Confounding factors for early death in incident end-stage renal disease patients: Role of emergency dialysis start

Care trajectory differences in women and men with end-stage renal disease after dialysis initiation

Few studies investigated sex-related differences in care consumption after dialysis initiation. Therefore, the aim of this study was to compare the care trajectory in the first year after dialysis start between men and women by taking into account the context of dialysis initiation. All patients who started dialysis in France in 2015 were included. Clinical data of patients and context of dialysis initiation were extracted from the Renal Epidemiology and Information Network (REIN) registry. Data on care consumption in the first year after dialysis start came from the French national health data system (SNDS): hospital stays <24h, hospital stays to prepare or maintain vascular access, hospital stays >24h for kidney problems and hospital stays >24h for other problems, and consultations with a general practitioner. Variables were compared between men and women with the χ2 test and Student's or Welch t-test and logistic regression models were used to identify the factors associated with care consumption after dialysis start. The analysis concerned 8,856 patients (36% of women). Men were less likely to have a hospital stays >24h for kidney problems than women (OR = 0.8, 95% CI = [0.7-0.9]) and less general practitioner consultations (OR = 0.8, 95% CI = [0.8-0.9]), in the year after dialysis initiation, after adjustment on patient's characteristics. Moreover, hospital stays for vascular access preparation or maintenance were longer in women than men (median duration: 2 days [0-2] vs. 1 day [0-2], p < 0.001). In conclusion, despite greater comorbidities in men, this study found few differences in post-dialysis care trajectory between men and women.

Pre-dialysis care trajectory and post-dialysis survival and transplantation access in patients with end-stage kidney disease

BACKGROUND

The pre-dialysis care trajectory impact on post-dialysis outcomes is poorly known. This study assessed survival, access to kidney transplant waiting list and to transplantation after dialysis initiation by taking into account the patients' pre-dialysis care consumption (inpatient and outpatient) and the conditions of dialysis start: initiation context (emergency or planned) and vascular access type (catheter or fistula).

METHODS

Adults who started dialysis in France in 2015 were included. Clinical data came from the French REIN registry and data on the care trajectory from the French National Health Data system (SNDS). The Cox model was used to assess survival and access to kidney transplantation.

RESULTS

We included 8856 patients with a mean age of 68 years. Survival was shorter in patients with emergency or planned dialysis initiation with a catheter compared to patients with planned dialysis with a fistula. The risk of death was lower in patients who were seen by a nephrologist more than once in the 6 months before dialysis than in those who were seen only once. The rate of kidney transplant at 1 year post-dialysis was lower for patients with emergency or planned dialysis initiation with a catheter (respectively, HR = 0.5 [0.4; 0.8] and HR = 0.7 [0.5; 0.9]) compared to patients with planned dialysis start with a fistula. Patients who were seen by a nephrologist more than three times between 0 and 6 months before dialysis start were more likely to access the waiting list 1 and 3 years after dialysis start (respectively, HR = 1.3 [1.1; 1.5] and HR = 1.2 [1.1; 1.4]).

CONCLUSIONS

Nephrological follow-up in the year before dialysis initiation is associated with better survival and higher probability of access to kidney transplantation. These results emphasize the importance of early patient referral to nephrologists by general practitioners.

Effect of emergency start and central venous catheter on outcomes in incident hemodialysis patients: a prospective observational cohort

BACKGROUND

Unfavorable conditions at hemodialysis inception reduce the survival rate. However, the relative contribution to outcomes of predialysis follow-up, symptoms, emergency start or central venous catheter (CVC) is unknown.

METHODS

We analyzed the determinants of survival according to dialysis initiation conditions in the nationwide REIN registry, using two methods based either on clinical classification or data mining. We divided patients into four groups according to dialysis initiation (emergency vs planned, symptoms or not, previous follow-up). "Followed planned starters" began dialysis as outpatients and with an arteriovenous fistula (AVF). "Followed symptomatic non-urgent starters" were patients who started earlier because of any non-urgent symptomatic event. "Followed urgent starters" had seen a nephrologist before inception but started dialysis in an emergency condition. "Unknown urgent starters" were patients without any follow-up and who had a CVC at inception.

