Impact of Prior Abdominal Procedures on Peritoneal Dialysis Catheter Outcomes: Findings From the North American Peritoneal Dialysis Catheter Registry.

RATIONALE & OBJECTIVE: A history of prior abdominal procedures may influence the likelihood of referral for peritoneal dialysis (PD) catheter insertion. To guide clinical decision making in this population, this study examined the association between prior abdominal procedures and outcomes in patients undergoing PD catheter insertion. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Adults undergoing their first PD catheter insertion between November 1, 2011, and November 1, 2020, at 11 institutions in Canada and the United States participating in the International Society for Peritoneal Dialysis North American Catheter Registry. EXPOSURE: Prior abdominal procedure(s) defined as any procedure that enters the peritoneal cavity. OUTCOMES: The primary outcome was time to the first of (1) abandonment of the PD catheter or (2) interruption/termination of PD. Secondary outcomes were rates of emergency room visits, hospitalizations, and procedures. ANALYTICAL APPROACH: Cumulative incidence curves were used to describe the risk over time, and an adjusted Cox proportional hazards model was used to estimate the association between the exposure and primary outcome. Models for count data were used to estimate the associations between the exposure and secondary outcomes. RESULTS: Of 855 patients who met the inclusion criteria, 31% had a history of a prior abdominal procedure and 20% experienced at least 1 PD catheter-related complication that led to the primary outcome. Prior abdominal procedures were not associated with an increased risk of the primary outcome (adjusted HR, 1.12; 95% CI, 0.68-1.84). Upper-abdominal procedures were associated with a higher adjusted hazard of the primary outcome, but there was no dose-response relationship concerning the number of procedures. There was no association between prior abdominal procedures and other secondary outcomes. LIMITATIONS: Observational study and cohort limited to a sample of patients believed to be potential candidates for PD catheter insertion. CONCLUSION: A history of prior abdominal procedure(s) does not appear to influence catheter outcomes following PD catheter insertion. Such a history should not be a contraindication to PD. PLAIN-LANGUAGE SUMMARY: Peritoneal dialysis (PD) is a life-saving therapy for individuals with kidney failure that can be done at home. PD requires the placement of a tube, or catheter, into the abdomen to allow the exchange of dialysis fluid during treatment. There is concern that individuals who have undergone prior abdominal procedures and are referred for a catheter might have scarring that could affect catheter function. In some institutions, they might not even be offered PD therapy as an option. In this study, we found that a history of prior abdominal procedures did not increase the risk of PD catheter complications and should not dissuade patients from choosing PD or providers from recommending it.

Short Timeframe Prediction of Kidney Failure among Patients with Advanced Chronic Kidney Disease.

BACKGROUND: Development of a short timeframe (6-12 months) kidney failure risk prediction model may serve to improve transitions from advanced chronic kidney disease (CKD) to kidney failure and reduce rates of unplanned dialysis. The optimal model for short timeframe kidney failure risk prediction remains unknown. METHODS: This retrospective study included 1757 consecutive patients with advanced CKD (mean age 66 years, estimated glomerular filtration rate 18 mL/min/1.73 m2). We compared the performance of Cox regression models using (a) baseline variables alone, (b) time-varying variables and machine learning models, (c) random survival forest, (d) random forest classifier in the prediction of kidney failure over 6/12/24 months. Performance metrics included area under the receiver operating characteristic curve (AUC-ROC) and maximum precision at 70% recall (PrRe70). Top-performing models were applied to 2 independent external cohorts. RESULTS: Compared to the baseline Cox model, the machine learning and time-varying Cox models demonstrated higher 6-month performance [Cox baseline: AUC-ROC 0.85 (95% CI 0.84-0.86), PrRe70 0.53 (95% CI 0.51-0.55); Cox time-varying: AUC-ROC 0.88 (95% CI 0.87-0.89), PrRe70 0.62 (95% CI 0.60-0.64); random survival forest: AUC-ROC 0.87 (95% CI 0.86-0.88), PrRe70 0.61 (95% CI 0.57-0.64); random forest classifier AUC-ROC 0.88 (95% CI 0.87-0.89), PrRe70 0.62 (95% CI 0.59-0.65)]. These trends persisted, but were less pronounced, at 12 months. The random forest classifier was the highest performing model at 6 and 12 months. At 24 months, all models performed similarly. Model performance did not significantly degrade upon external validation. CONCLUSIONS: When predicting kidney failure over short timeframes among patients with advanced CKD, machine learning incorporating time-updated data provides enhanced performance compared with traditional Cox models.

