Hospital readmission in children on maintenance dialysis: a multicenter, prospective cohort study

Patient survival on dialysis in Korea: a different story?

Antibody response and safety of COVID-19 vaccine in peritoneal dialysis patients

This month, I review three recent studies from the literature addressing issues important to the care of the peritoneal dialysis (PD) patient. A number of core questions related to modality choice center on whether PD offers specific patient-centered outcomes benefits or whether specific PD prescriptions might result in improved hard (non-surrogate) patient-centered outcomes. When considering whether an intervention results in changes in outcomes, the randomized controlled trial (RCT) has been considered the “holy grail,” as when it is performed rigorously the opportunity for the introduction of bias or confounding is minimized. However, the challenges of conducting RCTs with dialysis modality choice are well documented.1 In this literature watch, I review an RCT that highlights additional limitations that might arise from a well-designed RCT of the small size typical of many RCTs in nephrology. Specifically, I consider what might happen if the baseline risk of individuals randomly assigned to the experimental and control treatments differ significantly. Bias is reduced by randomization if sufficient numbers of patients are included in the study such that by chance alone all important baseline prognostic (known and unknown) factors that might influence the outcome are distributed equally to both groups, and that the groups differ only in the intervention under investigation. In small RCTs the equivalence of prognostic characteristics in each arm of the study cannot be assumed.2, 3 Additionally, when addressing the issue of whether a particular clinical finding might predict poorer outcomes or even result in harm, the RCT is not the ideal study design. To identify a factor as potentially harmful and likely to be causal of an adverse outcome, observational findings evaluated in the context of the Bradford-Hill considerations are preferred. In addition to the ethical constraints on conducting an RCT on a question of causation or harm, well-designed observational/epidemiological studies may be most informative because they are conducted under real-world conditions and may include patients expressing the full spectrum of baseline risk. Here too the size of the study population is likely to matter. In this literature watch I review two recent observational studies that interrogate patient databases to provide evidence about potential harm related to a clinical feature or the lack thereof. The first study evaluates the use of PD for initiation of unplanned dialysis compared with an initiation with hemodialysis (HD). In the second observational study, a study exploiting a very large observational database, the authors investigate whether depressed serum albumin levels are similarly associated with mortality in HD and PD patients. Citation: Takatori Y, Akagi S, Sugiyama H, et al. Icodextrin increases technique survival rates in peritoneal dialysis patients with diabetic nephropathy by improving body fluid management: A randomized controlled trial. Clin J Am Soc Nephrol. 2011;6:1337–1344. Analysis: Takatori and colleagues report the results of an RCT evaluating whether use of icodextrin as the osmotic agent in PD fluid results in preservation of the PD technique in patients with newly diagnosed end-stage renal disease (ESRD) and diabetes. They define technique preservation largely around the ability of the PD to adequately remove fluid.4, 5 As a secondary outcome, they evaluated preservation of renal function and peritoneal membrane function. It has been established in multiple clinical trails that use of icodextrin in place of dextrose solutions (2.5%) results in improved net ultrafiltration and control of volume. The novel finding in this study is that these previously reported findings extend to incident dialysis patients with diabetes. The study was pre-registered in the Japanese clinical trials registry (JPRN registry WMIN00001040) with the control of volume as the primary outcome and with the intended enrollment of 100 patients. The primary finding of this study was that icodextrin resulted in preservation of function defined as the ability to achieve adequate volume removal when compared with standard PD with 2.5% Dianeal. Validity and threats to validity: The optimal study design to assess a question regarding a therapeutic intervention remains the RCT or a systematic review of high-quality RCTs. When well conducted, an RCT can reduce the risk of bias. There are significant limitations to RCTs when performed less than optimally that may distort the findings reported. Some of these are widely recognized and include non-masking of group assignment, non-blinding leading to secondary interventions impacting outcomes, misclassification of outcomes, and so on. Recently, M.W. Walsh and colleagues have attempted to quantify the risk of important imbalances in baseline prognostic characteristics that might occur by chance in RCTs that are too small to ensure that a balance has occurred as a result of random group allocation (personal communication, June 2011). Although this study appears to be a randomized trial with concealment of allocation, a number of the features of the current study may be problematic in the interpretation of the results and their application. First, the study is very small; significantly smaller than the size indicated as necessary in the pre-study plan. No formal power calculations are included in the published report. In such a small study, if prognostic characteristics are not balanced the results might deviate significantly from the “truth.” A recalculation of the effect size using non-parametric statistical tests and changing the outcome of one subject in each group would result in a significant change of the primary finding reported. Importantly, the study is underpowered to evaluate the patient-centered outcomes of peritoneal membrane and renal function survival or any major side effects including mortality and infection. It appears that group assignment may not have been masked after the initial randomization, so that the clinicians could have intervened in other ways (e.g., education, diet) that might have influenced volume control independent of the PD fluid interventions under study. Patients in the control arm were not treated with higher percentage glucose solutions as might be the case in the U.S. for patients who failed to achieve adequate net volume removal. Application of the results and the clinical bottom line: This is a randomized controlled trial that demonstrates improvement in volume management using icodextrin to perform PD as compared with glucose-containing solutions. These findings reiterated multiple other RCT and observational trial findings in renal-failure patient populations. This study does not provide any new evidence about whether icodextrin might result in improvements in peritoneal membrane or renal survival. Before the conversion to icodextrin as the PD fluid of choice can be recommended, additional RCTs of sufficient duration and size need to be conducted. These RCTs need to determine if patient-centered outcomes can be improved upon significantly with the substitution of icodextrin for glucose-based PD solutions. Citation: Koch M, Kohnle M, Trapp R, Haastert B, Rump LC, Aker S. Comparable outcome of acute unplanned peritoneal dialysis and haemodialysis [published online ahead of print May 28, 2011]. Nephrol Dial Transplant. doi:10.1093/ndt/gfr262. Analysis: The issue of whether patients requiring urgent renal replacement therapy (RRT) can be safely managed with PD has here-to-fore not been rigorously investigated. The current study by Koch and colleagues