Expanding the role of objectively structured clinical examinations in nephrology training

Objectively structured clinical examinations (OSCEs) are widely used in medical education, but we know of none described that are specifically for nephrology fellowship training. OSCEs use simulation to educate and evaluate. We describe a technically simple, multidisciplinary, low-cost OSCE developed by our program that contains both examination and training features and focuses on management and clinical knowledge of rare hemodialysis emergencies. The emergencies tested are venous air embolism, blood leak, dialysis membrane reaction, and hemolysis. Fifteen fellows have participated in the OSCE as examinees and/or preceptors since June 2010. All have passed the exercise. Thirteen responded to an anonymous survey in July 2013 that inquired about their confidence in managing each of the 4 tested emergencies pre- and post-OSCE. Fellows were significantly more confident in their ability to respond to the emergencies after the OSCE. Those who subsequently saw such an emergency reported that the OSCE experience was somewhat or very helpful in managing the event. The OSCE tested and trained fellows in the recognition and management of rare hemodialysis emergencies. OSCEs and simulation generally deserve greater use in nephrology subspecialty training; however, collaboration between training programs would be necessary to validate such exercises.

Influence of race on kidney transplantation in the Department of Defense healthcare system

BACKGROUND

We report the influence of race on transplant outcomes in the Department of Defense (DOD) system.

METHODS

Retrospective cohort analysis of all kidney transplants performed at WRAMC from 1996 to 2005. Kaplan-Meier analysis was used to assess for differences in graft survival, and Cox regression was used to calculate adjusted hazard ratios for graft loss. For our analyses, we used the cutoff of 6 years (year 2000) when we introduced thymoglobulin induction; maintenance immunosuppression consisted of mycophenolate mofetil and tacrolimus, and rapid steroid taper (completed withdrawal at 6 weeks) was used for all patients.

RESULTS

There were 220 transplants (91 Blacks, 107 Caucasians and 22 Asians). Because the curve for graft survival for Blacks over time violated the proportional hazards assumption (at 6 years post-transplant), analysis was segregated into two segments. Through 6 years of follow-up, graft survival was 77% for Blacks and 81% for non-Blacks (p = 0.74 by log rank). Through 9 potential years of follow-up, graft survival for Blacks was 56% and 78% for Whites (p = 0.005). In Cox regression analysis, Black race, compared with non-Black race, was not significantly associated with graft loss at 6 years, but was significantly associated with graft loss occurring after 6 years.

CONCLUSIONS

In the DOD health system, no significant differences were seen in graft survival among recipients of different races at 6 years. Black recipients who received a kidney transplant before the year 2000 showed decreased graft survival compared to non-Blacks. This was consistent with change in immunosuppressive regimen in our institution with the introduction of thymoglobulin induction and maintenance therapy with tacrolimus, mycophenolate mofetil and withdrawal of prednisone at 6 weeks.

Association of oral sodium phosphate purgative use with acute kidney injury

Oral sodium phosphate (OSP) is a commonly used purgative before colonoscopy. There have been numerous reports of acute phosphate nephropathy attributed to the use of OSP. This study evaluated the association between the use of OSP and acute kidney injury (AKI) in an observational, retrospective, cohort study. Of 9799 patients who underwent colonoscopy and had serum creatinine values recorded within 365 days before and after the procedure, AKI, defined as > or =50% increase in baseline serum creatinine, was identified in 114 (1.16%). After adjustment for significant covariates in a multiple logistic regression model, the use of OSP was associated with increased risk for AKI (odds ratio 2.35; 95% confidence interval 1.51 to 3.66; P < 0.001) with an adjusted number need to harm of 81. Age was also independently associated with AKI in this cohort; therefore, until larger, prospective studies define the population at risk for acute phosphate nephropathy, the use of polyethylene glycol-based purgatives should be considered for older patients and possibly for those with comorbid medical conditions.

Acute renal allograft rejection following pegylated IFN-alpha treatment for chronic HCV in a repeat allograft recipient on hemodialysis: a case report

Interferon alpha (IFN-alpha) can be effective therapy for patients with chronic kidney disease who have chronic hepatitis C (HCV). However, acute allograft rejection has been reported in association with IFN-alpha following kidney transplantation, and therefore IFN therapy is recommended prior to, rather than after, kidney transplantation whenever feasible. The special case of repeat allograft recipients who contract HCV after the first transplantation presents special difficulties. This report features the case of a repeat allograft recipient who presented with neutropenic fevers after 5 months of pegylated IFN-alpha therapy, initiated 6 months following the functional loss of his third graft and the reinitiation of hemodialysis (HD). Physical exam, radiographic and laboratory findings led to allograft nephrectomy. The pathologic findings supported a diagnosis of acute-on-chronic rejection. This represents a rare case of IFN-alpha induced rejection following allograft failure and return to HD in a repeat allograft recipient. It also calls attention to the need for a high index of suspicion for the development of allograft rejection, which may require allograft nephrectomy even after allograft 'failure'.

