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BACKGROUND AND OBJECTIVES: Patients receiving hemodialysis are at high risk from coronavirus disease 2019 (COVID-19) and demonstrate impaired immune responses to vaccines. There have been several descriptions of their immunologic responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination, but few studies have described the clinical efficacy of vaccination in patients on hemodialysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In a multicenter observational study of the London hemodialysis population undergoing surveillance PCR testing during the period of vaccine rollout with BNT162b2 and AZD1222, all of those positive for SARS-CoV-2 were identified. Clinical outcomes were analyzed according to predictor variables, including vaccination status, using a mixed effects logistic regression model. Risk of infection was analyzed in a subgroup of the base population using a Cox proportional hazards model with vaccination status as a time-varying covariate. RESULTS: SARS-CoV-2 infection was identified in 1323 patients of different ethnicities (Asian/other, 30%; Black, 38%; and White, 32%), including 1047 (79%) unvaccinated, 86 (7%) after first-dose vaccination, and 190 (14%) after second-dose vaccination. The majority of patients had a mild course; however, 515 (39%) were hospitalized, and 172 (13%) died. Older age, diabetes, and immune suppression were associated with greater illness severity. In regression models adjusted for age, comorbidity, and time period, prior two-dose vaccination was associated with a 75% (95% confidence interval, 56 to 86) lower risk of admission and 88% (95% confidence interval, 70 to 95) fewer deaths compared with unvaccinated patients. No loss of protection was seen in patients over 65 years or with increasing time since vaccination, and no difference was seen between vaccine types. CONCLUSIONS: These data demonstrate a substantially lower risk of severe COVID-19 after vaccination in patients on dialysis who become infected with SARS-CoV-2.

Background and objectives The Edmonton Symptom Assessment System Revised: Renal is a patient-reported outcome measure used to assess physical and psychosocial symptom burden in patients treated with maintenance dialysis. Studies of patient-reported outcome measures suggest the need for deeper understanding of how to optimize their implementation and use. This study examines patient and provider perspectives of the implementation process and the influence of the Edmonton Symptom Assessment System Revised: Renal on symptom management, patient-provider communication, and interdisciplinary communication. Design, setting, participants, & measurements Eight in-facility hemodialysis programs in Ontario, Canada, assessed patients using the Edmonton Symptom Assessment System Revised: Renal every 4–6 weeks for 1 year. Screening and completion rates were tracked, and pre- and postimplementation surveys and midimplementation interviews were conducted with patients and providers. A chart audit was conducted 12 months postimplementation. Results In total, 1459 patients completed the Edmonton Symptom Assessment System Revised: Renal; 58% of eligible patients completed the preimplementation survey (n=718), and 56% of patients who completed the Edmonton Symptom Assessment System Revised: Renal at least once completed the postimplementation survey (n=569). Provider survey response rates were 71% (n=514) and 54% (n=319), respectively. Nine patients/caregivers from three sites and 48 providers from all sites participated in interviews. A total of 1207 charts were audited. Seven of eight sites had mean screening rates over 80%, suggesting that routine use of the Edmonton Symptom Assessment System Revised: Renal in clinical practice is feasible. However, the multiple data sources painted an inconsistent picture of the value and effect of the Edmonton Symptom Assessment System Revised: Renal. The Edmonton Symptom Assessment System Revised: Renal standardized symptom screening processes across providers and sites; improved patient and provider symptom awareness, particularly for psychosocial symptoms; and empowered patients to raise issues with providers. Yet, there was little, if any, statistically significant improvement in the metrics used to assess symptom management, patient-provider communication, and interdisciplinary communication. Conclusions The Edmonton Symptom Assessment System Revised: Renal patient-reported outcome measure may be useful to standardize symptom screening, enhance awareness of psychosocial symptoms among patients and providers, and empower patients rather than to reduce symptom burden.

Summary Background and objectives Physicians frequently search bibliographic databases, such as MEDLINE via PubMed, for best evidence for patient care. The objective of this study was to develop and test search filters to help physicians efficiently retrieve literature related to dialysis (hemodialysis or peritoneal dialysis) from all other articles indexed in PubMed, Ovid MEDLINE, and Embase. Design, setting, participants, & measurements A diagnostic test assessment framework was used to develop and test robust dialysis filters. The reference standard was a manual review of the full texts of 22,992 articles from 39 journals to determine whether each article contained dialysis information. Next, 1,623,728 unique search filters were developed, and their ability to retrieve relevant articles was evaluated. Results The high-performance dialysis filters consisted of up to 65 search terms in combination. These terms included the words “dialy” (truncated), “uremic,” “catheters,” and “renal transplant wait list.” These filters reached peak sensitivities of 98.6% and specificities of 98.5%. The filters’ performance remained robust in an independent validation subset of articles. Conclusions These empirically derived and validated high-performance search filters should enable physicians to effectively retrieve dialysis information from PubMed, Ovid MEDLINE, and Embase.