Patient and Clinician Perspectives on Shared Decision Making in Vascular Access Selection: A Qualitative Study.

RATIONALE & OBJECTIVE: Collaborative approaches to vascular access selection are being increasingly encouraged to elicit patients' preferences and priorities where no unequivocally superior choice exists. We explored how patients, their caregivers, and clinicians integrate principles of shared decision making when engaging in vascular access discussions. STUDY DESIGN: Qualitative description. SETTING & PARTICIPANTS: Semistructured interviews with a purposive sample of patients, their caregivers, and clinicians from outpatient hemodialysis programs in Alberta, Canada. ANALYTICAL APPROACH: We used a thematic analysis approach to inductively code transcripts and generate themes to capture key concepts related to vascular access shared decision making across participant roles. RESULTS: 42 individuals (19 patients, 2 caregivers, 21 clinicians) participated in this study. Participants identified how access-related decisions follow a series of major decisions about kidney replacement therapy and care goals that influence vascular access preferences and choice. Vascular access shared decision making was strengthened through integration of vascular access selection with dialysis-related decisions and timely, tailored, and balanced exchange of information between patients and their care team. Participants described how opportunities to revisit the vascular access decision before and after dialysis initiation helped prepare patients for their access and encouraged ongoing alignment between patients' care priorities and treatment plans. Where shared decision making was undermined, hemodialysis via a catheter ensued as the most readily available vascular access option. LIMITATIONS: Our study was limited to patients and clinicians from hemodialysis care settings and included few caregiver participants. CONCLUSIONS: Findings suggest that earlier, or upstream, decisions about kidney replacement therapies influence how and when vascular access decisions are made. Repeated vascular access discussions that are integrated with other higher-level decisions are needed to promote vascular access shared decision making and preparedness.

Social determinants of health and the transition from advanced chronic kidney disease to kidney failure.

BACKGROUND: The transition from chronic kidney disease (CKD) to kidney failure is a vulnerable time for patients, with suboptimal transitions associated with increased morbidity and mortality. Whether social determinants of health are associated with suboptimal transitions is not well understood. METHODS: This retrospective cohort study included 1070 patients with advanced CKD who were referred to the Ottawa Hospital Multi-Care Kidney Clinic and developed kidney failure (dialysis or kidney transplantation) between 2010 and 2021. Social determinant information, including education level, employment status and marital status, was collected under routine clinic protocol. Outcomes surrounding suboptimal transition included inpatient (versus outpatient) dialysis starts, pre-emptive (versus delayed) access creation and pre-emptive kidney transplantation. We examined the association between social determinants of health and suboptimal transition outcomes using multivariable logistic regression. RESULTS: The mean age and estimated glomerular filtration rate were 63 years and 18 ml/min/1.73 m2, respectively. Not having a high school degree was associated with higher odds for an inpatient dialysis start compared with having a college degree {odds ratio [OR] 1.71 [95% confidence interval (CI) 1.09-2.69]}. Unemployment was associated with higher odds for an inpatient dialysis start [OR 1.85 (95% CI 1.18-2.92)], lower odds for pre-emptive access creation [OR 0.53 (95% CI 0.34-0.82)] and lower odds for pre-emptive kidney transplantation [OR 0.48 (95% CI 0.24-0.96)] compared with active employment. Being single was associated with higher odds for an inpatient dialysis start [OR 1.44 (95% CI 1.07-1.93)] and lower odds for pre-emptive access creation [OR 0.67 (95% CI 0.50-0.89)] compared with being married. CONCLUSIONS: Social determinants of health, including education, employment and marital status, are associated with suboptimal transitions from CKD to kidney failure.

Vaccine Effectiveness Against SARS-CoV-2 Infection and Severe Outcomes in the Maintenance Dialysis Population in Ontario, Canada.