Use of beta-blockers and aspirin after myocardial infarction by patient renal function in the Department of Defense health care system

BACKGROUND

Whether the previously reported underutilization of standard-of-care medications in the management of patients with acute myocardial infarction (AMI) persists in more recent years or differs by ward of admission has not been reported.

METHODS

We performed a retrospective cross-sectional study of patients hospitalized with a discharge diagnosis of incident AMI to a Department of Defense hospital (Walter Reed Army Medical Center, Washington, DC) from 2001 through 2004. Use of beta-blockers and aspirin at the time of discharge after AMI was assessed according to Modification of Diet in Renal Disease (MDRD) estimated glomerular filtration rate (eGFR) in milliliters per minute per 1.73 m2, stratified by admission to the coronary care unit (CCU) versus other wards. Adjusted odds ratios for discharge beta-blocker and aspirin therapy were calculated by using logistic regression.

RESULTS

Among 431 patients, overall discharge use of beta-blockers was 86.8%, and aspirin, 86.8%, both significantly greater after CCU admission than admission to other wards (93%, aspirin use; 91.7%, beta-blocker use; P < 0.001 and P < 0.001). In logistic regression, CCU admission was the only independent factor associated with either beta-blocker or aspirin use; MDRD eGFR was not associated significantly with beta-blocker and aspirin use regardless of admission to the CCU or non-CCU.

CONCLUSION

Future studies of disparities in use of standard-of-care medications after AMI according to renal function should account for the primary site of admission, particularly CCU versus others. In addition, legitimate contraindications to the use of beta-blockers and aspirin may be subtle, including appropriate end-of-life decisions.

Myeloma, Hodgkin disease, and lymphoid leukemia after renal transplantation: characteristics, risk factors and prognosis

BACKGROUND

Hodgkin disease and myeloma were recently included in the classification of posttransplant lymphoproliferative disorder (PTLD). However, because their incidence is low, not much is known about their particular features.

METHODS

The incidence, characteristics, risk, and prognostic factors of myeloma, Hodgkin disease, and lymphoid leukemia using the United States Renal Data System from 1991 to 2000 among 66,159 Medicare patients were analyzed.

RESULTS

In all, 1,169 recipients developed a lymphoid disease: 823 (1.2%) non-Hodgkin's lymphomas (NHL), 160 (0.24%) myelomas, 60 (0.1%) Hodgkin lymphomas, and 126 (0.2%) lymphoid leukemias. Older age was associated with an increased risk of myeloma and leukemia. The incidence of hepatitis C virus infection was higher in recipients with myeloma (6.9 vs. 3.9%, P=0.05). Induction therapy was associated with a greater risk of myeloma and leukemia, but not Hodgkin disease. Azathioprine was associated with a lower risk of myeloma, and tacrolimus with a lower risk of Hodgkin disease. According to the type of malignancy, ten-year survival rates were significantly different: 42, 26, 55 and 39% respectively for NHL, myeloma, Hodgkin disease, and leukemia.

CONCLUSION

These results support specific features and risk factors related to the occurrence of each type of lymphoid-proliferation and suggest for the first time a possible association between hepatitis C virus and myeloma in kidney transplant recipients.

Thrombotic microangiopathy in United States long-term dialysis patients

BACKGROUND

The incidence, risk factors, recurrence rates and prognosis of thrombotic microangiopathy (TMA) among long-term dialysis patients in the United States have not been previously described in a national population.

METHODS

272 024 Medicare primary patients in the United States Renal Data System (USRDS) initiated on end-stage renal disease (ESRD) therapy between 1 April 1995 and 31 December 1999 with Medicare as primary payer were analysed in a retrospective cohort study of USRDS of TMA. Cox regression was used to calculate adjusted hazard ratios (AHR) for risk of TMA and risk of death after TMA.

