Long-Term Administration of Tolvaptan in Autosomal Dominant Polycystic Kidney Disease

BACKGROUND AND OBJECTIVES

In the 3-year Tolvaptan Efficacy and Safety in Management of ADPKD and Its Outcomes (TEMPO) 3:4 and 1-year Replicating Evidence of Preserved Renal Function: an Investigation of Tolvaptan Safety and Efficacy in ADPKD (REPRISE) trials, tolvaptan slowed the decline of eGFR in patients with autosomal dominant polycystic kidney disease at early and later stages of CKD, respectively. Our objective was to ascertain whether the reduction associated with the administration of tolvaptan is sustained, cumulative, and likely to delay the need for kidney replacement therapy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

One hundred and twenty-eight patients with autosomal dominant polycystic kidney disease participated in clinical trials of tolvaptan at the Mayo Clinic. All had the opportunity to enroll into open-label extension studies. Twenty participated in short-term studies or received placebo only. The remaining 108 were analyzed for safety. Ninety seven patients treated with tolvaptan for ≥1 year (mean±SD, 4.6±2.8; range, 1.1-11.2) were analyzed for efficacy using three approaches: (1) comparison of eGFR slopes and outcome (33% reduction from baseline eGFR) to controls matched by sex, age, and baseline eGFR; (2) Stability of eGFR slopes with duration of follow-up; and (3) comparison of observed and predicted eGFRs at last follow-up.

RESULTS

Patients treated with tolvaptan had lower eGFR slopes from baseline (mean±SD, -2.20±2.18 ml/min per 1.73 m2 per year) and from month 1 (mean±SD, -1.97±2.44 ml/min per 1.73 m2 per year) compared with controls (mean±SD, -3.50±2.09 ml/min per 1.73 m2 per year; P<0.001), and lower risk of a 33% reduction in eGFR (risk ratio, 0.63; 95% confidence interval, 0.38 to 0.98 from baseline; risk ratio, 0.53; 95% confidence interval, 0.31 to 0.85 from month 1). Annualized eGFR slopes of patients treated with tolvaptan did not change during follow-up and differences between observed and predicted eGFRs at last follow-up increased with duration of treatment.

CONCLUSIONS

Follow-up for up to 11.2 years (average 4.6 years) showed a sustained reduction in the annual rate of eGFR decline in patients treated with tolvaptan compared with controls and an increasing separation of eGFR values over time between the two groups.

Younger Adults Initiating Hemodialysis: Antidepressant Use for Depression Associated With Higher Health Care Utilization

OBJECTIVE

To examine associations between antidepressant use and health care utilization in young adults beginning maintenance hemodialysis (HD) therapy.

PATIENTS AND METHODS

Antidepressant use, hospitalizations, and emergency department (ED) visits were examined in young adults (N=130; age, 18-44 years) initiating HD (from January 1, 2001, through December 31, 2013) at a midwestern US institution. Primary outcomes included hospitalizations and ED visits during the first year.

RESULTS

Depression diagnosis was common (47; 36.2%) at HD initiation, yet only 28 patients (21.5%) in the cohort were receiving antidepressant therapy. The antidepressant use group was more likely to have diabetes mellitus (18 [64.3%] vs 33 [32.4%]), coronary artery disease (8 [28.6%] vs 12 [11.8%]), and heart failure (9 [32.1%] vs 15 [14.7%]) (P<.05 for all) than the untreated group. Overall, 68 (52.3%) had 1 or more hospitalizations and 33 (25.4%) had 1 or more ED visits in the first year. The risk of hospitalization during the first year was higher in the antidepressant use group (hazard ratio, 2.35; 95% CI, 1.39-3.96; P=.001), which persisted after adjustment for diabetes, coronary artery disease, and heart failure (hazard ratio, 1.94; 95% CI, 1.22-3.10; P=.006). Emergency department visit rates were similar between the groups.

CONCLUSION

Depression and antidepressant use for mood indication are common in young adult incident patients initiating HD and and are associated with higher hospitalization rates during the first year. Further research should determine whether antidepressants are a marker for other comorbidities or whether treated depression affects the increased health care use in these individuals.

