The aim of this work was to perform a comparative analysis of the prevalence and clinical and laboratory features of the course of COVID-19 infection in patients with end-stage chronic kidney disease receiving kidney replacement therapy (KRT). Methods. A retrospective analysis of 73 medical records of patients undergoing KRT and infected COVID-19 between January 1, 2021 and December 31, 2021. The patients were divided into two groups. The first group consisted of 54 hemodialysis (HD) patients, and the second group included 19 peritoneal dialysis (PD) patients. Routine clinical and laboratory characteristics, morbidity, and mortality of COVID-19 depending on KRT modality were analysed. Results. The overall prevalence of COVID-19 was 37.63%. Mortality in this cohort of patients was 19.07%, and mortality associated with COVID-19 was 6.19%. Despite the predominance of COVID-19-associated morbidity in HD patients (46.55% vs. 24.36%, p = 0.05), mortality was not statistically significantly different between the studied groups (26.32% in PD patients vs. 12.96% in HD patients, p = 0.17). HD patients had more severe lung injury as measured by SpO2 (p=0.18) and CT (p=0.003), while PD patients had lower hemoglobin (p=0.001), platelet (p=0.001), total protein (p<0.001), and albumin (p<0.001) levels. A direct correlation was found between the percentage of lung injury according to the CT data and the leukocyte count in both the HD (r = 0.24) and PD (r = 0.56) groups. In addition, an inverse correlation between leukocyte and SpO2 values and between the percentage of lung injury according to the CT data and SpO2 indicators was found in the HD (r = -0.51 and r = -0.66) and PD (r = -0.47 and r = -0.63) groups, respectively. Conclusions. The results of our study are in complete agreement with published data and show the same COVID-19-associated mortality in HD and PD patients, with a statistically significantly higher prevalence of COVID-19 in HD patients. The course of COVID-19 in HD patients is characterized by more severe lung injury compared to PD patients, while PD patients had more pronounced anemia and significantly lower platelet, total protein, and blood albumin concentrations.

Microscopic polyangiitis (MPA) is one of the three clinical phenotypes of vasculitis associated with antineutrophil cytoplasmic antibodies (ANCA). Although MPA is considered a rare form of ANCA-associated vasculitis (AAV), clinical evidence shows that it is fairly common among nephrologists, as it manifests as a systemic, weak-immune vasculitis affecting glomerular capillaries, resulting in necrotizing glomerulonephritis (GN) diagnosed in nearly 100% of MPA patients. The issue of AAV in general, and MPA specifically, has gained significant importance in the context of the ongoing SARS-CoV-2 coronavirus pandemic, as both conditions share common anatomical sites of infection and inflammation. This study presents three new cases of MPA in post-COVID-19 patients. The analysis and presentation encompassed demographic data, patient history regarding comorbidities, details of follow-up care, chronology with COVID-19, and laboratory findings at the time of MPA diagnosis. A comparative analysis of the chronological progression of MPA in the documented clinical cases reveals the polymorphic nature of early-stage clinical manifestations, as well as diverse patterns of disease progression in the advanced stage. Additionally, we provide a brief literature review on diagnostic challenges, pathogenetic mechanisms underlying the relationship between SARS-CoV-2 and AAV, and peculiarities of clinical presentations in early and advanced stages of MPA.

The review describes the problem of studying progressive changes of hormones concentrations (parathyroid hormone, insulin, somatotropin, prolactin) in patients with chronic renal failure on the pre-dialysis and dialysis stages. The pathogenetic relationships between kidney function deterioration and hormone concentrations as well as changes of their biological effects were evaluated. Parathyroid hormone is considered as an uraemic toxin, since its concentration in the blood begins to increase when the glomerular filtration rate decreases below 50 ml/min. All stages of chronic kidney disease are accompanied by disorders of calcium-phosphorus metabolism. Prolonged excess of parathyroid hormone leads to bone loss and to the progression to secondary hyperparathyroidism that is a frequent complication in patients with the later stages of chronic renal failure and, especially, in those on dialysis treatment. The elevation of insulin level in chronic renal failure is the consequence of progressive decrease in glomerular filtration rate and insulin excretion by proximal tubules. So, it results in insulin half-life prolongation. Long-term dialysis therapy eliminates factors that reduce the degradation of insulin by extrarenal tissues, which results in an improvement of their insulin sensitivity. Experimental and clinical studies have shown that an excess of somatotropin can adversely affect the kidneys that leads to glomerular hyperfiltration and the progression to glomerulosclerosis. The risk of possible side effects on kidneys should be taken into account when prescribing recombinant human insulin-like growth factor. The prolactin concentration is usually increased in chronic kidney disease due to reduced clearance and increased secretion. Hyperprolactinemia manifests as galactorrhea and hypogonadism. Dialysis therapy can’t normalize the increased concentration of prolactin. Modern options for pathogenetic treatment of endocrine disorders in patients with chronic renal failure are outlined in this article. It was found that kidneys play an important role in regulating hormones concentrations in the blood. Endocrine disorders are one of the most important components of the uraemic syndrome, which requires further clinical studies, aimed on the searching of better treatment strategies and prevention of hormonal imbalance on the pre-dialysis and dialysis stages of chronic kidney disease.

In the previous article, we presented the results of literature review showing the changes in hormone concentrations (parathyroid hormone, insulin, growth factor, prolactin) in patients with chronic renal failure (CRF) at the pre-dialysis and dialysis stages, described pathological relationships between renal failure and serum hormones concentrations, as well as changes in their biological effects. In this article, that continues the general topic, we provide the results of literature review that shows changes in serum concentrations of thyroid, adrenal, sex hormones and the features of the functioning of hypothalamus-pituitary-peripheral glands axis in patients with CRF. The presence of close pathogenic interactions of renal functional condition with hormonal activity of the thyroid gland was evaluated, as well as the ability of thyroid gland to influence the CRF progression both during pre-dialysis and dialysis sta­ges of CRF. Most patients with CRF have low serum triiodothyronine and thyroxine levels. It means that CRF is a pathological condition associated with thyroid hypofunction that progressively worsening as glomerular filtration rate decreases. For patients receiving dialysis treatment, hypothyroidism is associated with higher mortality. Secondary adrenal insufficiency is usually progresses in patients on renal replacement therapy. Non-diagnosed chronic adrenal failure may be life-threating that’s why the analysis of adrenal function is especially actual for patients on both pre-­dialysis and dialysis stages of CRF. Secondary adrenal insufficiency caused by long-lasting treatment with corticoids is a diagnostic problem for patients on dialysis treatment, because many nephrological diseases are treated by corticoids, and immunosuppressive therapy protocols used after the kidney transplantation are usually include prednisone. As the endocrine dysfunction progresses in patients with CRF, sexual dysfunction develops due to sex hormone imbalance. Abnormal androgen concentration is a typical fin­ding in CRF. A negative correlation was found between endogenic testosterone concentration and CRF stages I–V that indicated an abnormal profile of male sex hormones. There are gender-specific features of the development and progression of clinical symptoms of hormonal imbalance. The number of experimental studies show that continuous estradiol treatment may prevent the development of glomerulosclerosis. The results of clinical trials concluded that lower CRF progression and the lower incidence of CRF observed in young females compared to males, as well as the absence of gender protection in post-menopausal period, shows the important role of female sex hormones.