The use of intravascular contrast media in patients with impaired kidney function - joint clinical practice position statement of the Polish Society of Nephrology and the Polish Medical Society of Radiology.

Radiological procedures utilising intravascular contrast media (ICM) are fundamental to modern medicine, enhancing diagnostics and treatment in diverse medical fields. However, the application of ICM has been constrained in patients with compromised kidney function due to perceived nephrotoxic risks, called contrast-induced nephropathy or contrastinduced acute kidney injury. Historical evidence marked ICM as a possible contributor to kidney damage. This led to restrictive guidelines advocating limited ICM use in patients with impaired renal function, preventing crucial radiographic interventions in patients with acute kidney injury (AKI) and chronic kidney disease. Recent advances challenge these traditional views. In particular, no direct causal relationship has been confirmed between contrast admi-nistration and elevated serum creatinine concentrations in humans. Furthermore, contemporary research models and meta-analyses do not associate AKI with contrast usage. This paper, prepared by a cross-disciplinary team of nephrologists and radiologists, presents updated guidelines for ICM application amid renal function impairments, emphasising the reduced nephrotoxic risks currently understood and loosening the previous restrictive approach in patients with renal dysfunction.

The Role of Probiotics in the Prevention of Clostridioides difficile Infection in Patients with Chronic Kidney Disease.

In patients suffering from chronic kidney disease (CKD), substantial unfavourable alterations in the intestinal microbiota composition, i.e., dysbiosis, have been noted. The main causes of such dysbiosis among others are insufficient dietary fibre content in the diet, fluid restrictions, medications used, and physical activity limitation. One clinically important consequence of dysbiosis in CKD patients is high risk of Clostridioides difficile infection (CDI). In observational studies, it was found that CDI is more frequent in CKD patients than in the general population. This appears to be related to high hospitalization rate and more often antibiotic therapy use, leading up to the occurrence of dysbiosis. Therefore, the use of probiotics in CKD patients may avert changes in the intestinal microbiota, which is the major risk factor of CDI. The aim of this review paper is to summarize the actual knowledge concerning the use of probiotics in CDI prevention in CKD patients in the context of CDI prevention in the general population.

Lipid disorders before and after successful liver transplantation.

INTRODUCTION: Liver transplantation (LTx) is the only successful treatment for end-stage liver disease. The results of liver transplantation depend not only on graft survival but may be also affected by superimposed cardiovascular morbidities. The aim of this retrospective study was to assess the prevalence of lipid disorders as one of the important cardiovascular risk factors in patients before and after successful LTx. MATERIAL AND METHODS: One hundred eleven patients who underwent liver transplantation because of liver cirrhosis and survived at least 2 years with functioning graft between November 2005 and May 2014 were included in this retrospective analysis. The mean age of the patients at the time of liver transplantation was 49.7±12.2 years. The prevalence of dyslipidemia was assessed before and two years after liver transplantation. This was analyzed in relation to the etiology of liver disease, including alcohol toxicity, viral or autoimmune diseases. RESULTS: The prevalence of hypertriglyceridemia before and after LTx was 13.5% and 40.5%, respectively (P<0.001). Similarly, hypercholesterolemia was noted in 17.1% and 51.4% respectively (P<0.001). The annual incidence of hypertriglyceridemia and hypercholesterolemia during the first two years after LTx was 16.2% and 20.7%, respectively. The prevalence of hypertriglyceridemia (18.5% vs 66.7%, P<0.001) and hypercholesterolemia (29.6% vs 70.0%, P=0.002) was significantly lower in patients with the autoimmune cause of liver cirrhosis in comparison to patients with the alcoholic liver disease. CONCLUSIONS: The prevalence of dyslipidemia is increased after liver transplantation. The prevalence of dyslipidemia may be related to the cause of liver injury before LTx.

Hyponatremia in patients with arterial hypertension: pathophysiology and management.

