). The odds ratio for having diabetes is 78 (95 % CI: 7.8 - 784) times higher in a person who has calcification in the blood vessels of their ankle than in a person without calcification after adjusting for confounders CONCLUSION: This study has demonstrated that vascular calcification in the anterior and posterior blood vessels is over 90 % predictive of a diagnosis of diabetes. This screening test could be used in future clinics when interpreting radiographs, aiding in the diagnosis of diabetes and altering patient management.

10 best practice tips with radial arterial catheterization.

Radial arterial catheters (RAC) are used extensively across critical care settings (Anesthesia, Intensive Care, Emergency Medicine) for continuous hemodynamic monitoring, allowing for immediate adjustments in vasopressor therapies and blood collection. Radial catheter failures are an ongoing significant issue for critical care clinicians with reported incidences at almost 25%. Common complications include loss of function, lack of blood return, poor quality waveforms and dislodgement, posing potential patient risks, and sudden loss of intra-arterial monitoring frequently requires prompt replacement. Contemporary research and technological improvements have highlighted several concepts to enhance the approach of RAC insertion and management while reducing immediate and late complications. The authors have prioritized the following 10 "best practice" aspects that may improve overall device function and reliability.

Arterial insertion method: A new method for systematic evaluation of ultrasound-guided radial arterial catheterization.

INTRODUCTION: Peripheral arterial catheter insertion is a common procedure for critically ill patients requiring frequent blood gas sampling and continuous blood pressure monitoring. There are clear advantages of ultrasound-guided arterial cannulation, which have shown to be more effective in reducing complications, time to successful cannulation, number of attempts, and overall first-time success rates. Evidence suggests that using palpation alone has a first-time success rate of less than 70% yet is still a widely performed technique. A systematic evaluation may be required to reduce variations in arterial catheterization practices. DESIGN: The arterial insertion method is a systematic evaluation to aid in arterial catheter insertion with ultrasound guidance, intended to improve the procedural approach. The process of arterial insertion method ensures appropriate choice of zone selection to optimize catheter longevity and performance in patients requiring arterial access. Moving the insertion site proximally 4 cm from the red zone into the green zone may reduce mechanical complications and preserve catheter performance and dwell time. CONCLUSION: The standardization of ultrasound guidance in arterial catheterization promotes vessel health and patient safety through device and site optimization. The arterial insertion method systematic evaluation may be utilized to reduce variation in practice and promote the use of ultrasound as a standard for the insertion of radial arterial catheters.

Laparoscopy allows the harvest of the DIEP flap with shorter fascial incisions as compared to endoscopic harvest: A single surgeon retrospective cohort study.

BACKGROUND: We present a comparative series to utilize minimally invasive endoscopic, total extraperitoneal laparoscopic (TEP-lap), and transabdominal preperitoneal robotic perforator (TAP-RAP) harvest of the deep inferior epigastric (DIE) vessels for autologous breast reconstruction (ABR) to mitigate donor site morbidity. We hypothesized that TEP-lap and TAP-RAP harvests of abdominal-based free flaps are safe techniques associated with decreased fascial incision when compared with the endoscopic harvest. METHODS: We designed a retrospective cohort series of subjects with newly diagnosed breast cancer who presented for ABR using endoscopic (control), laparoscopic, or robotic assistance between September 2017 and April 2019. The primary outcome variables were flap success (i.e., absence of perioperative flap loss), fascial incision length, and intraoperative complications. Secondary variables included operating time, costs, and postoperative complications within 90 days (arterial thrombosis, venous congestion, bulge/hernia, and operative revision). Exclusion criteria included < 90 days follow-up. RESULTS: In total 94, 38, and 3 subjects underwent endoscopic, TEP-lap, and TAP-RAP flap harvests. Mean lengths of fascial incisions for the endoscopic and laparoscopic cohorts were 4.5 ±â€¯0.5 cm and 2.0 ±â€¯0.6 cm (p < 0.0001), while incision length depended on the concurrent procedure in the robotic cohort. No subjects required conversion to an open harvest. There were no bleeding complications, intra-abdominal injuries, flap losses, or abdominal bulges/hernias noted in the TEP-lap and TAP-RAP cohorts. CONCLUSION: Minimally invasive DIEP flap harvest may decrease fascial injury when compared with conventional open harvest. There are significant trade-offs among harvest methods. TEP-lap harvest may better balance the trade-off related to abdominal wall morbidity.