RESULTS

"Followed urgent" starters had the lowest 2-year survival rate (66.8%) compared to "followed planned" (77.3%), "followed symptomatic non urgent" (79.2%), and "unknown urgent" (71.7%). Compared to other groups, the risk of mortality was lower in followed symptomatic non urgent (HR 0.86 95% CI 0.75-0.99) and higher in followed urgent starters (HR 1.05 (95% CI 0.94-1.18). In data mining Classification And Regression Tree regrouping in five categories, the lowest 2-year survival (52.3%) was in over 70-year-old starters with a CVC. The survival was 93.2% in under 57-year-old patients without active cancer, 82.5% in 57-70-year-old individuals without cancer, 72.4% in over 70-year-old patients without CVC and 61.4% in under 70-year-old subjects with cancer. The hazard ratio of data mining categories varied between 2.12 (95% CI 1.73-2.60) in 57-70-year-old subjects without cancer and 4.42 (95% CI 3.64-5.37) in over 70-year-old patients with CVC. Therefore, regrouping incident patients into five data mining categories, identified by age, cancer, and CVC use, could discriminate the 2-year survival in patients starting hemodialysis.

CONCLUSIONS

Although each classification captured different prognosis information, both analyses showed that starting hemodialysis on a CVC has more dramatic outcomes than emergency start per se.

Urgent-start dialysis in patients referred early to a nephrologist-the CKD-REIN prospective cohort study

BACKGROUND

The lack of a well-designed prospective study of the determinants of urgent dialysis start led us to investigate its individual- and provider-related factors in patients seeing nephrologists.

METHODS

The Chronic Kidney Disease Renal Epidemiology and Information Network (CKD-REIN) is a prospective cohort study that included 3033 patients with CKD [mean age 67 years, 65% men, mean estimated glomerular filtration rate (eGFR) 32 mL/min/1.73 m2] from 40 nationally representative nephrology clinics from 2013 to 2016 who were followed annually through 2020. Urgent-start dialysis was defined as that 'initiated imminently or <48 hours after presentation to correct life-threatening manifestations' according to the Kidney Disease: Improving Global Outcomes 2018 definition.

RESULTS

Over a 4-year (interquartile range 3.0-4.8) median follow-up, 541 patients initiated dialysis with a known start status and 86 (16%) were identified with urgent starts. The 5-year risks for the competing events of urgent and non-urgent dialysis start, pre-emptive transplantation and death were 4, 17, 3 and 15%, respectively. Fluid overload, electrolytic disorders, acute kidney injury and post-surgery kidney function worsening were the reasons most frequently reported for urgent-start dialysis. Adjusted odds ratios for urgent start were significantly higher in patients living alone {2.14 [95% confidence interval (CI) 1.08-4.25] or with low health literacy [2.22 (95% CI 1.28-3.84)], heart failure [2.60 (95% CI 1.47-4.57)] or hyperpolypharmacy [taking >10 drugs; 2.14 (95% CI 1.17-3.90)], but not with age or lower eGFR at initiation. They were lower in patients with planned dialysis modality [0.46 (95% CI 0.19-1.10)] and more nephrologist visits in the 12 months before dialysis [0.81 (95% CI 0.70-0.94)] for each visit.

CONCLUSIONS

This study highlights several patient- and provider-level factors that are important to address to reduce the burden of urgent-start dialysis.

Analysis of the association between emergency dialysis start in patients with end-stage kidney disease and non-steroidal anti-inflammatory drugs, proton-pump inhibitors, and iodinated contrast agents

BACKGROUND

The association between the use of potentially nephrotoxic drugs [Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), Iodinated Contrast Agents, Proton Pump Inhibitors (PPIs)] and emergency start of dialysis in patients with chronic kidney disease has not been well explored, although these compounds are commonly prescribed or available without prescription.

