Effect of Age on the Association of Vascular Access Type with Mortality in a Cohort of Incident End-Stage Renal Disease Patients

Definition and clinical management of haemodialysis central venous catheter local infections (exit site and tunnel infection): An international consensus assessment

AIM

To evaluate the relevance of signs and symptoms for the clinical identification of ESI and TI in HD-CVC, by means of international expert consensus, and to reach a consensus on a definition and clinical management (CM) for these infections.

BACKGROUND

A recent systematic review showed a high heterogeneity in the signs/symptoms used for determining exit site infection (ESI) and tunnel infection (TI) of haemodialysis central venous catheter (HD-CVC).

DESIGN

A modified Delphi ranking process was carried out between November 2020 and March 2021, consisting of four rounds using an online questionnaire with a panel of 26 experts from 12 countries.

METHODS

Experts responded on the level of relevance for the identification of ESI and TI, based on a list of 22 signs/symptoms obtained from a previous systematic review, using a 4-point Likert-type scale. After reaching consensus on the signs/symptoms, they followed the same method to reach consensus on the CM. The STROBE Checklist was used to report this study.

RESULTS

A high degree of consensus was reached to identify the presence of ESI based on nine signs/symptoms: presence of pain at the exit site (ES) during interdialysis period, with fever ≥38°C do not suspect other cause, local signs at the ES (inflammation, induration, swelling, hyperemia/erythema ≥2 cm from ES) and obvious abscess or purulent exudate at ES; and of TI. Likewise, 5 cm were agreed upon.

CONCLUSION

This Delphi study provides international expert consensus definitions of ESI and TI in HD-CVC, laying the groundwork for the validation of an HD-CVC ES clinical assessment scale for early identification of ESI.

RELEVANCE TO CLINICAL PRACTICE

In addition, this study provides a series of attitudes to consensual clinics regarding signs/symptoms of local infections in HD-CVC, which may be useful as expert opinion in clinical practice guidelines, when there is insufficient scientific evidence.

Hemodialysis vascular access in elderly patients: A comprehensive review

The number of elderly patients initiating hemodialysis (HD) increased considerably over the past decade. Arteriovenous fistulas (AVFs) are the preferred vascular access (VA) type in most HD patients. Choice of VA for older hemodialysis patients presents a challenge. The higher incidence of comorbidities, longer AVF maturation times, risk of primary failure, risk of patency loss, and shorter life expectancy are important factors to consider. In this review we provide a comprehensive analysis on maturation rates, primary failure, patency, and mortality regarding vascular access in patients older than 75 years of age.

Development and Validation of a Prediction Model for Incident Hypothyroidism in a National Chronic Kidney Disease Cohort

CONTEXT

Hypothyroidism is a common yet under-recognized condition in patients with chronic kidney disease (CKD), which may lead to end-organ complications if left untreated.

OBJECTIVE

We developed a prediction tool to identify CKD patients at risk for incident hypothyroidism.

METHODS

Among 15 642 patients with stages 4 to 5 CKD without evidence of pre-existing thyroid disease, we developed and validated a risk prediction tool for the development of incident hypothyroidism (defined as thyrotropin [TSH] > 5.0 mIU/L) using the Optum Labs Data Warehouse, which contains de-identified administrative claims, including medical and pharmacy claims and enrollment records for commercial and Medicare Advantage enrollees as well as electronic health record data. Patients were divided into a two-thirds development set and a one-third validation set. Prediction models were developed using Cox models to estimate probability of incident hypothyroidism.

RESULTS

There were 1650 (11%) cases of incident hypothyroidism during a median follow-up of 3.4 years. Characteristics associated with hypothyroidism included older age, White race, higher body mass index, low serum albumin, higher baseline TSH, hypertension, congestive heart failure, exposure to iodinated contrast via angiogram or computed tomography scan, and amiodarone use. Model discrimination was good with similar C-statistics in the development and validation datasets: 0.77 (95% CI 0.75-0.78) and 0.76 (95% CI 0.74-0.78), respectively. Model goodness-of-fit tests showed adequate fit in the overall cohort (P = .47) as well as in a subcohort of patients with stage 5 CKD (P = .33).

CONCLUSION

In a national cohort of CKD patients, we developed a clinical prediction tool identifying those at risk for incident hypothyroidism to inform prioritized screening, monitoring, and treatment in this population.