BACKGROUND: Vaccination studies in the hemodialysis population have demonstrated decreased antibody response compared with healthy controls, but vaccine effectiveness for preventing SARS-CoV-2 infection and severe disease is undetermined. METHODS: We conducted a retrospective cohort study in the province of Ontario, Canada, between December 21, 2020, and June 30, 2021. Receipt of vaccine, SARS-CoV-2 infection, and related severe outcomes (hospitalization or death) were determined from provincial health administrative data. Receipt of one and two doses of vaccine were modeled in a time-varying cause-specific Cox proportional hazards model, adjusting for baseline characteristics, background community infection rates, and censoring for non-COVID death, recovered kidney function, transfer out of province, solid organ transplant, and withdrawal from dialysis. RESULTS: Among 13,759 individuals receiving maintenance dialysis, 2403 (17%) were unvaccinated and 11,356 (83%) had received at least one dose by June 30, 2021. Vaccine types were BNT162b2 (n=8455, 74%) and mRNA-1273 (n=2901, 26%); median time between the first and second dose was 36 days (IQR 28-51). The adjusted hazard ratio (HR) for SARS-CoV-2 infection and severe outcomes for one dose compared with unvaccinated was 0.59 (95% CI, 0.46 to 0.76) and 0.54 (95% CI, 0.37 to 0.77), respectively, and for two doses compared with unvaccinated was 0.31 (95% CI, 0.22 to 0.42) and 0.17 (95% CI, 0.1 to 0.3), respectively. There were no significant differences in vaccine effectiveness among age groups, dialysis modality, or vaccine type. CONCLUSIONS: COVID-19 vaccination is effective in the dialysis population to prevent SARS-CoV-2 infection and severe outcomes, despite concerns about suboptimal antibody responses.

Differences in mRNA-1273 (Moderna) and BNT162b2 (Pfizer-BioNTech) SARS-CoV-2 vaccine immunogenicity among patients undergoing dialysis.

BACKGROUND: Differences in immunogenicity between mRNA SARS-CoV-2 vaccines have not been well characterized in patients undergoing dialysis. We compared the serologic response in patients undergoing maintenance hemodialysis after vaccination against SARS-CoV-2 with BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna). METHODS: We conducted a prospective observational cohort study at 2 academic centres in Toronto, Canada, from Feb. 2, 2021, to July 20, 2021, which included 129 and 95 patients who received the BNT162b2 and mRNA-1273 SARS-CoV-2 vaccines, respectively. We measured SARS-CoV-2 immunoglobulin G antibodies to the spike protein (anti-spike), receptor binding domain (anti-RBD) and nucleocapsid protein (anti-NP) at 6-7 and 12 weeks after the second dose of vaccine and compared those levels with the median convalescent serum antibody levels from 211 controls who were previously infected with SARS-CoV-2. RESULTS: At 6-7 weeks after 2-dose vaccination, we found that 51 of 70 patients (73%) who received BNT162b2 and 83 of 87 (95%) who received mRNA-1273 attained convalescent levels of anti-spike antibody (p < 0.001). In those who received BNT162b2, 35 of 70 (50%) reached the convalescent level for anti-RBD compared with 69 of 87 (79%) who received mRNA-1273 (p < 0.001). At 12 weeks after the second dose, anti-spike and anti-RBD levels were significantly lower in patients who received BNT162b2 than in those who received mRNA-1273. For anti-spike, 70 of 122 patients (57.4%) who received BNT162b2 maintained the convalescent level versus 68 of 71 (96%) of those who received mRNA-1273 (p < 0.001). For anti-RBD, 47 of 122 patients (38.5%) who received BNT162b2 maintained the anti-RBD convalescent level versus 45 of 71 (63%) of those who received mRNA-1273 (p = 0.002). INTERPRETATION: In patients undergoing hemodialysis, mRNA-1273 elicited a stronger humoral response than BNT162b2. Given the rapid decline in immunogenicity at 12 weeks in patients who received BNT162b2, a third dose is recommended in patients undergoing dialysis as a primary series, similar to recommendations for other vulnerable populations.

Factors Affecting Cuff Extrusion of Tunneled Hemodialysis Catheters.