METHODS

In this study, the Renal Epidemiology Information Network (REIN) registry data of all patients ≥ 18 years of age who started dialysis in France in 2015 were matched with those in the French National Health Insurance Database. The association between clinical characteristics, nephrotoxic drug exposure and emergency dialysis start was investigated. Patients were categorized into four classes of NSAID and PPI exposure (new, current, past, no user) on the basis of the pre-dialysis exposure period (1-30, 31-90, and 91-365 days). For iodinated contrast agents, exposure in the 72 h and 7 days before dialysis was analyzed.

RESULTS

Among the 8805 matched patients, 30.2% needed to start dialysis in emergency. After adjustment for socio-demographic and clinical variables, new NSAID users were more likely to experience emergency dialysis start [OR = 1.95; 95% CI (1.1-3.4)]. This association was higher for new than for current users [OR: 1.44; 95% CI (1.08-1.92)]. Emergency dialysis start was also associated with iodinated contrast agent exposure in the previous 7 days [OR: 1.44; 95% CI (1.2-1.7)]. No significant relationship was detected between PPIs and emergency dialysis start.

CONCLUSIONS

Using both clinical and healthcare data, this study shows that emergency dialysis start is independently associated with recent exposure to NSAIDs and iodinated contrast agents. This suggests the need to strengthen the information given to healthcare professionals and patients with regard to nephrotoxic drugs.

Association between initial vascular access and survival in hemodialysis according to age

BACKGROUND/AIMS

This study aims to demonstrate whether the association between initial vascular access and mortality among hemodialysis patients varies by age.

METHODS

We conducted a retrospective study that included 2,552 patients who started hemodialysis. Vascular access was divided into three categories: percutaneous catheter, tunneled cuffed catheter, and arteriovenous (AV) access.

RESULTS

Survival rates for patients who received a central venous catheter, such as percutaneous or tunneled cuffed catheter, aged 65 to 74 years and those ≥ 75 years were reduced, but not for those aged < 65 years (log-rank test; p < 0.001, p = 0.007, and p = 0.278). After fully adjusting for potential confounding factors in the patients aged < 65 years, percutaneous and tunneled cuffed catheter were not associated with 5-year mortality. On the other hand, for patients aged 65 to 74 or ≥ 75 years, percutaneous catheter and tunneled cuffed catheter were associated with higher 5-year mortality rates. As age increased, the conversion rate from central venous catheter, including percutaneous catheter and tunneled cuffed catheter, to AV access decreased (94.1%, 90.5%, and 80.3% for patients aged < 65, 65 to 74, and ≥ 75 years, respectively; p < 0.001).

CONCLUSION

In patients aged ≥ 65 years, initial vascular access was associated with long-term mortality. We suggest that a "fistula first" strategy is superior for elderly patients and demonstrates that it is desirable to change to AV access, and not maintain an initial central vascular catheter.

Risk Factors for Unplanned Dialysis Initiation: A Systematic Review of the Literature

Background:

Unplanned dialysis initiation is common in patients with chronic kidney disease (CKD).

Objective:

To determine common definitions and patient risk factors for unplanned dialysis.

Design:

Systematic review.

Setting:

MEDLINE, EMBASE, and the Cochrane Library were searched from inception to February 2018.

Patients:

Studies that included incident chronic dialysis patients or patients with CKD that cited a definition or examined risk factors for unplanned dialysis were included.

Measurements:

Definitions and criteria for unplanned dialysis reported across studies. Patient characteristics associated with unplanned dialysis.

Methods:

Two reviewers independently extracted data using a standardized data abstraction form and assessed study quality using a modified New Castle Ottawa Scale.

Results:

From 2797 citations, 48 met eligibility criteria. Reported definitions for unplanned dialysis were variable. Most publications cited dialysis initiation under emergency conditions and/or with a central venous catheter. The association of patient characteristics with unplanned dialysis was reported in 26 studies, 18 were retrospective and 21 included incident dialysis patients. The most common risk factors in univariate analyses were (number of studies) increased age (n = 7), cause of kidney disease (n = 6), presence of cardiovascular disease (n = 7), lower serum hemoglobin (n = 9), lower serum albumin (n = 10), higher serum phosphate (n = 6), higher serum creatinine or lower estimated glomerular filtration rate (eGFR) at dialysis initiation (n = 7), late referral (n = 5), lack of dialysis education (n = 6), and lack of follow-up in a predialysis clinic prior to dialysis initiation (n = 5). A minority of studies performed multivariable analyses (n = 10); the most common risk factors were increased age (n = 4), increased comorbidity score (n = 3), late referral (n = 5), and lower eGFR at dialysis initiation (n = 3).

