IL-6 and IL-17 as potential links between pre-existing hypertension and long-term COVID sequelae in patients undergoing hemodialysis: a multicenter cross-sectional study

Long COVID, characterized by persistent symptoms following acute infection, poses a significant health challenge, particularly for patients with pre-existing chronic conditions such as hypertension. 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-term COVID sequelae in patients undergoing hemodialysis (HD). This cross-sectional study examined serum IL-6 and IL-17 levels in 80 patients undergoing HD, considering preinfection BP, the presence of long-term COVID sequelae, and the time interval after acute COVID-19 infection, which was either 5 or 10 months. Controlled BP was defined as a 3-month average pre-dialysis BP < 140/90 mmHg and post-dialysis < 130/80 mmHg. The findings suggest that the prevalence of long-term 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-term 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. Further research and prospective studies are warranted to validate these findings.

Long-COVID sequelae are associated with oxidative stress in hemodialysis patients

pathophysiology of long-COVID sequelae in the general population of SARS-CoV-2-infected patients has been shown to be strongly influenced by oxidative stress. However, the potential role of oxidative stress in the development of long-COVID sequelae in hemodialysis patients (HD) has never been investigated. The present study aimed to evaluate the oxidative status of HD patients 3.5 months after SARS-CoV-2 infection in relation to the presence of long-COVID sequelae and the severity of the acute phase COVID-19. Methods. This cross-sectional cohort study included 63 HD patients with a median age of 55 (43-62.5) years and a dialysis vintage of 42 (25-73) months who had been infected with COVID-19 at least 3 months before recruitment. Patients were divided into two groups according to the occurrence of long-COVID sequelae: Group 1 included 31 (49.2%) HD patients with sequelae, while Group 2 included 32 (50.8%) fully recovered individuals. At 3.5 (3.2-4.6) months after the acute phase of COVID-19, malondialdehyde (MDA) and erythrocyte levels (MDAe), sulfhydryl groups (SH -groups), serum catalase activity, transferrin, and ceruloplasmin were measured. A comparison of the obtained data was performed using the Student’s test or the Mann-Whitney test according to the data distribution. A correlation was evaluated with the Spearman test. Results. HD patients with persistent long-COVID sequelae had significantly higher concentrations of MDAs (p = 0.002), MDAe (p = 0.0006), and CTs (p = 0.02), and lower serum levels of SH-groups (p = 0.03) and ceruloplasmin (p = 0.03) compared with Group 2. The concentration of most studied indicators of pro- and antioxidant status did not depend on the severity of the acute phase COVID-19, and only catalase activity was statistically significantly related to the need for hospitalization (r = 0.59; p = 0.001), oxygen support (r = 0.44; p = 0.02), and the percentage of lung injury according to computed tomography (p = 0.03). Although the serum concentration of transferrin did not differ between the studied groups, the individual analysis showed that its value was statistically higher in HD patients with severe COVID-19 even 3.5 months after infection (p < 0.0001). Conclusions. Long-term COVID-19 sequelae in HD patients are associated with oxidative stress. High levels of catalase activity and serum transferrin 3.5 months after COVID-19 may be a consequence of the severe course of the acute phase of the disease. The obtained data suggest that the use of antioxidants may be one of the possible strategies to treat the long-term consequences of COVID in HD patients.  

MO878: Does Haemodiafiltration Versus Haemodialysis Have Clinical Benefits for Covid-19 Severity and Mortality in Maintenance Haemodialysis Patients?

BACKGROUND AND AIMS

It has been demonstrated that online haemodiafiltration (HDF) provides higher clearance of middle molecular solutes compared with high-flux haemodialysis (HD) due to its convective component and may improve clinical outcomes in maintenance haemodialysis patients. However, the clinical superiority of HDF compared with standard HD is still controversial. Moreover, there is a general lack of these data on the current topic in patients infected with COVID-19. The present study aimed to prospectively analyze whether HDF has benefits for COVID-19 severity and mortality in maintenance haemodialysis patients.

METHOD

A total of 340 maintenance haemodialysis patients aged 53.5 ± 12.9 years and a median dialysis vintage of 40 (24–74) months were included in this prospective multicentre cohort study conducted across 5 dialysis centers. All patients were not infected with COVD-19 at the time of the enrollment and subsequently followed up from March 2020 to September 2021 (the mean duration was 7 (4.2–15.4) months). The study outcomes were COVID-19-associated hospitalization needs due to supplemental oxygen requirements and COVID-19-associated mortality.

The data were presented as the mean and the standard deviation (M ± SD) or the median and the interquartile ranges [Me (Q25–Q75)] and compared using the Student's t-test or the Mann–Whitney U-test as appropriate. The Chi-squared test was used to determine the differences between categorical variables. The univariate logistic regression analyses were performed to evaluate the predictive factors for COVID-19-associated severity and mortality. Then, the Cox proportional-hazards regression model was carried out using the factors found to be significant by the univariate analysis.

