Remote surveillance technology of dialysis arteriovenous access. Retrospective evaluation in a UK renal centre.

BACKGROUND: Early identification of dysfunctional arteriovenous hemodialysis (HD) vascular access (VA) is important for timely referral and intervention. METHOD: We retrospectively calculated the VA risk score using Vasc-Alert surveillance software technology from HD treatment sessions in 2 satellite HD units over 18 months. We included in the analysis HD patients dialyzing with arteriovenous fistula or graft (AVF/G) with available Vasc-Alert data for≥ 2 months. For group one (eventful) which included patients who developed vascular access thrombosis or stenosis over the study period, we collected Vasc-Alert risk score 2 months prior to the event, and for group two (uneventful) over 5 consecutive months. Vasc-Alert technology utilizes routinely collected data during HD to calculate the VA risk score and triggers an alert if the score is ≥7 in 3 consecutive dialysis sessions. Patients with> 2 alerts (vascular access score ≥ 7) per month were considered to have positive alerts. RESULTS: From 140 HD patients, 81 patients dialyzed via AVF/G. 77/81 had available Vasc-Alert data and were included in the final analysis. Out of 17 eventful patients, 11 (64.7%) had positive alerts 2 months prior to the vascular event. Out of the 60 patients without vascular events, 20 patients (33.3%) had positive alerts. Vasc-Alert's sensitivity and specificity for vascular events were 64.7% and 66.6% respectively. Within the 6 patients with thrombosed access, 2 patients (33.3%) detected by Vasc-Alert were not detected with clinical monitoring. CONCLUSION: Vascular access risk score can be a useful non-invasive vascular access surveillance method to assist clinical decision-making.

Safely reducing haemodialysis frequency during the COVID-19 pandemic.

BACKGROUND: Patients undergoing haemodialysis (HD) are at higher risk of developing worse outcomes if they contract COVID-19. In our renal service we reduced HD frequency from thrice to twice-weekly in selected patients with the primary aim of reducing COVID 19 exposure and transmission between HD patients. METHODS: Dialysis unit nephrologists identified 166 suitable patients (38.4% of our HD population) to temporarily convert to twice-weekly haemodialysis immediately prior to the peak of the COVID-19 pandemic in our area. Changes in pre-dialysis weight, systolic blood pressure (SBP) and biochemistry were recorded weekly throughout the 4-week project. Hyperkalaemic patients (serum potassium > 6.0 mmol/L) were treated with a potassium binder, sodium bicarbonate and received responsive dietary advice. RESULTS: There were 12 deaths (5 due to COVID-19) in the HD population, 6 of which were in the twice weekly HD group; no deaths were definitively associated with change of dialysis protocol. A further 19 patients were either hospitalised and/or developed COVID-19 and thus transferred back to thrice weekly dialysis as per protocol. 113 (68.1%) were still receiving twice-weekly HD by the end of the 4-week project. Indications for transfer back to thrice weekly were; fluid overload (19), persistent hyperkalaemia (4), patient request (4) and compliance (1). There were statistically significant increases in SBP and pre-dialysis potassium during the project. CONCLUSIONS: Short term conversion of a large but selected HD population to twice-weekly dialysis sessions was possible and safe. This approach could help mitigate COVID-19 transmission amongst dialysis patients in centres with similar organisational pressures.

The influence of multiple episodes of acute kidney injury on survival and progression to end stage kidney disease in patients with chronic kidney disease.