Sodium is the main cation in the extracellular space. In physiological conditions, sodium concentration in plasma is 135-145 mmol/l. The kidneys play the most important role in the regulation of sodium homeostasis. In recent years, a significant role of glycosaminoglycans, localized mainly in the subcutaneous tissue, and the role of glycocalyx on the surface of vascular endothelial cells, have been documented in the regulation of sodium metabolism. Hyponatremia is defined by a plasma sodium concentration lower than 135 mmol/l. Hyponatremia significantly worsens the prognosis of patients with different chronic diseases. In patients with arterial hypertension, the risk of hyponatremia is 1.5 times higher than in the general population. One of the causes of hyponatremia in patients with arterial hypertension is the use of thiazide or thiazide-like diuretics. The symptoms of hyponatremia are caused mainly by the swelling of cells in the central nervous system. Treatment of hyponatremia depends on the degree and duration (acute or chronic) of hyponatremia as well as presence of clinical symptoms. Too rapid correction of hyponatremia might result in a potentially fatal osmotic demyelinating syndrome. In the present review paper, pathophysiology and management of hyponatremia in patients with arterial hypertension are discussed.

Pharmacological Nephroprotection in Non-Diabetic Chronic Kidney Disease-Clinical Practice Position Statement of the Polish Society of Nephrology.

Chronic kidney disease (CKD) is a modern epidemic worldwide. Introducing renin-angiotensin system (RAS) inhibitors (i.e., ACEi or ARB) not only as blood-pressure-lowering agents, but also as nephroprotective drugs with antiproteinuric potential was a milestone in the therapy of CKD. For decades, this treatment remained the only proven strategy to slow down CKD progression. This situation changed some years ago primarily due to the introduction of drugs designed to treat diabetes that turned into nephroprotective strategies not only in diabetic kidney disease, but also in CKD unrelated to diabetes. In addition, several drugs emerged that precisely target the pathogenetic mechanisms of particular kidney diseases. Finally, the role of metabolic acidosis in CKD progression (and not only the sequelae of CKD) came to light. In this review, we aim to comprehensively discuss all relevant therapies that slow down the progression of non-diabetic kidney disease, including the lowering of blood pressure, through the nephroprotective effects of ACEi/ARB and spironolactone independent from BP lowering, as well as the role of sodium-glucose co-transporter type 2 inhibitors, acidosis correction and disease-specific treatment strategies. We also briefly address the therapies that attempt to slow down the progression of CKD, which did not confirm this effect. We are convinced that our in-depth review with practical statements on multiple aspects of treatment offered to non-diabetic CKD fills the existing gap in the available literature. We believe that it may help clinicians who take care of CKD patients in their practice. Finally, we propose the strategy that should be implemented in most non-diabetic CKD patients to prevent disease progression.

Diagnosis of cardiovascular disease in patients with chronic kidney disease.

Patients with chronic kidney disease (CKD) are at high risk of cardiovascular disease (CVD) and cardiovascular death. Identifying and monitoring cardiovascular complications and hypertension is important for managing patients with CKD or kidney failure and transplant recipients. Biomarkers of myocardial ischaemia, such as troponins and electrocardiography (ECG), have limited utility for diagnosing cardiac ischaemia in patients with advanced CKD. Dobutamine stress echocardiography, myocardial perfusion scintigraphy and dipyridamole stress testing can be used to detect coronary disease in these patients. Left ventricular hypertrophy and left ventricular dysfunction can be detected and monitored using various techniques with differing complexity and cost, including ECG, echocardiography, nuclear magnetic resonance, CT and myocardial scintigraphy. Atrial fibrillation and other major arrhythmias are common in all stages of CKD, and ambulatory heart rhythm monitoring enables precise time profiling of these disorders. Screening for cerebrovascular disease is only indicated in asymptomatic patients with autosomal dominant polycystic kidney disease. Standardized blood pressure is recommended for hypertension diagnosis and treatment monitoring and can be complemented by ambulatory blood pressure monitoring. Judicious use of these diagnostic techniques may assist clinicians in detecting the whole range of cardiovascular alterations in patients with CKD and enable timely treatment of CVD in this high-risk population.

Cardiovascular complications in chronic kidney disease: a review from the European Renal and Cardiovascular Medicine Working Group of the European Renal Association.

