The Cost of Day-Case Surgery for Varicose Veins

A methodology is described to calculate the cost of day-case surgery at University Hospital, Nottingham during 1988/89, which may be suitable for use elsewhere. Day-case surgery for varicose veins is cheaper than the corresponding inpatient surgery.

Dickkopf-3 is upregulated in osteoarthritis and has a chondroprotective role

OBJECTIVE

Dickkopf-3 (Dkk3) is a non-canonical member of the Dkk family of Wnt antagonists and its upregulation has been reported in microarray analysis of cartilage from mouse models of osteoarthritis (OA). In this study we assessed Dkk3 expression in human OA cartilage to ascertain its potential role in chondrocyte signaling and cartilage maintenance.

METHODS

Dkk3 expression was analysed in human adult OA cartilage and synovial tissues and during chondrogenesis of ATDC5 and human mesenchymal stem cells. The role of Dkk3 in cartilage maintenance was analysed by incubation of bovine and human cartilage explants with interleukin-1β (IL1β) and oncostatin-M (OSM). Dkk3 gene expression was measured in cartilage following murine hip avulsion. Whether Dkk3 influenced Wnt, TGFβ and activin cell signaling was assessed in primary human chondrocytes and SW1353 chondrosarcoma cells using qRT-PCR and luminescence assays.

RESULTS

Increased gene and protein levels of Dkk3 were detected in human OA cartilage, synovial tissue and synovial fluid. DKK3 gene expression was decreased during chondrogenesis of both ATDC5 cells and humans MSCs. Dkk3 inhibited IL1β and OSM-mediated proteoglycan loss from human and bovine cartilage explants and collagen loss from bovine cartilage explants. Cartilage DKK3 expression was decreased following hip avulsion injury. TGFβ signaling was enhanced by Dkk3 whilst Wnt3a and activin signaling were inhibited.

CONCLUSIONS

We provide evidence that Dkk3 is upregulated in OA and may have a protective effect on cartilage integrity by preventing proteoglycan loss and helping to restore OA-relevant signaling pathway activity. Targeting Dkk3 may be a novel approach in the treatment of OA.

Meta-Analysis of Rare Variant Association Tests in Multiethnic Populations

Several methods have been proposed to increase power in rare variant association testing by aggregating information from individual rare variants (MAF < 0.005). However, how to best combine rare variants across multiple ethnicities and the relative performance of designs using different ethnic sampling fractions remains unknown. In this study, we compare the performance of several statistical approaches for assessing rare variant associations across multiple ethnicities. We also explore how different ethnic sampling fractions perform, including single-ethnicity studies and studies that sample up to four ethnicities. We conducted simulations based on targeted sequencing data from 4,611 women in four ethnicities (African, European, Japanese American, and Latina). As with single-ethnicity studies, burden tests had greater power when all causal rare variants were deleterious, and variance component-based tests had greater power when some causal rare variants were deleterious and some were protective. Multiethnic studies had greater power than single-ethnicity studies at many loci, with inclusion of African Americans providing the largest impact. On average, studies including African Americans had as much as 20% greater power than equivalently sized studies without African Americans. This suggests that association studies between rare variants and complex disease should consider including subjects from multiple ethnicities, with preference given to genetically diverse groups.

Modeling Linkage Disequilibrium Increases Accuracy of Polygenic Risk Scores

Polygenic risk scores have shown great promise in predicting complex disease risk and will become more accurate as training sample sizes increase. The standard approach for calculating risk scores involves linkage disequilibrium (LD)-based marker pruning and applying a p value threshold to association statistics, but this discards information and can reduce predictive accuracy. We introduce LDpred, a method that infers the posterior mean effect size of each marker by using a prior on effect sizes and LD information from an external reference panel. Theory and simulations show that LDpred outperforms the approach of pruning followed by thresholding, particularly at large sample sizes. Accordingly, predicted R(2) increased from 20.1% to 25.3% in a large schizophrenia dataset and from 9.8% to 12.0% in a large multiple sclerosis dataset. A similar relative improvement in accuracy was observed for three additional large disease datasets and for non-European schizophrenia samples. The advantage of LDpred over existing methods will grow as sample sizes increase.