Cystatin C Predicts Renal Recovery Earlier Than Creatinine Among Patients With Acute Kidney Injury

Introduction

Serum cystatin C increases earlier than creatinine during acute kidney injury. However, whether cystatin C decreases earlier during recovery is unknown. This retrospective study aimed to determine the temporal trend between creatinine and cystatin C in acute kidney injury.

Methods

We identified hospitalized patients with nonoliguric acute kidney injury who had serial creatinine and cystatin C values measured between May 2015 and May 2016. Demographic and laboratory data, causes of acute kidney injury, and relevant comorbidity data were collected through chart review.

Results

For the 63 identified patients, mean (SD) age was 58.7 (13.9) years; male sex, 62%; white race/ethnicity, 95%. Baseline median (range) creatinine was 1.1 (0.5-3.0) mg/dl; 13% were kidney transplant recipients and 37% received corticosteroids. Comorbidities included malignancy (38%), diabetes mellitus (33%), heart failure (19%), and thyroid disorder (16%). The cause of kidney injury was acute tubular necrosis in 71%, 61% had acute kidney injury stage III, and 33% required dialysis. Cystatin C began to decrease before creatinine in 68% of patients: 1 day earlier, 46%; 2 days earlier, 16%; and 3 days earlier, 6%. In 24% of cases, both began decreasing on the same day; in only 8%, cystatin C decreased after creatinine. Overall, cystatin C mean (95% confidence interval) decrease was 0.92 (0.65-1.18) days before creatinine (P < 0.001).

Conclusion

In summary, cystatin C decreases before creatinine in most hospitalized patients with acute kidney injury. If confirmed in large prospective studies, these findings may have important management implications, possibly shortening hospital stay and reducing costs.

The Rate of Acute Kidney Injury After Total Hip Arthroplasty Is Low but Increases Significantly in Patients with Specific Comorbidities

BACKGROUND

The purpose of this study was to investigate the rate and risk factors associated with the development of acute kidney injury after total hip arthroplasty, including the perioperative use of nonsteroidal anti-inflammatory drugs (NSAIDs).

METHODS

We retrospectively collected the demographic and comorbidity data of all patients who underwent total hip arthroplasty between 2004 and 2014 at our institution (n = 8,949). We conducted analyses of the entire cohort and a nested case-control subset. Subjects who developed acute kidney injury were matched by age, sex, and year of surgical procedure to subjects without acute kidney injury. Variables associated with acute kidney injury were determined using univariate and multivariate logistic regressions.

RESULTS

The mean patient age (and standard deviation) was 64.6 ± 13.8 years, 48.6% of patients were male, and 114 cases (1.1%) developed acute kidney injury, mostly stage 1 (79%). Variables associated with acute kidney injury included older age (odds ratio [OR], 1.4 per decade; p < 0.001), male sex (OR, 1.78; p = 0.005), chronic kidney disease (OR, 4.6; p < 0.001), heart failure (OR, 4.5; p < 0.001), diabetes (OR, 2.1; p < 0.001), and hypertension (OR, 2.1; p = 0.007). The results were consistent in the case-control analysis. NSAIDs were not associated with acute kidney injury (OR, 1.26; p = 0.36), but were avoided in subjects at risk, making any interpretation difficult because of confounding. A risk model for acute kidney injury after total hip arthroplasty was developed for clinical use and had good discrimination (area under the curve, 0.82; p < 0.001).

CONCLUSIONS

The rate of acute kidney injury after total hip arthroplasty is low, but increases significantly, from <1% to >20%, in those with several independent risk factors present preoperatively. Increasing awareness of these risk factors may help to decrease the risk of acute kidney injury after total hip arthroplasty.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Autosomal Dominant Polycystic Kidney Patients May Be Predisposed to Various Cardiomyopathies

Introduction

Mutations in PKD1 and PKD2 cause autosomal dominant polycystic kidney disease (ADPKD). Experimental evidence suggests an important role of the polycystins in cardiac development and myocardial function. To determine whether ADPKD may predispose to the development of cardiomyopathy, we have evaluated the coexistence of diagnoses of ADPKD and primary cardiomyopathy in our patients.