Chronic kidney disease (CKD) is classified into five stages with kidney failure being the most severe stage (stage G5). CKD conveys a high risk for coronary artery disease, heart failure, arrhythmias, and sudden cardiac death. Cardiovascular complications are the most common causes of death in patients with kidney failure (stage G5) who are maintained on regular dialysis treatment. Because of the high death rate attributable to cardiovascular (CV) disease, most patients with progressive CKD die before reaching kidney failure. Classical risk factors implicated in CV disease are involved in the early stages of CKD. In intermediate and late stages, non-traditional risk factors, including iso-osmotic and non-osmotic sodium retention, volume expansion, anaemia, inflammation, malnutrition, sympathetic overactivity, mineral bone disorders, accumulation of a class of endogenous compounds called 'uremic toxins', and a variety of hormonal disorders are the main factors that accelerate the progression of CV disease in these patients. Arterial disease in CKD patients is characterized by an almost unique propensity to calcification and vascular stiffness. Left ventricular hypertrophy, a major risk factor for heart failure, occurs early in CKD and reaches a prevalence of 70-80% in patients with kidney failure. Recent clinical trials have shown the potential benefits of hypoxia-inducible factor prolyl hydroxylase inhibitors, especially as an oral agent in CKD patients. Likewise, the value of proactively administered intravenous iron for safely treating anaemia in dialysis patients has been shown. Sodium/glucose cotransporter-2 inhibitors are now fully emerged as a class of drugs that substantially reduces the risk for CV complications in patients who are already being treated with adequate doses of inhibitors of the renin-angiotensin system. Concerted efforts are being made by major scientific societies to advance basic and clinical research on CV disease in patients with CKD, a research area that remains insufficiently explored.

Nephro-oncology: clinical and biochemical aspects of kidney disease and cancer.

Onco-nephrology is a new field of medicine which combines many aspects of kidney injury in cancer patients and cancers in patients with kidney disease. This connection takes many forms and includes drug-induced nephrotoxicity, electrolyte disorders, numerous paraneoplastic syndromes and an increased rate cancers in dialysis and transplanted patients. The appropriate laboratory assessment of the kidney function allows to optimize chemotherapy and thus minimizes the risk of complications. This article focuses on acute kidney injury (AKI), chronic kidney disease (CKD), various electrolyte and acid-base disorders, the most common cancers after kidney transplantation and the kidney disorders associated with HSCT (hematopoietic stem cell transplantation). The possibility of the application of novel cancer therapy, such as cancer immunotherapy and proton therapy in transplant recipients was also discussed.

Effect of Renal Denervation on the Plasma Adiponectin Concentration in Patients with Resistant Hypertension.

(1) Introduction: Adiponectin is synthetized by white adipose tissue and has anti-diabetic, anti-atherosclerotic, anti-thrombotic, anti-inflammatory, and cardioprotective properties. In patients with arterial hypertension, plasma concentration of adiponectin is lower than in healthy subjects. Renal denervation, i.e., percutaneous ablation of fibers from the sympathetic nervous system located in the wall of the renal arteries by radio frequency waves, is a method of resistant arterial hypertension treatment. (2) The aim of this single center, interventional, clinical study was to assess the effect of renal denervation on the plasma adiponectin concentration in patients with resistant arterial hypertension. (3) Materials and methods: 28 patients (13 women, 15 men) aged 54.4 ± 9.2 years with resistant hypertension who underwent renal denervation using Simplicity catheters (Medtronic, Inc., Northridge, CA, USA) were enrolled in the study. Plasma adiponectin concentration was determined using the Human Adiponectin ELISA Kit (Otsuka Pharmaceutical Co, Tokyo, Japan) before the renal denervation and 6 and 12 months after this procedure. (4) Results: Blood pressure (BP) values before renal denervation and 6 and 12 months after this procedure were as follows: systolic BP 190.4 ± 24.5, 160.8 ± 14.5, 155.7 ± 17.9 mmHg (p < 0.001) and diastolic BP 111.7 ± 18.9, 88.9 ± 8.3, 91.2 + 10.2 mmHg (p < 0.001), respectively. Body mass index (BMI) before renal denervation, 6 and 12 months after this procedure were 31.5 ± 4.2, 30.5 ± 4.4, 30.2 ± 4.0 kg/m2, (p = 0.057), respectively. Plasma adiponectin concentration before the renal denervation and 6 and 12 months after this procedure were 4.79 (3.95; 9.49), 7.58 (5.04; 9.51), 6.62 (4.57; 11.65) [µg/mL] (p = 0.007), respectively. (5) Conclusions: Plasma adiponectin concentration increases significantly after successful renal denervation in patients with resistant hypertension. Higher plasma adiponectin concentration may participate-beyond blood pressure reduction-in the cardiovascular benefits related to successful renal denervation; however' clinical consequences of these results need further investigations.

