Objective. We hypothesized that an increase in the production of interleukins (IL)-6 and IL-17 could serve as a potential mechanism linking pre-existing uncontrolled blood pressure (BP) to the occurrence of long-COVID sequelae in patients undergoing hemodialysis (HD). Methods. In this cross-sectional study, we examined serum IL-6 and IL-17 levels in 80 patients undergoing HD, taking into account preinfection BP, the presence of long-COVID sequelae, and the time interval after acute COVID-19 infection, which was either 5 or 10 months. The cytokines were measured by ELISA assay. Controlled BP was defined as a 3-month average pre-dialysis BP <140/90 mmHg and post-dialysis <130/80 mmHg. Results. The prevalence of long-COVID sequelae was significantly higher in patients with uncontrolled BP than in the BP-controlled group. Both IL-6 and IL-17 concentrations were also significantly higher in patients with uncontrolled BP compared with the BP-controlled group. The patients with long-COVID sequelae had higher IL-6 and IL-17 values than the fully recovered patients at both time points, but their concentrations decreased significantly over time. Conclusions. Elevated levels of serum IL-6 and IL-17 in patients undergoing HD with pre-existing uncontrolled BP may be associated with developing long-COVID sequelae.

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Objective: Hypertension, a nearly ubiquitous complication in hemodialysis (HD) patients, has been identified as a risk factor for COVID -19 and its associated adverse outcomes. In turn, both hypertensive and COVID-19-infected patients with long- COVID sequelae have been reported to have elevated serum interleukin-17 (IL-17) levels. Although HD patients belong to the high-risk group for long COVID sequelae, the association between pre-infection blood pressure (BP) control, serum IL-17 levels, and long COVID sequelae has never been investigated in this cohort. Design and method: A total of 80 HD patients aged 56 (44-63.2) years with a dialysis vintage of 40 (23-74) months who had experienced COVID-19 before enrollment were included in this cross-sectional cohort study. Controlled BP was defined as a 3-month average pre-dialysis BP < 140/90 mmHg and post-dialysis < 130/80 mmHg. IL-17 was measured at least 5 months after acute COVID-19 by ELISA assay. Data were expressed as proportion or median (Me) and interquartile ranges (Q25-Q75) and compared with the Chi-squared test or the Mann-Whitney test as appropriate. Results: Of the 80 patients included, 46 (57.5%) had uncontrolled BP and 34 (42.5%) had controlled BP before infection with COVID -19. Long-term COVID sequelae were observed in 26/46 (56.5%) patients with uncontrolled BP and 11/34 (32.4%) of the BP -controlled group (⇙2 = 4.6, p = 0.03). Serum levels of IL-17 ranged from 0.01 to 15.14 pg/ml and were significantly higher in patients with uncontrolled BP than in the controlled BP group [0.34 (0.08-0.98) vs 0.06 (0.03-0.14) pg/mL, p = 0.001]. In addition, IL-17 was also higher in patients with long-COVID sequelae than in fully recovered patients [0.43 (0.07-1.58) vs 0.08 (0.02-0.16) pg/mL, p = 0.0003], while those with long-COVID sequelae and preinfection uncontrolled BP had the highest value IL-17 (p = 0.04) (Fig. 1). Conclusions: Uncontrolled BP before COVID-19 is associated with increased serum IL-17 levels and long-COVID sequelae in HD patients. Further studies are needed to understand the role of IL-17 in BP control and long-term COVID sequelae in HD patients.

