Newer cardiac troponin I assays have similar performance to troponin T in patients with end-stage renal disease

Background: Troponin T is present in the blood of a majority of patients with end-stage renal disease (ESRD) undergoing regular dialysis and presence of troponin T is a predictor of adverse outcome in these patients. With several new formulations of troponin I assays available, this study was performed to see whether these newer assays were able to detect troponin I in these patients more effectively than the older assays. Methods: One hundred and forty-three patients undergoing regular haemodialysis or peritoneal dialysis had plasma collected and troponin T and troponin I measured by a variety of assays. Results: The newer troponin I assays (Abbott Architect, Bayer Centaur and Beckman Accu-TnI) were able to detect troponin I (>75% of samples) as effectively as the Roche assay was able to detect troponin T, while other troponin I assays had a much lower rate of detection of troponin - DPC Immulite 2000 16% and Abbott AxSYM 35%. However, the troponin T assay had more samples detected at concentrations corresponding to an assay CV of 10% (59% of samples) than did the newer troponin I assays (highest on the Bayer Centaur at 37%). Conclusions: Newer assays demonstrate that troponin I is present in a similar number of samples as is troponin T, in the blood of patients with dialysis-dependent renal failure, and these newer troponin I assays identify patients at risk of experiencing a cardiac event

Sleep apnea prevalence in chronic kidney disease - association with total body water and symptoms

Background: Sleep apnea is common and associated with poor outcome in severe chronic kidney disease, but validated screening tools are not available. Our objectives were to determine the prevalence of sleep apnea in this population, to assess the validity of screening for sleep apnea using an ApneaLink device and to investigate the relationship of sleep apnea to; symptoms, spirometry and body water. Methods: Patients with glomerular filtration rate ≤30 mL/min/1.73 m2, whether or not they were receiving haemodialysis, were eligible for enrolment. Participants completed symptom questionnaires, performed an ApneaLink recording and had total body water measured using bioimpedance. This was followed by a multi-channel polysomnography recording which is the gold-standard diagnostic test for sleep apnea. Results: Fifty-seven participants were enrolled and had baseline data collected, of whom only 2 did not have sleep apnea. An apnea hypopnea index ≥30/h was found in 66% of haemodialysis and 54% of non-dialysis participants. A central apnea index ≥5/h was present in 11 patients, with only one dialysis patient having predominantly central sleep apnea. ApneaLink underestimated sleep apnea severity, particularly in the non-dialysis group. Neither total body water corrected for body size, spirometry, subjective sleepiness nor overall symptom scores were associated with sleep apnea severity. Conclusions: This study demonstrates a very high prevalence of severe sleep apnea in patients with chronic kidney disease. Sleep apnea severity was not associated with quality of life or sleepiness scores and was unrelated to total body water corrected for body size. Routine identification of sleep apnea with polysomnography rather than screening is more appropriate in this group due to the high prevalenceThis study was funded by a grant from The Canberra Hospital Private Practice Fund

Machine Learning Improves Upon Clinicians' Prediction of End Stage Kidney Disease

Background and ObjectivesChronic kidney disease progression to ESKD is associated with a marked increase in mortality and morbidity. Its progression is highly variable and difficult to predict. MethodsThis is an observational, retrospective, single-centre study. The cohort was patients attending hospital and nephrology clinic at The Canberra Hospital from September 1996 to March 2018. Demographic data, vital signs, kidney function test, proteinuria, and serum glucose were extracted. The model was trained on the featurised time series data with XGBoost. Its performance was compared against six nephrologists and the Kidney Failure Risk Equation (KFRE). ResultsA total of 12,371 patients were included, with 2,388 were found to have an adequate density (three eGFR data points in the first 2 years) for subsequent analysis. Patients were divided into 80%/20% ratio for training and testing datasets.ML model had superior performance than nephrologist in predicting ESKD within 2 years with 93.9% accuracy, 60% sensitivity, 97.7% specificity, 75% positive predictive value. The ML model was superior in all performance metrics to the KFRE 4- and 8-variable models.eGFR and glucose were found to be highly contributing to the ESKD prediction performance. ConclusionsThe computational predictions had higher accuracy, specificity and positive predictive value, which indicates the potential integration into clinical workflows for decision support.</p

Outcomes of cinacalcet withdrawal in Australian dialysis patients

Background: Secondary hyperparathyroidism (SHPT) in chronic kidney disease is associated with cardiovascular and bone pathology. Measures to achieve parathyroid hormone (PTH) target values and control biochemical abnormalities associated with SHPT require complex therapies, and severe SHPT often requires parathyroidectomy or the calcimimetic cinacalcet. In Australia, cinacalcet was publicly funded for dialysis patients from 2009 to 2015 when funding was withdrawn following publication of the EVOLVE study, which resulted in most patients on cinacalcet ceasing therapy. We examined the clinical and biochemical outcomes associated with this change at Australian renal centres. Methods: We conducted a retrospective study of dialysis patients who ceased cinacalcet after August 2015 in 11 Australian units. Clinical outcomes and changes in biochemical parameters were assessed over a 24‐ and 12‐month period respectively from cessation of cinacalcet. Results: 228 patients were included (17.7% of all dialysis patients from the units). Patients were aged 63±15 years with 182 patients on haemodialysis and 46 on peritoneal dialysis. Over 24 months following cessation of cinacalcet, we observed 26 parathyroidectomies, 3 episodes of calciphylaxis, 8 fractures and 50 deaths. Seven patients recommenced cinacalcet, meeting criteria under a special access scheme. Biochemical changes from baseline to 12 months after cessation included increased levels of serum PTH from 54 (IQR 27‐90) pmol/L to 85 (IQR 41‐139) pmol/L (

