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.

The Association of Intra-Abdominal Adhesions with Peritoneal Dialysis Catheter-Related Complications.

BACKGROUND: This study investigated the association of intra-abdominal adhesions with the risk of peritoneal dialysis (PD) catheter complications. METHODS: Individuals undergoing laparoscopic PD catheter insertion were prospectively enrolled from eight centers in Canada and the United States. Patients were grouped based on the presence of adhesions observed during catheter insertion. The primary outcome was the composite of PD never starting, termination of PD, or the need for an invasive procedure caused by flow restriction or abdominal pain. RESULTS: Seven hundred and fifty-eight individuals were enrolled, of whom 201 (27%) had adhesions during laparoscopic PD catheter insertion. The risk of the primary outcome occurred in 35 (17%) in the adhesion group compared with 58 (10%) in the no adhesion group (adjusted HR, 1.64; 95% confidence interval [CI], 1.05 to 2.55) within 6 months of insertion. Lower abdominal or pelvic adhesions had an adjusted HR of 1.80 (95% CI, 1.09 to 2.98) compared with the no adhesion group. Invasive procedures were required in 26 (13%) and 47 (8%) of the adhesion and no adhesion groups, respectively (unadjusted HR, 1.60: 95% CI, 1.04 to 2.47) within 6 months of insertion. The adjusted odds ratio for adhesions for women was 1.65 (95% CI, 1.12 to 2.41), for body mass index per 5 kg/m 2 was 1.16 (95% CI, 1.003 to 1.34), and for prior abdominal surgery was 8.34 (95% CI, 5.5 to 12.34). Common abnormalities found during invasive procedures included PD catheter tip migration, occlusion of the lumen with fibrin, omental wrapping, adherence to the bowel, and the development of new adhesions. CONCLUSIONS: People with intra-abdominal adhesions undergoing PD catheter insertion were at higher risk for abdominal pain or flow restriction preventing PD from starting, PD termination, or requiring an invasive procedure. However, most patients, with or without adhesions, did not experience complications, and most complications did not lead to the termination of PD therapy.

Lived Experiences of Patients Receiving Hemodialysis during the COVID-19 Pandemic: A Qualitative Study from the Quebec Renal Network.

Background: Hemodialysis patients have faced unique challenges during the COVID-19 pandemic. They face high risk of death if infected and have unavoidable exposure to others when they come to hospital three times weekly for their life-saving treatments. The objective of this study was to gain a better understanding of the scope and magnitude of the effects of the pandemic on the lived experience of patients receiving in-center hemodialysis. Methods: We conducted semi-structured interviews with 22 patients who were undergoing dialysis treatments in five hemodialysis centers in Montreal from November 2020 to May 2021. Interviews were transcribed and then analyzed using thematic content analysis. Results: Most participants reported no negative effects of the COVID-19 pandemic on their hemodialysis care. Several patients had negative feelings related to forced changes in their dialysis schedules, and this was especially pronounced for indigenous patients in a shared living situation. Some patients were concerned about contracting COVID-19, especially during public transportation, whereas others expressed confidence that the physical distancing and screening measures implemented at the hospital would protect them and their loved ones. Some participants reported that masks negatively affected their interactions with health care workers, and for many others, the pandemic was associated with feelings of loneliness. Finally, some respondents reported some positive effects of the pandemic, including use of telemedicine and creating a sense of solidarity. Conclusions: Patients undergoing hemodialysis reported no negative effects on their medical care but faced significant disruptions in their routines and social interactions due to the COVID-19 pandemic. Nevertheless, they showed great resilience in their ability to adapt to the new reality of their hemodialysis treatments. We also show that studies focused on understanding the lived experiences of indigenous patients and patients from different ethnic backgrounds are needed in order reduce inequities in care during public health emergencies.