Outcomes of arteriovenous graft vs. fistula for haemodialysis access in the elderly: A systematic review and meta‑analysis

The impact of the type of vascular access on the outcomes in the elderly haemodialysis patients is still unclear. The goal of the present study was to compare survival outcomes in elderly haemodialysis patients who received either arteriovenous graft (AVG) or arteriovenous fistula (AVF). A systematic literature search was performed in EMBASE, Cochrane, MEDLINE, ScienceDirect and Google Scholar databases for papers published from January 1954 until January 2022. Risk of bias in the selected publications was assessed by Newcastle Ottawa scale or Cochrane risk of bias tool depending on the study design. Meta-analysis was carried out using the random-effects model. Data were reported as pooled odds ratio (OR) or hazard ratio (HR) with 95% confidence interval (CI). A total of 12 studies were included in the analysis. The majority of the studies had poor quality. Elderly patients receiving AVG had significantly worse survival rate compared with patients that received AVF for the haemodialysis access, with a pooled HR of 1.38 (95% CI, 1.24-1.53; I²=79.9%). Pooled HR for access survival was 1.60 (95% CI, 1.54-1.66; I²=0%). Pooled OR for primary patency rate, maturation failure and infections were 1.81 (95% CI, 0.73-4.49; I²=79.2%), 0.33 (95% CI, 0.12-0.91; I²=70.4%) and 9.74 (95% CI, 2.60-36.49; I²=52.4%), respectively. These results suggested that in elderly patients undergoing haemodialysis, AVG was associated with reduced overall survival and access survival, and higher infection rate, compared with AVF. Notably, AVG was also associated with a lower risk of maturation failure, presenting a potential advantage in specific patient populations (study registration: PROSPERO, no. CRD42022313199).

Association of Four Types of Vascular Access Including Arterial Superficialization with Mortality in Maintenance Hemodialysis Patients: A Nationwide Cohort Study in Japan

INTRODUCTION

Vascular access usage varies widely across countries. Previous studies have evaluated the association of clinical outcomes with the three types of vascular access, namely, arteriovenous fistula (AVF), arteriovenous graft (AVG), and tunneled and cuffed central venous catheter (TC-CVC). However, little is known regarding the association between arterial superficialization (AS) and the mortality of patients.

METHODS

A nationwide cohort study was conducted using data from the Japanese Society for Dialysis Therapy Renal Data Registry (2006-2007). We included patients aged ≥20 years undergoing hemodialysis with a dialysis vintage ≥6 months. The exposures of interest were the four types of vascular access: AVF, AVG, AS, and TC-CVC. Cox proportional hazard models were used to evaluate the associations of vascular access types with 1-year all-cause and cause-specific mortality.

RESULTS

A total of 183,490 maintenance hemodialysis patients were included: 90.7% with AVF, 6.9% with AVG, 2.0% with AS, and 0.4% with TC-CVC. During the 1-year follow-up period, 13,798 patients died. Compared to patients with AVF, those with AVG, AS, and TC-CVC had a significantly higher risk of all-cause mortality after adjustment for confounding factors: adjusted hazard ratios (95% confidence intervals) - 1.30 (1.20-1.41), 1.56 (1.39-1.76), and 2.15 (1.77-2.61), respectively. Similar results were obtained for infection-related and cardiovascular mortality.

CONCLUSION

This nationwide cohort study conducted in Japan suggested that AVF usage may have the lowest risk of all-cause mortality. The study also suggested that the usage of AS may be associated with better survival rates compared to those of TC-CVC in patients who are not suitable for AVF or AVG.

Cannabis Use and Risk of Acute Kidney Injury in Patients with Advanced Chronic Kidney Disease Transitioning to Dialysis

Background: The current social and legal landscape is likely to foster the medicinal and recreational use of cannabis. Synthetic cannabinoid use is associated with acute kidney injury (AKI) in case reports; however, the association between natural cannabis use and AKI risk in patients with advanced chronic kidney disease (CKD) is unknown. Materials and Methods: From a nationally representative cohort of 102,477 U.S. veterans transitioning to dialysis between 2007 and 2015, we identified 2215 patients with advanced CKD who had undergone urine toxicology (UTOX) tests within a year before dialysis initiation and had inpatient serial serum creatinine levels measured within 7 days after their UTOX test. The exposure of interest was cannabis use compared with no use as ascertained by the UTOX test. We examined the association of this exposure with AKI using logistic regression and inverse probability of treatment weighting with extensive adjustment for potential confounders. Results: The mean age of the overall cohort was 61 years; 97% were males, 51% were African Americans, 97% had hypertension, 76% had hyperlipidemia, and 75% were diabetic. AKI occurred in 56% of the cohort, and in multivariable-adjusted analysis, cannabis use (when compared with no substance use) was not associated with significantly higher odds of AKI (odds ratio 0.85, 95% confidence interval 0.38-1.87; p=0.7). These results were robust to various sensitivity analyses. Conclusions: In this observational study examining patients with advanced CKD, cannabis use was not associated with AKI risk. Additional studies are needed to characterize the impact of cannabis use on risk of kidney disease and injury.