RESULTS

The incidence of TMA in the first year of dialysis was 0.5% overall. Among patients with renal failure due to haemolytic uraemic syndrome (HUS), the incidence of TMA was highest in the first year of dialysis (HUS, 11.3% first year, 4.5% per year thereafter), while among patients without HUS the incidence of TMA was much lower and more constant over time (0.3% per year). In Cox regression analysis, independent risk factors for TMA were renal failure due to HUS (adjusted hazard ratio (AHR) 179, 95% CI 95-338), paediatric age (<or=18 years vs older, AHR 2.59, 95% CI 1.48-4.55), female gender (AHR 1.99, 95% CI 1.43-2.78), and systemic lupus erythematosus (SLE, AHR 3.66, 95% CI 1.49-8.51). One-year survival after TMA was poor at 58% (AHR for mortality 2.04, 95% CI 1.23-3.38).

CONCLUSIONS

TMA is an uncommon cause of hospitalization after dialysis, but does recur in patients with HUS at a substantial rate. Younger age and SLE were risk factors for new onset TMA, which was associated with poor survival. Vigilant monitoring of select patients with HUS-related ESRD and higher-risk patients with SLE is warranted in the dialysis population.

Maintenance immunosuppression use and the associated risk of avascular necrosis after kidney transplantation in the United States

BACKGROUND

Avascular necrosis (AVN) after renal transplantation has been largely attributed to the use of corticosteroids. However, other risk factors such as microvascular thrombosis and hyperlipidemia have been well described and may be of increased importance in the era of early steroid cessation and avoidance. We hypothesized that maintenance immunosuppressive medications known to be associated with these risk factors for AVN would also be associated with a higher risk of AVN.

METHODS

By using the U.S. Renal Data System database, we studied 27,772 primary patients on Medicare who received a solitary kidney transplant between January 1, 1996, and July 31, 2000. Cox proportional hazards regression models were used to calculate adjusted hazard ratios (AHRs) for patient- and transplant-related factors (including allograft rejection) with Medicare claims for AVN. The intensity and duration of corticosteroid use could not be assessed.

RESULTS

Among patients who were prescribed sirolimus at discharge, 3.5% of patients who received the combination of sirolimus-cyclosporine A (CsA) demonstrated AVN, compared with 1.4% of patients who received the combination of sirolimus-tacrolimus (P=0.06 by chi). In Cox regression, CsA use (vs. tacrolimus) (AHR 1.36, 95% confidence interval, 1.09-1.71) was independently associated with an increased risk of AVN. Sirolimus use showed a trend toward significance (AHR 1.59, 95% confidence interval, 0.99-2.56), with no significant interaction with CsA.

CONCLUSIONS

Compared with other maintenance immunosuppression, AVN was significantly more common after use of CsA prescribed at the time of discharge for renal transplantation. Whether this increased risk of AVN was directly attributable to hyperlipidemia, microvascular thrombosis, or differences in corticosteroid dosing could not be determined.

Late urinary tract infection after renal transplantation in the United States

BACKGROUND

Although urinary tract infection (UTI) occurring late after renal transplantation has been considered "benign," this has not been confirmed in a national population of renal transplant recipients.

METHODS

We conducted a retrospective cohort study of 28,942 Medicare primary renal transplant recipients in the United States Renal Data System (USRDS) database from January 1, 1996, through July 31, 2000, assessing Medicare claims for UTI occurring later than 6 months after transplantation based on International Classification of Diseases, 9th Revision (ICD-9), codes and using Cox regression to calculate adjusted hazard ratios (AHRs) for time to death and graft loss (censored for death), respectively.

RESULTS

The cumulative incidence of UTI during the first 6 months after renal transplantation was 17% (equivalent for both men and women), and at 3 years was 60% for women and 47% for men (P < 0.001 in Cox regression analysis). Late UTI was significantly associated with an increased risk of subsequent death in Cox regression analysis (P < 0.001; AHR, 2.93; 95% confidence interval [CI], 2.22, 3.85); and AHR for graft loss was 1.85 (95% CI, 1.29, 2.64). The association of UTI with death persisted after adjusting for cardiac and other infectious complications, and regardless of whether UTI was assessed as a composite of outpatient/inpatient claims, primary hospitalized UTI, or solely outpatient UTI.

CONCLUSION

Whether due to a direct effect or as a marker for serious underlying illness, UTI occurring late after renal transplantation, as coded by clinicians in the United States, does not portend a benign outcome.

