COVID - 19 in two dialysis centers situated in two neighbouring states of the Western Balkans.

BACKGROUND: Bosnia and Herzegovina (BiH) and Serbia are countries in the Western Balkans that share parts of their social and political legacy from the former Yugoslavia, such as their health care system and the fact that they are not members of European Union. There are very scarce data on COVID - 19 pandemic from this region when compared to other parts of the world and even less is known about its impact on the provision of renal care or differences between countries in the Western Balkans. MATERIALS AND METHODS: This observational prospective study was conducted in two regional renal centres in BiH and Serbia, during the COVID - 19 pandemic. We obtained demographic and epidemiological data, clinical course and outcomes of dialysis and transplant patients with COVID - 19 in both units. Data were collected a via questionnaire for two consecutive time periods: February - June 2020 with a total number of 767 dialysis and transplant patients in the two centres, and July - December 2020 with a total number of 749 studied patients, corresponding to two of the largest waves of the pandemic in our region. Departmental policies and infection control measures in both units were also recorded and compared. RESULTS: For a period of 11 months, from February to December 2020, 82 patients on in-centre haemodialysis (ICHD), 11 peritoneal dialysis patients and 25 transplant patients who tested positive for COVID-19. In the first study period, the incidence of COVID - 19 positive in Tuzla was 1.3% among ICHD patients, and there were no positive peritoneal dialysis patients, or any transplant patients who tested positive. The incidence of COVID-19 was significantly higher in both centres in the second time period, which corresponds to the incidence in general population. Total deaths of COVID-19 positive patients was 0% in Tuzla and 45.5% in Nis during first, and 16.7% in Tuzla and 23.4% in Nis during the second period. There were notable differences in the national and local/departmental approach to the pandemic between the two centres. CONCLUSION: There was poor survival overall when compared to other regions of Europe. We suggest that this reflects the lack of preparedness of both of our medical systems for such situations. In addition, we describe important differences in outcome between the two centres. We emphasize the importance of preventative measures and infection control and highlight the importance of preparedness.

Risk factors for urosepsis in chronic kidney disease patients with urinary tract infections.

Occurrence of urosepsis is not uncommon following urinary tract infections (UTI). However, there is a lack of evidence explaining the risk factors predisposing to urosepsis in patients with chronic kidney disease (CKD). This retrospective study was undertaken to evaluate the incidence and possible risk factors for urosepsis among patients hospitalized with UTI in a cohort of CKD patients. Patients were divided into the urosepsis group and the non-urosepsis group. Of 489 hospitalized patients with UTI, 70 (14.3%) acquired urosepsis. Stepwise multivariate logistic regression demonstrated that diabetes, urinary catheter and length of hospital stay (p < 0.001 for all) were significant independent predictive risk factors for urosepsis in CKD patients with UTI in addition to age, glomerular filtration rate, hydronephrosis, acute kidney injury and E. coli infection (p < 0.05 for all). Finally, Klebsiella spp. cases were associated with significantly higher odds for urosepsis than E. coli cases (OR: 3.5, 95% CI: 2.86-7.23, p < 0.001 vs. OR: 1.38, 95% CI: 1.19-3.69, p = 0.038). Diabetes, presence of an indwelling urinary catheter, length of hospitalization, and infection with Klebsiella spp were independent risk factors for urosepsis in CKD patients with UTI.

Combined Effect of Inter- and Intrapatient Variability in Tacrolimus Exposure on Graft Impairment Within a 3-Year Period Following Kidney Transplantation: A Single-Center Experience.