begins to investigate this question. Ideally, an RCT comparing urgent PD to HD would most unambiguously address this question. The ability to conduct such a study despite equipoise has been restricted, however, by a strong clinical bias in the nephrology community that urgent PD cannot be conducted safely in most clinical circumstances. In such an environment, a well-designed observational study can provide evidence supporting the safety (lack of harm) of PD for urgent initiation of dialysis opening up the possibility for the appropriate RCT. Koch and colleages have exploited their unique clinical environment that allows them to provide PD urgently in a closely observed hospital setting to compare their experience with urgent PD versus urgent HD. Validity and threats to validity: As an observational study, it is impossible to exclude bias that might have influenced the results. The most important of these is a selection bias where healthier patients are systematically more likely to receive one versus the other treatments being compared. In the case of the current study, it appears that patients with more severe cardiac disease were more likely to be encouraged to choose PD as treatment. Such an imbalance would be expected to negatively impact the outcomes (mortality, hospitalization rates, etc.) amongst patients undergoing PD. The absence of an observed difference (possibly even a trend favoring PD) can be attributed to the study being underpowered. Alternatively, the absence of a difference in outcomes might be due to an imbalance in prognostic factors, which would be expected in the case of this study to make a superior treatment option such as PD appear less favorable in comparison. Statistical methods to manage the differences in important prognostic factors between the two groups are imperfect. Application of the results and the clinical bottom line: Importantly, this study may provide the necessary evidence of safety with the use of PD in urgent initiation of RRT and, therefore, open up the possibility of an RCT that will test the use of PD for emergency initiation of dialysis. The study results support the conclusion that urgent PD is safe and can be implemented equally effectively as HD for urgent initiation of RRT. If safe, a potential strategy based on PD for urgent RRT warrants further study as a means of reducing HD catheter-related infections—a significant cause of morbidity and mortality among patients new to dialysis. Treating a larger fraction of incident ESRD patients with PD might have other favorable consequences on morbidity, mortality, and quality of life yet to be determined. Citation: Mehrotra R, Duong U, Jiwakanon S, et al. Serum albumin as a predictor of mortality in peritoneal dialysis: Comparisons with hemodialysis [published online ahead of print May 19, 2011]. Am J Kidney Dis. doi:10.1053/j.ajkd.2011.03.018. Analysis: Mehrotra and colleagues exploit a large observational database to investigate whether depressed serum albumin levels are similarly associated with mortality in HD and PD patients. This study is important for two major reasons: First, if the impact of a low albumin is similar in PD and HD patients, PD patients may be placed in higher risk from excessive peritoneal protein losses and therefore, incentives and quality measures designed to prevent hypoalbuminemia might be warranted; and second, if interventions are to be tested or advocated to correct the hypoalbuminemia, the optimal target for serum albumin in PD versus HD patients should be established. This may be seen as an important precursor to studying interventions to alter albumin and to stratify the study populations according to who is most likely to benefit. In the current study, the authors have used the DaVita dataset containing the clinical parameters and outcomes for all patients receiving RRT by DaVita over a five-year period. They demonstrated a significant adjusted risk of mortality and cardiovascular mortality among all patients receiving RRT who were significantly hypoalbuminemic. Importantly, they demonstrated that the increase risk is not seen in PD patients until their serum albumin levels are observed to be below 3.8 g/dL. In contrast, in HD patients the threshold for increased risk with a depressed albumin begins at values below 4.0 g/dL. Validity and threats to validity: Prior to initiation of RCTs to test interventions to normalize serum albumin levels in patients undergoing RRT, it should be firmly established that there is an increased mortality risk associated with the lower serum albumin and whether this risk is modified by treatment modality. This study provides substantial evidence of this association and that the risk might be different for patients treated with PD versus HD. The power of this study rests in that the observations are made using a very large database representing the full spectrum of patients and their comorbidities. The interrogated database represents a long enough period of observation of sufficient duration that it would be reasonable to expect to observe an impact of hypoalbuminemia on mortality. The study cannot, however, prove a causal relationship between a low albumin and mortality. In particular, despite the large size of the population, the robustness of the data allowing for morbidity adjustments, and the precision of the estimates, confounding cannot be excluded. The authors note these limitations. It is, however, fair to note (as the authors do) that despite the limitations of the evidence, agencies that monitor healthcare quality often chose to measure quality using parameters that arise from such observational studies. The rigor of this observational study and the precision of the estimates of the threshold make the findings from this study most compelling. Application of the results and the clinical bottom line: While it is uncertain whether hypoalbuminemia itself is causal for some of the observed increased cardiovascular and all-cause mortality in ESRD patients, the current study by Mehrotra and colleageus adds significantly to our current understandings about serum albumin and nutrition in ESRD patients by more precisely describing the impact of a low albumin on different classes of ESRD patients. This study should provide evidence that will help in the design of clinical trials investigating interventions to correct low serum albumin levels in ESRD patients. Since the decision to switch patients from PD to HD is often influenced by the persistence of a lower serum albumin in PD patients, the results of this study might provide rationale—pending confirmation by an RCT—for a strategy that results in fewer patients switching off of PD and moving to HD. At a minimum, this study should raise the possibility that a slightly higher albumin achieved by switching a PD patient to HD might not translate into a significant survival advantage. This hypothesis requires further testing. The two observational studies reviewed above provide significant insights into safety and harm or risk. As such, these observational studies may be informative for clinical practice. Thus, well-conducted observational studies can provide important insights especially related to risk or harm. In contrast, the first study reviewed above highlights some of the limitations presented by RCTs of small size—sizes typical of the nephrology literature. While the RCT is the optimal study design to investigate a therapy, the RCT reviewed here demonstrates that the results of even a well-designed and well-conducted RCT may, at times, need to be interpreted with caution. The plethora of small RCTs in nephrology and the difficulty of conducting larger trials in ESRD patients should not provide justification for our failure to conduct large, sufficiently powered RCTs on many of our current therapies for the complications of ESRD.