Cardiovascular Risk Factors in Patients Before and After Successful Liver Transplantation.

BACKGROUND Liver transplantation (LTx) is useful in the treatment of end-stage liver disease. Outcomes of transplantation are dependent upon graft survival and can also be affected by superimposed cardiovascular morbidities. The present retrospective study was performed to assess the prevalence of cardiovascular risk factors before and after LTx. MATERIAL AND METHODS A retrospective review of 130 patients undergoing liver transplantation between October 2005 and April 2014 was completed. The mean age of the patients was 49.3±11.9 years. The prevalence of cardiovascular risk factors was assessed before and 2 years after transplantation. The prevalence of cardiovascular risk factors was assessed using a comparison based upon the etiologies of liver disease resulting in transplantation including alcohol, viral, and autoimmune processes using a chi-square analysis. RESULTS The prevalence of diabetes mellitus before and 2 years after liver transplantation (LTx) were 18% and 48% (P<0.001). Hypertension was documented in 24% of patients at baseline and 70% after 2 years of follow-up (P<0.001). The prevalence rates of diabetes mellitus before and 2 years after LTx were 18% and 48% (P<0.001). The prevalence of hypertriglyceridemia before and after LTx was 15% and 38%, respectively (P<0.001). Hypercholesterolemia was noted in 16% and 46%, respectively (P<0.001). Thirteen percent of patients before LTx and 18% after were obese (body mass index higher than 30 kg/m²). The annual incidence of diabetes mellitus, hypertension, hypertriglyceridemia, hypercholesterolemia, and obesity during the first 2 years after LTx was 15%, 23.5%, 15%, 18.5%, and 6%, respectively. Twenty-four percent of patients before and 10% after LTx admitted to tobacco use (P<0.001). The prevalence of diabetes (38% vs 67%, P=0.02), hypertriglyceridemia (19% vs 63%, P<0.001), hypercholesterolemia (28% vs 67%, P=0.002), and obesity (9% vs 33%, P=0.02) was lower in patients with an autoimmune cause of liver cirrhosis in comparison to patients with alcoholic disease. CONCLUSIONS The prevalence of hypertension and glucose and lipid metabolism abnormalities may increase in patients after liver transplantation. The prevalence of cardiovascular risk factors in patients after LTx may be related to the cause of liver injury before LTx.

Clostridioides difficile Infection in Patients after Organ Transplantation-A Narrative Overview.

Clostridioides difficile infection (CDI) is one of the most common causes of antibiotic-associated diarrhea. The pathogenesis of this infection participates in the unstable colonization of the intestines with the physiological microbiota. Solid-organ-transplant (SOT) patients and patients after hematopoietic stem cell transplantation are more prone to CDI compared to the general population. The main CDI risk factors in these patients are immunosuppressive therapy and frequent antibiotic use leading to dysbiosis. The current review article provides information about the risk factors, incidence and course of CDI in patients after liver, kidney, heart and lung transplantation and hematopoietic stem cell transplantation.

Impaired fertility in women and men with chronic kidney disease.

Chronic kidney disease (CKD) is accompanied by a great number of comorbidities. One of the most clinically important, present in women as well as in men, is infertility. In this review paper, the entire issue of impaired fertility in women and men with CKD is discussed. In both genders, impaired fertility is caused by the interconnection of several factors. In women, these are as follows: the accumulation of uremic toxins; endocrine disorders (e.g., reduced renal clearance of different hormones, disturbed activity of the pituitary-gonadal axis); the impairment of the ovarian function; a reduced ovarian reserve; sexual function disorders; and depression. In men, quite similarly: the accumulation of uremic toxins; endocrine disorders; the impairment of spermatogenesis; direct testicular damage; erectile dysfunction (ED); and depression. The prevalence of impaired fertility increases with the degree of kidney function deterioration in women and men. The highest prevalence of these disturbances is observed in patients with CKD stage 5. Successful kidney transplantation (KTx) in women reduces the accumulation of uremic toxins, restores the function of the endocrine system and improves, but does not normalize, fertility. Similarly in men, KTx restores the function of the endocrine system and improves fertility up to a point, but cannot fully reverse the morphological damage already done to the gonads by the uremia itself. Infertility is one of the important, yet sometimes depreciated complications in women and men with CKD. The etiology and pathogenesis of infertility in CKD is complicated. Kidney transplantation alleviates, but does not fully reverse fertility impairment in CKD patients.