BACKGROUND AND OBJECTIVE: Tacrolimus is a cornerstone of the most immunosuppressive protocols after kidney transplantation, but its use is complicated by notable interpatient and intrapatient variability (IPV). The goal of this study was to evaluate whether or not tacrolimus IPV, or average dose-adjusted trough concentration (C0/D), during 6-12 months post-transplantation might have contributed to graft function decline in a 3-year period following kidney transplantation. After primary evaluation of individual effects of tacrolimus IPV and C0/D, the study aimed to estimate the combined effect of tacrolimus IPV and C0/D on composite endpoint (consisting of graft failure, chronic allograft dysfunction, chronic rejection, and doubling of serum creatinine concentration) in the period between 13 and 36 months after kidney transplantation. In addition, the goal was to analyze the impact of genetics on interpatient variability in tacrolimus exposure in the early and late post-transplantation periods. METHODS: The study enrolled 104 Caucasian patients and included 2541 patient examinations up to 36 months after kidney transplantation. All patients were genotyped on CYP3A5 6986A>G and ABCB1 3435C>T gene polymorphism. Patients were divided into groups based on the tacrolimus IPV tertiles and the median value of average C0/D during 6-12 months post-transplantation. RESULTS: The results showed a more pronounced decline in estimated glomerular filtration rate values within the high IPV tertile group (p = 0.018), as well as within the low C0/D group (p = 0.013) in a 3-year period after kidney transplantation. The carriers of CYP3A5*1/*3 genotype had lower C0/D compared to the CYP3A5*3/*3 carriers during the entire study period, while the results for ABCB1 were inconsistent when considering tacrolimus C0/D. Patients with high IPV/low C0/D had significantly reduced graft survival compared to the other tacrolimus IPV/C0/D combination groups (i.e., high IPV/high C0/D, low IPV/low C0/D, low IPV/high C0/D) with the hazard ratio of 3.14 in Cox analysis for reaching the composite endpoint. CONCLUSION: The findings of this study suggest that combined assessment of tacrolimus IPV and tacrolimus C0/D may categorize patients towards risk of graft deterioration in the long-term post-transplantation period.

Investigation of CYP 3A5 and ABCB1 gene polymorphisms in the long-term following renal transplantation: Effects on tacrolimus exposure and kidney function.

The clinical use of tacrolimus (Tac) is complicated by the large inter-individual variability in its pharmacokinetics as well as by chronic adverse effects on renal function. The main goal of this study was to evaluate the potential influence of cytochrome P450 3A5 (CYP 3A5) and ATP-binding cassette transporter B1 (ABCB1) gene polymorphisms on Tac dose requirements and dose-adjusted concentrations in different long-term periods following renal transplantation. Another aim was to investigate whether these polymorphisms affect renal function in late post-transplant period. A total of 91 renal transplant recipients were enrolled for genotyping analysis, and 53 of these entered into a pharmacokinetic-pharmacogenetic study. Allele-specific polymerase chain reaction was used for CYP 3A5 and ABCB1 polymorphism determination. Pharmacokinetic data (dose, trough concentration and dose-adjusted concentration of Tac) and renal function parameters [creatinine (Cre) clearance and serum Cre level] were analyzed in relation to patient genotype at 6, 12 and 24 months after transplantation. Also, linear regression analysis was performed to evaluate the effect of CYP 3A5 and ABCB1 genotypes on Tac exposure and renal function up to 24 months post-transplant. Individuals carrying the CYP 3A5*1/*3 genotype had higher Tac dose requirements than CYP 3A5*3/*3 carriers at 6, 12 and 24 months after renal transplantation. The results revealed that ABCB1 polymorphism did not influence Tac dose requirements independently. Regression analysis showed that CYP 3A5 influenced the Tac dose-adjusted concentration as well as renal function up to 24 months post-transplant. These findings confirmed that CYP 3A5 polymorphism represents the most important determinant of Tac dose and exposure in the late period following renal transplantation. Furthermore, the obtained results indicate that the decline in renal function may be more pronounced in patients with CYP 3A5*1 in the long-term period after renal transplantation.

Gender-dependent predictable pharmacokinetic method for tacrolimus exposure monitoring in kidney transplant patients.