Dyslipidemia is common among patients with end-stage renal disease, whether treated by hemodialysis (HD) or peritoneal dialysis (PD). To better understand the specific lipoprotein abnormalities in PD patients, we measured the lipid and apolipoprotein (Apo) composition of the four major classes of plasma lipoproteins in PD patients, HD patients, and healthy control subjects: very low density (VLDL), intermediate density (IDL), low density (LDL), and high density lipoproteins (HDL). Fasting plasma samples were obtained from 15 nondiabetic PD patients, 15 nondiabetic HD patients, and 16 healthy control subjects, all from a cross section of patients and subjects in the region of Göteborg, Sweden. Lipoproteins were isolated by preparative ultracentrifugation, and lipid and apolipoprotein concentrations were measured by gas chromatography and electroimmunoassay, respectively. Alterations in lipoprotein composition were apparent in all four lipoprotein density classes from PD and HD patients. VLDL contained a significantly higher concentration of ApoCIII in both HD and PD patients, and an elevation of free cholesterol, triglyceride, ApoB, ApoCII, and ApoE in PD patients. IDL from both PD and HD patients contained an excess of free and esterified cholesterol and triglyceride and significantly elevated levels of ApoB, ApoCII, ApoCIII, and ApoE. LDL had a higher concentration of ApoB in PD patients and elevated triglyceride and ApoCIII in both PD and HD patients. HDL isolated from PD patients had lower free cholesterol and ApoAI levels compared to control subjects, but these were not significantly different from HD patients. An increase in lipid and apolipoprotein mass in IDL, and an enrichment of ApoCIII in VLDL, IDL, and LDL were observed in both HD and PD patients. The predominant alteration in lipoprotein composition distinguishing PD patients from HD patients was an elevation of ApoB in LDL. Further study of these alterations in lipoprotein composition in PD patients will be helpful in understanding the underlying causes of dyslipidemia and, ultimately, to the selection of hypolipidemic drugs or other treatments to reduce the cardiovascular risks associated with dyslipidemia in these patients.