The Interplay between Dietary Phosphorous, Protein Intake, and Mortality in a Prospective Hemodialysis Cohort

(1) Background: Current dietary recommendations for dialysis patients suggest that high phosphorus diets may be associated with adverse outcomes such as hyperphosphatemia and death. However, there has been concern that excess dietary phosphorus restriction may occur at the expense of adequate dietary protein intake in this population. We hypothesized that higher dietary phosphorus intake is associated with higher mortality risk among a diverse cohort of hemodialysis patients. (2) Methods: Among 415 patients from the multi-center prospective Malnutrition, Diet, and Racial Disparities in Kidney Disease Study, we examined the associations of absolute dietary phosphorus intake (mg/day), ascertained by food frequency questionnaires, with all-cause mortality using multivariable Cox models. In the secondary analyses, we also examined the relationship between dietary phosphorus scaled to 1000 kcal of energy intake (mg/kcal) and dietary phosphorus-to-protein ratio (mg/g) with survival. (3) Results: In expanded case-mix + laboratory + nutrition adjusted analyses, the lowest tertile of dietary phosphorus intake was associated with higher mortality risk (ref: highest tertile): adjusted HR (aHR) (95% CI) 3.33 (1.75–6.33). In the analyses of dietary phosphorus scaled to 1000 kcal of energy intake, the lowest tertile of intake was associated with higher mortality risk compared to the highest tertile: aHR (95% CI) 1.74 (1.08, 2.80). Similarly, in analyses examining the association between dietary phosphorus-to-protein ratio, the lowest tertile of intake was associated with higher mortality risk compared to the highest tertile: aHR (95% CI) 1.67 (1.02–2.74). (4) Conclusions: A lower intake of dietary phosphorus was associated with higher mortality risk in a prospective hemodialysis cohort. Further studies are needed to clarify the relationship between specific sources of dietary phosphorus intake and mortality in this population.

Prognostic Machine Learning Models for First-Year Mortality in Incident Hemodialysis Patients: Development and Validation Study

BACKGROUND

The first-year survival rate among patients undergoing hemodialysis remains poor. Current mortality risk scores for patients undergoing hemodialysis employ regression techniques and have limited applicability and robustness.

OBJECTIVE

We aimed to develop a machine learning model utilizing clinical factors to predict first-year mortality in patients undergoing hemodialysis that could assist physicians in classifying high-risk patients.

METHODS

Training and testing cohorts consisted of 5351 patients from a single center and 5828 patients from 97 renal centers undergoing hemodialysis (incident only). The outcome was all-cause mortality during the first year of dialysis. Extreme gradient boosting was used for algorithm training and validation. Two models were established based on the data obtained at dialysis initiation (model 1) and data 0-3 months after dialysis initiation (model 2), and 10-fold cross-validation was applied to each model. The area under the curve (AUC), sensitivity (recall), specificity, precision, balanced accuracy, and F1 score were used to assess the predictive ability of the models.

RESULTS

In the training and testing cohorts, 585 (10.93%) and 764 (13.11%) patients, respectively, died during the first-year follow-up. Of 42 candidate features, the 15 most important features were selected. The performance of model 1 (AUC 0.83, 95% CI 0.78-0.84) was similar to that of model 2 (AUC 0.85, 95% CI 0.81-0.86).

CONCLUSIONS

We developed and validated 2 machine learning models to predict first-year mortality in patients undergoing hemodialysis. Both models could be used to stratify high-risk patients at the early stages of dialysis.

Vascular access placement and mortality in elderly incident hemodialysis patients

BACKGROUND

Arteriovenous fistulas (AVFs) are the preferred vascular access type in most hemodialysis patients. However, the optimal vascular access type in octogenarians and older (≥80 years) hemodialysis patients remains widely debated given their limited life expectancy and lower AVF maturation rates.