Acute kidney injury in patients with COVID-19: Epidemiology, pathogenesis and treatment.

Acute kidney injury occurs in about 30% of patients hospitalized with coronavirus disease 2019 (COVID-19) and is one of the most common extrapulmonary complications of this disease. The highest risk of acute kidney injury is found in hospitalized patients who require mechanical ventilation. The pathogenesis of acute kidney injury in COVID-19 is multifactorial and seems to not be fully understood. Both direct and indirect mechanisms of kidney injury caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) should be considered. The histological picture of kidney specimens obtained from patients with acute kidney injury in the course of COVID-19 is dominated by acute tubular necrosis. Some patients also have acute interstitial nephritis, blood clots in the kidney vessels and focal segmental glomerulosclerosis (the variant with collapsing vascular loops). Acute kidney injury in COVID-19 is primarily caused not by direct viral effect, but by indirect pathophysiological mechanisms. The histopathological findings in these patients does not differ from the majority of the other patients with acute kidney injury. The main pathophysiological mechanisms underlying acute kidney injury in COVID-19 are: hemodynamic abnormalities, hypoxia and cytokine storm. The methods of treating the underlying disease, i.e., COVID-19 in patients with acute kidney injury and those without acute kidney injury are similar. However, it should be stressed that in the treatment of COVID-19 accompanied by acute kidney injury, the contraindication to remdesivir is estimated using glomerular filtration rate (eGFR) <30 mL/min/1.73 m2. The general principles of management in patients with both, COVID-19 and acute kidney injury do not differ from the principles of management in patients with acute kidney injury due to the other causes.

Metabolic Acidosis in Patients with CKD: Epidemiology, Pathogenesis, and Treatment.

BACKGROUND: Metabolic acidosis in CKD is diagnosed in patients with plasma or venous blood bicarbonate concentration lower than 22 mmol/L. Metabolic acidosis occurs in about 20% of patients with CKD. Metabolic acidosis may lead to dysfunction of many systems and organs as well as CKD progression. Currently, sodium bicarbonate is mainly used for pharmacological treatment of metabolic acidosis in patients with CKD. Veverimer is a new drug dedicated to treatment of metabolic acidosis in patients with CKD. Orally given veverimer binds hydrogen ions in the intestines and subsequently is excreted from the body with feces. Clinical studies have shown that veverimer is effective in increasing serum bicarbonate concentrations in CKD patients with metabolic acidosis. Here, we present review of the epidemiology, pathogenesis, diagnosis, treatment, and prevention of metabolic acidosis in CKD patients. SUMMARY: Metabolic acidosis is common in patients with CKD and contributes to CKD progression and many complications, which worsen the prognosis in these patients. Currently, sodium bicarbonate is mainly used in metabolic acidosis treatment. The role of the new drug veverimer in the metabolic acidosis therapy needs further studies. KEY MESSAGE: The aim of this review article is to summarize the current knowledge concerning the epidemiology, pathogenesis, diagnosis, treatment, and prevention of metabolic acidosis in CKD patients.

Difficulties in the diagnostics of chronic hyponatremia based on the case study of a 66-year old female patient during antihypertensive therapy.

Clinical consequences of hyponatremia might be serious. It is often related to the administration of diuretics, especially thiazide and thiazide-like diuretics. It is known that elderly subjects are prone to thiazide induced hyponatremia (TIH). A CASE REPORT: A 66-year old female patient was admitted to our Department. The aim of the admission was to complete a differential diagnosis of chronic hyponatremia. For about two years the patient had suffered from the following symptoms: severe headaches, fatigue, episodic mental confusions, stomachaches, and diarrhea. Before admission to the hospital, the patient was treated with bisoprolol, amlodipine, telmisartan, indapamide, furosemide, acetylsalicylic acid, thiamazole, and zolpidem. The general clinical picture might suggest that the cause of hyponatremia was the indapamide diuretic therapy. However, only moderate hyponatremia, normokalemia, as well as, an increased antidiuretic hormone serum concentration were observed. These findings are not typical for TIH. Despite those findings, natremia improved after the cessation of indapamide therapy. CONCLUSIONS: This case report described the atypical presentation of TIH resembling SIADH. TIH diagnosis should be primarily based on the improvement of hyponatremia after the termination of thiazide or thiazide-like diuretic treatment.