This study aimed to determine the relationship between magnesium and PTH levels in peritoneal dialysis (PD) and hemodialysis (HD) patients. This cross-sectional study was performed on HD and PD patients in Kerman, Iran. After recording demographic and clinical data, the pre-dialysis levels of hemoglobin, 25-hydroxy vitamin D, ferritin, creatinine, calcium, phosphorus, albumin, PTH, and magnesium were measured for all patients. The P value of less than 0.05 was considered statistically significant. Magnesium levels in PD patients were significantly higher than in HD patients (P < 0.001). The median PTH level in PD patients was significantly lower than in HD patients (P = 0.046). The correlation between PTH and serum magnesium levels was not significant in PD or HD patients. In the regression model, dialysis modality (PD or HD) was the only significant variable in determining serum magnesium levels (P = 0.005). Magnesium is a neglected ion in peritoneal dialysis and hemodialysis patients. In dialysis centers that use a dialysate with standard magnesium concentration (0.5mmol/L in HD and 0.75mmol/L in PD), special attention is necessary to hypomagnesia and its complications because magnesium levels in PD patients were significantly higher than in HD patients. As the correlation between magnesium and PTH levels in both PD and HD patients were not significant, the association of high magnesium levels with low PTH in PD patients should be considered in terms of increasing the potential for adynamic bone disease. It seems that ordering serum magnesium in the routine tests of dialysis patients is necessary.