Laparoscopically Assisted DIEP Flap Harvest Minimizes Fascial Incision in Autologous Breast Reconstruction.

BACKGROUND: Total extraperitoneal laparoscopically assisted harvest of the deep inferior epigastric vessels permits a decrease in myofascial dissection in deep inferior epigastric artery perforator flap breast reconstruction. The authors present a reliable technique that further decreases donor-site morbidity in autologous breast reconstruction. METHODS: The authors conducted a retrospective cohort study of female subjects presenting to the senior surgeon (S.K.K.) from March of 2018 to March of 2019 for autologous breast reconstruction after a newly diagnosed breast cancer. The operative technique is summarized as follows: a supraumbilical camera port is placed at the medial edge of the rectus muscle to enter the retrorectus space; the extraperitoneal plane is developed using a balloon dissector and insufflation; two ports are placed through the linea alba below the umbilicus to introduce dissection instruments; the deep inferior epigastric vessels are dissected from the underside of the rectus muscle; muscle branches and the superior epigastric are ligated using a Ligasure; and the deep inferior epigastric pedicle is ligated and the vessels are delivered through a minimal fascial incision. The flap(s) is transferred to the chest for completion of the reconstruction. RESULTS: Thirty-three subjects totaling 57 flaps were included. All flaps were single-perforator deep inferior epigastric artery perforator flaps. Mean fascial incision length was 2.0 cm. Sixty percent of subjects recovered without narcotics. Mean length of stay was 2.5 days. Flap salvage occurred in one subject after venous congestion. Two pedicle transections occurred during harvest that required perforator-to-pedicle anastomosis. CONCLUSION: Total extraperitoneal laparoscopically assisted harvest of the deep inferior epigastric pedicle is a reliable method that decreases the donor-site morbidity of autologous breast reconstruction. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

The psychology of bio-banding: a Vygotskian perspective.

CONTEXT: Bio-banding is the process of grouping players by their maturational status rather than chronological age. It is designed to limit the impact of maturational timing on talent identification and development and expose early and late maturing players to new learning experiences and challenges. A common criticism of bio-banding is that it does not consider age related differences in psychosocial and behaviour development. OBJECTIVE: The purpose of this case study is to describe how theory and research pertaining to the design and delivery of mixed-aged classrooms can be used to prepare early and late maturing players for bio-banding and optimise the benefits of this practice. METHOD: After placing the players in their bio-banded groups, one Elite Premier League Academy provided bespoke group psychology sessions for early and late maturing players for six weeks. RESULTS: Providing bespoke psychology sessions for players maturation age allows for the cognitive processes of both early and late maturity status to work within the zone of proximal development. CONCLUSION: Pedagogical practice associated with mixed age classrooms can be used in bio-banded contexts to benefit both early and late maturing players. Delivering psychological sessions alongside bio-banding permits learning and development to both ends of the maturity spectrum.

Upper limb entrapment neuropathies in multiple sclerosis.

INTRODUCTION: Entrapment neuropathies of upper limbs such as carpal tunnel and cubital tunnel syndromes are common in the general population. Identification of entrapment neuropathies of upper limbs in patients with multiple sclerosis can be clinically challenging as signs and symptoms could be attributed to multiple sclerosis. People at later stages of multiple sclerosis use mobility aids and wheelchairs. Weakness of hands in this cohort due to entrapment neuropathies could adversely affect their mobility and independence. METHODS: This was a retrospective review of records of patients with multiple sclerosis referred for clinical neurophysiological studies with clinical suspicion of upper limb entrapment neuropathies over a 10-year period. We collected demographic details, clinical features, clinical neurophysiological data and details of aids and appliances used for mobility. RESULTS: Among 71 patients, 38 (53.5%) patients had at least one entrapment neuropathy of upper limb confirmed by clinical neurophysiological studies. Twelve (31%) patients had median nerve entrapment, 20 (53%) had ulnar nerve entrapment and six (16%) had both. Risk of ulnar nerve entrapment was significantly higher in patients using a powered wheelchair (odds ratio 5.7, 95% confidence interval (1.7-18.7, p = 0.0037). DISCUSSION: Entrapment neuropathies should be considered in patients with multiple sclerosis reporting sensory and motor symptoms of hands.