External validation of prediction models for mortality in an incident dialysis population
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AIMS: Different prediction models have been established to estimate mortality in the dialysis population. This study aims to externally validate the different available mortality prediction models in an incident dialysis population. MATERIALS: This was a retrospective cohort study of incident hemodialysis and peritoneal dialysis patients at two academic tertiary care centers. METHODS: Three previously published prediction models were used: the Liu index, the Urea5 score, and a predictive model estimating the survival probability by Hemke et al. [6]. Models were compared using the C-statistic, net reclassification index, and integrated discrimination improvement. Only the subgroup of 193 patients with enough data to be included in all models was used. RESULTS: 377 patients were started on dialysis in both institutions between 2006 and 2011. Median follow-up was 787 days. 104 patients (27.6%) died during follow-up and 181 were admitted to the hospital (48.0%). All three models were predictive of mortality and hospital admissions. The survival probability model by Hemke et al. [6] performed better than the other two models for mortality (C-statistic 0.72). The Liu index had the highest performance for hospital admissions (C-statistic 0.65). Using reclassification statistics (reference = Urea5), the only model to improve discriminatory ability was the Liu index for the outcome of hospital admission. CONCLUSION: The survival probability model by Hemke et al. [6] may be preferred for mortality prediction in incident dialysis patients. The Liu index could be used to predict hospital admissions in the same population. Available models demonstrated only modest performance in predicting either outcome. Therefore, alternative models need to be developed.
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The Impact of Intradialytic Pedaling Exercise on Arterial Stiffness: A Pilot Randomized Controlled Trial in a Hemodialysis Population.

OBJECTIVES: Regular exercise is known to reduce arterial stiffness (AS) in hemodialysis patients. However, the impact of a more realistic intradialytic form of exercise, such as pedaling, is unclear. We aimed to examine (i) the effect of intradialytic pedaling exercise on AS over 4 months and (ii) the longer term effect of pedaling on AS 4 months after exercise cessation. METHODS: Patients on stable in-center hemodialysis (3 x/week) were randomly assigned 1:1 to either intradialytic pedaling exercise (EX) or to a control group receiving usual hemodialysis (nonEX) for 4 months. At baseline and 4 months, peripheral and central blood pressure (BP) indices, heart rate (HR), augmentation index HR corrected (AIx75), and carotid-femoral pulse wave velocity (cfPWV) were assessed (applanation tonometry). Measurements were repeated in the EX group 4 months postexercise cessation. RESULTS: As per protocol analysis was completed in 10 EX group participants (58 ± 17 years, body mass index 26 ± 4 kg/m2) and 10 nonEX group participants (53 ± 15 years, body mass index 27 ± 6 kg/m2). Peripheral and central BP was unchanged in both groups. AIx75 was unchanged in the EX group, however, a significant median increase of 3.5% [interquartile range, IQR 1.0, 8.5] was noted in the nonEX group (P = 0.009). We noted a significantly greater absolute decrease in cfPWV in the EX group compared to controls: -1.00 [IQR -1.95, 0.05] vs. 0.20 [IQR -0.10, 0.90] (P = 0.033). Interestingly, the decrease in cfPWV observed in the EX group was partially reversed 4 months after exercise cessation. CONCLUSION: Intradialytic pedaling exercise has a beneficial impact on AS. This relationship warrants further investigation. CLINICAL TRIALS REGISTRATION: Trial Number #NCT03027778 (clinicaltrials.gov).

High Ultrafiltration Rates Increase Troponin Levels in Stable Hemodialysis Patients.

BACKGROUND: An elevated troponin level is commonly found in asymptomatic patients on hemodialysis (HD) and is associated with higher risk of mortality and major adverse cardiovascular events. The underlying mechanism for the association between adverse outcomes and elevated troponin levels has not been elucidated. METHODS: Two hundred thirty-six stable chronic HD patients from 2 tertiary care centers were enrolled in this study. We measured pre-dialysis troponin I levels with routine monthly bloods for 3 consecutive months. Troponin I was considered to be elevated if it exceeded the laboratory reference range of 0.06 µg/l. RESULTS: The study population had a mean age of 67.5, 56% were male, 47% had diabetes and 28% had pre-existing coronary artery disease. Eighty-eight positive troponin values were recorded (13% of the available values) in 52 patients. In a repeated measures linear random effects model (univariate analysis), high ultrafiltration (UF), high inter-dialytic weight gain, and duration of the dialysis session, but not intra-dialytic hypotension, were associated with troponin I elevation. In the multivariate model, only high UF explained troponin I elevation (p = 0.04). The intraclass correlation coefficient was found to be 5.8%, suggesting that observed variability is within and not between subjects, with session-related parameters being more important than inter-individual differences. CONCLUSIONS: A high UF rate during HD is associated with a biochemical evidence of myocardial injury. If confirmed, efforts to avoid rapid UF, protect residual kidney function or minimize weight gain between sessions may impact cardiovascular outcomes in this high-risk population.

