Erythropoietin resistance index and erythropoiesis stimulating agents use in haemodialysis patients with previous SARS-CoV-2 infection

The SARS-CoV-2 virus, the agent of the infectious disease COVID -19 infected about 600 million people and killed more than 7 million. This virus did not take long to spread among the most susceptible patients, including patients with Chronic Kidney Disease (CKD). CKD is a common medical problem affecting millions of people worldwide. According to the Global Burden of Disease Survey data, about 9.1% of the world's population is affected by CKD. People with CKD have an altered immune system and are more susceptible to infections, which are worse compared to the general population. Among people with CKD, haemodialysis (HD) patients are a particularly susceptible target group for the virus. Up to 37% of HD patients are at high risk of developing SARS-CoV-2, with a high percentage of hospitalization risk and fatal outcomes than the overall population . HD patients are highly susceptible to infection because they have a number of risk factors that make them the perfect "target" for the virus: a possibly advanced age, a high degree of comorbidity, possible immunosuppressive therapy, the use of "collective" transport ” to reach dialysis centres, and sharing a close environment with other patients and healthcare workers during HD treatment are just some of the many factors responsible for their higher susceptibility to infection risk. In addition, several studies show that these patients are more prone to develop a moderately severe form of the disease, which entails a higher need for intensive treatment and a higher mortality rate compared to the general population. Moreover, patients with a past infection exhibit symptoms such as prolonged asthenia, muscular weakness, broad discomfort, and decline in subjective health status even after remission. A common feature of both HD and COVID-19 patients is a higher susceptibility of anemia. A common feature of HD and COVID-19 patients is a higher susceptibility to anaemia and a compromised iron metabolism . In an observational study of 11,265 COVID 19 patients elevated D-dimer was linked to lower mean Haemoglobin (Hb) and greater serum ferritin. This also applies to patients with AKI and those who are on dialysis . Although the precise processes of COVID 19 are not fully understood, individuals with severe COVID 19 frequently have a prothrombotic state and an extensive inflammatory phase. Erythropoietin-Stimulating drugs (ESA) effectiveness in these situations is matter of debat. In presence of COVID 19 infection, some authors advised continuing ESA treatment at the same posology but with a lower Hb target (Hb 8–9 g/dL) in the case of maintenance dialysis . Another aspect that should be considered is that systemic inflammatory reactions, such as those that occur in severe COVID 19, limit iron availability in the case of iron supplementation. Iron is also necessary for viral replication . Patients with iron excess and viral infections have a poor prognosis. Consequently, limiting iron supplementation may be beneficial for patients with severe COVID 19, although further research is needed to clarify this point . More authors proposed to promote trials to study the administration of EPO in severe cases COVID-19 . The aim of this study was to investigate the anaemia parameters and changes in the erythropoietin resistance index (ERI) in HD patients with previous SARS-CoV-2 virus infection.