Methods

Clinical data were retrieved from medical records for patients with a coexisting diagnosis of ADPKD and cardiomyopathies evaluated at the Mayo Clinic (1984-2015).

Results

Among the 58 of 667 patients with available echocardiography data, 39 (5.8%) had idiopathic dilated cardiomyopathy (IDCM), 17 (2.5%) had hypertrophic obstructive cardiomyopathy, and 2 (0.3%) had left ventricular noncompaction. Genetic data were available for 19, 8, and 2 cases of IDCM, hypertrophic obstructive cardiomyopathy, and left ventricular noncompaction, respectively. PKD1 mutations were detected in 42.1%, 62.5%, and 100% of IDCM, hypertrophic obstructive cardiomyopathy, and left ventricular noncompaction cases, respectively. PKD2 mutations were detected only in IDCM cases and were overrepresented (36.8%) relative to the expected frequency in ADPKD (15%). In at least 1 patient from 3 IDMC families and 1 patient from a hypertrophic obstructive cardiomyopathy family, the cardiomyopathy did not segregate with ADPKD, suggesting that the PKD mutations may be predisposing factors rather than solely responsible for the development of cardiomyopathy.

Discussion

Coexistence of ADPKD and cardiomyopathy in our tertiary referral center cohort appears to be higher than expected by chance. We suggest that PKD1 and PKD2 mutations may predispose to primary cardiomyopathies and that genetic interactions may account for the observed coexistence of ADPKD and cardiomyopathies.

Survival, Risk Factors, and Effect of Treatment in 101 Patients With Calciphylaxis

OBJECTIVE

To report on the survival and the associations of treatments upon survival of patients with calciphylaxis seen at a single center.

PATIENTS AND METHODS

Using the International Classification of Diseases, Ninth Revision diagnosis code of 275.49 and the keyword "calciphylaxis" in the dismissal narrative, we retrospectively identified 101 patients with calciphylaxis seen at our institution between January 1, 1999, through September 20, 2014, using a predefined, consensus-developed classification scheme.

RESULTS

The average age of patients was 60 years: 81 (80.2%) were women; 68 (68.0%) were obese; 19 (18.8%) had stage 0 to 2 chronic kidney disease (CKD), 19 (18.9%) had stage 3 or 4 CKD; 63 (62.4%) had stage 5 or 5D (dialysis) CKD. Seventy-five patients died during follow-up. Six-month survival was 57%. Lack of surgical debridement was associated with insignificantly lower 6-month survival (hazard ratio [HR]=1.99; 95% CI, 0.96-4.15; P=.07) and significantly poorer survival for the entire duration of follow-up (HR=1.98; 95% CI, 1.15-3.41; P=.01), which was most pronounced in stage 5 or 5D CKD (HR=1.91; 95% CI, 1.03-3.56; P=.04). Among patients with stage 5/5D CKD, subtotal parathyroidectomy (performed only in patients with hyperparathyroidism) was associated with better 6-month (HR=0.12; 95% CI, 0.02-0.90; P=.04) and overall survival (HR= 0.37; 95% CI, 0.15-0.87; P=.02).

CONCLUSION

Calciphylaxis is associated with a high mortality rate. Significantly effective treatments included surgical debridement and subtotal parathyroidectomy in patients with stage 5/5D CKD with hyperparathyroidism. Treatments with tissue-plasminogen activator, sodium thiosulfate, and hyperbaric oxygen therapy were not associated with higher mortality.

Calciphylaxis: A Disease of Pannicular Thrombosis

OBJECTIVE

To identify coagulation risk factors in patients with calciphylaxis and the relationship between anticoagulation use and overall survival.

PATIENTS AND METHODS

Study subjects were 101 patients with calciphylaxis seen at Mayo Clinic from 1999 to September 2014. Data including thrombophilia profiles were extracted from the medical records of each patient. Survival status was determined using patient registration data and the Social Security Death Index. Survival was estimated using the Kaplan-Meier method, and associations were evaluated using Cox proportional hazards models.