Video Interviewing: A Review and Recommendations for Implementation in the Era of COVID-19 and Beyond.

Due to the COVID-19 pandemic, it is very likely that many radiology residency and fellowship programs will adopt interactive videoconference interviewing for the 2020-2021 residency match cycle. Although video interviewing has become a common part of the hiring process for business, experience with video interviewing for resident and fellow selection has been limited. Advantages of video interviews over traditional on-site interviews include cost-savings to both applicants and residency programs, less disruption to an applicant's educational activities, and potential for training programs to access a wider pool of candidates. The loss of the casual interactions that occur during an on-site interview and the inability of candidates to evaluate training facilities and their surrounding environments in-person are among the obstacles posed by video interviews, but training programs can mitigate these challenges with enhanced website content and creative media solutions. Through a review of the existing literature and internet resources, this article recommends specific measures medical schools, applicants, and radiology residency and fellowship programs can take to optimize the virtual interview experience for all involved parties.

Risk Factors for Lower Extremity Amputation Following Attempted Free Flap Limb Salvage.

BACKGROUND: Traumatic limb salvage with free flap reconstruction versus primary amputation for lower extremity (LE) injuries remains an oft debated topic. Limb salvage has well-studied benefits and advances in microsurgery have helped reduce the complication rates. A subset of patients eventually requires secondary amputation after a failed attempt at limb salvage. A better understanding of risk factors that predict subsequent amputation after failed free flap reconstruction of LE injuries may improve operative management. PATIENTS AND METHODS: A retrospective study (2002-2019) was conducted on all patients who underwent free flap reconstruction of the LE within 120 days of the original inciting event at a single institution. Patient and operative factors were reviewed including comorbidities, severity of the injury, flap choice, outcomes, and complications. Predictors of subsequent amputation were analyzed. RESULTS: A total of 129 patients requiring free flap reconstructions for LE limb salvage met inclusion criteria. Anterolateral thigh flaps (70.5%) were performed most frequently. Secondary amputation occurred in 10 (7.8%) patients. Preoperative factors associated with eventual amputation include diabetes mellitus (p = 0.044), number of preoperative debridements (p = 0.013), evidence of any arterial injury/pathology (p = 0.008), specifically posterior tibial artery (p = < 0.0001), and degree of three-vessel runoff (p = 0.007). Operative factors associated with subsequent amputation include evidence of recipient artery injury/pathology (p = 0.008). Postoperative factors associated with secondary amputation include total flap failure (p = 0.001), partial flap failure (p = 0.002), minor complications (p = 0.037), and residual osteomyelitis (p = 0.028). CONCLUSION: Many factors contribute to the reconstructive surgical team's decision to proceed with limb salvage or perform primary amputation. Several variables are associated with failed limb salvage resulting in secondary amputation. Further studies are required to better guide management during the limb salvage process.

Pre- and post-review of a standardized ultrasound-guided central venous catheterization curriculum evaluating procedural skills acquisition and clinician confidence.