Renoprotective effects of continuous positive airway pressure in chronic kidney disease patients with sleep apnea.

PURPOSE: Chronic kidney disease (CKD) is associated with a high incidence of obstructive sleep apnea (OSA). We assessed the effect of continuous positive airway pressure (CPAP) on renal function in patients with CKD and OSA. METHODS: In this retrospective cohort study, 42 patients with Stage 3-5 CKD and OSA were stratified into two groups: patients who use CPAP more (average >4 h/night on >70 % of nights) and patients who use CPAP less (average ≤4 h/night on ≤70 % of nights). Median follow-up time was 2.3 (1.6-2.9) years for greater and 2.0 (0.6-3.5) years for lesser CPAP users. Chart reviews were carried out to record clinical characteristics, proteinuria measurements by urine dipstick, and eGFR values calculated by CKD-EPI equations. Univariate analyses were performed using Wilcoxon rank-sum and Kruskal-Wallis tests. Multivariate logistic regression models were applied to assess eGFR decline after CPAP prescription. RESULTS: Twelve (29 %) of the 42 subjects used CPAP more. Groups were similar with respect to age, body mass index, blood pressure, Charlson Comorbidity Index, and baseline eGFR and proteinuria. The median rate of decline of eGFR was significantly slower at -0.07 mL/min/1.73 m(2)/year (range -30 to 13) in those who used more CPAP compared to those who used it less at -3.15 mL/min/1.73 m(2)/year (range -27 to 7) (p = 0.027).Greater use of CPAP was also associated with a significantly reduced level of proteinuria at 0.15 (range 0.0-3.0) versus 0.70 g/L (range 0.0-3.0) (p = 0.046). Less compliant CPAP users were more likely to have progressive decline of eGFR (decline >3 mL/min/1.73 m(2)/year), with unadjusted OR 5.0 (95 % CI 0.93-26.8) and adjusted OR 8.9 (95 % CI 1.1-72.8), adjusting for CCI and baseline eGFR. CONCLUSIONS: Compliance to CPAP therapy is associated with a slower rate of progression of CKD in patients with CKD and OSA.

Management of aboriginal and nonaboriginal people with chronic kidney disease in Quebec: quality-of-care indicators.

OBJECTIVE: To compare quality-of-care indicators for management of patients with chronic kidney disease (CKD) and type 2 diabetes among the James Bay Cree of Northern Quebec with those among residents of Montreal, Que. DESIGN: A cross-sectional survey using medical records from patients seen between 2002 and 2008. SETTING: Predialysis clinics of the McGill University Health Centre in Montreal. PARTICIPANTS: Thirty Cree and 51 nonaboriginal patients older than 18 years of age with type 2 diabetes mellitus and estimated glomerular filtration rates of less than 60 mL/min/1.73 m2. MAIN OUTCOME MEASURES: Rates of anemia, iron deficiency, obesity, and renoprotective medication use among aboriginal and nonaboriginal patients. RESULTS: Overall, the Cree patients were younger (59 vs 68 years of age, P < .0035) and weighed more (101 vs 77 kg,P < .001). The 2 groups were prescribed medication to control blood pressure, lipids, and phosphate levels at similar rates, but the Cree patients were more likely to receive renoprotective agents (87% vs 65%, P = .04). Despite similar rates of erythropoietin supplementation, the Cree patients were at greater risk of anemia, with an adjusted risk ratio of 2.80 (95% CI 1.01 to 7.87). CONCLUSION: Cree patients with CKD were younger, weighed more, and were more likely to receive renoprotective agents. With the exception of the management of anemia, quality of CKD care was similar between the 2 groups.Anemia education for family physicians and continuous monitoring of quality indicators must be implemented in northern Quebec.