PURPOSE: To identify patient and procedural factors associated with extrusion of the Dacron cuff from the subcutaneous tunnel of tunneled hemodialysis catheters (THDCs). MATERIALS AND METHODS: Single center 5-year retrospective analysis of 625 catheters in 293 adult patients. Patient data included age, gender, body mass index (BMI), and common comorbidities. Procedural details included type of procedure (new insertion vs. exchange), operator seniority, side of insertion, catheter model and presence of catheter wings skin-sutures. Complications were reported as cumulative risk over time and Cox proportional hazards model was used to evaluate risk factors for cuff extrusion (CE). RESULTS: Median patient follow-up was 503 days (188,913 catheter-days) and median catheter survival 163 days. CE occurred in 23.8% of catheters, at a rate of 0.79 per 1,000 catheter-days and a median time of 64 days. It was more common than infection (14.6%) and inadequate flow (15.5%). The 1-month and 12-month risk of CE was 5.9% and 21.3% respectively. A first episode of CE was a strong predictor of future CE episodes. The only patient factor that affected the risk of CE was BMI (Hazard Ratio 2.36 for obese patients). Procedural factors that affected the risk of CE, adjusted for BMI, were catheter model, type of procedure (lower risk for new insertions) and catheter wings skin-sutures; the latter reduced the 30-day CE risk by 76% without increasing catheter-related infections. CONCLUSION: Cuff extrusion is common in long-term THDCs. The risk increases with obesity, history of previous cuff extrusion, certain catheter models and absence of wing-sutures.

A satellite-based mobile warning system to reduce interactions with an endangered species.

Earth-observing satellites are a major research tool for spatially explicit ecosystem nowcasting and forecasting. However, there are practical challenges when integrating satellite data into usable real-time products for stakeholders. The need of forecast immediacy and accuracy means that forecast systems must account for missing data and data latency while delivering a timely, accurate, and actionable product to stakeholders. This is especially true for species that have legal protection. Acipenser oxyrinchus oxyrinchus (Atlantic sturgeon) were listed under the United States Endangered Species Act in 2012, which triggered immediate management action to foster population recovery and increase conservation measures. Building upon an existing research occurrence model, we developed an Atlantic sturgeon forecast system in the Delaware Bay, USA. To overcome missing satellite data due to clouds and produce a 3-d forecast of ocean conditions, we implemented data interpolating empirical orthogonal functions (DINEOF) on daily observed satellite data. We applied the Atlantic sturgeon research model to the DINEOF output and found that it correctly predicted Atlantic sturgeon telemetry occurrences over 90% of the time within a 3-d forecast. A similar framework has been utilized to forecast harmful algal blooms, but to our knowledge, this is the first time a species distribution model has been applied to DINEOF gap-filled data to produce a forecast product for fishes. To implement this product into an applied management setting, we worked with state and federal organizations to develop real-time and forecasted risk maps in the Delaware River Estuary for both state-level managers and commercial fishers. An automated system creates and distributes these risk maps to subscribers' mobile devices, highlighting areas that should be avoided to reduce interactions. Additionally, an interactive web interface allows users to plot historic, current, future, and climatological risk maps as well as the underlying model output of Atlantic sturgeon occurrence. The mobile system and web tool provide both stakeholders and managers real-time access to estimated occurrences of Atlantic sturgeon, enabling conservation planning and informing fisher behavior to reduce interactions with this endangered species while minimizing impacts to fisheries and other projects.

COVID-19 in patients undergoing long-term dialysis in Ontario.

BACKGROUND: Patients undergoing long-term dialysis may be at higher risk of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and of associated disease and mortality. We aimed to describe the incidence, risk factors and outcomes for infection in these patients in Ontario, Canada. METHODS: We used linked data sets to compare disease characteristics and mortality between patients receiving long-term dialysis in Ontario who were diagnosed SARS-CoV-2 positive and those who did not acquire SARS-CoV-2 infection, between Mar. 12 and Aug. 20, 2020. We collected data on SARS-CoV-2 infection prospectively. We evaluated risk factors for infection and death using multivariable logistic regression analyses. RESULTS: During the study period, 187 (1.5%) of 12 501 patients undergoing dialysis were diagnosed with SARS-CoV-2 infection. Of those with SARS-CoV-2 infection, 117 (62.6%) were admitted to hospital and the case fatality rate was 28.3%. Significant predictors of infection included in-centre hemodialysis versus home dialysis (odds ratio [OR] 2.54, 95% confidence interval [CI] 1.59-4.05), living in a long-term care residence (OR 7.67, 95% CI 5.30-11.11), living in the Greater Toronto Area (OR 3.27, 95% CI 2.21-4.80), Black ethnicity (OR 3.05, 95% CI 1.95-4.77), Indian subcontinent ethnicity (OR 1.70, 95% CI 1.02-2.81), other non-White ethnicities (OR 2.03, 95% CI 1.38-2.97) and lower income quintiles (OR 1.82, 95% CI 1.15-2.89). INTERPRETATION: Patients undergoing long-term dialysis are at increased risk of SARS-CoV-2 infection and death from coronavirus disease 2019. Special attention should be paid to addressing risk factors for infection, and these patients should be prioritized for vaccination.