BACKGROUND: To evaluate novice and expert clinicians' procedural confidence utilizing a blended learning mixed fidelity simulation model when applying a standardized ultrasound-guided central venous catheterization curriculum. METHODS: Simulation-based education and ultrasound-guided central venous catheter insertion aims to provide facility-wide efficiencies and improves patient safety through interdisciplinary collaboration. The objective of this quality improvement research was to evaluate both novice (<50) and expert (>50) clinicians' confidence across 100 ultrasound-guided central venous catheter insertion courses were performed at a mixture of teaching and non-teaching hospitals across 26 states within the United States between April 2015 and April 2016. A total of 1238 attendees completed a pre- and post-survey after attending a mixed method clinical simulation course. Attendees completed a 4-h online didactic education module followed by 4 h of hands-on clinical simulation stations (compliance/sterile technique, needling techniques, vascular ultrasound assessment, and experiential complication management). RESULTS: The use of a standardized evidence-based ultrasound-guided central venous catheter curriculum improved confidence and application to required clinical tasks and knowledge across all interdisciplinary specialties, regardless of level of experience. Both physician and non-physician groups resulted in statistically significant results in both procedural compliance (p < 0.001) and ultrasound skills (p < 0.001). CONCLUSION: The use of a standardized clinical simulation curriculum enhanced all aspects of ultrasound-guided central venous catheter insertion skills, knowledge, and improved confidence for all clinician types. Self-reported complications were reported at significantly higher rates than previously published evidence, demonstrating the need for ongoing procedural competencies. While there are growing benefits for the role of simulation-based programs, further evaluation is needed to explore its effectiveness in changing the quality of clinical outcomes within the healthcare setting.

Subgroup analysis and interpretation for phase 3 confirmatory trials: White paper of the EFSPI/PSI working group on subgroup analysis.

Subgroup by treatment interaction assessments are routinely performed when analysing clinical trials and are particularly important for phase 3 trials where the results may affect regulatory labelling. Interpretation of such interactions is particularly difficult, as on one hand the subgroup finding can be due to chance, but equally such analyses are known to have a low chance of detecting differential treatment effects across subgroup levels, so may overlook important differences in therapeutic efficacy. EMA have therefore issued draft guidance on the use of subgroup analyses in this setting. Although this guidance provided clear proposals on the importance of pre-specification of likely subgroup effects and how to use this when interpreting trial results, it is less clear which analysis methods would be reasonable, and how to interpret apparent subgroup effects in terms of whether further evaluation or action is necessary. A PSI/EFSPI Working Group has therefore been investigating a focused set of analysis approaches to assess treatment effect heterogeneity across subgroups in confirmatory clinical trials that take account of the number of subgroups explored and also investigating the ability of each method to detect such subgroup heterogeneity. This evaluation has shown that the plotting of standardised effects, bias-adjusted bootstrapping method and SIDES method all perform more favourably than traditional approaches such as investigating all subgroup-by-treatment interactions individually or applying a global test of interaction. Therefore, these approaches should be considered to aid interpretation and provide context for observed results from subgroup analyses conducted for phase 3 clinical trials.

Make Your Own Deep Inferior Epigastric Artery Perforator Flap: Perforator Delay Improves Deep Inferior Epigastric Artery Perforator Flap Reliability.

Abdominal-based autologous breast reconstruction remains a conflict between blood supply and donor site complication. Optimizing esthetics and minimizing recovery and postoperative pain add further complexity. We present a 2-stage technique of deep inferior epigastric artery perforator flap reconstruction to (1) reliably harvest single-vessel flaps while minimizing fat necrosis, (2) decrease abdominal wall morbidity, and (3) improve breast and donor site esthetics. METHODS: Female subjects presenting between August 2017 and January 2019 to the senior surgeon for abdominal-based breast reconstruction were included. After mastectomy, the subjects underwent subcutaneous placement of tissue expanders and in situ selection of a low, centrally located perforator based on preoperative computed tomographic angiography imaging through an infraumbilical "T" incision with ligation of all other perforators and superficial system. Subjects underwent tissue expander explant and flap transfer at a second stage. RESULTS: One hundred thirty-five subjects undergoing 215 free flaps met criteria. Mean age and body mass index were 52.1 years and 29.3 kg/m2, respectively. Seven perforator complications (3.3%) occurred with 2 (0.9%) total and 5 (2.3%) partial flap losses. There were 20 (14.8%) readmissions and 26 (19.3%) reoperations. Breast complications included arterial thrombosis (0.5%), venous congestion (1.9%), and fat necrosis (5.1%). The mastectomy skin flap necrosis rate decreased from 14.9% to 2.3% following staged reconstruction. Abdominal donor site complications included delayed healing (11.1%), seroma (5.9%), and hematoma (2.2%). CONCLUSIONS: The 2-stage delayed deep inferior epigastric artery perforator flap technique represents a safe, efficacious modality to allow for reliable harvest of single-vessel flaps with low rates of fat necrosis while improving donor site esthetics and morbidity.

