The exchange rate: what's in it for prices?

Large movements in the exchange rate are quite common, and they substantially alter one's purchasing power when traveling abroad. Yet these exchange rate movements tend to have a smaller impact on the price of foreign goods that are imported. Following an appreciation of the euro against the dollar, European firms selling products to American firms for import do not raise their prices by nearly as much as the prices they charge consumers in the European market. Similarly, American firms sell their products at higher prices in Europe than at home. This incomplete, or partial, pass-through of exchange rate movements to domestic import prices is important for inflation, American purchasing power, and the pattern of trade between countries. In this article, George Alessandria and Jarcy Zee discuss some of the reasons why changes in the exchange rate may not be fully passed through to import prices.Prices

Survival Analysis With Uncertain Endpoints Using an Internal Validation Subsample

When a true survival endpoint cannot be assessed for some subjects, an alternative endpoint that measures the true endpoint with error may be collected, which often occurs when the true endpoint is too invasive or costly to obtain. We develop nonparametric and semiparametric estimated likelihood functions that incorporate both uncertain endpoints available for all participants and true endpoints available for only a subset of participants. We propose maximum estimated likelihood estimators of the discrete survival function of time to the true endpoint and of a hazard ratio representing the effect of a binary or continuous covariate assuming a proportional hazards model. We show that the proposed estimators are consistent and asymptotically normal and develop the analytical forms of the variance estimators. Through extensive simulations, we also show that the proposed estimators have little bias compared to the naïve estimator, which uses only uncertain endpoints, and are more efficient with moderate missingness compared to the complete-case estimator, which uses only available true endpoints. We illustrate the proposed method by estimating the risk of developing Alzheimer\u27s disease using data from the Alzheimer\u27s Disease Neuroimaging Initiative. Using our proposed semiparametric estimator, we develop optimal study design strategies to compare survival across treatment groups for a new trial with these data characteristics. We demonstrate how to calculate the optimal number of true events in the validation set with desired power using simulated data when assuming the baseline distribution of the true event, effect size, correlation between outcomes, and proportion of true outcomes that are missing can be estimated from pilot studies. We also propose a sample size formula that does not depend on baseline distribution of the true event and show that power calculated by the formula matches well with simulation based results. Using results from a Ginkgo Evaluation of Memory study, we calculate the number of true events in the validation set that would need to be observed for new studies comparing development of Alzheimer\u27s disease among those with and without antihypertensive use, as well as the total number of subjects and number in the validation set to be recruited for these new trials

Coping with kidney disease – qualitative findings from the Empowering Patients on Choices for Renal Replacement Therapy (EPOCH-RRT) study

Abstract Background The highly burdensome effects of kidney failure and its management impose many life-altering changes on patients. Better understanding of successful coping strategies will inform patients and help health care providers support patients’ needs as they navigate these changes together. Methods A qualitative, cross-sectional study involving semi-structured telephone interviews including open- and closed-ended questions, with 179 U.S. patients with advanced chronic kidney disease (CKD), either not yet on dialysis ([CKD-ND], n = 65), or on dialysis (hemodialysis [HD], n = 76; or peritoneal dialysis [PD], n = 38) recruited through social media and in-person contacts from June to December 2013. Themes identified through content analysis of interview transcripts were classified based on the Coping Strategies Index (CSI) and compared across groups by demographics, treatment modality, and health status. Results Overall, more engagement than disengagement strategies were observed. “Take care of myself and follow doctors’ orders,” “accept it,” and “rely on family and friends” were the common coping themes. Participants often used multiple coping strategies. Various factors such as treatment modality, time since diagnosis, presence of other chronic comorbidities, and self-perceived limitations contributed to types of coping strategies used by CKD patients. Conclusions The simultaneous use of coping strategies that span different categories within each of the CSI subscales by CKD patients reflects the complex and reactive response to the variable demands of the disease and its treatment options on their lives. Learning from the lived experience of others could empower patients to more frequently use positive coping strategies depending on their personal context as well as the stage of the disease and associated stressors. Moreover, this understanding can improve the support provided by health care systems and providers to patients to better deal with the many challenges they face in living with kidney disease.https://deepblue.lib.umich.edu/bitstream/2027.42/136225/1/12882_2017_Article_542.pd