Hospital admissions in pediatric dialysis patients need to be better studied, and most existing studies are retrospective and based on registry data. This study aimed to analyse and compare hospital admission rates, causes, length of stay (LOS), and outcomes in children treated with peritoneal dialysis (PD) and hemodialysis (HD). Data from 236 maintenance PD and 138 HD patients across 16 European dialysis centers were collected between 1 July 2017 and 30 June 2018. A total of 178 hospitalized patients (103 PD, 75 HD) were included for further analyses. There were 465 hospitalization events (268 PD, 197 HD) with a rate of 0.39 admissions per 100 patient-days at risk (PDAR) and 2.4 hospital days per 100 PDAR. The admission rates were not significantly different between HD and PD patients. The most common causes of hospitalization were access-related infections (ARI) (17%), non-infectious complications of access (NIAC) (14%), and infections unrelated to access (12%). ARI was the leading cause in PD patients (24%), while NIAC was more common in HD patients (19%). PD patients had more ARIs, diagnostic procedures, and treatment adjustments (P<.05), while HD patients had more NIACs, infections unrelated to access, access placement procedures, and interventional/surgical procedures (P<.001). LOS was longer with acute admissions than non-acute admissions (P<.001). Overall LOS and LOS in the intensive care unit were similar between HD and PD patients. High serum uric acid and low albumin levels were significant predictors of longer LOS (P=.022 and P=.045, respectively). Young age, more significant height deficit, and older age at the start of dialysis were predictors of longer cumulative hospital days (P=.002, P=.001, and P=.031, respectively). Access-related complications are the main drivers of hospitalization in pediatric dialysis patients, and growth and nutrition parameters are significant predictors of more extended hospital stays.

Prevalence of anemia in erythropoietin-treated pediatric as compared to adult chronic dialysis patients

Given that it is difficult to randomize end-stage renal disease (ESRD) patients to either hemodialysis (HD) or peritoneal dialysis (PD), differences between these renal replacement therapy (RRT) modalities are of major interest and remain controversial. All data on maintenance dialysis patients during 2009 to 2013 in the Renji Hospital in Shanghai, China and in the San Bortolo Hospital in Vicenza, Italy were selected. Patients who changed their therapy from HD to PD or PD to HD during this study were excluded. 919 maintenance dialysis patients were included in the present study, including 509 patients on HD and 410 on PD. During the 5-year follow-up, mean arterial pressure (MAP) was higher in HD patients. The level of serum HCO3- was significantly better in PD patients than in HD patients. Phosphate was significantly higher in HD patients than in PD patients. With respect to lipid metabolism, triglyceride, total cholesterol and LDL were significantly higher in PD patients. Serum protein and albumin were higher in HD patients than in PD patients. Overall, 236 patients died (25.7%); 150 (16.3%) on HD and 86 (9.4%) on PD. The main cause of death in HD and PD patients was cerebral vascular disease and infection, respectively. After adjusting for dialysis vintage, the Kaplan-Meier patient survival was similar between HD and PD patients. Based on 5 years of data, we demonstrate that lipid metabolism and nutritional status were better in HD patients. However, blood pressure control, acid-base balance, phosphate (P) control were better in PD patients. The main cause of death in HD and PD was cerebral vascular disease and infection, respectively. Considering the dialysis vintage, the Kaplan-Meier patient survival was similar between HD and PD patients.