METHODS

Among incident hemodialysis patients receiving care in a large national dialysis organization during 2007-2011, we examined patterns of vascular access type conversion in 1 year following dialysis initiation in patients <80 versus ≥80 years of age. Among a subcohort of patients ≥80 years of age, we examined the association between vascular access type conversion and mortality using multivariable survival models.

RESULTS

In the overall cohort of 100 804 patients, the prevalence of AVF/arteriovenous graft (AVG) as the primary vascular access type increased during the first year of hemodialysis, but plateaued thereafter. Among 8356 patients ≥80 years of age and treated for >1 year, those with initial AVF/AVG use and placement of AVF from a central venous catheter (CVC) had lower mortality compared with patients with persistent CVC use. When the reference group was changed to patients who had AVF placement from a CVC in the first year of dialysis, those with initial AVF use had similar mortality. A longer duration of CVC use was associated with incrementally worse survival.

CONCLUSIONS

Among incident hemodialysis patients ≥80 years of age, placement of an AVF from a CVC within the first year of dialysis had similar mortality compared with initial AVF use. Our data suggest that initial CVC use with later placement of an AVF may be an acceptable option among elderly hemodialysis patients.

Age-related outcomes of arteriovenous grafts for hemodialysis access

BACKGROUND

The prevalence of end-stage renal disease spans the spectrum of age. Arteriovenous grafts are viable alternatives for hemodialysis access in patients whose anatomy precludes placement of an arteriovenous fistula. This report describes the age-related outcomes after arteriovenous graft placement in a population-based cohort.

METHODS

A retrospective cohort study was conducted of all patients who initiated hemodialysis in the U.S. Renal Data System (2007-2014). The χ² test, t-test, Kaplan-Meier analysis, log-rank test, and multivariable logistic and Cox regression analyses were employed to evaluate access maturation, interventions, patency, and mortality.

RESULTS

Of the 78,341 patients studied, 10,150 (13%) were younger than 50 years, 13,167 (16.8%) were 50 to 59 years, 19,975 (25.5%) were 60 to 69 years, 20,307 (25.9%) were 70 to 79 years, and 14,742 (18.8%) were 80+ years. There was no significant difference in access maturation time for patients in the older age categories compared to patients younger than 50 years. Primary patency at 5 years comparing <50 years vs 50 to 59 years vs 60 to 69 years vs 70 to 79 years vs 80+ years was 12% vs 12% vs 9% vs 9% vs 8% (P < .001). Primary assisted patency at 5 years was 20% vs 21% vs 18% vs 17% vs 14% (P < .001). Secondary patency at 5 years was 36% vs 39% vs 36% vs 30% vs 31% (P < .001). There was no significant difference in primary patency (adjusted hazard ratio [aHR], 1.00; 95% confidence interval [CI], 1.00-1.00; P < .001), primary assisted patency (aHR, 1.00; 95% CI, 1.00-1.00; P < .001), and secondary patency (aHR, 1.00; 95% CI, 1.00-1.00; P = .029) with increasing age. However, there was a decrease in severe prosthetic graft infection requiring graft excision (aHR, 0.99; 95% CI, 0.99-0.99; P < .001) and increase in mortality (aHR, 1.03; 95% CI, 1.03-1.03; P < .001) for the older age categories compared with the younger patients.

CONCLUSIONS

In this population-based cohort of hemodialysis patients, there was no significant association between older age and prosthetic graft maturation or patency. However, older age was associated with a decrease in severe graft infection and the expected increase in mortality.

In-hospital mortality among incident hemodialysis older patients in Peru

BACKGROUND

Understanding the pattern of mortality linked to end stage renal disease (ESRD) is important given the increasing ageing population in low- and middle-income countries.

METHODS

We analyzed older patients with ESRD with incident hemodialysis, from January 2012 to August 2017 in one large general hospital in Peru. Individual and health system-related variables were analyzed using Generalized Linear Models (GLM) to estimate their association with in-hospital all-cause mortality. Relative risk (RR) with their 95% confidence intervals (95% CI) were calculated.