Immune Thrombocytopenia after Renal Transplantation for IgA Nephropathy

Immune thrombocytopenic purpura associated with renal disease is usually therapy-related, occurring after administration of intravenous immunoglobulin therapy or anti-D. Secondary cases occurring after renal transplantation are extremely rare. We presen

Calcineurin inhibitor withdrawal or tapering for kidney transplant recipients

What is the issue? Calcineurin inhibitors (CNI, cyclosporin and tacrolimus) are an important part of treatment to suppress the immune system to prevent rejection of transplanted kidneys. However, CNI can cause high blood pressure and kidney scarring which contribute to worsening of risk factors for heart attack, stroke, and loss of the transplanted organ over time. There are conflicting data on the results of withdrawing these drugs from kidney transplant recipients; some studies suggest improved kidney function but others report a moderate risk of developing rejection. Because of this uncertainty, we assessed the benefits and harms of CNI withdrawal or tapering in kidney transplant recipients to identify which approach was more beneficial. What did we do? We included 83 studies that involved more than 16,000 people in our review. Studies which compared standard dose CNI regimens with withdrawal, tapering or low dose CNI in the post-transplant period were analysed. What did we find? Although withdrawing CNI treatment resulted in more rejections in the short term, there was no clear change in transplanted organ failure, death, development of cancer, or infections. Replacing CNI with another group of drugs - the mTOR inhibitors - did not significantly change outcomes, except for fewer cytomegalovirus (CMV) infections. Lower CNI dose was associated with fewer episodes of kidney transplant rejection and loss, but only in the first year to up to five years after the transplant. Conclusions We found that the long-term outcomes for stopping or gradually reducing CNI therapy were not clear, and that mTOR inhibitors can reduce CMV infections with a higher risk of acute rejection. There were insufficient studies with long term follow-up to clearly determine which treatment is better for people who receive kidney transplants

Contextualising renal patient routines: Everyday space-time contexts, health service access, and wellbeing

Stable routines are key to successful illness self-management for the growing number of people living with chronic illness around the world. Yet, the influence of chronically ill individuals' everyday contexts in supporting routines is poorly understood. This paper takes a space-time geographical approach to explore the everyday space-time contexts and routines of individuals with chronic kidney disease (CKD). We ask: what is the relationship between renal patients' space-time contexts and their ability to establish and maintain stable routines, and, what role does health service access play in this regard? We draw from a qualitative case study of 26 individuals with CKD in Australia. Data comprised self-reported two day participant diaries and semi-structured interviews. Thematic analysis of interview transcripts was guided by an inductive-deductive approach. We examined the embeddedness of routines within the space-time contexts of participants' everyday lives. We found that participants' everyday space-time contexts were highly complex, especially for those receiving dialysis and/or employed, making routines difficult to establish and vulnerable to disruption. Health service access helped shape participants' everyday space-time contexts, meaning that incidences of unpredictability in accessing health services set-off ‘ripple effects’ within participants' space-time contexts, disrupting routines and making everyday life negotiation more difficult. The ability to absorb ripple effects from unpredictable health services without disrupting routines varied by space-time context. Implications of these findings for the deployment of the concept of routine in health research, the framing of patient success in self-managing illness, and health services design are discussed. In conclusion, efforts to understand and support individuals in establishing and maintaining routines that support health and wellbeing can benefit from approaches that contextualise and de-centre everyday human behaviour. Opportunities to support renal patients in managing illness and experiencing wellbeing outside the clinical setting lie in a space-time re-design of chronic care servicesThis research was conducted with financial support from University of New South Wales, a National Cancer Institute Training Grant 2T32 CA113710-11, and recruitment assistance from Ms Patricia Johnson and The Canberra Hospital

Spontaneous Coronary Artery Dissection in a Woman With Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD), characterized by renal cyst formation, is known to cause such vascular abnormalities as arterial dilatation and dissection. However, spontaneous coronary artery dissection (SCAD) is observed only rarely in patients with ADPKD. We report a patient with ADPKD who developed SCAD and presented with acute myocardial infarction. Her coronary angiography showed a long spiral dissection of the left anterior descending coronary artery. She underwent successful coronary angioplasty with insertion of 3 drug-eluting stents. To the best of our knowledge, this is the first reported case of percutaneous coronary intervention for coronary dissection in a patient with ADPKD. The pathophysiological characteristics of vascular complications in patients with ADPKD are discussed. Polycystins are strongly expressed in human adult vascular smooth muscle cells, and the vascular abnormalities in patients with ADPKD may be related to altered expression of polycystins. Because early recoginition and prompt efforts at mechanical reperfusion, if indicated, are crucial for successful management of SCAD, it would be worthwhile to consider SCAD in the differential diagnoses of acute coronary syndrome in patients with ADPKD