Steven Cheng

Gadolinium-Containing Magnetic Resonance Imaging Contrast and Nephrogenic Systemic Fibrosis: A Case-Control Study

BACKGROUND Nephrogenic systemic fibrosis (NSF) is a newly described disorder occurring in persons with renal failure. Gadolinium-based contrast used in magnetic resonance imaging (MRI) has been suggested as a cause. A cluster of patients with NSF was investigated to identify risk factors. Limited preliminary findings from this investigation were presented in the Morbidity and Mortality Weekly Report. STUDY DESIGN Matched case-control. SETTING & PARTICIPANTS Dialysis patients with and without a diagnosis of NSF treated at an academic medical center. PREDICTOR Exposure to gadolinium-based contrast. OUTCOMES & MEASUREMENTS Laboratory and clinical characteristics of NSF. RESULTS 19 of 28 cases identified at the hospital from December 2002 to August 2006 met inclusion criteria and were matched to 57 controls. In univariate analysis, receipt of gadolinium-containing MRI contrast in the preceding year (odds ratio [OR], 7.99; 95% confidence interval, 2.22 to 28.8) was associated with NSF; the measure of association increased as cumulative dose increased. Gadodiamide exposure (OR, 9.83; 95% confidence interval, 2.09 to 46.2) was associated more strongly with NSF than gadoversetamide (OR, 1.82; 95% confidence interval, 0.33 to 10.2). Although not statistically significant, cases were more likely than controls to have undergone primarily peritoneal dialysis in the preceding 6 months. There was no significant difference in receipt of high-dose recombinant erythropoietin between cases and controls. In multivariable analysis, gadolinium contrast exposure (OR, 8.97; 95% confidence interval, 1.28 to 63.0) remained significantly associated with NSF. LIMITATIONS Retrospective design, small sample size, inability to completely evaluate erythropoietin. CONCLUSIONS Receipt of gadolinium-containing MRI contrast is associated with NSF in a dose-dependent manner. The risk associated with gadolinium may differ by contrast agent and dialysis modality. Use of gadolinium-based contrast agents should be avoided when possible in patients with renal failure.

A Randomized, Double-Blind, Placebo-Controlled Trial of Niacinamide for Reduction of Phosphorus in Hemodialysis Patients

BACKGROUND AND OBJECTIVES Niacinamide inhibits intestinal sodium/phosphorus transporters and reduces serum phosphorus in open-label studies. A prospective, randomized, double-blind, placebo-controlled crossover trial was performed for assessment of the safety and efficacy of niacinamide. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Hemodialysis patients with phosphorus levels > or =5.0 mg/dl were randomly assigned to 8 wk of niacinamide or placebo, titrated from 500 to 1500 mg/d. After a 2-wk washout period, patients switched to 8 wk of the alternative therapy. Vitamin D analogs and calcimimetics were held constant; phosphorus binders were not changed unless safety criteria were met. RESULTS Thirty-three patients successfully completed the trial. Serum phosphorus fell significantly from 6.26 to 5.47 mg/dl with niacinamide but not with placebo (5.85 to 5.98 mg/dl). A concurrent fall in calcium-phosphorus product was seen with niacinamide, whereas serum calcium, intact parathyroid hormone, uric acid, platelet, triglyceride, LDL, and total cholesterol levels remained stable in both arms. Serum HDL levels rose with niacinamide (50 to 61 mg/dl but not with placebo. Adverse effects were similar between both groups. Among patients who were > or =80% compliant, results were similar, although the decrease in serum phosphorus with niacinamide was more pronounced (6.45 to 5.28 mg/dl) and the increase in HDL approached significance (49 to 58 mg/dl). CONCLUSIONS In hemodialysis patients, niacinamide effectively reduces serum phosphorus when co-administered with binders and results in a potentially advantageous increase in HDL cholesterol. Further study in larger randomized trials and other chronic kidney disease populations is indicated.

Vitamin D and outcomes in chronic kidney disease.