Health Outcomes and Cost Considerations of Assisted Peritoneal Dialysis: A Narrative Review.

BACKGROUND: Peritoneal dialysis (PD) is underutilized in many parts of the world despite pro-PD health policies. The physical and cognitive demands of PD means that over half of eligible patients require some form of assistance. As such, many countries now offer assisted PD (aPD) programs to help patients start or stay on PD as opposed to in-center hemodialysis (HD). In order to evaluate the potential scope of aPD, it is important to review the outcomes and cost considerations of aPD. SUMMARY: We reviewed available data from different countries and regions for health outcomes between aPD and in-center HD, with a focus on quality of life (QoL), mortality, hospitalization, and technique survival. We also evaluated studies discussing the overall costs of delivering aPD, including training, operating costs, and indirect costs and compared these to in-center HD costs for the same regions. Key Messages: aPD patients are older and more frail than either self-care PD patients and many in-center HD patients. We found no evidence for any difference in QoL, mortality, or hospitalization between aPD and in-center HD after adjustment for these differences. There is some evidence for an association between nurse assistance and improved technique survival as compared to family assistance or self-care PD. Despite increased cost of providing assistance in PD, it is still significantly less expensive than in-center HD in Western Europe and Canada.

Importance of Early Inpatient Geriatric Rehabilitation on Outcomes in Individuals on Dialysis.

OBJECTIVE: To report short-term functional outcomes of patients incident to dialysis undergoing inpatient rehabilitation within 3 months of dialysis initiation. DESIGN: Retrospective observation study using prospectively collected data. SETTING: Single-center, hospital-based geriatric dialysis rehabilitation unit. All patients incident to hemodialysis admitted to the geriatric dialysis rehabilitation unit between May 2002 and April 2016 were identified using a retrospective observational design. Clinical and demographic data were collected prospectively and linked, using the unique hospital number and dates of admission and discharge, to FIM scores (used to assess functional recovery) at admission and discharge. PARTICIPANTS: Patients (N=449; mean age ± SD, 74±9y) newly started on hemodialysis (within 3mo). INTERVENTIONS: Inpatient rehabilitation care, short daily dialysis therapy with nephrologist support, and geriatrician assessment. MAIN OUTCOMES: Change in FIM score; discharge location. RESULTS: Patients were admitted within 3 months of hemodialysis initiation. The median length of stay in the rehabilitation program was 43 days (25th and 75th quartile, 33-55 days). Of those with complete data (n=370), 95% had improvement in FIM scores (median changes in total FIM score 25 [quartiles, 16, 33]; in motor FIM 23 [quartiles, 15, 32]; and in cognitive FIM 1 [quartiles, 0, 3], respectively). Most improvement was seen in transfer abilities, grooming, and mobility. A total of 324 patients (72%; 95% CI, 68%-76%) were discharged to a private home. An additional 11 were discharged to a seniors' residence. CONCLUSION: The data suggest that older patients incident to dialysis with functional decline respond well to specialized rehabilitation care and suggest this may be a novel approach to dialysis initiation.

Influence of Mortality on Estimating the Risk of Kidney Failure in People with Stage 4 CKD.