Despite all the attention given to issues such as adequacy of clearances, ultrafiltration failure, and lack of home support, peritonitis remains the leading cause of technique failure in most peritoneal dialysis (PD) centers ([1][1],[2][2]). Furthermore, recent audits from a number of regions

Blood flow in peripheral arteriovenous fistulae and grafts as used for hemodialysis access can be derived from simultaneous measurements of 1) the amount of access recirculation (AR) induced by reversing the dialysis blood lines, and 2) the dialyzer blood flow rate (Qb). The hemodynamic monitor (HDM) uses magnetic principles to measure AR. The measurement is based on differential conductivity between arterial (A) and venous (V) blood flows in the dialysis blood tubing sets after the injection of hypertonic saline into the V line as a conductivity tracer. Access blood flow rates (Qa) derived from AR measurements by the HDM are predictive of access outcome. The measurement of AR is traditionally done from the comparison of urea levels simultaneously taken from the A and V blood lines and from the systemic circulation. Thus, the urea method can also be used to estimate access blood flow rates. The purpose of this study was to determine whether urea based Qa values are also predictive of outcome. Forty-one patients with arteriovenous fistulae (n = 25) or Gore-Tex grafts (n = 16) were studied by a standard protocol. The protocol involved temporarily reversing the A and V lines, taking three blood samples for urea estimation, performing an HDM recirculation test, and recording Qb as per the machine blood pump setting. The data allowed calculation of Qa by the HDM (Qa [HDM]) and urea (Qa [urea]) methods. Qa (HDM) was 1,177 +/- 887 ml/min (mean +/- standard deviation) and Qa (urea) 964 +/- 793 ml/min, a statistically significant difference (paired t-test p < 0.001). There was a significant linear correlation between the results (r = 0.94, p < 0.0001), but the regression equation also showed that Qa (urea) values were less than Qa (HDM). The influence of the Qa value on access outcome was determined after an 8 month follow-up. Nine of the 41 accesses were lost to clotting. Chi-square and discriminate analyses showed that Qa (HDM) significantly (p = 0.005) predicted access outcome, whereas Qa (urea) did not (p = 0.164). The specificity of a low Qa (HDM) in predicting access clotting was 0.78, compared with 0.62 for Qa (urea). The data show that although Qa can be estimated by the urea method, the finding of a low Qa (urea) is a poor predictor of access outcome and may lead to cost ineffective investigations.

Landmark studies relevant to the adequacy of peritoneal dialysis have recently been published. The Canada/USA peritoneal dialysis study has shown a relationship between clearance indices and patient survival rate, but the study is confounded by residual renal function. Registry data show conflicting results concerning survival rates on peritoneal dialysis and haemodialysis. The complicated pathogenesis of malnutrition in dialysis patients is now becoming further appreciated.

The Crit-Line Model III (CRIT) was compared with the Transonics Hemodialysis Monitor (TRANS) with regard to its ability to measure access recirculation (AR). Patients were studied during routine dialysis before and after dialysis line reversal done to induce AR. A strong correlation between CRIT and TRANS AR measurements was obtained (r = 0.95; p = 0.000; n = 58) and CRIT values were repeatable (normalized SD from mean 7.82%). The CRIT values were not identical to TRANS; at low AR values (< 20%) they overestimated, and at higher values they underestimated. Provided this is appreciated, CRIT AR values are clinically useful.

The ability to accurately measure access recirculation (AR) is of importance because its presence indicates access dysfunction and may explain why a prescribed Kt/V (urea) has not been delivered. The ability to measure access flow (Qa) allows access monitoring and the detection of impending access dysfunction. AR can be measured by indicator dilution or conductivity tracer techniques. Qa calculation is simple if AR can be detected. The previous techniques are used while the patient's blood lines are reversed to induce AR, and the Krivitski equation gives: Qa = Qb [1-r/r] where Qb = dialyzer blood flow and r = proportion of AR induced. Three methods for AR and Qa measurements were directly compared: 1) ultrasound dilution (Transonics Hemodialysis Monitor, Transonics Systems Incorporated) (TRANS); 2) hematocrit dilution (Crit-Line Monitor, In-Line Diagnostics) (CRIT); and 3) differential conductivity (Hemodynamic Monitor, GAMBRO Healthcare Incorporated) (HDM). Patients were cannulated in a standard fashion and dialysis commenced with lines in normal configuration. A HDM test was performed and, if AR = zero, the lines were reversed to induce AR. HDM, TRANS, and CRIT tests for AR were next done in rapid succession for direct comparison. Each test was repeated three times in succession, the device in random order, to assess test repeatability. Qb was taken from the 1) dialysis machine pump, and 2) directly from TRANS and Qa calculated, using 1) and 2) AR results. In comparison to TRANS, AR results were virtually identical for HDM (TRANS AR = 1.04 HDM-AR + 0.02, r = 0.98, p = 0.0000), and good for CRIT (CRIT-AR = 0.84 TRANS-AR - 0.2, r = 0.81, p = 0.001), but CRIT underestimated the values. Repeatability was assessed by normalizing (%) the SD of repeated measurements; values were 7.5% (HDM), 9.1 % (TRANS), and 17.4% (CRIT). Qa value comparisons were similar (minimal r = 0.83) regardless of Qb source, but CRIT overestimated the value; repeatability data showed 10.6% (HDM), 13.0% (TRANS), and 25.2% (CRIT) (n ranged from 15-64). In summary, TRANS and HDM appear equal as far as accuracy and repeatability of measurements; CRIT results correlated well, but tended to underestimate AR and overestimate Qa, and was less reproducible.