BACKGROUND: Acute kidney injury (AKI) and chronic kidney disease (CKD) are common syndromes associated with significant morbidity, mortality and cost. The extent to which repeated AKI episodes may cumulatively affect the rate of progression of all-cause CKD has not previously been investigated. In this study, we explored the hypothesis that repeated episodes of AKI increase the rate of renal functional deterioration loss in patients recruited to a large, all-cause CKD cohort. METHODS: Patients from the Salford Kidney Study (SKS) were considered. Application of KDIGO criteria to all available laboratory measurements of renal function identified episodes of AKI. A competing risks model was specified for four survival events: Stage 1 AKI; stage 2 or 3 AKI; dialysis initiation or transplant before AKI event; death before AKI event. The model was adjusted for patient age, gender, smoking status, alcohol intake, diabetic status, cardiovascular co-morbidities, and primary renal disease. Analyses were performed for patients' first, second, and third or more AKI episodes. RESULTS: A total of 48,338 creatinine measurements were available for 2287 patients (median 13 measures per patient [IQR 6-26]). There was a median age of 66.8years, median eGFR of 28.4 and 31.6% had type 1 or 2 diabetes. Six hundred and forty three (28.1%) patients suffered one or more AKI events; 1000 AKI events (58% AKI 1) in total were observed over a median follow-up of 2.6 years [IQR 1.1-3.2]. In patients who suffered an AKI, a second AKI was more likely to be a stage 2 or 3 AKI than stage 1 [HR 2.04, p 0.01]. AKI events were associated with progression to RRT, with multiple episodes of AKI progressively increasing likelihood of progression to RRT [HR 14.4 after 1 episode of AKI, HR 28.4 after 2 episodes of AKI]. However, suffering one or more AKI events was not associated with an increased risk of mortality. CONCLUSIONS: AKI events are associated with more rapid CKD deterioration as hypothesised, and also with a greater severity of subsequent AKI. However, our study did not find an association of AKI with increased mortality risk in this CKD cohort.

Outcomes in dialysis versus conservative care for older patients: A prospective cohort analysis of stage 5 Chronic Kidney Disease.

BACKGROUND: The benefits of dialysis in older people with ESKD are not clear. We prospectively evaluated whether dialysis has survival advantage compared to conservative care (CC) in older people who were medically suitable for dialysis therapy. METHODS: This was a prospective observational study of CKD patients aged ≥75 years when eGFR first reached ≤15ml/min/1.73m2. Hazard ratios (HR) for death were compared between patients who chose dialysis versus conservative care (CC) from when first seen in pre-dialysis clinic (eGFR ≤15ml/min/1.73m2), and when initiation of dialysis was first considered (eGFR ≤10ml/min/1.73m2). Patients with co-morbidities likely to significantly reduce life expectancy such as advanced heart failure, advanced dementia, and malignancy, were excluded. RESULTS: There were 204 patients (123 dialysis, 81 CC). 115 went on to record eGFR of ≤10ml/min/1.73m2 (73 dialysis, 42 CC). The median survival from eGFR first ≤15ml/min/1.73m2 for the dialysis and CC groups were 42 (33-50) months and 31 (21-41) months. The adjusted hazard ratio (HR) for death in the dialysis group compared to CC was 0.61 (0.41-0.61, p = 0.01). The median survival from eGFR first ≤10ml/min/1.73m2 for dialysis and CC group were 36 (25-47) months and 12 (0-5) months. The adjusted HR for death in the dialysis group compared to CC was 0.36 (0.21-0.62, p <0.001). CONCLUSION: Dialysis confers a survival benefit in older patients medically suitable for dialysis. This study is novel in being both prospective and in excluding patients with co-morbidities which may limit suitability for dialysis and life expectancy. A future focus on quality of life is needed to establish the true benefits of dialysis in older people.

Comparing the impact of older age on outcome in chronic kidney disease of different etiologies: a prospective cohort study.