BACKGROUND: Most kidney failure risk calculators are based on methods that censor for death. Because mortality is high in people with severe, nondialysis-dependent CKD, censoring for death may overestimate their risk of kidney failure. METHODS: Using 2002-2014 population-based laboratory and administrative data for adults with stage 4 CKD in Alberta, Canada, we analyzed the time to the earliest of kidney failure, death, or censoring, using methods that censor for death and methods that treat death as a competing event factoring in age, sex, diabetes, cardiovascular disease, eGFR, and albuminuria. Stage 4 CKD was defined as a sustained eGFR of 15-30 ml/min per 1.73 m2. RESULTS: Of the 30,801 participants (106,447 patient-years at risk; mean age 77 years), 18% developed kidney failure and 53% died. The observed risk of the combined end point of death or kidney failure was 64% at 5 years and 87% at 10 years. By comparison, standard risk calculators that censored for death estimated these risks to be 76% at 5 years and >100% at 7.5 years. Censoring for death increasingly overestimated the risk of kidney failure over time from 7% at 5 years to 19% at 10 years, especially in people at higher risk of death. For example, the overestimation of 5-year absolute risk ranged from 1% in a woman without diabetes, cardiovascular disease, or albuminuria and with an eGFR of 25 ml/min per 1.73 m2 (9% versus 8%), to 27% in a man with diabetes, cardiovascular disease, albuminuria >300 mg/d, and an eGFR of 20 ml/min per 1.73 m2 (78% versus 51%). CONCLUSIONS: Kidney failure risk calculators should account for death as a competing risk to increase their accuracy and utility for patients and providers.

Complications From Tunneled Hemodialysis Catheters: A Canadian Observational Cohort Study.

RATIONALE & OBJECTIVE: Clinical practice guidelines discourage the use of central venous catheters (CVCs) for vascular access in dialysis. However, some patients have inadequate vessels for arteriovenous fistula creation or choose to use a dialysis catheter. The risks associated with CVC use and their relationship to patient age are poorly characterized. STUDY DESIGN: Observational retrospective cohort study. SETTING & PARTICIPANTS: Cohort of 1,041 patients older than 18 years from 5 Canadian dialysis programs who initiated outpatient maintenance hemodialysis therapy with a tunneled CVC between 2004 and 2012 and who had no creation of an arteriovenous fistula or arteriovenous graft. EXPOSURES: Age, sex, body size, initiating dialysis therapy in the hospital, and comorbid conditions. OUTCOMES: CVC-related procedures, hospitalization, and death. ANALYTICAL APPROACH: Complications were reported as a cumulative risk at 1 and 2 years. Cox proportional hazards regression for recurrent events was used to evaluate risk factors for study outcomes. RESULTS: At 1 year, risks for CVC-related bacteremia, malfunction, and central stenosis were 9%, 15%, and 2%, respectively. Risks for any CVC-related complication at 1 and 2 years were 30% and 38%, respectively. Death related to CVC complications occurred in 6 of 1,041 (0.5%) patients. Compared with patients younger than 60 years, patients aged 70 to 79 and those 80 years or older experienced lower rates of CVC complications: HRs of 0.67 (95% CI, 0.52-0.85; P = 0.001) and 0.69 (95% CI, 0.52-0.92; P = 0.01), respectively. LIMITATIONS: This Canadian dialysis population may not be representative of populations in other countries. CVC use was not compared with other types of hemodialysis vascular access. CONCLUSIONS: Approximately one-third of hemodialysis patients who used tunneled CVCs during 1 to 2 years experienced complications. Bacteremia occurred in ∼9% of patients at 1 year and were the most common cause of CVC-related hospitalizations. CVC-related death was infrequent. This information could be used to communicate the risk for CVC complications to patients treated with this type of hemodialysis vascular access.

Outcomes of the First and Second Hemodialysis Fistula: A Cohort Study.