Tacrolimus (Tac) is an immunosuppressive drug with a narrow therapeutic width and highly variable pharmacokinetics. Therefore, monitoring of Tac blood concentrations is of utmost importance in the management of renal transplant recipients. The occurrence and intensity of adverse effects depend on blood concentration and total exposure of the organism to this drug. This implies finding a new gender-dependent predictable method for Tac exposure monitoring based on determination of the area under the time concentration curve (AUC). The primary aim of this study was to investigate gender differences in systemic body exposure to Tac in renal transplant patients after the first oral dose and in a steady state by determining 12-h AUC (AUC(0-12)). The secondary objective was to find the best sampling time in which measured Tac concentration best predicts AUC value with respect to gender. Tac pharmacokinetic study was conducted in 20 kidney transplant recipients (10 men/10 women) on quaternary immunosuppressive therapy. The first oral Tac dose (0.05 mg/kg) was given on the fifth day post-transplant. After reaching steady state, regimen stabilized and dosage was adjusted in accordance with the level of Tac. Blood concentrations were measured by microparticle enzyme immunoassay method. AUC(0-12) for each patient was calculated after the first oral Tac dose and in the steady state from a plot of Tac concentration versus time from 0 to 12 h using the trapezoid rule. Associations between each sampling time point of concentrations within 12 h after the administration and AUC(0-12) were evaluated by Pearson correlation coefficients. Abbreviated sampling equations were derived by multiple stepwise regression analyses. Statistically significant difference was found in AUC(0-12) between male and female patients after the first oral dose (p < 0.01), but this difference was lost in a steady state. In female recipients C(2) seemed to be good indicator of total body exposure to Tac after the first oral dose and this was also confirmed in a steady state. The three-point sampling method was required for calculating AUC after the first oral dose in male patients, whereas in the steady state, concentration of C(8) seemed to be a good indicator of abbreviated AUC for a Tac monitoring strategy in male patients. Non-compartment Tac pharmacokinetic and regression analysis showed gender difference in total Tac exposure and determined the best predictable Tac concentrations after the first oral dose. Our study confirmed gender-dependent pharmacokinetics in a steady state in terms of best sampling time in which measured Tac concentration best predicts AUC value.

Immunosuppressive medication adherence in kidney transplant patients.

OBJECTIVES: To assess the degree of immunosuppressive medication adherence in kidney transplant patients (KTPs) and to determine if there is a difference in the rate of adherence to tacrolimus (Tac), cyclosporine (CsA) and sirolimus (Sir). SUBJECTS AND METHODS: From a total of 63 KTPs treated at the Clinic of Nephrology, Clinical Centre Nis, Serbia, 60 participated in the study by responding to questionnaires. They were divided into the adherence group (n = 43) and the nonadherence group (n = 17) according to their degree of adherence which was measured using a validated survey form, the simplified medication adherence questionnaire. The KTP adherence to the different immunosuppressive regimens (Tac, CsA and Sir) was compared. Statistical analysis was performed using the Student t test. RESULTS: Adherence was observed in 43 (71.7%) patients, and only 17 (28.3%) did not follow the prescribed therapy. The estimated glomerular filtration rate was significantly lower in the nonadherence group (38.52 ± 18.22 ml/min) than in the adherence group (52.43 ± 16.91 ml/min, p < 0.05). With regard to the Tac level, a significant difference was also found between the adherers and the nonadherers (6.30 ± 2.06 vs. 5.0 ± 1.52 ng/ml, p < 0.05). CONCLUSION: The KTPs in this study demonstrated a high level of adherence. Nonadherence was associated with worse graft function and a lower Tac level. Knowledge about the degree of adherence could help the early identification of nonadherent patients and the development of strategies to improve this.

Gender differences in oxidative and nitrosative stress parameters in kidney transplant patients on tacrolimus-based immunosuppression.