BACKGROUND AND AIMS Several recent studies have demonstrated the association between low high-density lipoprotein cholesterol (HDL-C) levels and poor outcomes in COVID-19-infected patients. However, there is a general lack of research in this field in the haemodialysis population. Therefore, in the present study, we retrospectively examined the association between HDL-C levels and the risk of developing severe outcomes of COVID-19 infection in haemodialysis (HD) patients. METHOD A total of 428 HD patients aged 55 (44–64) years and a dialysis vintage of 44 (21–76.6) months were enrolled in this multicentre retrospective cohort study between March 2020 and September 2021. Baseline HDL-C levels were obtained from electronic health records of the patients in the dialysis centres. (The last measurements were carried out before the COVID-19 onset.) Severe COVID-19-associated pneumonia was estimated based on chest computed tomography (CT) findings of pulmonary involvement and assessed using the following scoring system: (1) indicating &lt;5% involvement, (2) indicating 5%–25% involvement, (3) indicating 26%–49% involvement, (4) indicating 50%–75% involvement and (5) indicating more &gt;75% involvement. The primary and the secondary endpoints were COVID-19-related hospitalization and death, respectively. The data were presented as the median and the interquartile ranges [Me (Q25–Q75)] and compared using the Kruskal–Wallis test. The Spearmen correlation test was used to assess the association between HDL-C and other markers. The multivariate logistic regression and the receiver operating characteristic (ROC) analyses were performed to evaluate the ability of HDL-C for predicting the severity of COVID-19 infection. RESULTS Among 428 enrolled patients, there were 142 (33.2%) patients infected with COVID-19 and 286 (66.8%) patients who had a negative result in COVID-19 PCR tests. A total of 108 (76%) patients of 142 COVID-19 positive patients did not require any oxygen support; 40 patients (28%) were hospitalized, 34 patients (24%) needed oxygen supplements and 16 patients (11.3%) died. The chest CT findings were scored from 2 to 4 in almost all HD patients (99.3%), and only 2 patients had 75% pulmonary involvement. The baseline HDL-C level was significantly lower in the patients with severe COVID-19-associated pneumonia compared with the patients with mild and moderate pneumonia scores (Fig. 1). Moreover, HDL-C was negatively correlated with serum C-reactive protein (CRP) (r = –0.42; P = 0.0002) and D-dimer (r = –0.31; P = 0.001) levels. In the multivariate logistic regression analysis adjusted for age, diabetes, CRP and D-dimer, HDL-C was found to be associated with COVID-19-related hospitalization {OR: 2.4, [95% confidence interval (95% CI) 1.19–4.7]; P = 0.001} and deaths (OR: 3.1, 95% CI 1.28–5.6; P = 0.008) in the HD patients. The ROC curve analysis demonstrated that the most appropriate cut-off point for baseline HDL-C level for predicting severe COVID-19 prognosis in the HD patients was ≤1.2 2 mmol/L with a sensitivity of 93.7% and a specificity of 63.2%. The area under the ROC curve was 0.83 (95% CI 0.76–0.89; P &lt; 0.0001). CONCLUSION HDL-C level ≤1.22 mmol/L was independently associated with a severe COVID-19 prognosis in the cohort of our HD patients. Further research with a greater cohort is needed to confirm this preliminary evidence and validate HDL-C level as a predictive biomarker for COVID-19 severity and mortality in HD patients.

Background and Aims Hemodialysis (HD) patients are at high risk for post-COVID conditions and a high mortality rate over a 1-year period after diagnosis of COVID-19, especially in the first 3 months. Evidence shows that vaccinated individuals who experience breakthrough infection are less likely to report post-COVID conditions compared with unvaccinated individuals. Although oxidative stress has been shown to be an important cause of post-COVID conditions, there is a general lack of data on oxidant/antioxidant status in HD patients with post-COVID conditions. The present study aimed to evaluate the oxidant/antioxidant markers in HD patients with post-COVID conditions according to vaccination status. Method A total of 106 HD patients, aged 52.4 ± 10.2 years, and dialysis vintage of 68 (29-134) months, were enrolled in this cross-sectional observational cohort study. Patients were divided into 3 groups according to their vaccination status and the presence of post-COVID conditions. Group 1 consisted of 36 HD patients who had been fully vaccinated against COVID-19 with either Pfizer-BNT-162b2 or Moderna-mRNA-1273 vaccine and had experienced a post-vaccination SARS-CoV-2 infection and had at least 1 post-COVID symptom. Group 2 consisted of 35 fully vaccinated HD patients who had never been infected with COVID-19 (vaccinated control group), and Group 3 included 35 unvaccinated HD patients who had experienced COVID-19 and had post-COVID conditions (unvaccinated control group). Concentrations of malondialdehyde in serum (MDAs) and erythrocytes (MDAe), sulfhydryl groups (SH-groups), serum catalase activity (CTs), serum transferrin and ceruloplasmin levels were determined 3 months after COVID -19 recovery. Data were expressed as a median and interquartile range [Me (Q25-Q75)] and compared with the Kruskal-Wallis test. Results The vaccinated HD patients with post-COVID conditions had the highest concentrations of MDAs and ceruloplasmin, and lower serum levels of CTs and transferrin compared with the vaccinated and unvaccinated control groups (Table 1). Conclusion Our findings suggest a significant oxidative imbalance in HD patients with post-COVID syndrome most likely due to the synergistic effects of the virus and the vaccine. The use of antioxidant supplements might be a possible strategy to treat post-COVID conditions in HD patients.