RATIONALE & OBJECTIVE: Fistulas are the preferred form of hemodialysis access; however, many fistulas fail to mature into usable accesses after creation. Data for outcomes after placement of a second fistula are limited. STUDY DESIGN: Cohort study. SETTING & PARTICIPANTS: People who initiated hemodialysis therapy in any of 5 Canadian dialysis programs (2004-2012) and had at least 1 hemodialysis fistula placed. PREDICTOR: Second versus initial fistula; receipt of 2 versus 1 fistula; second versus first fistula in recipients of 2 fistulas. OUTCOMES: Catheter-free fistula use during 1 year following initiation of hemodialysis therapy or following fistula creation, if created after hemodialysis therapy start; proportion of time with catheter-free use; time to catheter free use; time of functional patency. ANALYTICAL APPROACH: Logistic regression; fractional regression. RESULTS: Among the 1,091 study participants (mean age, 64±15 [SD] years; 63% men; 59% with diabetes), 901 received 1 and 190 received 2 fistulas. 38% of second fistulas versus 46% of first fistulas were used catheter free at least once. Average percentages of time that second and initial fistulas were used catheter free were 34% and 42%, respectively (OR, 0.72; 95% CI, 0.54-0.94). Compared with people who received 1 fistula, those who received 2 fistulas were less likely to achieve catheter-free use (26% vs 56%) and remain catheter free (23% vs 49% of time; OR, 0.30, 95% CI, 0.24-0.39). Among people who received 2 fistulas, the proportion of time that the second fistula was used catheter free was 11% higher with each 10% greater proportion of time that the first fistula was used catheter free (95% CI, 1%-22%). Model discrimination was modest (C index, 0.69). LIMITATIONS: Unknown criteria for patient selection for 1 or 2 fistulas; unknown reasons for prolonged catheter use. CONCLUSIONS: Outcomes of a second fistula may be inferior to outcomes of the initial fistula. First and second fistula outcomes are weakly correlated and difficult to predict based on clinical characteristics.

Predictors of Care Gaps in Home Dialysis: The Home Dialysis Virtual Ward Study.

BACKGROUND: Home dialysis patients may be at an increased risk of adverse events after transitional states. The home dialysis virtual ward (HDVW) trial was conducted in Canadian dialysis centers and aimed to evaluate potential care gaps and patient satisfaction during the HDVW. METHODS: The HDVW was a multicenter single-arm trial including peritoneal dialysis and home hemodialysis patients after 4 different events (hospital discharge, medical procedure, antibiotics, completion of training). Telephone-led interviews using a standardized assessment tool were performed over a 2-week period to assess a patient's care and adjust treatment as required. Upon completion, patients were surveyed to evaluate their perceived impact on domains of care using a rating scale; 1 not satisfied to 10 completely satisfied. RESULTS: The HDVW trial included 193 patients with a median number of potential care gaps/interventions of 1 (0-2) per patient. Patients admitted to the HDVW after hospital discharge were at a higher risk of potential gaps in care (OR 2.16, 95% CI 1.29-3.62), while longer dialysis vintage was -associated with a lower number of gaps/interventions (OR 0.97 per year, 95% CI 0.95-0.98). A total of 105/193 (54%) patients completed satisfaction surveys. Patients were highly satisfied with the HDVW (median rating scale score 8, IQR 2) and felt it had a positive impact (rating scale score ≥7) on their overall health, understanding of treatment and access to a nephrologist. CONCLUSION: The HDVW was effective at identifying several potential care gaps, and patients were satisfied across several domains of care. This intervention may be valuable in supporting home dialysis patients during care transitions.

Patient-reported advantages and disadvantages of peritoneal dialysis: results from the PDOPPS.

BACKGROUND: Patient-reported measures are increasingly recognized as important predictors of clinical outcomes in peritoneal dialysis (PD). We sought to understand associations between patient-reported perceptions of the advantages and disadvantages of PD and clinical outcomes. METHODS: In this cohort study, 2760 PD patients in the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS) completed a questionnaire on their PD experience, between 2014 and 2017. In this questionnaire, PDOPPS patients rated 17 aspects of their PD experience on a 5-category ordinal scale, with responses scored from - 2 (major disadvantage) to + 2 (major advantage). An advantage/disadvantage score (ADS) was computed for each patient by averaging their response scores. The ADS, along with each of these 17 aspects, were used as exposures. Outcomes included mortality, transition to hemodialysis (HD), patient-reported quality of life (QOL), and depression. Cox regression was used to estimate associations between ADS and mortality, transition to HD, and a composite of the two. Logistic regression with generalized estimating equations was used to estimate cross-sectional associations of ADS with QOL and depression. RESULTS: While 7% of PD patients had an ADS < 0 (negative perception of PD), 59% had an ADS between 0 and < 1 (positive perception), and 34% had an ADS ≥1 (very positive perception). Minimal association was observed between mortality and the ADS. Compared with a very positive perception, patients with a negative perception had a higher transition rate to HD (hazard ratio [HR] = 1.67; 95% confidence interval [CI]: 1.21, 2.30). Among individual items, "space taken up by PD supplies" was commonly rated as a disadvantage and had the strongest association with transition to HD (HR = 1.28; 95% CI 1.07, 1.53). Lower ADS was strongly associated with worse QOL rating and greater depressive symptoms. CONCLUSIONS: Although patients reported a generally favorable perception of PD, patient-reported disadvantages were associated with transition to HD, lower QOL, and depression. Strategies addressing these disadvantages, in particular reducing solution storage space, may improve patient outcomes and the experience of PD.