Limitations:

Comparison of results across studies was limited by inconsistent definitions for unplanned dialysis. High-quality data on patient risk factors for unplanned dialysis are lacking.

Conclusions:

Well-designed prospective studies to determine modifiable risk factors are needed. The lack of a consensus definition for unplanned dialysis makes research and quality improvement initiatives in this area more challenging.

Geographic Variations in the Risk of Emergency First Dialysis for Patients with End Stage Renal Disease in the Bretagne Region, France

Emergency first dialysis start considerably increases the risk of morbidity and mortality. Our objective was to identify the geographic variations of emergency first dialysis risk in patients with end-stage renal disease in the Bretagne region, France. The spatial scan statistic approach was used to determine the clusters of municipalities with significantly higher or lower risk of emergency first dialysis. Patient data extracted from the REIN registry (sociodemographic, clinical, and biological characteristics) and indicators constructed at the municipality level, were compared between clusters. This analysis identified a cluster of municipalities in western Bretagne with a significantly higher risk (RR = 1.80, p = 0.044) and one cluster in the eastern part of the region with a significantly lower risk (RR = 0.59, p < 0.01) of emergency first dialysis. The degree of urbanization (the proportion of rural municipalities: 76% versus 66%, p < 0.001) and socio-demographic characteristics (the unemployment rate: 11% versus 8%, p < 0.001, the percentage of managers in the labor force was lower: 9% versus 13% p < 0.001) of the municipalities located in the higher-risk cluster compared with the lower-risk cluster. Our analysis indicates that the patients' clinical status cannot explain the geographic variations of emergency first dialysis incidence in Bretagne. Conversely, where patients live seems to play an important role.

Deleterious effects of dialysis emergency start, insights from the French REIN registry

Background

Emergency start (ES) of dialysis has been associated with worse outcome, but remains poorly documented. This study aims to compare the profile and outcome of a large cohort of patients starting dialysis as an emergency or as a planned step in France.

Methods

Data on all patients aged 18 years or older who started dialysis in mainland France in 2012 or in 2006 were collected from the Renal Epidemiology and Information Network and compared, depending on the dialysis initiation condition: ES or Planned Start (PS). ES was defined as a first dialysis within 24 h after a nephrology visit due to a life-threatening event. Three-year survival were compared, and a multivariate model was performed after multiple imputation of missing data, to determine the parameters independently associated with three-year survival.

Results

In 2012, 30.3% of all included patients (n = 8839) had ES. Comorbidities were more frequent in the ES than PS group (≥ 2 cardiovascular diseases: 39.2% vs 28.8%, p &lt; 0.001). ES was independently associated with worse three-year survival (57% vs. 68.2%, p = 0.029, HR 1.10, 95% CI 1.01–1.19) in multivariate analysis. Among ES group, a large part had a consistent previous follow-up: 36.4% of them had ≥3 nephrology consultations in the previous year. This subgroup of patients had a particularly high comorbidity burden. ES rate was stable between 2006 and 2012, but some proactive regions succeeded in reducing markedly the ES rate.

Conclusion

ES remains frequent and is independently associated with worse three-year survival, demonstrating that ES deleterious impact is never overcome. This study shows that a large part of patients with ES had a previous follow-up, but high comorbidity burden that could favor acute decompensation with life-threatening conditions before uremic symptoms appearance. This suggests the need of closer end-stage renal disease follow-up or early dialysis initiation in these high-risk patients.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1036-9) contains supplementary material, which is available to authorized users.