Serum testosterone concentrations in male patients with end-stage kidney disease treated with haemodialysis.

INTRODUCTION: Testosterone deficiency is frequently found in male patients with chronic kidney disease (CKD) and may participate in the pathogenesis of osteoporosis, sarcopaenia, anaemia, impotence, infertility, and other comorbidities observed in these patients. The aim of the study was the evaluation of the frequency of testosterone deficiency in male patients with CKD on maintenance haemodialysis (HD). MATERIAL AND METHODS: In 79 male HD patients, serum total (TT), free (FT) testosterone, C-reactive protein (CRP), and interleukin 6 (IL-6) serum concentrations were assessed before an HD procedure. Patients were divided into three subgroups based on age categories: 19-39 years (18 patients), 40-59 years (34 patients), and ≥ 60 years (27 patients). TT insufficiency and deficiency were diagnosed when the serum TT concentration was below 4.0 ng/mL and 2.9 ng/mL, respectively. FT deficiency was diagnosed in patients with serum FT concentration below 8.9, 6.6, and 4.9 pg/mL in the abovementioned age subgroups, respectively. RESULTS: In the abovementioned age subgroups the serum TT concentration was 5.9 (4.6-7.1), 4.8 (3.9-5.4), and 4.6 (3.9-5.3) ng/mL, respectively. The serum FT concentration was 7.9 (5.2-10.1), 6.1 (5.1-7.2), and 6.0 (5.0-7.1) pg/mL, respectively. In the whole group TT insufficiency was found in 40%, TT deficiency in 15% of patients, and FT deficiency in 50% of patients. Significant negative correlations were found between both serum TT and FT concentrations and age (r = -0.23, p = 0.05 and r = -0.27, p = 0.02, respectively). Additionally, negative correlations were found between both serum TT and FT and IL-6 concentrations (r = -0.43, p < 0.05 and r = -0.29, p < 0.05), respectively. CONCLUSIONS: 1. Testosterone deficiency is common in male patients with chronic kidney disease treated with HD. 2. In HD patients the serum testosterone concentration decreases with age. 3. Chronic inflammation may participate in the pathogenesis of testosterone deficiency in haemodialysis patients.

Prevalence of hypokalemia in older persons: results from the PolSenior national survey.

PURPOSE: Hypokalemia is one of the most common electrolyte disturbances in clinical practice. There are only a few epidemiological studies analyzing the occurrence of hypokalemia in older persons. The aim of the study was to determine the prevalence of hypokalemia in the Polish older population. METHODS: Serum potassium concentration was estimated in 4654 participants (2270 females and 2384 males, mean age 76.5 [11.0] years), who participated in the PolSenior study. Hypokalemia was defined as serum potassium concentration below 3.5 mmol/L. Hypokalemia was found in 39 participants (0.84%) and was significantly more frequent among females (28 females = 1.23% and 11 males = 0.46%; p = 0.003). The prevalence of hypokalemia was not related to age. Among 3303 participants suffering from arterial hypertension, 1093 were treated with potassium-losing diuretics. RESULTS: Hypokalemia was significantly more frequent among hypertensive than normotensive older participants (1.06 vs. 0.30% respectively; p = 0.007) and among hypertensive participants treated with potassium losing diuretics than ones untreated with these drugs (1.96 vs. 0.46% respectively; p < 0.001). In hypertensive participants, the prevalence of hypokalemia did not depend significantly on oral supplementation of potassium (1.92 and 0.98% respectively, NS). None of 81 participants using laxative agents presented hypokalemia. CONCLUSIONS: This study demonstrates that: older age seems not to appear to be a significant risk factor of hypokalemia. Hypokalemia is more often found in the older hypertensive patients treated with potassium losing diuretics, and prevention of diuretic-induced hypokalemia with oral supplementation of potassium seems to be insufficient.

Clostridioides difficile Infection in Chronic Kidney Disease-An Overview for Clinicians.

