Background The immediate and longer-term effects of hemodialysis on cerebral circulation, cerebral structure, and cognitive function are poorly understood.Methods In a prospective observational cohort study of 97 adults (median age 59 years) receiving chronic hemodialysis, we used transcranial Doppler ultrasound to measure cerebral arterial mean flow velocity (MFV) throughout dialysis. Using a well validated neuropsychological protocol, we assessed cognitive function during and off dialysis and after 12 months of treatment. We also used brain magnetic resonance imaging (MRI) to assess atrophy, white matter hyperintensities (WMHs), and diffusion parameters, and tested correlations between MFV, cognitive scores, and changes on MRI.Results MFV declined significantly during dialysis, correlating with ultrafiltrate volumes. Percentage of decline in MFV correlated with intradialytic decline in cognitive function, including global function, executive function, and verbal fluency. At follow-up, 73 patients were available for repeat testing, 34 of whom underwent repeat MRI. In a subgroup of patients followed for 12 months of continued dialysis, percentage of decline in MFV correlated significantly with lower global and executive function and with progression of WMH burden (a marker of small vessel disease). Twelve of 15 patients who received renal transplants during follow-up had both early and follow-up off-dialysis assessments. After transplant, patients' memory (on a delayed recall test) improved significantly; increased fractional anisotropy of white matter (a measure of cerebral diffusion) in these patients correlated with improving executive function.Conclusions Patients undergoing hemodialysis experience transient decline in cerebral blood flow, correlating with intradialytic cognitive dysfunction. Progressive cerebrovascular disease occurred in those continuing dialysis, but not in transplanted patients. Cognitive function and cerebral diffusion improved after transplant.

Background: Patients with kidney failure requiring kidney replacement therapy (KRT) are at high risk of complications and death following SARS-CoV-2 infection with variable antibody responses to vaccination reported. We investigated the effects of COVID-19 vaccination on incidence of infection, hospitalization and death of COVID-19 infection. Methods: Study design was an observational data linkage cohort study. Multiple healthcare datasets were linked to ascertain all SARS-CoV-2 testing, vaccination, hospitalization, and mortality data for all patients treated with KRT in Scotland, from the start of the pandemic over a period of 20 months. Descriptive statistics, survival analyses, and vaccine effectiveness were calculated. Results: As of 19th September 2021, 93% (n=5281) of the established KRT population in Scotland had received two doses of an approved SARS-CoV-2 vaccine. Over the study period, there were 814 cases of SARS-CoV-2 infection (15.1% of the KRT population). Vaccine effectiveness against infection and hospitalization was 33% (95% CI 0-52) and 38% (95% CI 0-57) respectively. 9.2% of fully vaccinated individuals died within 28 days of a SARS-CoV-2 positive PCR test (7% dialysis patients and 10% kidney transplant recipients). This compares to <0.1% of the vaccinated Scottish population being admitted to hospital or dying death due to COVID19 during that period. Conclusions: These data demonstrate a primary vaccine course of two doses has limited impact on COVID-19 infection and its complications in patients treated with KRT. Adjunctive strategies to reduce risk of both COVID-19 infection and its complications in this population are urgently required.

Death following dialysis withdrawal is common. Factors important to physical independence-prior cerebrovascular disease and increasing age-are associated with withdrawal. When combined with clinician comments this study provides an insight into the clinical decline affecting patients and the complexity of this decision. Early recognition of those likely to withdraw may improve end of life care.

Background and Purpose— End-stage renal disease (ESRD) requiring hemodialysis carries up to a 10-fold greater risk of stroke than normal renal function. Knowledge on risk factors and management strategies derived from the general population may not be applicable to those with ESRD. We studied a large ESRD population to identify risk factors and outcomes for stroke. Methods— All adult patients receiving hemodialysis for ESRD from January 1, 2007, to December 31, 2012, were extracted from the electronic patient record. Variables associated with stroke were identified by survival analysis; demographic, clinical, imaging, and dialysis-related variables were assessed, and case-fatality was determined. Follow-up was until December 31, 2013. Results— A total of 1382 patients were identified (mean age, 60.5 years; 58.5% men). The prevalence of atrial fibrillation was 21.2%, and 59.4% were incident hemodialysis patients. One hundred and sixty patients (11.6%) experienced a stroke during 3471 patient-years of follow-up (95% ischemic). Stroke incidence was 41.5/1000 patient-years in prevalent and 50.1/1000 patient-years in incident hemodialysis patients. Factors associated with stroke on regression analysis were prior stroke, diabetes mellitus, and age at starting renal replacement therapy. Atrial fibrillation was not significantly associated with stroke, and warfarin did not affect stroke risk in warfarin-treated patients. Fatality was 18.8% at 7 days, 26.9% at 28 days, and 56.3% at 365 days after stroke. Conclusions— Incidence of stroke is high in patients with ESRD on hemodialysis with high case-fatality. Incident hemodialysis patients had the highest stroke incidence. Many, but not all, important risk factors commonly associated with stroke in the general population were not associated with stroke in patients receiving hemodialysis.

Background Infection with the severe acute respiratory coronavirus 2 (SARS-CoV-2) has led to a worldwide pandemic with coronavirus disease 2019 (COVID-19), the disease caused by SARS-CoV-2, overwhelming healthcare systems globally. Preliminary reports suggest a high incidence of infection and mortality with SARS-CoV-2 in patients receiving kidney replacement therapy (KRT). The aims of this study are to report characteristics, rates and outcomes of all patients affected by infection with SARS-CoV-2 undergoing KRT in Scotland. Methods Study design was an observational cohort study. Data were linked between the Scottish Renal Registry, Health Protection Scotland and the Scottish Intensive Care Society Audit Group national data sets using a unique patient identifier (Community Health Index (CHI)) for each individual by the Public Health and Intelligence unit of Public Health, Scotland. Descriptive statistics and survival analyses were performed. Results During the period 1st March 2020 to 31st May 2020, 110 patients receiving KRT tested positive for SARS-CoV-2 amounting to 2% of the prevalent KRT population. Of those affected, 86 were receiving haemodialysis or peritoneal dialysis and 24 had a renal transplant. Patients who tested positive were older and more likely to reside in more deprived postcodes. Mortality was high at 26.7% in the dialysis patients and 29.2% in the transplant patients. Conclusion The rate of detected SARS-CoV-2 in people receiving KRT in Scotland was relatively low but with a high mortality for those demonstrating infection. Although impossible to confirm, it appears that the measures taken within dialysis units coupled with the national shielding policy, have been effective in protecting this population from infection.