Use of telemedicine for haemodialysis in very remote areas: the Canadian First Nations.

We used a pre-post design to compare the health and care utilization of patients receiving telehaemodialysis services in two James Bay Cree communities. The Cree are an Amerindian First Nation living in the remote James Bay region. The same group of dialysed patients (n = 19) was followed longitudinally over a two-year period: 12 months pre and 12 months post. Analysis of variables measuring the patients' health conditions showed that the quality of care provided was well within recognized good practice guidelines. Repeated measures ANOVA on the variables measuring care utilization showed a significant decrease in the monthly number of medication changes over time (P < 0.01). Different telehaemodialysis models were used in the two communities (virtual patient rounds and telecase reviews with multidisciplinary teams), but they did not lead to differences in health condition or care utilization. This suggests that there is no single prescriptive model for the delivery of tele-expertise.

Vascular access-related bloodstream infections in First Nations, community and teaching Canadian dialysis units, and other centre-level predictors.

BACKGROUND/AIMS: Vascular access-related bloodstream infection (BSI) is frequent among patients undergoing hemodialysis increasing their morbidity and mortality, but its occurrence across various dialysis centre types is not known. The aims of this study were to describe the incidence rates and assess the variability in BSI risk between dialysis centre types and other centre-level variables. METHODS: We conducted a retrospective cohort study of 621 patients initiating hemodialysis in 7 Canadian dialysis centres. Cox regression models, where access type was continuously updated, were used to identify predictors of BSI occurrence. RESULTS: During follow-up of the cohort (median age 68.1 years, 41.7% female, and 76.7% initiating with a central venous catheter, CVC), 73 patients had a BSI (rate: 0.21/1000 person-days). The BSI risk was not different in First Nation units (adjusted relative risk: 0.47, 95% confidence interval: 0.06-3.72) and teaching hospitals (1.33, 0.70-2.54) compared to community hospitals. No other centre-related variables were associated with the risk of BSI. CONCLUSION: We did not find differences in the BSI risk among dialysis unit types, or any other centre-related variables. The rates of BSI in our population were lower than those observed in other settings, but the high proportion of patients using CVCs is concerning.

Correlation between physical functioning and sleep disturbances in hemodialysis patients.

The study set out to investigate the relationship between physical functioning, inflammatory status, and sleep disturbance in a chronic hemodialysis (HD) population. Forty-six maintenance HD patients from the McGill University Health Centre were enrolled in this study between October 2005 and 2006. The well-validated Human Activity Profile (HAP) questionnaire and the RAND 36-item survey were used to assess physical functioning. Subjects were given the Pittsburgh Sleep Quality Index (PSQI) survey to evaluate the degree of sleep disturbance. Inflammatory status was assessed with the average value of serial C-reactive protein (CRP) levels for each patient, over a period of 12 months before their enrollment in the study. A multivariate logistic regression model was created for these analyses to control for potential confounders, including dialysis adequacy, inflammation, and hemoglobin. Seventy-six percent of the study population had poor sleep as per the Pittsburgh Sleep Quality Index (PSQI score > or = 5). In addition, 65% of subjects had high CRP values (>5 mg/L). On univariate analysis, both a CRP >5 mg/L and a lower adjusted activity score (AAS) on the HAP were significantly associated with poor sleep (PSQI score > or = 5). Multivariate logistic analysis demonstrated that the AAS remained significantly associated with poor sleep, with a 6% decrease in the odds of poor sleep for each score increase in the AAS of the HAP. Poor physical functioning in chronic HD patients, as measured by the HAP, is associated with sleep disturbance, after controlling for inflammation and dialysis adequacy.