Purpose of reviewThere is a high prevalence of vitamin D deficiency in the chronic kidney disease population. Vitamin D is often administered to patients to mitigate detrimental effects on bone health and mineral metabolism, though this treatment may be limited by elevations in serum calcium and phosphorus. This article reviews the basic physiology of vitamin D, the survival data in patients receiving vitamin D, and the current quandary of whether vitamin D administration is beneficial in chronic kidney disease. Recent findingsDespite potential increases in serum calcium and phosphorus due to activation of vitamin D receptors in the gut, vitamin D administration has been associated with a survival benefit in recent studies. While the mechanism for this possible benefit is unknown, vitamin D administration may have effects beyond its traditional role in mineral metabolism, mediated through the activation of vitamin D receptors distributed in a variety of tissues. SummaryData currently suggests that the administration of vitamin D confers a survival benefit to patients on dialysis. There is no clear mechanism, however, to explain this association. Further research is needed to clarify the expanding role of vitamin D receptor activation, particularly in vascular calcification, and the effects of the different forms of vitamin D.

Paricalcitol capsules for the control of secondary hyperparathyroidism in chronic kidney disease

Secondary hyperparathyroidism is a common complication of patients with chronic kidney disease. Treatment with calcitriol, the active form of vitamin D, reduces parathyroid hormone levels, but may result in elevations in serum calcium and phosphorus. New vitamin D analogues have been developed to reduce parathyroid hormone secretion without concomitant hypercalcaemia and hyperphosphataemia. Recent data from studies with paricalcitol capsules, the oral formulation of 19-nor-1,25(OH)2D2, show a significant reduction in parathyroid hormone levels with no change in calcium and phosphorus levels when compared with placebo. Paricalcitol also compares favourably to other oral vitamin D analogues, effectively decreasing parathyroid secretion with less hypercalcaemia and hypercalciuria than other agents.

Nephrogenic systemic fibrosis: A nephrologist's perspective

Nephrogenic systemic fibrosis (NSF) is a debilitating disorder that affects patients with renal insufficiency. Recent evidence suggests that the development of NSF may be related to the administration of gadolinium‐based contrast media (GBCM) in the setting of magnetic resonance imaging. As no treatment has consistently been effective in the management of NSF, strategies to prevent the development of this condition appear to be the best therapy. Identification of patients at greatest risk for developing NSF after exposure to GBCM is crucial. Risk factors include advanced chronic kidney disease (stages 4 and 5) and acute or chronic inflammatory events. The United States Food and Drug Administration has updated its public health advisory to include patients with moderate renal insufficiency (chronic kidney disease stage 3) as being at risk for developing NSF. However, these data require further verification and the vast majority of affected patients are already on renal replacement therapy. Another strategy in prevention may include consultation with a radiologist for imaging alternatives. If GBCM must be administered, immediate hemodialysis may be protective in patients already on hemodialysis; however, given the lack of data to support this, we do not recommend routine dialysis for patients not yet on dialysis or who are currently being treated with peritoneal dialysis. Decisions such as this should be made on a case by case basis after evaluating additional risk factors.

A Novel Approach to Assessing Professionalism in Preclinical Medical Students Using Multisource Feedback Through Paired Self- and Peer Evaluations

ABSTRACT Phenomenon: Professionalism is integral to the role of the physician. Most professionalism assessments in medical training are delayed until clinical rotations where multisource feedback is available. This leaves a gap in student assessment portfolios and potentially delays professional development. Approach: A total of 246 second-year medical students (2013–2015) completed self- and peer assessments of professional behaviors in 2 courses following a series of Team-Based Learning exercises. Correlation and regression analyses were used to examine the alignment or misalignment in the relationship between the 2 types of assessments. Four subgroups were formed based on observed patterns of initial self- and peer assessment alignment or misalignment, and subgroup membership stability over time was assessed. A missing data analysis examined differences between average peer assessment scores as a function of selective nonparticipation. Findings: Spearman correlation demonstrated moderate to strong correlation between self-assessments completed alone (no simultaneous peer assessment) and self-assessments completed at the time of peer assessments (ρ = .59, p < .0001) but weak correlation between the two self-assessments and peer assessments (alone: ρ = .13, p < .013; at time of peer: ρ = .21, p < .0001). Generalized estimating equation models revealed that self-assessments done alone (p < .0001) were a significant predictor of self-assessments done at the time of peer. Course was also a significant predictor (p = .01) of self-assessment scores done at the time of peer. Peer assessment score was not a significant predictor. Bhapkars test revealed subgroup membership based on the relationship between self- and peer ratings was relatively stable across Time 1 and Time 2 assessments (χ2 = 0.83, p = .84) for all but one subgroup; members of the subgroup with initially high self-assessment and low peer assessment were significantly more likely to move to a new classification at the second measurement. A missing data analysis revealed that students who completed all self-assessments had significantly higher average peer assessment ratings compared to students who completed one or no self-assessments with a difference of –0.32, 95% confidence interval [–0.48, –0.15]. Insights: Multiple measurements of simultaneous self- and peer assessment identified a subgroup of students who consistently rated themselves higher on professionalism attributes relative to the low ratings given by their peers. This subgroup of preclinical students, along with those who elected to not complete self-assessments, may be at risk for professionalism concerns. Use of this multisource feedback tool to measure perceptual stability of professionalism behaviors is a new approach that may assist with early identification of at-risk students during preclinical years.