Increased incidence of Clostridioides difficile infection (CDI), occurrence of severe and complicated CDI, and more frequent occurrence of drug-resistant, recurrent or non-hospital CDI has become a worldwide clinical problem. CDI is more common in patients with chronic kidney disease (CKD) than in the general population. CDI seems to be associated with frequent hospitalization, frequently used antibiotic therapy, dysbiosis, and abnormalities of the immune system observed in CKD patients. Dysbiosis is a common disorder found in CKD patients. It may be related to insufficient fiber content in the diet, reduced amount of consumed fluids and often reduced physical activity, constipation, impaired gastrointestinal motility, multidrug pharmacotherapy, and uremic milieu in CKD stage 5. In patients with CKD the clinical manifestations of CDI are similar to the general population; however, more frequent recurrence of CDI and higher prevalence of severe CDI are reported. Moreover, the increase in CDI related mortality is observed more in CKD patients than in the general population. The aim of this review paper is to summarize the current knowledge concerning the epidemiology, pathogenesis, clinical picture, and prevention and treatment in CKD patients.

The Prevalence of Metabolic Acidosis in Patients with Different Stages of Chronic Kidney Disease: Single-Centre Study.

BACKGROUND: Metabolic acidosis (MA) is one of the most common consequences of CKD. MA is also a risk factor of CKD progression and increased mortality in these patients. AIM: The aim of this retrospective, cross-sectional study was to assess the prevalence of MA in different stages of CKD and renal replacement therapy (RRT) modalities - haemodialysis (HD) and peritoneal dialysis (PD). Additionally, the relationship between the prevalence of MA and aetiology of kidney disease was analysed. METHODS: One thousand five patients in different stages of CKD, or modalities of RRT were enrolled into this single-centre cross-sectional study. Forty-one patients were ruled out because of oral bicarbonate supplementation. In the remaining 964 patients (698 CKD stages 1-5, 226 HD, 40 PD), venous blood HCO3- concentration, as well as serum Cr and urea concentrations were assessed. MA was diagnosed when blood HCO3- concentration was below 22 mmol/L. RESULTS: The prevalence of MA increased among all stages of CKD. Patients on HD had lower prevalence of MA in comparison with CKD 5 patients with no RRT (38.5 vs. 56.0%; p = 0.02) In PD patients, the prevalence of MA was significantly lower than in HD patients (2.5 vs. 38.5%; p < 0.001). In the whole study group, there were no significant differences in the prevalence of MA between different aetiologies of CKD (glomerulonephritis 24%, hypertension 23%, diabetes 25%, and tubule-interstitial diseases 24%). Also, when only patients in stages CKD 3-5 were compared, no significant differences in the prevalence of acidosis were found (glomerulonephritis 28%, hypertension 22%, diabetes 24%, and tubule-interstitial 21%). CONCLUSIONS: (1) MA is more frequent in patients with more advanced stages of CKD. (2) RRT reduces the prevalence of MA. (3) In PD patients, MA is rare. (4) Aetiology of CKD seems not to have a significant impact on MA prevalence.

Is Metabolic Acidosis a Novel Risk Factor for a Long-Term Graft Survival in Patients after Kidney Transplantation?

BACKGROUND: Results of both experimental and clinical studies suggest that metabolic acidosis (MA) contributes to the progression of chronic kidney disease (CKD) and mortality in CKD patients. It is unknown whether the same relationship exists in kidney transplantation (KTx) patients. The aim of this observational study was to examine this relationship between MA and both mortality and renal outcomes in patients after KTx. METHODS: Four hundred eighty-six (290 male; 196 female) patients aged 48 ± 12 years, at least 1 year after KTx, were analyzed. Blood HCO3- was measured, and patients were then observed over 3 years. MA was defined as the blood HCO3- concentration <22 mmol/L. The end points of survival analysis were death and initiation of dialysis therapy. In patients who did not reach the above-mentioned end points, the difference between final (after 3 years of follow-up) and initial estimated glomerular filtration rate (eGFR) was calculated. RESULTS: MA was initially diagnosed in 57 (12%) patients after KTx. Three-year patient survival was 89.5% in the MA group and 97.4% in the non-MA group (p = 0.001). Three-year graft survival was 73.7% for patients with MA and 93.0% for patients without MA (p < 0.001). In patients with MA who did not reach study end points, blood bicarbonate concentration at baseline correlated positively with a change in eGFR (R = 0.48, p = 0.002, n = 36). Such a correlation was not found in patients without MA (n = 388). CONCLUSIONS: (1) MA significantly increases the risk of mortality in patients after KTx. (2) The intensity of MA may be associated with progression of transplanted kidney dysfunction in KTx patients.