Permanent Arteriovenous Fistula or Catheter Dialysis for Heart Failure Patients

Heart failure (HF) is the most frequent cardiovascular disease associated with chronic kidney disease and represents a high risk for cardiovascular mortality in incident hemodialysis (HD) patients. This risk is especially high during the arteriovenous fistula (AVF) maturation period due to the marked hemodynamic changes related to the large increase in the blood flow and also within the first 120 days after HD inception because in this period the highest mortality rate occurs. When planning the vascular access for each incident HF patient, the risk of aggravating HF after AVF creation must be evaluated carefully alongside the risk of catheter-related complications, but avoiding a non-selective ‘catheter first’ approach for all these patients. HF patients classified within the New York Heart Association (NYHA) Class I-II and the American College of Cardiology/American Heart Association (ACC/AHA) Stage A-B could initiate HD through a distal arm AVF. High-flow brachial artery-based AVF creation must be avoided because it displays the highest risk of worsening the cardiac function. The decision for AVF creation or tunneled central catheter placement in HF patients classified within the NYHA Class III and the ACC/AHA Stage C must have been individualized according the degree of systolic and/or diastolic dysfunction. HF patients with significant reduction in systolic function (ejection fraction lower than 30%) or classified within the NYHA Class IV and the ACC/AHA Stage D, are candidates for tunneled catheter placement to start HD treatment.

The impact of an "acute dialysis start" on the mortality attributed to the use of central venous catheters: a retrospective cohort study

Background

Central venous catheters (CVCs) are associated with early mortality in dialysis patients. However, some patients progress to end stage renal disease after an acute illness, prior to reaching an estimated glomerular filtration rate (eGFR) at which one would expect to establish alternative access (fistula/peritoneal dialysis catheter). The purpose of this study was to determine if exclusion of this “acute start” patient group alters the association between CVCs and mortality.

Methods

We conducted a retrospective cohort study of 406 incident dialysis patients from 1 Jan 2006 to 31 Dec 2009. Patients were classified as acute starts if 1) the eGFR was >25 ml/min/1.73 m², ≤3 months prior to dialysis initiation and declined after an acute event (n = 45), or 2) in those without prior eGFR measurements, there was no supporting evidence of chronic kidney disease on history or imaging (n = 12). Remaining patients were classified as chronic start (n = 349).

Results

98 % and 52 % of acute and chronic starts initiated dialysis with a CVC. There were 148 deaths. The adjusted mortality hazard ratio (HR) for acute vs. chronic start patients was 1.84, (95 % CI [1.19-2.85]). The adjusted mortality HR for patients dialyzing with a CVC compared to alternative access was 1.19 (95 % CI [0.80-1.77]). After excluding acute start patients, the adjusted HR fell to 1.03 (95 % CI [0.67-1.57]).

Conclusions

A significant proportion of early dialysis mortality occurs after an acute start. Exclusion of this population attenuates the mortality risk associated with CVCs.

Survival advantage of hemodialysis relative to peritoneal dialysis in patients with end-stage renal disease and congestive heart failure

Peritoneal dialysis (PD) has been proposed as a therapeutic option for patients with end-stage renal disease and associated congestive heart failure (CHF). Here, we compare mortality risks in these patients by dialysis modality by including all patients who started planned chronic dialysis with associated congestive heart failure and were prospectively enrolled in the French REIN Registry. Survival was compared between 933 PD and 3468 hemodialysis (HD) patients using a Kaplan-Meier model, Cox regression, and propensity score analysis. The patients were followed from their first dialysis session and stratified by modality at day 90 or last modality if death occurred prior. There was a significant difference in the median survival time of 20.4 months in the PD group and 36.7 months in the HD group (hazard ratio, 1.55). After correction for confounders, the adjusted hazard ratio for death in PD compared to the HD patients remained significant at 1.48. Subgroup analyses showed that the results were not changed with regard to the New York Heart Association stage, age strata, or estimated glomerular filtration rate strata at first renal replacement therapy. The use of propensity score did not change results (adjusted hazard ratio, 1.55). Thus, mortality risk was higher with PD than with HD among incident patients with end-stage renal disease and congestive heart failure. These results may help guide clinical decisions and also highlight the need for randomized clinical trials.