RESULTS

Sixty-four of the 101 patients underwent thrombophilia testing. Of these, a complete test panel was performed in 55 and a partial panel in 9. Severe thrombophilias observed in 60% (33 of 55) of the patients included antiphospholipid antibody syndrome protein C, protein S, or antithrombin deficiencies or combined thrombophilias. Of the 55 patients, severe thrombophilia (85%, 23 of 27) was noted in patients who were not on warfarin at the time of testing (27). Nonsevere thrombophilias included heterozygous factor V Leiden (n=2) and plasminogen deficiency (n=1). For the comparison of survival, patients were divided into 3 treatment categories: Warfarin (n=63), other anticoagulants (n=20), and no anticoagulants (n=18). There was no statistically significant survival difference between treatment groups.

CONCLUSION

Laboratory testing reveals a strikingly high prevalence of severe thrombophilias in patients with calciphylaxis, underscoring the importance of congenital and acquired thrombotic propensity potentially contributing to the pathogenesis of this disease. These findings may have therapeutic implications; however, to date, survival differences did not vary by therapeutic choice.

Effect of genotype on the severity and volume progression of polycystic liver disease in autosomal dominant polycystic kidney disease

BACKGROUND

The autosomal dominant polycystic kidney disease (APDKD) genotype influences renal phenotype severity but its effect on polycystic liver disease (PLD) is unknown. Here we analyzed the influence of genotype on liver phenotype severity.

METHODS

Clinical data were retrieved from electronic records of patients who were mutation screened with the available liver imaging (n = 434). Liver volumes were measured by stereology (axial or coronal images) and adjusted to height (HtLV).

RESULTS

Among the patients included, 221 (50.9%) had truncating PKD1 (PKD1-T), 141 (32.5%) nontruncating PKD1 (PKD1-NT) and 72 (16.6%) PKD2 mutations. Compared with PKD1-NT and PKD2, patients with PKD1-T had greater height-adjusted total kidney volumes (799 versus 610 and 549 mL/m; P < 0.001). HtLV was not different (1042, 1095 and 1058 mL/m; P = 0.64) between the three groups, but females had greater HtLVs compared with males (1114 versus 1015 mL/m; P < 0.001). Annualized median liver growth rates were 1.68, 1.5 and 1.24% for PKD1-T, PKD1-NT and PKD2 mutations, respectively (P = 0.49), and remained unaffected by the ADPKD genotype when adjusted for age, gender and baseline HtLV. Females <48 years of age had higher annualized growth rates compared with those who were older (2.65 versus 0.09%; P < 0.001). After age 48 years, 58% of females with severe PLD had regression of HtLV, while HtLV continued to increase in males.

CONCLUSIONS

In contrast to the renal phenotype, the ADPKD genotype was not associated with the severity or growth rate of PLD in ADKPD patients. This finding, along with gender influence, indicates that modifiers beyond the disease gene significantly influence the liver phenotype.

Volume regression of native polycystic kidneys after renal transplantation

BACKGROUND

The natural course of native kidneys after renal transplantation (RT) or dialysis in patients with autosomal dominant polycystic kidney disease (ADPKD) remains poorly understood.

METHODS

We measured the total volumes of native kidneys and liver in 78 and 68 ADPKD patients, respectively, who had pre-transplant (within 2 years) and at least one post-transplant computed tomography (CT)/magnetic resonance imaging (MRI); in 40 patients with at least two post-transplant but no pre-transplant CT/MRIs; in 9 patients on chronic hemodialysis with at least one CT/MRI before and after beginning dialysis; and in 5 patients who had no image before and more than one image after dialysis. The last imaging was used in patients with multiple studies.