Developing Professionalism via Multisource Feedback in Team-Based Learning.

CGEA 2015 CONFERENCE ABSTRACT (EDITED) A Novel Approach to Assessing Professionalism in Preclinical Medical Students Using Paired Self- and Peer Evaluations. Amanda R. Emke, Steven Cheng, and Carolyn Dufault Construct: This study sought to assess the professionalism of 2nd-year medical students in the context of team-based learning. Background: Professionalism is an important attribute for physicians and a core competency throughout medical education. Preclinical training often focuses on individual knowledge acquisition with students working only indirectly with faculty assessors. As such, the assessment of professionalism in preclinical training continues to present challenges. We propose a novel approach to preclinical assessment of medical student professionalism to address these challenges. Approach: Second-year medical students completed self- and peer assessments of professionalism in two courses (Pediatrics and Renal/Genitourinary Diseases) following a series of team-based learning exercises. Assessments were composed of nearly identical 9-point rating scales. Correlational analysis and linear regression were used to examine the associations between self- and peer assessments and the effects of predictor variables. Four subgroups were formed based on deviation from the median ratings, and logistic regression was used to assess stability of subgroup membership over time. A missing data analysis was conducted to examine differences between average peer-assessment scores as a function of selective nonparticipation. Results: There was a significant positive correlation (r = .62, p < .0001) between self-assessments completed alone and those completed at the time of peer assessment. There was also a significant positive correlation between average peer-assessment and self-assessment alone (r = .19, p < .0002) and self-assessment at the time of peer assessment (r = .27, p < .0001). Logistic regression revealed that subgroup membership was stable across measurement at two time points (T1 and T2) for all groups, except for members of the high self-assessment/low peer assessment at T1, who were significantly more likely to move to a new group at T2, χ2(3, N = 129) = 7.80, p < .05. Linear regression revealed that self-assessment alone and course were significant predictors of self-assessment at the time of peer assessment (Fself_alone = 144.74, p < .01 and Fcourse = 4.70, p < .05), whereas average peer rating, stage (T1, T2) and academic year (13–14, 14–15) were not. Linear regression also revealed that students who completed both self-assessments had significantly higher average peer assessment ratings (average peer rating in students with both self-assessments = 8.42, no self-assessments = 8.10, self_at_peer = 8.37, self_alone = 8.28) compared to students who completed one or no self-assessments (F = 5.34, p < .01). Conclusions: When used as a professionalism assessment within team-based learning, stand-alone and simultaneous peer and self-assessments are highly correlated within individuals across different courses. However, although self-assessment alone is a significant predictor of self-assessment made at the time of assessing ones peers, average peer assessment does not predict self-assessment. To explore this lack of predictive power, we classified students into four subgroups based on relative deviation from median peer and self-assessment scores. Group membership was found to be stable for all groups except for those initially sorted into the high self-assessment/low peer assessment subgroup. Members of this subgroup tended to move into the low self-assessment/low peer assessment group at T2, suggesting they became more accurate at self-assessing over time. A small group of individuals remained in the group that consistently rated themselves highly while their peers rated them poorly. Future studies will track these students to see if similar deviations from accurate professional self-assessment persist into the clinical years. In addition, given that students who fail to perform self-assessments had significantly lower peer assessment scores than their counterparts who completed self-assessments in this study, these students may also be at risk for similar professionalism concerns in the clinical years; follow-up studies will examine this possibility.