Perceptions about the dialysis modality decision process among peritoneal dialysis and in-center hemodialysis patients

Abstract Background Patients reaching end-stage renal disease must make a difficult decision regarding renal replacement therapy (RRT) options. Because the choice between dialysis modalities should include patient preferences, it is critical that patients are engaged in the dialysis modality decision. As part of the Empowering Patients on Choices for RRT (EPOCH-RRT) study, we assessed dialysis patients’ perceptions of their dialysis modality decision-making process and the impact of their chosen modality on their lives. Methods A 39-question survey was developed in collaboration with a multi-stakeholder advisory panel to assess perceptions of patients on either peritoneal dialysis (PD) or in-center hemodialysis (HD). The survey was disseminated to participants in the large US cohorts of the Dialysis Outcomes and Practice Patterns Study (DOPPS) and the Peritoneal DOPPS (PDOPPS). Survey responses were compared between PD and in-center HD patients using descriptive statistics, adjusted logistic generalized estimating equation models, and linear mixed regression models. Results Six hundred fourteen PD and 1346 in-center HD participants responded. Compared with in-center HD participants, PD participants more frequently reported that they were engaged in the decision-making process, were provided enough information, understood differences between dialysis modalities, and felt satisfied with their modality choice. PD participants also reported more frequently than in-center HD participants that partners or spouses (79% vs. 70%), physician assistants (80% vs. 66%), and nursing staff (78% vs. 60%) had at least some involvement in the dialysis modality decision. Over 35% of PD and in-center HD participants did not know another dialysis patient at the time of their modality decision and over 60% did not know the disadvantages of their modality type. Participants using either dialysis modality perceived a moderate to high impact of dialysis on their lives. Conclusions PD participants were more engaged in the modality decision process compared to in-center HD participants. For both modalities, there is room for improvement in patient education and other support for patients choosing a dialysis modality.https://deepblue.lib.umich.edu/bitstream/2027.42/146147/1/12882_2018_Article_1096.pd

Association between serum ferritin and mortality : findings from the USA, Japan and European Dialysis Outcomes and Practice Patterns Study

Background: The Kidney Disease: Improving Global Outcomes guidelines have cautioned against administering intravenous (IV) iron to hemodialysis patients with high serum ferritin levels due to safety concerns, but prior research has shown that the association between high ferritin and mortality could be attributed to confounding by malnutrition and inflammation. Our goal was to better understand the ferritin-mortality association and relative influence of IV iron and inflammation in the USA, where ferritin levels have recently increased dramatically, and in Europe and Japan, where ferritin levels are lower and anemia management practices differ. Methods: Data from 18 261 patients in Phases 4 and 5 (2009-15) of the international Dialysis Outcomes and Practice Patterns Study, a prospective cohort study, were analyzed. Using Cox regression, we modeled the association between baseline ferritin and 1-year mortality with restricted cubic splines and assessed the impact of potential confounders. Results: Median ferritin levels were 718 ng/mL in the USA, 405 in Europe and 83 in Japan. High ferritin levels were associated with elevated mortality (relative to region-specific medians) in all three regions. The strength of this association was attenuated more by adjustment for malnutrition and inflammation than by IV iron and erythropoiesis-stimulating agent dose in each region. Conclusion: The utility of high ferritin as a biomarker for clinical risk due to excess iron stores may be limited, although caution regarding IV iron dosing to higher upper ferritin targets remains warranted. Research to resolve biomarker criteria for iron dosing, and whether optimal anemia management strategies differ internationally, is still needed

The adoption of generic immunosuppressant medications in kidney, liver, and heart transplantation among recipients in Colorado or nationally with Medicare part D

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144701/1/ajt14722.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144701/2/ajt14722_am.pd

Prescription of reninâ angiotensinâ aldosterone system inhibitors (RAASi) and its determinants in patients with advanced CKD under nephrologist care