Satisfaction with care in peritoneal dialysis patients

The K/DOQI guideline for bone metabolism and disease in chronic kidney disease is predominantly based on studies in haemodialysis (HD) patients. However, in clinical practice, this guideline is also applied to peritoneal dialysis (PD) patients. To validate the implementation of this guideline in PD patients, we evaluated the associations between plasma concentrations outside the K/DOQI-targets and the risk of cardiovascular morbidity and mortality in incident PD patients compared with HD patients. In a large prospective multicentre study in the Netherlands (The Netherlands Cooperative Study on the Adequacy of Dialysis, NECOSAD), we included patients starting PD or HD between 1997 and 2004. Relative risk of cardiovascular morbidity and mortality were estimated using time-dependent Cox regression modelling. We included 586 PD patients with mean age 52 +/- 15 years (66% males) and 1043 HD patients with mean age 63 +/- 14 years (58% males). Cardiovascular disease (CVD) was the reason for hospitalization in 102 PD and 271 HD patients. In HD patients, the relative risk of CVD-related hospitalization increased with elevated plasma calcium concentrations (hazard ratio: 1.4; 95% CI: 1.1-1.9). Cardiovascular mortality was significantly higher for phosphorus concentrations above the K/DOQI-threshold in PD (2.4; 95% CI: 1.3-4.2) and HD patients (1.5; 95% CI: 1.1-2.1), and for elevated Ca x P in PD (2.2; 95% CI: 1.3-3.8) and HD patients (1.5; 95% CI: 1.1-2.1). Plasma calcium concentrations above the K/DOQI-threshold increase the relative risk of CVD-related hospitalization in HD patients. Associations with cardiovascular mortality were more pronounced. Both in PD and HD patients with elevated plasma phosphorus and Ca x P concentrations, the cardiovascular mortality risk is increased. Therefore, it seems appropriate to adopt the current guideline in PD patients.

Background: Several studies have shown an association between erythropoietin-stimulating agent (ESA) responsiveness and mortality in chronic kidney disease (CKD) patients. In our present study, we examined the association between prescribed ESA dose and mortality in peritoneal dialysis (PD) and hemodialysis (HD) patients. We hypothesized that PD patients received lower ESA dose for the same achieved hemoglobin compared to HD patients and that ESA dose-mortality associations were different between PD and HD patients. Methods: We compared the prescribed doses of ESA between 139,103 HD and 10,527 PD patients treated in DaVita dialysis clinics from 7/2001 through 6/2006 using adjusted Poisson regression and examined mortality-predictability of prescribed ESA dose and ESA responsiveness index (ESA/hemoglobin) in PD and HD with follow-up through 6/2007 using Cox regression models. Results: Poisson adjusted ratio of ESA dose of HD to PD was 3.6 (95% CI 3.5–3.7). In PD patients, adjusted all-cause death hazard ratios (HR) for ESA doses of 3,000–5,999, 6,000–8,999 and ≧9,000 U/week (reference <3,000 U/week) were 0.97 (0.87–1.07), 0.85 (0.76–0.95) and 1.08 (0.98–1.18), respectively; whereas in HD patients across commensurate ESA dose increments of 10,000–19,999, 20,000–29,999 and ≧30,000 U/week (reference <10,000 U/week) were 1.14 (1.11–1.17), 1.54 (1.50–1.58) and 2.15 (2.10–2.21), respectively. In PD and HD patients, the adjusted death HR of the 4th to 1st quartile of ESA responsiveness index were 1.14 (1.04–1.26) and 2.37 (2.31–2.43), respectively. Conclusions: Between 2001 and 2006, most PD patients received substantially lower ESA dose for same achieved hemoglobin levels, and low ESA responsiveness was associated with higher mortality in both HD and PD patients.