RESULTS

Mean total kidney volume (TKV) ( ± SD) prior to transplantation was 3187 ± 1779 mL in the 78 patients who had imaging before and after transplantation and decreased by 20.2, 28.6, 38.3 and 45.8% after 0.5-1 (mean 0.7), 1-3 (1.8), 3-10 (5.7) and >10 (12.6) years, respectively. In the multivariable analysis, time on dialysis prior to RT and time from baseline to transplantation were negatively associated with reduction in TKV, whereas estimated glomerular filtration rate (eGFR) after transplantation and time from transplantation were positively associated with percent reduction in TKV. In the 40 patients with imaging only after transplantation, TKV decreased by 3.2 ± 16.3% between 7.2 ± 6.0 and 11.2 ± 6.8 years after transplantation (P < 0.001). TKV was 11.2 ± 35.6% higher (P = NS) after a follow-up of 3.4 ± 2.0 years in the 9 patients with imaging before and after initiation of hemodialysis and 3.4 ± 40.2% lower (P = NS) in the 5 patients with imaging between 2.0 ± 2.1 and 3.5 ± 3.6 years after initiation of hemodialysis. In the 68 patients with liver measurements, volume increased by 5.8 ± 17.9% between baseline and follow-up at 3.7 ± 3.8 years after transplantation (P = 0.009).

CONCLUSIONS

TKV of native polycystic kidneys decreases substantially after RT. The reduction occurs mainly during the early post-transplantation period and more slowly thereafter.

Imaging classification of autosomal dominant polycystic kidney disease: a simple model for selecting patients for clinical trials

The rate of renal disease progression varies widely among patients with autosomal dominant polycystic kidney disease (ADPKD), necessitating optimal patient selection for enrollment into clinical trials. Patients from the Mayo Clinic Translational PKD Center with ADPKD (n=590) with computed tomography/magnetic resonance images and three or more eGFR measurements over ≥6 months were classified radiologically as typical (n=538) or atypical (n=52). Total kidney volume (TKV) was measured using stereology (TKVs) and ellipsoid equation (TKVe). Typical patients were randomly partitioned into development and internal validation sets and subclassified according to height-adjusted TKV (HtTKV) ranges for age (1A-1E, in increasing order). Consortium for Radiologic Imaging Study of PKD (CRISP) participants (n=173) were used for external validation. TKVe correlated strongly with TKVs, without systematic underestimation or overestimation. A longitudinal mixed regression model to predict eGFR decline showed that log2HtTKV and age significantly interacted with time in typical patients, but not in atypical patients. When 1A-1E classifications were used instead of log2HtTKV, eGFR slopes were significantly different among subclasses and, except for 1A, different from those in healthy kidney donors. The equation derived from the development set predicted eGFR in both validation sets. The frequency of ESRD at 10 years increased from subclass 1A (2.4%) to 1E (66.9%) in the Mayo cohort and from 1C (2.2%) to 1E (22.3%) in the younger CRISP cohort. Class and subclass designations were stable. An easily applied classification of ADPKD based on HtTKV and age should optimize patient selection for enrollment into clinical trials and for treatment when one becomes available.

Impact of molecular adsorbent recirculating system therapy on tacrolimus elimination: a case report

BACKGROUND

We report a unique case which quantifies the effect of molecular adsorbent recirculating system (MARS [Gambro, Sweden]) therapy on blood concentrations of tacrolimus in a patient treated for refractory pruritus associated with recurrent hepatitis C of the liver allograft. Tacrolimus is a low-molecular-weight, highly protein-bound drug with the potential to be removed during MARS therapy.

CASE REPORT

Results of therapeutic drug monitoring revealed extracorporeal tacrolimus elimination accounted for only 0.3% of total drug removal during the session.

CONCLUSIONS

Although no explanation can be offered as to why MARS contributed so little to overall tacrolimus elimination, the data clearly show minimal impact of MARS on tacrolimus blood level.

Kidney allograft function and histology in recipients dying with a functioning graft