Impact of Levovist ultrasonographic contrast agent on the diagnosis and management of hypertensive patients with suspected renal artery stenosis: a Canadian multicentre pilot study.

OBJECTIVES: To compare the diagnoses obtained with unenhanced ultrasonography (US), contrast-enhanced US and captopril-enhanced renal scintigraphy and to determine whether use of a contrast agent improves ability to assess the renal arteries with duplex Doppler US. SUBJECTS AND METHODS: The study was an open-label controlled trial involving 78 patients with hypertension suspected to have a renovascular cause. The patients underwent captopril-enhanced scintigraphy or routine unenhanced US (the usual diagnostic methods at the centres where the study was conducted) and contrast-enhanced US (with Levovist, Berlex Canada, Lachine, Que.). The patients were followed for 3 months after the diagnostic tests were performed. RESULTS: Enhanced US yielded a diagnosis for a significantly greater proportion of patients than did unenhanced US (77 [99%] v. 64 [82%] of 78 patients; p = 0.002) or captopril-enhanced scintigraphy (71 [99%] v. 58 [81%] of 72 patients; p = 0.002). Diagnosis was possible with both enhanced and unenhanced duplex Doppler US in only 64 (82%) of the 78 patients, and the diagnosis was the same with both methods for 63 (98%) of these 64 patients. In contrast, diagnosis was possible for only 58 (81%) of the 72 patients who underwent both enhanced US and captopril-enhanced scintigraphy; the same diagnosis was reported in 53 (91%) of these 58 cases. During follow-up, 11 patients (21 kidneys) underwent angiography. Significant stenosis was detected in 6 (55%) of the patients (8 [38%] of the kidneys). Both the enhanced and unenhanced US results agreed more often with angiography than did captopril-enhanced scintigraphy (9 [82%] v. 8 [73%] of the 11 patients). The proportion of patients in whom the left and right renal artery could be assessed by duplex Doppler US increased significantly (by 58% and 43%, respectively) with use of the contrast agent. CONCLUSION: Enhanced US had a higher rate of successful diagnosis than unenhanced US and captopril-enhanced renal scintigraphy. Enhanced US might therefore be suitable as a screening method for hypertensive patients with suspected renal artery stenosis.

Economic impact of an ultrasonographic contrast agent on the diagnosis and initial management of patients with suspected renal artery stenosis.

OBJECTIVES: To determine resource use in the diagnosis and management of Canadian hypertensive patients with suspected renal artery stenosis and to estimate the impact of diagnosis with contrast-enhanced duplex Doppler ultrasonography (US) on resource use. SUBJECTS AND METHODS: Seventy-eight patients with suspected renal artery stenosis underwent usual diagnostic tests (captopril-enhanced renal scintigraphy or duplex Doppler US) and contrast-enhanced US. A management pathway ("planned") describing the medical resources required for further patient care was outlined on the basis of results from each test (separately), and a modified management pathway ("recommended"), which considered data from both diagnostic methods, was also outlined. Medical resources and productivity losses were assessed prospectively for a 3-month period after patients underwent both tests ("actual" management pathway). RESULTS: With usual diagnostic methods, 14 (18%) of the tests were inconclusive, whereas only 1 (1%) of the enhanced US examinations was inconclusive; the cost-efficacy ratio was $422 and $343 per successful diagnosis, respectively. Further management costs for patients with an inconclusive diagnosis were estimated at $6370 after the usual diagnostic tests, but only $1278 with enhanced US. Although the costs of the planned and recommended management pathways were similar ($227 and $294 per patient respectively), the proportion of patients requiring further resources was lower with enhanced US (56% v. 46%). Three-month actual management costs ranged from $121 to $1605 per patient (mean $360). Diagnostic tests and surgical procedures were the major cost drivers in all pathways, and costs were highest for patients in whom stenosis was diagnosed. CONCLUSIONS: For patients with suspected renal artery stenosis, contrast-enhanced US had a higher diagnostic success rate than usual diagnostic methods and afforded savings through lower administrative costs and lower medical resource consumption for patients whose diagnosis was unclear after usual diagnostic tests.