Comparison of Patient Survival Between Hemodialysis and Peritoneal Dialysis Among Patients Eligible for Both Modalities.

BACKGROUND: Although peritoneal dialysis (PD) costs less to the health care system compared to in-center hemodialysis (HD), it is an underused therapy. Neither modality has been consistently shown to confer a clear benefit to patient survival. A key limitation of prior research is that study patients were not restricted to those eligible for both therapies. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: All adult patients developing end-stage renal disease from January 2004 to December 2013 at any of 7 regional dialysis centers in Ontario, Canada, who had received at least 1 outpatient dialysis treatment and had completed a multidisciplinary modality assessment. PREDICTOR: HD or PD. OUTCOMES: Mortality from any cause. RESULTS: Among all incident patients with end-stage renal disease (1,579 HD and 453 PD), PD was associated with lower risk for death among patients younger than 65 years. However, after excluding approximately one-third of all incident patients deemed to be ineligible for PD, the modalities were associated with similar survival regardless of age. This finding was also observed in analyses that were restricted to patients initiating dialysis therapy electively as outpatients. The impact of modality on survival did not vary over time. LIMITATIONS: The determination of PD eligibility was based on the judgment of the multidisciplinary team at each dialysis center. CONCLUSIONS: HD and PD are associated with similar mortality among incident dialysis patients who are eligible for both modalities. The effect of modality on survival does not appear to change over time. Future comparisons of dialysis modality should be restricted to individuals who are deemed eligible for both modalities to reflect the outcomes of patients who have the opportunity to choose between HD and PD in clinical practice.

Central venous catheters for chronic hemodialysis: Is "last choice" never the "right choice"?

Since the publication of the first vascular access clinical practice guidelines in 1997, the global nephrology community has dedicated significant time and resources toward increasing the prevalence of arteriovenous fistulas and decreasing the prevalence of central venous catheters for hemodialysis. These efforts have been bolstered by observational studies showing an association between catheter use and increased patient morbidity and mortality. To date, however, no randomized comparisons of the outcomes of different forms of vascular access have been conducted. There is mounting evidence that much of the difference in patient outcomes may be explained by patient factors, rather than choice of vascular access. Some have called into question the appropriateness of fistula creation for certain patient populations, such as those with limited life expectancy and those at high risk of fistula-related complications. In this review, we explore the extent to which catheters and fistulas exhibit the characteristics of the "ideal" vascular access and highlight the significant knowledge gaps that exist in the current literature. Further studies, ideally randomized comparisons of different forms of vascular access, are required to better inform shared decision making.

Variability in summer surface residence time within a West Antarctic Peninsula biological hotspot.

Palmer Deep canyon along the central West Antarctic Peninsula is known to have higher phytoplankton biomass than the surrounding non-canyon regions, but the circulation mechanisms that transport and locally concentrate phytoplankton and Antarctic krill, potentially increasing prey availability to upper-trophic-level predators such as penguins and cetaceans, are currently unknown. We deployed a three-site high-frequency radar network that provided hourly surface circulation maps over the Palmer Deep hotspot. A series of particle release experiments were used to estimate surface residence time and connectivity across the canyon. The majority of residence times fell between 1.0 and 3.5 days, with a mean of 2 days and a maximum of 5 days. We found a highly significant negative relationship between wind speed and residence time. Our residence time analysis indicates that the elevated phytoplankton biomass over the central canyon is transported into and out of the hotspot on time scales much shorter than the observed phytoplankton growth rate, suggesting that the canyon may not act as an incubator of phytoplankton productivity as previously suggested. It may instead serve more as a conveyor belt of phytoplankton biomass produced elsewhere, continually replenishing the phytoplankton biomass for the local Antarctic krill community, which in turn supports numerous top predators.This article is part of the theme issue 'The marine system of the West Antarctic Peninsula: status and strategy for progress in a region of rapid change'.