Death with function (DWF) is a major cause of kidney allograft failure. Allograft dysfunction may contribute to DWF. The aim of this study was to examine the relationship between DWF and allograft function using estimated GFR (eGFR) and histology. We retrospectively analyzed 1842 kidney allografts transplanted at our center from 1996 to 2010. eGFR was estimated using the MDRD equation. Biopsies obtained 12 months posttransplant and within 1 year of DWF were analyzed. Proportional hazards models were used to examine the relationship between eGFR and DWF. During 68 ± 43 months of follow-up, 14% (n = 256) of recipients experienced DWF. Risk factors of DWF included increasing recipient age (hazard ratio [HR] = 2.07, confidence interval [CI] 1.77-2.43, p < 0.0001), diabetes (HR = 2.58, CI 1.81-3.69, p < 0.0001), prior dialysis (HR = 1.47, CI 1.05-2.06, p = 0.03) and eGFR <40 mL/min/1.73 m(2) (HR 2.26 per 10 mL/min/1.73 m(2) decrease in eGFR, CI 1.82-2.81, p < 0.0001). Prior to death, only 15.9% (n = 39) of DWF recipients had stage 4 chronic kidney disease (CKD) and only 4.9% (n = 12) had stage 5 CKD. Most biopsies performed within 1 year of DWF (68%) demonstrated benign histology and were comparable to biopsies from matched controls. In conclusion, allograft dysfunction is independently associated with DWF. However, the majority of DWF recipients have well-preserved allograft function and histology prior to death.

Cardiovascular disease burden and risk factors before and after kidney transplant

Cardiovascular (CV) disease is the most common cause of mortality among kidney transplant candidates on the waiting-list and after kidney transplantation. The mechanisms of cardiovascular disease burden after transplant are multifactorial and the risk is largely determined by pre-transplant factors including CV disease and dialysis duration. Current pre-transplant cardiac evaluation protocols have proven to be inconsistent in predicting adverse cardiovascular outcome post-transplant. However, multiple biomarkers have been recognized as predictors of all-cause mortality and cardiovascular events including graft function, hemoglobin, homocysteine, C - reactive protein among others. Of these, elevation in the biomarker cardiac troponin T appears to be a significant predictor of cardiovascular events and mortality among wait-listed kidney transplant candidates and after transplantation. The relationship between CV risk reduction, normalization of cardiac troponin T levels and restoration of renal function after kidney transplant is complex but opens opportunities for the use of cardiac troponin T and other cardiovascular biomarkers as important endpoints of clinical interventions in kidney transplant recipients.

Rapid self-infusion of tap water

Intravenous self-infusion of tap water has never been reported in the literature.&nbsp; We present a 24-year-old healthy man who self-administered 2.5 L of tap water over 2 hours and developed acute illness including fever, change of mental status, acute hemolysis, low-grade disseminated intravascular coagulation, and acute kidney injury.&nbsp;&nbsp;

Cardiac troponin T before and after kidney transplantation: determinants and implications for posttransplant survival

Pretransplant cardiac troponin T(cTnT(pre) ) is a significant predictor of survival postkidney transplantation. We assessed correlates of cTnT levels pre- and posttransplantation and their relationship with recipient survival. A total of 1206 adult recipients of kidney grafts between 2000 and 2010 were included. Pretransplant cTnT was elevated (≥0.01 ng/mL) in 56.4%. Higher cTnT(pre) was associated with increased risk of posttransplant death/cardiac events independent of cardiovascular risk factors. Elevated cTnT(pre) declined rapidly posttransplant and was normal in 75% of recipients at 3 weeks and 88.6% at 1 year. Elevated posttransplant cTnT was associated with reduced patient survival (cTnT(3wks) : HR = 5.575, CI 3.207-9.692, p < 0.0001; cTnT(1year) : 3.664, 2.129-6.305, p < 0.0001) independent of age, diabetes, pretransplant dialysis, heart disease and allograft function. Negative/positive predictive values for high cTnT(3wks) were 91.4%/50% respectively. Normalization of cTnT posttransplant was associated with reduced risk. Variables related to elevated cTnT posttransplant included pretransplant diabetes, older age, time on dialysis, high cTnT(pre) and lower graft function. Patients with delayed graft function and those with GFR < 30 mL/min at 3 weeks were more likely to have an elevated cTnT(3wks) and remained at high risk. When allografts restore sufficient kidney function cTnT normalizes and patient survival improves. Lack of normalization of cTnT posttransplant identifies a group of individuals with high risk of death/cardiac events.

Urolithiasis and the risk of ESRD

BACKGROUND AND OBJECTIVES

The contribution of urolithiasis, if any, to the development of ESRD is unclear.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

All stone formers in Olmsted County, Minnesota, first diagnosed between 1984 and 2008 were identified by diagnostic codes with up to four controls matched on age and sex. Charts were reviewed to validate symptomatic stone formers in a random subset. Incident ESRD events were identified by the US Renal Data System.