Abstract 4611: Quantification and functional characterization of the shared heritability across multiple cancer sites: results from the GAME-ON Consortium

It is estimated that more than 1.6 million cancer diagnoses will occur in the US during 2014 and five common cancers_breast, colorectal, lung, ovarian and prostate cancer_together constitute more than 50% of new cancer diagnoses. Many cancers cluster within families and in some cases multiple tumor types affect one family. Quantifying the extent to which distinct cancer types share genetic predisposition will inform design for future genetic association studies and give insights to shared biological mechanisms underlying disease.

The GAME-ON consortium set out to conduct post-GWAS research for breast, colorectal, lung, ovarian and prostate cancer. Across the five cancer sites, a total of 51,725 cases and 62,155 controls were included as part of cancer-specific GWAS and summary statistics were shared between the cancer sites to conduct cross-cancer analysis. Using the recently developed LD score regression method, we leveraged these data to quantify the genetic correlation between these five cancers. In addition, we also estimated the genetic correlation between these cancers and 59 non-cancer traits using publically available GWAS summary statistics. Finally, we also functionally characterized the heritability across the five GAME-ON cancers.

We found a nominally significant positive genetic correlation between breast and lung cancer (rg = 0.26, p = 0.045), however this correlation did not remain significantly different from zero after adjusting for multiple testing. We found positive genetic correlations (all p&lt;0.003) between lung cancer and traits related to smoking (rg = 0.53-0.64) and adiposity (rg = 0.31-0.42). We also identified a positive genetic correlation between schizophrenia and breast cancer (rg = 0.16, p = 0.003) as well as a negative genetic correlation between adiposity and breast cancer (rg = -0.25, p = 0.01). However, these genetic correlations were not statistically significant after adjustment for number of tests performed.

In functional enrichment analysis across all cancers, we observed a 17-fold (se: 2.9) enrichment of heritability located within conserved regions. In addition, transcription factor binding sites (TFBS), super-enhancers and histone marks showed 6.6- (se: 1.2), 2.5- (se: 0.2) and 2.0-fold enrichments, respectively.

This is the first study to estimate the genetic correlation between these five common cancers in a population of unrelated individuals. Although we observe only modest evidence of a shared heritability of these cancers, the standard errors were large; larger samples will be needed to find modest, true genetic correlations. In addition, we found that conserved genetic regions are enriched for cancer heritability and future studies seeking to discover genetic variants associated with these cancers should focus on these regions.

Note: This abstract was not presented at the meeting.

Citation Format: Sara Lindstrom, Hilary Finucane, Brendan Bulik-Sullivan, Fredrick Schumacher, Christopher Amos, Stephen Gruber, Brian Henderson, David Hunter, Thomas Sellers, Benjamin Neale, Alkes Price, Peter Kraft, GAME-ON Consortium. Quantification and functional characterization of the shared heritability across multiple cancer sites: results from the GAME-ON Consortium. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4611. doi:10.1158/1538-7445.AM2015-4611

From Dyadic Ties to Information Infrastructures: Care-Coordination between Patients, Providers, Students and Researchers. Contribution of the Health Informatics Education Working Group

OBJECTIVE

To share how an effectual merging of local and online networks in low resource regions can supplement and strengthen the local practice of patient centered care through the use of an online digital infrastructure powered by all stakeholders in healthcare. User Driven Health Care offers the dynamic integration of patient values and evidence based solutions for improved medical communication in medical care.

INTRODUCTION

This paper conceptualizes patient care-coordination through the lens of engaged stakeholders using digital infrastructures tools to integrate information technology. We distinguish this lens from the prevalent conceptualization of dyadic ties between clinician-patient, patient-nurse, clinician-nurse, and offer the holistic integration of all stakeholder inputs, in the clinic and augmented by online communication in a multi-national setting.