Therapeutic plasma exchange as a nephrological procedure: A single-center experience

In the United States, therapeutic plasma exchange (TPE) is both performed and requested by a wide range of services, often on an empiric basis (before a diagnosis is established). Whether empiric therapy is beneficial has not been established. Patients were identified from an electronic procedure log that included those patients who received plasmapheresis at Walter Reed Army Medical Center from 1996 to 2003. The clinical indications, referring service, and outcomes (including deaths) that occurred were tabulated. Between March 1997 and August 2003, 568 TPE treatments were performed in 54 patients. The majority of the diagnoses were either neurologic (48%) or hematologic (37%). Thirty-three patients (61%) received TPE for a Category I indication. Twelve cases were performed empirically (without an established diagnosis) at the request of the referring service, most (7) performed for presumed thrombotic thrombocytopenic purpura (TTP). Almost 80% of patients required central venous catheters for treatment. Twelve patients (22%) experienced a major complication including death, and six patients (11%) died. Of the patients who died, 5 (83%) were treated empirically versus one death (17%) among patients not treated empirically, P < 0.001 by Chi Square. Only one of the seven patients treated empirically for TTP died, however. In logistic regression analysis, empiric treatment was the only factor independently associated with death, adjusted odds ratio, 34.2, 95% CI, 3.4, 334.8, P = 0.003. The most common indication for TPE was neurological disease, which also accounted for the highest proportion of complications. With the exception of presumed TTP, performing TPE in the absence of a confirmed diagnosis was not beneficial.

Induction sirolimus and delayed graft function after deceased donor kidney transplantation in the United States

BACKGROUND/AIMS

Previous studies have reported a link between the use of induction sirolimus (INDSRL) and delayed graft function (DGF) after kidney transplantation. However, none have had sufficient power to adjust for all factors known to be associated with DGF.

METHODS

We conducted a retrospective cohort study of US deceased donor kidney transplantation recipients in the United States Renal Data System (USRDS) from January 1, 2000 to May 31, 2001. Logistic regression analysis was used to model adjusted odds ratios (AOR) for the development of DGF, adjusted for other factors previously reported to be associated with DGF.

RESULTS

Among 8,319 patients meeting inclusion criteria, 361 patients received INDSRL, of whom 98 (27.1%) had DGF, compared to 22.5% among patients who did not receive INDSRL. In multivariate analysis, INDSRL was associated with an increased risk of DGF, with an adjusted odds ratio of 1.42 (95% CI: 1.07-1.90). Other factors associated with DGF were similar to those previously reported. INDSRL was not significantly associated with graft loss at 1 year in Cox regression.

CONCLUSIONS

INDSRL was independently associated with DGF in US deceased donor kidney transplantation recipients, adjusted for all other factors previously shown to be associated with DGF.

Analyzing process variation in chart review using a networked spreadsheet application in the Walter Reed Army Medical Center Nephrology Clinic

The role of reviewer variation in interpreting outcomes of outpatient clinic chart reviews has been poorly studied. The present study used results collected from a network-based spreadsheet application (Microsoft Excel), which is widely available throughout the Army Medical Department, for chart reviews. Data were collected from January 1998 to August 2000, and 2,308 charts of 1,127 patients were reviewed. Results showed a significant improvement in documentation of contact with the referring provider from 1998 to 2000 (55.9% in 1998, 81.6% in 1999, and 80.6% in 2000; p < 0.01 by chi 2 for both). The percentage of charts for new consultations with inadequately controlled blood pressure managed appropriately improved from 73.7% in 1999 to 89.2% in 2000 (p < 0.01 by chi 2). These results persisted in logistic regression analysis controlling for different reviewers. In conclusion, widely available office automation tools allow the systematic analysis of chart review data with the potential to improve practice patterns.

Review of thrombotic thrombocytopenic purpura in the setting of systemic lupus erythematosus

OBJECTIVE

Thrombotic thrombocytopenic purpura (TTP) has been described in association with systemic lupus erythematosus (SLE) rarely. The diagnosis of TTP as a process separate from SLE may be difficult because both share similar features, including thrombotic microangiopathy.

METHODS

A case is described of the simultaneous occurrence of TTP and SLE. The clinical, laboratory, and histologic findings of the patient are reported. The association of TTP and SLE in the literature is analyzed. We review separately the pathogenesis, role of antiphospholipid antibodies, and the differential diagnosis of TTP complicating the course of SLE.

RESULTS

Forty cases of TTP in association with SLE are reported in the world literature. Three distinct groups were defined by the presentation of TTP that occurred subsequent to, before, or simultaneous with SLE (groups 1, 2, and 3, respectively). Renal biopsy in a patient with lupus nephritis may reveal thrombotic microangiopathy, which may be seen independently or represent a concomitant systemic thrombotic process such as TTP, disseminated intravascular coagulation, or antiphospholipid antibody syndrome.