RESULTS

Altogether, 51 stone formers and 75 controls developed ESRD among 6926 stone formers and 24,620 matched controls followed for a mean of 9 years. Stone formers had an increased risk of ESRD after adjusting for diabetes, hypertension, dyslipidemia, gout, and CKD (hazard ratio: 2.09; 95% confidence interval: 1.45-3.01). This increased risk of ESRD remained in the subset of 2457 validated symptomatic stone formers (hazard ratio: 1.95; 95% confidence interval: 1.09-3.49). The attributable risk of ESRD from symptomatic urolithiasis was 5.1% based on a prevalence of 5.4% for stone formers. For stone formers versus controls who developed ESRD, there was an increased likelihood of past hydronephrosis (44% versus 4%), recurrent urinary tract infections (26% versus 4%), acquired single kidney (15% versus 3%), neurogenic bladder (12% versus 1%), and ileal conduit (9% versus 0%), but not diabetes (32% versus 49%) or hypertension (44% versus 52%).

CONCLUSIONS

Symptomatic stone formers are at increased risk for ESRD independent of several cardiovascular risk factors. Other urological disease is relatively common among stone formers who develop ESRD.

Recurrent idiopathic membranous nephropathy: early diagnosis by protocol biopsies and treatment with anti-CD20 monoclonal antibodies

Membranous nephropathy (MN) recurs posttransplant in 42% of patients. We compared MN recurrence rates in a historical cohort transplanted between 1990 and 1999 and in a current cohort diagnosed by protocol biopsies, we analyzed the progression of the disease and we assessed the effects of anti-CD20 antibodies (Rituximab) on recurrent MN. The incidence of recurrent MN was similar in the historical (53%) and the current cohorts (41%), although in the later the diagnosis was made earlier (median, 4[2-21] months vs. 83[6-149], p = 0.002) and the disease was clinically milder. Twelve out of 14 patients (86%) with recurrent MN in the current cohort had progressive increases in proteinuria. Eight recipients were treated with Rituximab after their proteinuria increased from median, 211 mg/day (64-4898) at diagnosis to 4489 (898-13 855) (p = 0.038). Twelve months post-Rituximab, 75% of patients had either partial (PR) or complete remission (CR). After 24 months 6/7 (86%) had PR/CR and one patient relapsed. Posttreatment biopsies showed resorption of electron dense immune deposits in 6/7 cases and were negative for C3 (4/7) and IgG (3/7). Protocol biopsies allow early diagnosis of subclinical recurrent MN, which is often progressive. Treatment of recurrent MN with Rituximab is promising and should be evaluated in a prospective randomized controlled trial.

Patient survival after kidney transplantation: relationship to pretransplant cardiac troponin T levels

Assessing cardiovascular (CV) risk pretransplant is imprecise. We sought to determine whether cardiac troponin T (cTnT) relates to patient survival posttransplant. The study includes 603 adults, recipients of kidney transplants. In addition to cTnT dobutamine stress echography and coronary angiography were done in 45% and 19% of the candidates respectively. During 28.4 +/- 12.9 months 5.6% of patients died or had a major cardiac event. cTnT levels were elevated (>0.01 ng/ml) in 56.2% of patients. Elevated cTnT related to reduced event-free survival (hazard ratio (HR) = 1.81, CI 1.33-2.45, p < 0.0001) whether those events occurred during the first year or beyond. This relationship was statistically independent of all other variables tested, including older age, reduced left ventricular ejection fraction (EF) and delayed graft function. cTnT levels allowed better definition of risk in patients with other CV risk factors. Thus, event-free survival was excellent in older individuals, patients with diabetes, low EF and those with preexisting heart disease if their cTnT levels were normal. However, elevated cTnT together with another CV risk factor(s) identified patient with very poor survival posttransplant. Pretransplant cTnT levels are strong and independent predictors of posttransplant survival. These results suggest that cTnT is quite helpful in CV risk stratification of kidney transplant recipients.