RESULTS

Among the enrolled patients, there were 312 (91.7%) patients on HDF and 28 (8.3%) patients treated with HD. Sex (χ² = 1.12 P = 0.29), age (55.3 ± 12.9 versus 59.6 ± 12.5 years; P = 0.07) and dialysis vintage [40 (23–72) versus 45 (29–84) months; P = 0.39] did not differ between the HDF and the HD groups at the study entry. During the follow-up period, 98 out of 312 (31.4%) of the HDF patients and 16 out of 28 (57.1%) of the HD patients were infected with COVID-19 (χ² = 9.6; P = 0.001). Among them, there were 54 out of 98 (55.1%) of the HDF patients and 12 out of 16 (75%) of the HD patients who required hospitalization with oxygen supplementation (χ² = 12.6; P = 0.0004). Out of 98, 4 (4.1%) of the HDF patients and 5 out of 16 (31.2%) of the HD patients died (χ2 = 31.3, P < 0.0001) during the follow-up period. In the univariate logistic regression analysis, older patient age {OR: 1.03, [95% confidence interval (95% CI) 1.01–1.05]}, diabetic status (OR: 2.8, 95% CI 1.4–5.5), long dialysis vintage (OR: 1.07, 95% CI 1.03–1.1), low blood flow (OR: 1.04, 95% CI 1.02–1.08) and HD treatment (OR: 4.1, 95% CI 1.5–11.2) were significantly associated with the requirement of oxygen supplementation. In the Cox regression model adjusted for all mentioned factors, HD treatment was significantly associated with COVID-19 severity and oxygen requirement (Figure 1). However, when we performed the same model to predict COVID-associated mortality, HD treatment lost its significance, and only patient age (P = 0.02) and dialysis vintage (P = 0.004) were significantly associated with reduced survival.

CONCLUSION

The HDF patients required fewer hospitalizations and oxygen support and had a lower mortality rate compared with the HD patients. Although HDF treatment versus HD treatment was significantly associated with better COVID-19 outcomes in our cohort, a predictive conclusion of the study was limited by the small sample size of the HD group and a relatively short follow-up period. Further large-scale studies are needed to determine the role of HDF versus HD in COVID-19-associated severity and mortality in maintenance haemodialysis patients.

MO825: Low High-Density Lipoprotein Level Predicts Covid-19 Severity and Mortality in Haemodialysis 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 <5% involvement, (2) indicating 5%–25% involvement, (3) indicating 26%–49% involvement, (4) indicating 50%–75% involvement and (5) indicating more >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 < 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.

High-density lipoproteins and clinical outcomes of COVID-19 in hemodialysis patients: A multicenter, propensity-score matched case-control study

Abstract. A decline in high-density lipoprotein (HDL) has been observed in the general population of COVID-19 infected patients. However, little research has been devoted to this topic in hemodialysis (HD) patients and there is a general lack of data on the association between the baseline HDL level and COVID-19 outcomes in HD patients. The present study aimed to assess the association between baseline HDL levels and the risk of developing severe outcomes of COVID-19 infection in HD patients. Methods. 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 multicenter propensity-score matched case-control study. After propensity-score matching (1 :1), 142 COVID-19 infected HD patients were compared with 142 HD patients who had never been infected with COVID-19. Propensity scores were estimated with MedCalc software based on potential confounding variables (age, diabetes, dialysis vintage and cardiovascular events). Baseline HDL levels were obtained from electronic health records of the patients (the last measurements were carried out before the COVID-19 onset). The endpoints of the study were COVID-19-related hospitalization, oxygen maintenance, and death. The data were presented as the median and the interquartile ranges [Me (Q25-Q75)] and compared using the Mann-Whitney or Kruskal-Wallis tests, as appropriate. The Spearmen correlation test was used to assess the association between HDL and other markers. The multivariate logistic regression and the receiver operating characteristic (ROC) analyses were performed to evaluate the ability of HDL for predicting the severity of COVID-19 infection. The Cox regression analysis was used to determine the association between HDL and COVID-19-associated mortality. Results. Among 142 patients infected with COVID-19, 40 patients (28%) patients were hospitalized, 34 patients (24%) needed oxygen supplements and 16 patients (11.3%) died. The baseline HDL level was significantly lower in the COVID-19 patients compared with the non-infected patients (1.22 (0.97-1.59) vs 1.52 (1.08-1.85) mmol/L, p = 0.011). Moreover, the baseline HDL level was significantly negatively associated with CT findings of pulmonary involvement (r = -0.76, p < 0.0001) and had a strong inverse correlation with serum C-reactive protein (r = -0.42, p = 0,0002) and D-dimer (r = -0.65, p < 0.0001). The multivariate logistic regression analysis demonstrated that HD patients with HDL concentration <1.22 mmol/l have 3 times higher risk of COVID-19 infection (OR 2.8; 95% CI 1.2; 6.5, p = 0.003).  In the Cox regression analysis adjusted for the patients’ age, diabetic status, dialysis vintage and cardiovascular events, low HDL level (<1.22 mmol/L) was found to be associated with COVID-19-related mortality in the HD patients (χ2 = 9.2, p = 0.002). Conclusions. Baseline low HDL-C level was independently associated with COVID-19 morbidity, severity and mortality in HD patients.