Background/Aims: Recent changes in clinical practice guidelines and reimbursement policies may have affected the use of anemia-related medications and red blood cell (RBC) transfusions in peritoneal dialysis (PD) and hemodialysis (HD) patients. We sought to compare patterns of erythropoiesis-stimulating agents (ESA) and intravenous (IV) iron use, achieved hemoglobin levels, and RBC transfusion use in PD and HD patients. Methods: In quarterly cohorts of prevalent dialysis patients receiving persistent therapy (>3 months), 2007-2011, with Medicare Parts A and B coverage, we assessed ESA and IV iron use and dose, RBC transfusions, and hemoglobin levels. Quarterly transfusion rates were calculated. Results: Observable PD and HD patients numbered 14,958 and 221,866 in Q1/2007 and 17,842 and 256,942 in Q4/2011. Adjusted ESA use was lower in PD (71.4-80.1%) than in HD (86.9-92.0%) patients, decreasing from 80.1% (Q1/2010) to 71.4% (Q4/2011) in PD patients, and from 92.0 to 86.9% in HD patients. The mean adjusted ESA dose decreased by 67.5% in PD and 58.4% in HD patients. IV iron use tended to increase, peaking at 39.3% for PD (Q3/2011) and 80.5% for HD (Q2/2011) patients. Adjusted mean hemoglobin levels fell from 11.7 to 10.6 mg/dl in PD and from 12.0 to 10.7 mg/dl in HD ESA users; adjusted transfusion rates increased from 2.4 to 3.0 per 100 patient-months in PD and from 2.6 to 3.3 in HD patients. Conclusions: In patients receiving persistent dialysis, dose and frequency of ESA administrations decreased during the period 2007-2011. Mean hemoglobin levels decreased by more than 1 g/dl, while transfusion rates increased by approximately 25%.

Hemoglobin predicts long-term survival in dialysis patients: A 15-year single-center longitudinal study and a correlation trend between prealbumin and hemoglobin: Management of comorbidities in kidney disease in the 21st century: Anemia and bone disease

ABSTRACTBackgroundLittle is known regarding the dynamics of antibody and T-cell responses in chronic kidney disease (CKD) following coronavirus disease 2019 (COVID-19) vaccination.MethodsProspective observational cohort study including 144 participants on haemodialysis (HD) (n = 52) or peritoneal dialysis (PD) (n = 14), those undergoing kidney transplantation (KT) (n = 30) or those with advanced CKD (ACKD) not on dialysis and healthy controls (n = 18). Anti-Spike (S) antibody and T-cell responses were assessed at 15 days (15D) and 3 months (3M) after complete vaccination schedule. HD, PD and KT patients received mRNA vaccines (mRNA-123 and BNT162b2). Most ACKD patients received BNT162b2 (n = 23), or Ad26.COV.2.S (4). Most controls received BNT162b2 (n = 12), or Ad26.COV.2.S (n = 5).ResultsAnti-S antibodies at 15D and 3M were detectable in 95% (48/50)/98% (49/50) of HD patients, 93% (13/14)/100% of PD patients, 67% (17/26)/75% (21/28) of KT patients and 96% (25/26)/100% (24/24) of ACKD patients. Rates for healthy controls were 81% (13/16)/100% (17/17). Previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2-S) infection was documented in four (7.7%) HD patients, two (14.3%) PD patients, two (6.7%) KT patients, one (5.55%) healthy control and in no ACKD patient. Antibody levels decreased at 3M in HD (P = .04), PD (P = .008) and ACKD patients (P = .0009). In KT patients, levels increased (P = .04) between 15D and 3M, although they were low at both time points.T-cell responses were detected in HD patients in 37 (80%) at baseline, 35 (70%) at 15D and 41 (91%) at 3M. In PD patients, T-cell responses appeared in 8 (67%) at baseline, 13 (93%) at 15D and 9 (100%) at 3M. In KT patients, T-cell responses were detected in 12 (41%) at baseline, 22 (84%) at 15D and 25 (96%) at 3M. In ACKD patients, T-cell responses were detected in 13 (46%) at baseline, 20 (80%) at 15D and 17 (89%) at 3M. None of healthy controls showed T-cell response at baseline, 10 (67%) at 15D and 8 (89%) at 3M.ConclusionsMost HD, PD and ACKD patients develop SARS-CoV-2-S antibody responses comparable to that of healthy controls, in contrast to KT recipients. Antibody waning at 3M was faster in HD, PD and ACKD patients. No differences in SARS-CoV-2 T-cell immunity responses were noticed across study groups.

Growing a peritoneal dialysis program: A single‐center experience