METHODS

We analyze an instance of the user-driven health care (UDHC), a network of providers, patients, students and researchers working together to help manage patient care. The network currently focuses on patients from LMICs, but the provider network is global in reach. We describe UDHC and its opportunities and challenges in care-coordination to reduce costs, bring equity, and improve care quality and share evidence.

CONCLUSION

UDHC has resulted in coordinated global based local care, affecting multiple facets of medical practice. Shared information resources between providers with disparate knowledge, results in better understanding by patients, unique and challenging cases for students, innovative community based research and discovery learning for all.

C1 inhibitor deficiency: 2014 United Kingdom consensus document

C1 inhibitor deficiency is a rare disorder manifesting with recurrent attacks of disabling and potentially life-threatening angioedema. Here we present an updated 2014 United Kingdom consensus document for the management of C1 inhibitor-deficient patients, representing a joint venture between the United Kingdom Primary Immunodeficiency Network and Hereditary Angioedema UK. To develop the consensus, we assembled a multi-disciplinary steering group of clinicians, nurses and a patient representative. This steering group first met in 2012, developing a total of 48 recommendations across 11 themes. The statements were distributed to relevant clinicians and a representative group of patients to be scored for agreement on a Likert scale. All 48 statements achieved a high degree of consensus, indicating strong alignment of opinion. The recommendations have evolved significantly since the 2005 document, with particularly notable developments including an improved evidence base to guide dosing and indications for acute treatment, greater emphasis on home therapy for acute attacks and a strong focus on service organization.

"I AM A KID AT HEART."

Ewing's sarcoma is a rare, malignant bone tumor that occurs in children/young adults, and is known as the "small, round, blue cell tumor." The infrequency makes it a challenging diagnosis, especially when the typical patient characteristics are bypassed for decades.

FOOD FOR THOUGHT: MITRAL STENOSIS WITH A SIDE OF MAC AND CHEESE

Caseous mitral annular calcification (CMAC) is a rare variant of mitral annular calcification (MAC), most commonly seen in elderly women on the posterior mitral annulus. CMAC is usually diagnosed incidentally and has a benign course. However, it may cause abnormal blood flow across the mitral valve resulting in mitral regurgitation, and rarely, functional mitral stenosis. MAC occurs in 10 percent of the population, while CMAC occurs in 0.06 percent. Most cases of CMAC are misdiagnosed as other intracardiac masses, such as tumors, abscesses, thrombi, and vegetation.

Meticillin-resistant Staphylococcus aureus and meticillin-susceptible Staphylococcus aureus screening in a cohort of haemodialysis patients: carriage, demographics and outcomes

BACKGROUND

Patients on haemodialysis are vulnerable to colonization with Staphylococcus aureus due to frequent hospital contact, indwelling devices, and impaired immunity. Additionally colonization is associated with increased risk of infection.

AIM

To determine the prevalence of both meticillin-resistant S. aureus (MRSA) and meticillin-susceptible S. aureus (MSSA) carriage in our haemodialysis cohort and to identify any risk factors predisposing to carriage, recolonization, or persistent carriage following a decolonization programme.

METHODS

All haemodialysis patients screened for S. aureus carriage between June 2009 and May 2011 were retrospectively followed up for 18 months using hospital electronic records. Statistical analysis was performed using IBM SPSS version 19.

FINDINGS

Out of 578 patients screened, 288 patients (49%) had at least one positive swab (10% MRSA, 90% MSSA). Of these patients, 265 completed a course of decolonization therapy following which 36% successfully eradicated (eradicators) and 64% did not (non-eradicators). There was no statistically significant difference in patient demography, type of vascular access, 18-month patient mortality, or number of hospital admissions between the two groups. Those who failed to eradicate were more likely to have had an episode of S. aureus bacteraemia within the study period compared to those who successfully decolonized (P = 0.003).

CONCLUSION

Half of our haemodialysis cohort was colonized with S. aureus at any one time over an 18-month period. Following decolonization, one-third of patients remained successfully eradicated for 18 months. Non-eradicators have an increased risk of bacteraemia, which is associated with poor mortality. We would recommend routine screening and aggressive attempts to decolonize.