BACKGROUND: Cardiovascular (CV) morbidity and mortality rates are still higher after kidney transplantation than in general population. It is known that oxidative and nitrosative stress may contribute to the progress of CV disease in a post-transplant period, but still gender aspect has not been elucidated completely. The aim of this study was to analyze the gender differences in the oxidative and nitrosative stress parameters, as well as asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) levels among kidney transplant patients on tacrolimus-based immunosuppression. METHODS: Our research included 35 patients (20 men and 15 women) with renal transplant and 25 healthy volunteers. Patients were on chronic immunosuppressive regimen, which included tacrolimus, mycophenolate mofetil and prednisone. In order to estimate oxidative and nitrosative stress, we determined plasma levels of thiobarbituric acid-reactive substances (TBARS), activity of catalase (CAT), levels of total (protein and non-protein) sulfhydryl (SH) groups, advanced oxidation protein products (AOPP), ADMA and SDMA, as well as nitrite/nitrate (NOx) ratio. RESULTS: TBARS, CAT and SH in plasma were significantly higher in male patients than in female patients (p < 0.05, p < 0.01 and p < 0.05, respectively). There were no gender-dependent differences in AOPP, ADMA, SDMA and NOx in kidney transplant patients. Correlation analysis, Pearson and Spearman, showed significant correlations between tested oxidative and nitrosative stress parameters in male kidney transplant patients. Alternatively, in female patients, there were no significant correlations between tested parameters. CONCLUSION: Our findings show that men might be more prone to oxidative damage than women. ADMA, the proven marker of CV morbidity and mortality, may be more significant in male kidney transplant patients concerning oxidative stress control of its level and function.

How the duration period of erythropoietin treatment influences the oxidative status of hemodialysis patients.

BACKGROUND: End-stage renal disease is a state of enhanced oxidative stress (OS) and hemodialysis (HD) and renal anemia further augment this disbalance. Anemia correction with erythropoietin (EPO) may improve oxidative status. However, there is no evidence of time dependent effects of EPO therapy on redox status of HD patients. OBJECTIVE: The aim of this study was to evaluate whether the duration of EPO treatment may affect OS parameters in uremic patients. PATIENTS AND METHODS: 104 HD patients and 29 healthy volunteers were included. Patients were divided into 3 groups according to the duration of EPO treatment. Forth group consisted of HD patients without EPO treatment. Plasma and erythrocyte malondialdehyde (MDA, MDA(rbc)), reactive carbonyl groups (RCG), plasma sulfhydryl (-SH) groups and total antioxidative capacity (TAC) levels were evaluated. RESULTS: HD patients both with and without EPO treatment, showed a significant increase in all oxidative parameters without significance between EPO treated and -untreated group. The decrease in MDA and MDA(rbc) levels coincided with the duration of EPO treatment. A negative correlation was observed between the duration of EPO treatment and serum MDA (r=-0.309, p=0.003). Increasing periods of EPO treatment were associated with decrease in RCG, without significance between EPO groups. Increase in TAC accompanied increasing durations of EPO treatment, with EPO treatment for more than 24 months causing the most striking changes (p<0.05). There were no significant differences in -SH levels between EPO subgroups. CONCLUSION: Our results suggest that long term administration of EPO attenuated the lipid peroxidation process and restored the levels of antioxidants.

Indirect serum fibrosis markers in hepatitis C virus (HCV) infection.

UNLABELLED: Assessment of liver fibrosis is important for making treatment decisions, as well as for predicting prognosis and therapeutic outcome in patients on chronic hemodialysis (HD) treatment and infected with hepatitis C virus (HCV). The aim of the present investigation was to evaluate changes in standard laboratory tests (AST, ALT, yGT, cholesterol and platelet count) and indirect serum fibrosis markers: AST-to-platelet ratio index (APRI), FIB-4 and Forns index, in chronically HCV-infected patients on maintenance HD with and without antiviral treatment. PATIENTS AND METHODS: A total of 38 patients on chronic HD program more than 3 months and with chronic hepatitis C, were included in the study. According to local legislature 14 patients receive antiviral therapy (24 or 48 weeks, according to HCV genotype) adjusted for patients on HD: eight of them achieved sustained virological response (SVR) and six did not. RESULTS: All treated patients were HCV genotype 1. Baseline blood samples for standard laboratory tests and indirect serum fibrosis markers were collected on the day of antiviral treatment initiation, as well as at the end of follow-up treatment, 36 month later. At the beginning of antiviral treatment there were no significant differences in APRI, FIB-4, Forns and its components between patients who will achieve SVR and those who did not. A significant decrease of AST, ALT, yGT and APRI, and moderate decrease FIB-4 and Forns index was found at the end of follow-up in patients with SVR. In non-sustained responders group those three indexes and its components remained unchanged. Using cut-of values for APRI and FIB-4 (APRI < 0.5 and FIB-4 < 1.45) it was registered that raised percentage of patients with "no fibrosis" at the end of follow-up in those who achieved SVR. Absence of fibrosis measured by Forns index remained unchanged in all groups of patients. CONCLUSION: Simple indexes as APRI and FIB-4, successfully decrease after antiviral treatment of chronic hepatitis C in hemodialysis patients. These parameters seems to be useful in monitoring for liver fibrosis rate after antiviral treatment in patients on maintenance HD infected by HCV and can be used for estimation liver fibrosis progression in candidates for cadaveric renal transplantation.