RESULTS

We evaluated 312 patients; mean age 69 years, 93.6% started hemodialysis with a transient central venous catheter, 1.7% had previous hemodialysis indication and 24.7% died during hospital stay. The mean length of stay was 16.1 days (SD 13.5). In the adjusted multivariate models, we found higher in-hospital mortality among those with encephalopathy (aRR 1.85, 95% CI 1.21-2.82 vs. without encephalopathy) and a lower in-hospital mortality among those with eGFR ≤7 mL/min (aRR 0.45, 95% CI 0.31-0.67 vs. eGFR>7 mL/min).

CONCLUSIONS

There is a high in-hospital mortality among older hemodialysis patients in Peru. The presence of uremic encephalopathy was associated with higher mortality and a lower estimated glomerular filtration rate with lower mortality.

Machine Learning to Identify Dialysis Patients at High Death Risk

Introduction

Given the high mortality rate within the first year of dialysis initiation, an accurate estimation of postdialysis mortality could help patients and clinicians in decision making about initiation of dialysis. We aimed to use machine learning (ML) by incorporating complex information from electronic health records to predict patients at risk for postdialysis short-term mortality.

Methods

This study was carried out on a contemporary cohort of 27,615 US veterans with incident end-stage renal disease (ESRD). We implemented a random forest method on 49 variables obtained before dialysis transition to predict outcomes of 30-, 90-, 180-, and 365-day all-cause mortality after dialysis initiation.

Results

The mean (±SD) age of our cohort was 68.7 ± 11.2 years, 98.1% of patients were men, 29.4% were African American, and 71.4% were diabetic. The final random forest model provided C-statistics (95% confidence intervals) of 0.7185 (0.6994–0.7377), 0.7446 (0.7346–0.7546), 0.7504 (0.7425–0.7583), and 0.7488 (0.7421–0.7554) for predicting risk of death within the 4 different time windows. The models showed good internal validity and replicated well in patients with various demographic and clinical characteristics and provided similar or better performance compared with other ML algorithms. Results may not be generalizable to non-veterans. Use of predictors available in electronic medical records has limited the assessment of number of predictors.

Conclusion

We implemented and ML-based method to accurately predict short-term postdialysis mortality in patients with incident ESRD. Our models could aid patients and clinicians in better decision making about the best course of action in patients approaching ESRD.

Determinants and outcomes of access-related blood-stream infections among Irish haemodialysis patients; a cohort study

Background

Infections are the second leading cause of death and hospitalisation among haemodialysis (HD) patients. Rates of access-related bloodstream infections (AR-BSI) are influenced by patient characteristics and local protocols. We explored factors associated with AR-BSI in a contemporary cohort of HD patients at a tertiary nephrology centre.

Methods

A retrospective cohort of 235 chronic HD patients was identified from a regional dialysis programme between Jan 2015 and Dec 2016. Data on demographics, primary renal disease, comorbid conditions and dialysis access type were obtained from the Kidney Disease Clinical Patient Management System (KDCPMS). Data on blood cultures were captured from the microbiology laboratory. Poisson regression with robust variance estimates was used to compare infection rates and relative risk of AR-BSI according to the site and type of vascular access.

Results

The mean age was 65 (± 15) years, 77% were men, and the median follow up was 19 months (IQR: 10–24 months), accumulating 2030 catheter-months and 1831 fistula-months. Overall rates of AR-BSI were significantly higher for central venous catheter (CVC) compared to arteriovenous fistula (AVF), (2.22, 95% (CI): 1.62–2.97) versus 0.11 (0.01–0.39) per 100 patient-months respectively), with a rate ratio of 20.29 (4.92–83.66), p < 0.0001. This pattern persisted across age, gender and diabetes subgroups. Within the CVC subgroup, presence of a femoral CVC access was associated with significantly higher rates of AR-BSI (adjusted RR 4.93, 95% CI: 2.69–9.01). Older age (75+ versus < 75 years) was not associated with significant differences in rates of AR-BSI in the unadjusted or the adjusted analysis. Coagulase negative Staphylococcus (61%) and Staphylococcus aureus (23%) were the predominant culprits. AR-BSIs resulted in access loss and hospitalisation in 57 and 72% of events respectively, and two patients died with concurrent AR-BSI.

Conclusions

Rates of AR-BSI are substantially higher in CVC than AVF in contemporary HD despite advances in catheter design and anti-infective protocols. This pattern was consistent in all subgroups. The policy of AVF preference over CVC should continue to minimise patient morbidity while at the same time improving anti-infective strategies through better care protocols and infection surveillance.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1253-x) contains supplementary material, which is available to authorized users.