(Lack of) Measurable Clinical or Knowledge Gains From Resident Participation in Noon Conference.

RATIONALE AND OBJECTIVES: The objective of this study was to determine whether noon conference attendance by diagnostic radiology residents is predictive of measurable performance. METHODS: This single-center retrospective Health Insurance and Portability and Accountability Act (HIPAA)-compliant cross-sectional study was considered "not regulated" by the institutional review board. All diagnostic radiology residents who began residency training from 2008 to 2012 were included (N = 54). Metrics of clinical performance and knowledge were collected, including junior and senior precall test results, American Board of Radiology scores (z-score transformed), American College of Radiology in-training scores (years 1-3), on-call "great call" and minor and major discrepancy rates, on-call and daytime case volumes, and training rotation scores. Multivariate regression models were constructed to determine if conference attendance, match rank order, or starting year could predict these outcomes. Pearson bivariate correlations were calculated. RESULTS: Senior precall test results were moderately correlated with American Board of Radiology (r = 0.41) and American College of Radiology (r = 0.38-0.48) test results and mean rotation scores (r = 0.41), indicating moderate internal validity. However, conference attendance, match rank order, and year of training did not correlate with (r = -0.16-0.16) or predict (P > .05) measurable resident knowledge. On multivariate analysis, neither match rank order (P = .14-.96) nor conference attendance (P = .10-.88) predicted measurable clinical efficiency or accuracy. Year started training predicted greater cross-sectional case volume (P < .0001, ß = 0.361-0.516) and less faculty-to-resident feedback (P < 0.0001, ß = [-0.628]-[-0.733]). CONCLUSIONS: Residents with lower conference attendance are indistinguishable from those who attend more frequently in a wide range of clinical and knowledge-based performance assessments, suggesting that required attendance may not be necessary to gain certain measurable core competencies.

An adaptive design for updating the threshold value of a continuous biomarker.

Potential predictive biomarkers are often measured on a continuous scale, but in practice, a threshold value to divide the patient population into biomarker 'positive' and 'negative' is desirable. Early phase clinical trials are increasingly using biomarkers for patient selection, but at this stage, it is likely that little will be known about the relationship between the biomarker and the treatment outcome. We describe a single-arm trial design with adaptive enrichment, which can increase power to demonstrate efficacy within a patient subpopulation, the parameters of which are also estimated. Our design enables us to learn about the biomarker and optimally adjust the threshold during the study, using a combination of generalised linear modelling and Bayesian prediction. At the final analysis, a binomial exact test is carried out, allowing the hypothesis that 'no population subset exists in which the novel treatment has a desirable response rate' to be tested. Through extensive simulations, we are able to show increased power over fixed threshold methods in many situations without increasing the type-I error rate. We also show that estimates of the threshold, which defines the population subset, are unbiased and often more precise than those from fixed threshold studies. We provide an example of the method applied (retrospectively) to publically available data from a study of the use of tamoxifen after mastectomy by the German Breast Study Group, where progesterone receptor is the biomarker of interest. © 2016 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.

Incorporating Functional Genomic Information in Genetic Association Studies Using an Empirical Bayes Approach.

