Dialysis decision making in Canada, the United Kingdom, and the United States

This study was designed to determine the extent to which differences in criteria for dialysis patient selection and availability of financial resources cause the wide variation in acceptance rates for dialysis in Canada, the United Kingdom, and the United States. We also sought to determine whether there is agreement among nephrologists in the three countries on which patients should not be offered dialysis. We used a cross-sectional survey of all members of the Canadian Society of Nephrology and the Renal Association of Great Britain, and a randomized sample of 800 members of the American Society of Nephrology. Five case vignettes were presented asking for yes/no decisions on offering or not offering dialysis, together with ranking of factors considered important. We also inquired about dialysis resources and physician demographics. We compared responses by country. More nephrologists from the United Kingdom returned responses (83%) than Canadian (53%) or American (36%) nephrologists. American nephrologists offered dialysis more than Canadian or British nephrologists (three of five cases; P < 0.04 to P < 0.001) and ranked patient/family wishes (three of five cases; P < 0.057 to P < 0.0001) and fear of lawsuit (P < 0.04 to P = 0.0012) higher than British or Canadian nephrologists. Canadian and British nephrologists reported their perception of patients' quality of life as a reason to provide (P = 0.0019) or not provide (P = 0.068 to P = 0.0026) dialysis more often than their American counterparts. Despite these differences, nephrologists from each country did not differ by more than 30% on any decision and ranked factors almost identically. Ten percent and 12% of Canadian and British nephrologists, respectively, but only 2% of American nephrologists, reported refusing dialysis due to lack of resources (P < 0.0001). We conclude that the wide variation in dialysis acceptance rates in the three countries is somewhat influenced by differences in patient selection criteria and withholding of dialysis by nephrologists based on financial constraints, but that other factors, such as differences in rates of patient nonreferral for dialysis, contribute more significantly to the variation. Generally agreed on practice guidelines for dialysis patient selection appear possible.     

Metabolomic Pathways to Osteoporosis in Middle‐Aged Women: A Genome‐Metabolome‐Wide Mendelian Randomization Study

The metabolic state of the body can be a major determinant of bone health. We used a Mendelian randomization approach to identify metabolites causally associated with bone mass to better understand the biological mechanisms of osteoporosis. We tested bone phenotypes (femoral neck, total hip, and lumbar spine bone mineral density [BMD]) for association with 280 fasting blood metabolites in 6055 women from TwinsUK cohort with genomewide genotyping scans. Causal associations between metabolites and bone phenotypes were further assessed in a bidirectional Mendelian randomization study using genetic markers/scores as instrumental variables. Significant associations were replicated in 624 participants from the Hong Kong Osteoporosis Study (HKOS). Fifteen metabolites showed direct associations with bone phenotypes after adjusting for covariates and multiple testing. Using genetic instruments, four of these metabolites were found to be causally associated with hip or spine BMD. These included androsterone sulfate, epiandrosterone sulfate, 5alpha‐androstan‐3beta17beta‐diol disulfate (encoded by CYP3A5), and 4‐androsten‐3beta17beta‐diol disulfate (encoded by SULT2A1). In the HKOS population, all four metabolites showed significant associations with hip and spine BMD in the expected directions. No causal reverse association between BMD and any of the metabolites were found. In the first metabolome‐genomewide Mendelian randomization study of human bone mineral density, we identified four novel biomarkers causally associated with BMD. Our findings reveal novel biological pathways involved in the pathogenesis of osteoporosis. © 2017 American Society for Bone and Mineral Research.     

The relationship between the duration of platelet storage and the development of transfusion reactions

BACKGROUND: The incidence of platelet transfusion reactions may depend partly on the length of storage. The influence of reactions on the effectiveness of platelet transfusions is not known. STUDY DESIGN AND METHODS: Platelet transfusion reactions, identified by prospective monitoring, were analyzed for the effects of component type, recipient lymphocytotoxic antibodies, bacterial contamination, and duration of storage. Posttransfusion corrected count increments (CCIs) were used to evaluate the effectiveness of transfusions associated with reactions by comparing them to those of randomly selected transfusions without reactions. RESULTS: Reactions accompanied 4 percent of the 4926 transfusions given and included 119 febrile nonhemolytic transfusion reactions, 62 allergic reactions, and 13 reactions with features of both. Platelet concentrates contained a mean of 0.5 × 10(8) white cells per unit. Lymphocytotoxic antibodies were detectable in 20 of 84 recipients tested proximate to a reaction. Bacterial cultures from 4 of 81 units were positive; 1 unit was associated with fatal Enterobacter sp. sepsis. The incidence of febrile nonhemolytic transfusion reactions but not allergic reactions was related to platelet storage duration. The CCI was not significantly different for transfusions associated with reactions (10.97 [median, range 0–72.5; n = 165]) or not so associated (13.1 [median, range 0–39.5; n = 174]) (p = 0.08). CONCLUSION: The incidence of febrile nonhemolytic transfusion reactions but not allergic reactions appears to be related to the duration of platelet storage. Transfusion reactions may not have an adverse impact on the effectiveness of platelet transfusions.     

Excimer laser surface ablation – a review

Corneal surface laser ablation procedures for the correction of refractive error have enjoyed a resurgence of interest, especially in patients with a possible increased risk of complications after lamellar surgery. Improvements in the understanding of corneal biomechanical changes, the modulation of wound healing, laser technology including ablation profiles and different methods for epithelial removal have widened the scope for surface ablation. This article discusses photorefractive keratectomy, trans‐epithelial photorefractive keratectomy, laser‐assisted sub‐epithelial keratomileusis and epithelial‐laser‐assisted in situ keratomileusis.