Identifying specific causes of kidney allograft loss

The causes of kidney allograft loss remain unclear. Herein we investigated these causes in 1317 conventional kidney recipients. The cause of graft loss was determined by reviewing clinical and histologic information the latter available in 98% of cases. During 50.3 +/- 32.6 months of follow-up, 330 grafts were lost (25.0%), 138 (10.4%) due to death with function, 39 (2.9%) due to primary nonfunction and 153 (11.6%) due to graft failure censored for death. The latter group was subdivided by cause into: glomerular diseases (n = 56, 36.6%); fibrosis/atrophy (n = 47, 30.7%); medical/surgical conditions (n = 25, 16.3%); acute rejection (n = 18, 11.8%); and unclassifiable (n = 7, 4.6%). Glomerular pathologies leading to failure included recurrent disease (n = 23), transplant glomerulopathy (n = 23) and presumed nonrecurrent disease (n = 10). In cases with fibrosis/atrophy a specific cause(s) was identified in 81% and it was rarely attributable to calcineurin inhibitor (CNI) toxicity alone (n = 1, 0.7%). Contrary to current concepts, most cases of kidney graft loss have an identifiable cause that is not idiopathic fibrosis/atrophy or CNI toxicity. Glomerular pathologies cause the largest proportion of graft loss and alloinmunity remains the most common mechanism leading to failure. This study identifies targets for investigation and intervention that may result in improved kidney transplantation outcomes.

Survival of patients on the kidney transplant wait list: relationship to cardiac troponin T

Patients waiting for a kidney transplant have high mortality despite careful preselection. Herein, we assessed whether cardiac troponin T (cTnT) can help stratify risk in patients selected for kidney transplantation. cTnT levels were measured in all kidney transplant candidates but the results were not used for patient selection. Among 644 patients placed on the kidney waiting list from 9/2004 to 12/2006, 61% had elevated cTnT levels (>0.01 ng/mL). Higher levels related to diabetes, longer time on dialysis, history of cardiovascular disease and low serum albumin. High cTnT also related to cardiac anomalies, including left ventricular hypertrophy (LVH), wall motion abnormalities and stress-inducible ischemia by dobutamine echo (DSE). However, 54% of patients without these cardiac findings had elevated cTnT. Increasing cTnT levels were associated with reduced survival (HR = 1.729, CI (1.25-2.39), p = 0.01) independently of low serum albumin (0.449 (0.24-0.83), p = 0.011) and history of stroke (3.368 (1.47-7.73), p = 0.0004). The results of the DSE and/or coronary angiography did not relate significantly to survival. However, high cTnT identified patients with abnormal echo findings and poor survival. Wait listed patients with normal cTnT have excellent survival irrespective of other factors. In contrast, high cTnT levels are strongly predictive of poor survival in the kidney transplant waiting list.

Survival of patients on the kidney transplant wait list: relationship to cardiac troponin T

Patients waiting for a kidney transplant have high mortality despite careful preselection. Herein, we assessed whether cardiac troponin T (cTnT) can help stratify risk in patients selected for kidney transplantation. cTnT levels were measured in all kidney transplant candidates but the results were not used for patient selection. Among 644 patients placed on the kidney waiting list from 9/2004 to 12/2006, 61% had elevated cTnT levels (>0.01 ng/mL). Higher levels related to diabetes, longer time on dialysis, history of cardiovascular disease and low serum albumin. High cTnT also related to cardiac anomalies, including left ventricular hypertrophy (LVH), wall motion abnormalities and stress-inducible ischemia by dobutamine echo (DSE). However, 54% of patients without these cardiac findings had elevated cTnT. Increasing cTnT levels were associated with reduced survival (HR = 1.729, CI (1.25-2.39), p = 0.01) independently of low serum albumin (0.449 (0.24-0.83), p = 0.011) and history of stroke (3.368 (1.47-7.73), p = 0.0004). The results of the DSE and/or coronary angiography did not relate significantly to survival. However, high cTnT identified patients with abnormal echo findings and poor survival. Wait listed patients with normal cTnT have excellent survival irrespective of other factors. In contrast, high cTnT levels are strongly predictive of poor survival in the kidney transplant waiting list.