There is a large amount of functional genetic data available, which can be used to inform fine-mapping association studies (in diseases with well-characterised disease pathways). Single nucleotide polymorphism (SNP) prioritization via Bayes factors is attractive because prior information can inform the effect size or the prior probability of causal association. This approach requires the specification of the effect size. If the information needed to estimate a priori the probability density for the effect sizes for causal SNPs in a genomic region isn't consistent or isn't available, then specifying a prior variance for the effect sizes is challenging. We propose both an empirical method to estimate this prior variance, and a coherent approach to using SNP-level functional data, to inform the prior probability of causal association. Through simulation we show that when ranking SNPs by our empirical Bayes factor in a fine-mapping study, the causal SNP rank is generally as high or higher than the rank using Bayes factors with other plausible values of the prior variance. Importantly, we also show that assigning SNP-specific prior probabilities of association based on expert prior functional knowledge of the disease mechanism can lead to improved causal SNPs ranks compared to ranking with identical prior probabilities of association. We demonstrate the use of our methods by applying the methods to the fine mapping of the CASP8 region of chromosome 2 using genotype data from the Collaborative Oncological Gene-Environment Study (COGS) Consortium. The data we analysed included approximately 46,000 breast cancer case and 43,000 healthy control samples.

Increasing the efficiency of a targeted methicillin-resistant Staphylococcus aureus screening program.

An interdisciplinary team implemented a screening program targeting patients with a history of methicillin-resistant Staphylococcus aureus (MRSA), to reduce unnecessary contact isolation. After converting from a 2-step culture-based protocol to single polymerase chain reaction (PCR) testing, we increased the efficiency of the screening program from 77% to 100%. Despite the higher cost of PCR-based testing, this program remained cost-saving.

Novel bayes factors that capture expert uncertainty in prior density specification in genetic association studies.

Bayes factors (BFs) are becoming increasingly important tools in genetic association studies, partly because they provide a natural framework for including prior information. The Wakefield BF (WBF) approximation is easy to calculate and assumes a normal prior on the log odds ratio (logOR) with a mean of zero. However, the prior variance (W) must be specified. Because of the potentially high sensitivity of the WBF to the choice of W, we propose several new BF approximations with logOR ∼N(0,W), but allow W to take a probability distribution rather than a fixed value. We provide several prior distributions for W which lead to BFs that can be calculated easily in freely available software packages. These priors allow a wide range of densities for W and provide considerable flexibility. We examine some properties of the priors and BFs and show how to determine the most appropriate prior based on elicited quantiles of the prior odds ratio (OR). We show by simulation that our novel BFs have superior true-positive rates at low false-positive rates compared to those from both P-value and WBF analyses across a range of sample sizes and ORs. We give an example of utilizing our BFs to fine-map the CASP8 region using genotype data on approximately 46,000 breast cancer case and 43,000 healthy control samples from the Collaborative Oncological Gene-environment Study (COGS) Consortium, and compare the single-nucleotide polymorphism ranks to those obtained using WBFs and P-values from univariate logistic regression.

Clinical, patient experience and cost impacts of performing active surveillance on known methicillin-resistant Staphylococcus aureus positive patients admitted to medical-surgical units.

BACKGROUND: There is a large and growing body of evidence that methicillin-resistant Staphylococcus aureus (MRSA) screening programs are cost effective, but such screening represents a significant cost burden for hospitals. This study investigates the clinical, patient experience and cost impacts of performing active surveillance on known methicillin-resistant S aureus positive (MRSA+) patients admitted to 7 medical-surgical units of a large regional hospital, specifically to allow discontinuation of contact isolation. METHODS: We conducted mixed-methods retrospective evaluation of a process improvement project that screened admitted patients with known MRSA+ status for continued MRSA colonization. RESULTS: Of those eligible patients on our institution's MRSA+ list who did complete testing, 80.2% (130/162) were found to be no longer colonized, and only 19.8% (32/162) were still colonized. Forty-one percent (13/32) of interviewed patients in contact isolation for MRSA reported that isolation had affected their hospital stay, and 28% (9/32) of patients reported emotional distress resulting from their isolation. Total cost savings of the program are estimated at $101,230 per year across the 7 study units. CONCLUSION: Our findings provide supporting evidence that a screening program targeting patients with a history of MRSA who would otherwise be placed in isolation has the potential to improve outcomes and patient experience and reduce costs.