Gender differences in pharmacokinetics of tacrolimus and their clinical significance in kidney transplant recipients.

BACKGROUND: The possible influence of gender on tacrolimus disposition and response in kidney transplant recipients is an issue of medical importance. OBJECTIVE: The aim of this study was to detect interpatient pharmacokinetic variability of tacrolimus due to patients' gender and to assess the predictability of individual tacrolimus concentrations using abbreviated AUC measurements. The secondary objective was to find the best sampling time to predict the exposure of tacrolimus in kidney transplant recipients. METHODS: Gender-related first oral dose tacrolimus pharmacokinetics studies were conducted in 20 Serbian kidney transplant recipients (10 men/10 women) on quaternary immunosuppressive therapy. The first tacrolimus oral dose (0.05 mg/kg) was given on day 5 post-transplant. Blood concentrations were measured by microparticle enzyme immunoassay method. Associations between each sampling time point of concentrations and 12 hours after the administration AUC (AUC(0-12)) were evaluated by Pearson correlation coefficients. Abbreviated sampling equations were derived by multiple stepwise regression analyses. RESULTS: AUC(0-12) showed remarkable interindividual variations after the first tacrolimus oral dose. There were significantly lower values of AUC in women than men (P < 0.05). The most important time point influencing AUC(0-12) was the concentration of tacrolimus measured 2 hours after administration(C(2)) in women, whereas in men the most important time points were the concentrations at 1 (C(1)), 4 (C(4)), and 12 (C(12)) hours as an abbreviated AUC. CONCLUSION: Our results show significant differences between men and women. C(2) seems to be indicator of total body exposure to tacrolimus in the early period after kidney transplant in women. The three-point sampling method seems to be a good indicator of abbreviated AUC for a tacrolimus monitoring strategy in men.

Clinical pharmacokinetics of tacrolimus after the first oral administration in renal transplant recipients on triple immunosuppressive therapy.

Monitoring of tacrolimus blood concentration is of utmost importance in the management of renal transplant recipients because of Narrow Therapeutic Index and highly variable pharmacokinetics. The aim of this study was to detect inter-patient pharmacokinetic variability of tacrolimus and to assess the predictability of individual tacrolimus concentrations at various times of the area under the curve (AUC) seeking to find the best sampling time to predict the exposure of tacrolimus in renal transplant recipients with triple therapy. This oral dose tacrolimus pharmacokinetics study was conducted in 18 Serbian renal transplant recipients on triple immunosuppressive therapy, including basiliximab. The first oral dose of tacrolimus (0.05 mg/kg) was given on day 5 post-transplant; blood concentration was measured by microparticle enzyme immunoassay method. Associations between each sampling time-point of concentrations and AUC(12) were evaluated by Pearson correlation coefficients. Abbreviated sampling equations were derived by multiple, stepwise regression analyses. The variance in the strength of association between predicted AUC (AUC(p)) and AUC(12) was reflected by linear regression coefficients. AUC(12) showed remarkable inter-individual variations after the first oral dose of tacrolimus. The area of the maximum AUC was four times higher than that of the minimum AUC. C(4) seems to be an indicator of total body exposure to tacrolimus. Alternatively, the concentrations at 1.5, 4 and 8 hr as an abbreviated AUC were as good a predictor as a full pharmacokinetic study. Our results show a significant difference between men and women. A three-point sampling method seemed to be the best abbreviated AUC for a cost-effective tacrolimus monitoring strategy.