BACKGROUND: In older patients with chronic kidney disease (CKD), the risk of progression to end stage renal disease and cardiovascular death both differ compared to younger patients. This likely reflects differences in case mix and co-morbid burdens. We sought to establish the extent to which age itself is an independent biomarker of adverse outcome in CKD. METHODS: This was an analysis of the Salford Kidney Study, a prospective, longitudinal, observational study of 2,667 patients with eGFR < 60 ml/min/1.73 m2. Patients were divided into four age groups (< 55, 55-65, 65-75 and > 75 years). Within group adjusted hazard ratios for death in older compared to younger patients were calculated for different primary renal diseases. A competing risk model of death and renal replacement therapy (RRT) as outcomes was performed. RESULTS: The median age of the cohort was 67.1 years [interquartile range (IQR): 55.6-75.3] and median eGFR 30.8 ml/min/1.73 m2 (IQR: 20.6-43.2). Follow up was 3.5 ± 2.9 years. Overall, the adjusted HR for death in patients aged > 75 years compared to those < 55 years was 4.4 (95% CI 3.4-5.9), p < 0.001. The HR for death differed between primary renal diseases and CKD stages. In diabetic nephropathy, the HR was 3.0 (1.8-5.3, p < 0.001), in glomerulonephritis the HR was 12.2 (5.6-25.5, p < 0.001). The cumulative incidence of RRT was < 0.1 at 10 years for patients > 75 years, compared with 0.50 in those < 55 years. Death was more likely at 20 months in those aged 75 years or older (0.17) than at 10 years in those aged < 55 years (0.10). CONCLUSION: This study demonstrates that the risk associated with older age shows significant variability between primary renal diseases. This is whilst acknowledging that observational studies carry the risk of hidden bias not adjusted for in the statistical model.

Estimating renal function in old people: an in-depth review.

Estimates of glomerular filtration rate (eGFR) should provide accurate measure of an individual's kidney function because important clinical decisions such as timing of renal replacement therapy and drug dosing may be dependent on eGFR. Formulae from which eGFR is derived are generally based on serum creatinine measurement, such as Cockcroft-Gault, MDRD and CKD-EPI. More recently, calculation of eGFR using other laboratory biomarkers such as cystatin C has emerged with apparent greater accuracy. In old people, there is age-related physiological change in the kidney, which could lead to reduced GFR. Likewise, physiological changes in body composition that occur with the ageing process impede the use of a single creatinine-based calculation of eGFR across all adult age groups. Studies have shown differences in the prevalence of CKD based on the type of equation used to estimate GFR. This review discusses the evolution of eGFR calculations and the relative accuracy of such equations in older population.

OLDER PEOPLE WITH CHRONIC KIDNEY DISEASE: DEFINITION, AND INFLUENCE OF BIOMARKERS AND MEDICATIONS UPON CARDIOVASCULAR AND RENAL OUTCOMES.

BACKGROUND: Chronic kidney disease (CKD) is a global problem. With an ageing population the burden on the health services has increased due to the growing number of older people with CKD. This group of individuals is far different to the younger CKD population and their risk of cardiovascular death is far greater than the risk of progressing to end stage kidney disease (ESKD). OBJECTIVE: In this review we explore the role of certain biomarkers and medications in predicting the risk of progression to ESKD and death in old people with CKD. METHODS: An electronic literature search of EMBASE and MEDLINE databases was performed using Healthcare Databases Advanced Search (HDAS) in December 2014. RESULTS: Albuminuria is a key biomarker in predicting the risk of death and progression to ESKD. Cystatin C appears to be superior in predicting the risk of cardiovascular and non-cardiovascular death compared to GFR or creatinine. Several inflammatory biomarkers can be used to predict the risk of death and progression to CKD but measuring and monitoring them in routine clinical practice will be expensive and impractical. The effects of long-term RAAS inhibition in older people are not well established. Older people especially those with CKD receive suboptimal secondary preventive measures. Due to multiple comorbidities older people with CKD are usually receiving a number of medications. This can potentially lead to significant adverse drug events (ADE) due to drug interactions. CONCLUSION: Novel non-traditional risk factors like albuminuria, Cystatin C and inflammatory biomarkers play an important role in predicting their risk of death and progression to ESKD. The efficacy and safety of medications in older people with CKD is not well established and requires more extensive, focused study.