CONCLUSION

TTP in association with SLE is rare, and the diagnosis may be challenging. Although the etiology of TTP remains elusive, certain autoimmune mechanisms, platelet abnormalities, and fibrinolytic disorders may be shared with SLE and provide the basis for their association. Management requires timely diagnosis and aggressive treatment by therapeutic plasma exchange.

Distribution of the cellular uptake of phosphorothioate oligodeoxynucleotides in the rat kidney in vivo

Previous animal studies have demonstrated that following systemic administration phosphorothioate oligodeoxynucleotides (S-ODNs) are primarily excreted by the kidneys and that renal tissue levels of S-ODNs exceed that of other organs. Thus, the kidney may be an ideal target organ for application of antisense S-ODNs in vivo. We examined which cells within the rat kidney have uptake of radiolabeled S-ODNs following intravenous infusion. A 20-base 35S-ODN was infused into 6 adult male Wistar rats. Three animals each were sacrificed 30 min and 4 h after infusion. The kidneys were then removed, fixed, and tissue autoradiography was performed. Similar results were obtained in both groups. The highest level of radioactivity was seen within the proximal tubules. Lower levels of activity were seen within the glomerulus, the parietal epithelial cells of Bowman's space, and distal tubular cells. Very weak activity was also detected within the cells of the loop of Henle and the medullary collecting ducts. These results demonstrated that within the kidney S-ODNs were taken up primarily by proximal tubular cells, with much lower uptake by cells in other segments of the nephron.

Effect of glycine on cisplatin nephrotoxicity and heat-shock protein 70 expression in the rat kidney

Glycine has been shown to protect against cisplatin (CP) nephrotoxicity in rats and to enhance the in vitro expression of heat-shock protein (hsp) 70 in renal epithelial cells following sublethal heat shock. We hypothesized that the protective effect of glycine against CP nephrotoxicity may be due to an up-regulation of Hsp 70 protein expression. Male Sprague-Dawley rats were divided into 4 treatment groups based upon infusion of glycine and injection of CP or their respective vehicles. At 5 days after treatment animals administered CP alone demonstrated a significant decrease in creatinine clearance compared to baseline (0.77 +/- 0.32 mL/min vs. 3.90 +/- 0.87 mL/min, p < 0.05). Treatment with glycine and CP attenuated this response, with no significant decline seen in creatinine clearance at day 5 compared to baseline (2.25 +/- 0.31 mL/min vs. 3.40 +/- 0.86 mL/min). Semiquantitative histological study revealed a marked decrease in proximal tubular injury at the juxtamedullary and outer medullary regions among animals treated with glycine and CP compared to those animals treated with CP alone. There were no differences in renal cortical and medullary Hsp 70 levels by Western immunoblotting between animals treated with glycine and CP compared to CP alone at 4 h and 5 days after treatment. Immunohistochemical studies of animals treated with CP alone revealed the diffuse presence of Hsp 70 in the cytoplasm of injured and necrotic proximal tubular cells 5 days after treatment. Animals receiving CP and glycine demonstrated a more focal presence of Hsp 70 restricted to injured proximal tubular cells, with no staining of uninjured cells. The protective effect of glycine in CP-induced acute and renal failure in the rat does not appear to be associated with enhancement of Hsp 70 expression.

Sublethal heat shock and cyclosporine exposure produce tolerance against subsequent cyclosporine toxicity

Sublethal heat shock has been shown to produce tolerance in cells and tissues subsequently exposed to heat or ischemia/ATP depletion. We tested whether heating LLC-PK1 cells for 2 h at 42 degrees C induced heat shock protein-70 (HSP-70) gene expression and conferred tolerance against subsequent cyclosporine A (CyA) toxicity. HSP-70 mRNA was increased immediately after heat shock, returning to baseline by 4 h. HSP-70 protein increased by 1 h after heat shock and declined thereafter, approaching baseline after 72 h. Cells heat shocked at 4 and 24 h prior to CyA exposure were significantly more viable than controls, at CyA concentrations near the median lethal dose (LD50). Cytoprotection declined with time after heat shock, concurrent with declining HSP-70 protein levels. Sublethal CyA exposure (50 micrograms/ml) for 24 h produced upregulation of HSP-70 mRNA and protein. Pretreatment with 50 micrograms/ml CyA for 24 h followed by exposure to a toxic concentration of CyA (200 micrograms/ml) produced significant cytoprotection compared with untreated controls. In conclusion, HSP-70 protein induction by sublethal heat shock or CyA exposure was associated with tolerance against subsequent lethal CyA exposure.