Reninâ angiotensinâ aldosterone system inhibitors (RAASi) are recommended for chronic kidney disease (CKD) patients. In this study, we describe RAASi prescription patterns in the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) in Brazil, Germany, France, and the United States (US). 5870 patients (mean age 66â 72 years; congestive heart failure [CHF] in 11%â 19%; diabetes in 43%â 54%; serum potassium â ¥5 in 20%â 35%) were included. RAASi prescription was more common in Germany (80%) and France (77%) than Brazil (66%) and the United States (52%), where the prevalence of prescription decreases particularly in patients with CKD stage 5. In the multivariable regression model, RAASi prescription was least common in the United States and more common in patients who were younger, had diabetes, hypertension, or less advanced CKD. In conclusion, RAASi prescription patterns vary by country, and by demographic and clinical characteristics. RAASi appear to be underused, even among patients with strong classâ specific recommendations. Although the reasons for this variation could not be fully identified in this crossâ sectional observation, our data indicate that the risk of hyperkalemia may contribute to the underuse of this class of agents in moderate to advanced CKD.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150590/1/jch13563.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150590/2/jch13563_am.pd

Clinical Characteristics and Treatment Patterns of Children and Adults With IgA Nephropathy or IgA Vasculitis: Findings From the CureGN Study

Introduction: The Cure Glomerulonephropathy Network (CureGN) is a 66-center longitudinal observational study of patients with biopsy-confirmed minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, or IgA nephropathy (IgAN), including IgA vasculitis (IgAV). This study describes the clinical characteristics and treatment patterns in the IgA cohort, including comparisons between IgAN versus IgAV and adult versus pediatric patients. Methods: Patients with a diagnostic kidney biopsy within 5 years of screening were eligible to join CureGN. This is a descriptive analysis of clinical and treatment data collected at the time of enrollment. Results: A total of 667 patients (506 IgAN, 161 IgAV) constitute the IgAN/IgAV cohort (382 adults, 285 children). At biopsy, those with IgAV were younger (13.0 years vs. 29.6 years, P < 0.001), more frequently white (89.7% vs. 78.9%, P = 0.003), had a higher estimated glomerular filtration rate (103.5 vs. 70.6 ml/min per 1.73 m2, P < 0.001), and lower serum albumin (3.4 vs. 3.8 g/dl, P < 0.001) than those with IgAN. Adult and pediatric individuals with IgAV were more likely than those with IgAN to have been treated with immunosuppressive therapy at or prior to enrollment (79.5% vs. 54.0%, P < 0.001). Conclusion: This report highlights clinical differences between IgAV and IgAN and between children and adults with these diagnoses. We identified differences in treatment with immunosuppressive therapies by disease type. This description of baseline characteristics will serve as a foundation for future CureGN studies

RIDGE REGRESSION FOR FUNCTIONAL FORM IDENTIFICATION OF CONTINUOUS PREDICTORS OF CLINICAL OUTCOMES IN GLOMERULAR DISEASE

Penalized regression models can be used to identify and rank risk factors for poor quality of life or other outcomes. They often assume linear covariate associations, but the true associations may be nonlinear. There is no standard, automated method for determining optimal functional forms (shapes of relationships) between predictors and the outcome in high-dimensional data settings. We propose a novel algorithm, Ridge regression for functional form Identification of continuous PRedictors (RIPR), that models each continuous covariate with linear, quadratic, quartile, and cubic spline basis components in a ridge regression model to capture potential nonlinear relationships between continuous predictors and outcomes. We used a simulation study to test the performance of RIPR compared to standard and spline ridge regression models. Then, we applied RIPR to identify top predictors of Patient-Reported Outcomes Measurement Information System (PROMIS) adult global mental and physical health scores using demographic and clinical characteristics among N=107 glomerular disease patients enrolled in the Nephrotic Syndrome Study Network (NEPTUNE). RIPR resulted in better predictive accuracy than the standard and spline ridge regression methods in 56-80% of simulation repetitions under a variety of data characteristics. When applied to PROMIS scores in NEPTUNE, RIPR resulted in the lowest error for predicting physical scores, and the second-lowest error for mental scores. Further, RIPR identified hemoglobin quartiles as an important predictor of physical health that was missed by the other models. The RIPR algorithm can capture nonlinear functional forms of predictors that are missed by standard ridge regression models. The top predictors of PROMIS scores vary greatly across methods. RIPR should be considered alongside other machine learning models in the prediction of patient-reported outcomes and other continuous outcomes