Yunus Erdem

Background: Cognitive impairment is a frequent yet underrecognized complication in dialysis patients, adversely affecting quality of life and clinical outcomes. With the growing prevalence of chronic kidney disease (CKD), understanding the relationship between dialysis and cognitive decline is increasingly important. Methods: This cross-sectional study was conducted in 3 major nephrology centers in Türkiye. Cognitive function was assessed using the AD8 Dementia Screening Interview. Demographic, clinical, laboratory data, and dialysis adequacy (Kt/V) were analyzed for associations with cognitive impairment. Results: A total of 261 dialysis patients were included (54.4% male; median age: 56 years, range 18-89; 29.1% ≥65 years). Among them, 57.9% received hemodialysis and 42.1% peritoneal dialysis, with a median kidney replacement therapy duration of 3 years. Cognitive impairment was present in 63.6% of patients. These patients had a longer CKD duration (10 vs. 6 years, P < .001) but lower hypertension prevalence (65.2% vs. 84.4%, P = .001). Cognitive decline was more common in hemodialysis patients (66.3% vs. 43.2%, P < .001) and associated with lower hemoglobin (P = .033) and sodium levels (P = .019). In the multivariable logistic regression model, age was not an independent predictor (P = .315); correlates of cognitive impairment included longer CKD duration (P = .001), hemodialysis modality (P = .003), and lower sodium levels (P = .014). Conclusion: Cognitive impairment was highly prevalent among dialysis patients, independent of age. Recognition of modifiable risk factors may help guide multidisciplinary strategies to improve cognitive and overall patient outcomes. Cite this article as: Yıldırım S, Erdut A, Altunok M, et al. Age and cognitive impairment in dialysis patients: a cross-sectional analysis. Turk J Nephrol. Published online February 24, 2026. doi: 10.5152/turkjnephrol.2026.251169

Objective: Renal transplantation is the best treatment for end-stage kidney disease, and tacrolimus has become an important immunosuppressive treatment for kidney transplant patients since it was introduced. After the first generic tacrolimus has been approved by the FDA, studies have begun to compare the effectiveness and safety of generic tacrolimus with the original tacrolimus. When using generic immunosuppressive therapies, it is also necessary to ensure that it provides adequate immunosuppression and does not cause severe toxicity. This study aims to compare clinical outcomes, including acute rejection, graft loss and adverse reactions, in patients receiving brand tacrolimus (Prograf, Astellas Pharma, U.S.) or generic tacrolimus (Adoport, Sandoz, UK) from the start of kidney transplant therapy. Study Design: Renal transplant recipients between 1 January 2015-1 March 2020 were screened retrospectively. All patients receiving de novo generic tacrolimus (n:51) and randomly selected 102 control renal transplant recipients receiving original tacrolimus were included in this study. Materials and Methods: We evaluated and recorded demographic, clinical and laboratory data including age, gender, primary kidney disease, donor type (live or dead), induction and death regimen, tacrolimus dose, tacrolimus through levels, serum creatinine, biopsy-confirmed acute rejection episodes, delayed transplant function, positive BK polyomavirus in the urine, BK polyomavirus-related nephropathy, cytomegalovirus infection in 1-year follow-up. Results: Most of the patients were male (64.1%) with a mean age of 38.3 years. There was no significant difference in demographic characteristics between the original and generic tacrolimus groups. No differences were found in terms of creatinine levels, total daily dose of tacrolimus and tacrolimus trough levels at discharge and the first year. Additionally, biopsy-confirmed acute rejection in the following year after transplantation, BKPyV positivity in urine, BKPyVAN, CMV viremia and adverse reactions related to tacrolimus were similar between the two groups. Conclusion: With this study, we aimed to contribute to the literature with our experience on the use of generic tacrolimus from our country. As a result of our study, we noted that generic tacrolimus can be safely preferred for de-novo use with close drug-level monitoring because it is an immunosuppressant agent with a narrow therapeutic index. There is a continuing need for randomized prospective-designed and multi-centric studies with a wide range of patients.

Objectives Cyclosporine is an immunosuppressive drug with a high potential for drug interactions that is frequently used in renal transplant patients. The purpose of this study was to assess the change in cyclosporine concentration in patients taking cyclosporine and lercanidipine concurrently. Methods The potential drug interactions in renal transplant patients who received lercanidipine and cyclosporine concurrently in a university hospital between January 2008 and January 2018 were evaluated retrospectively. Patients had renal transplantation from deceased donors or living related donors. The Drug Interaction Probability Scale (DIPS) criteria were used to assess the causality of cyclosporine and lercanidipine drug interaction. Results The study included six renal transplant patients. The median cyclosporine concentration before lercanidipine use was 325 ng/mL (min–max 101–356) and 592.5 ng/mL (min–max 198–799) thereafter (p=0.028). Serum creatinine and proteinuria levels did not change significantly during lercanidipine treatment (p=0.686 and p=0.116, respectively). According to the DIPS evaluation, cyclosporine and lercanidipine interaction was classified as “possible (score 3)". Conclusions Concomitant use of cyclosporine and lercanidipine increases the concentration of cyclosporine, which may result in side effects during effective treatment in renal transplant patients. Therefore, cyclosporine concentrations should definitely be monitored while patients are taking lercanidipine.

The COVID-19 pandemic process may affect the physical and psychosocial health in patients with chronic kidney disease (CKD). The aim of this study was to compare the quality of life, physical activity, fear of COVID-19 and mental health in CKD patients and healthy individualsand compare the aforementioned parameters in end-stage renal disease (ESRD) and renal transplantation (RTx) patients during the pandemic. Eighty-two patients (33 ESRD, 49 RTx) and age-gender matched 108 healthy individuals were included. Quality of life (Short Form 36 Health Survey Questionnaire-SF-36), physical activity (short form of the International Physical Activity Questionnaire -IPAQ-SF), fear of COVID-19 (Fear of COVID-19 Scale-FCV-19S) and mental health (Hospital Anxiety and Depression Scale-HADS) were evaluated. Physical activity levels and all SF-36 scores except mental health in CKD patients were significantly lower than healthy individuals (p < 0.05). FCV-19S and HADS scores were similar between the groups (p > 0.05). ESRD patients’ pain and general health perceptions scores of SF-36 were lower than RTx patients’ (p < 0.05). Quality of life and physical activity levels were worse in CKD patients compared to healthy individuals during the pandemic. The participants had fear of COVID-19, poor mental health and low physical activity. For these reasons, psychosocial and physical activity interventions for the both groups may be beneficial for the affected outcomes during COVID-19 pandemic.

Background We aimed to investigate the immuno-histochemical expression of C4d, ADAM10 and WT1 in kidney biopsies of immunoglobulin A nephropathy (IgAN) patients and correlate the findings with clinical, laboratory and histopathologic features in the hope of defining new parameters to better understand the pathogenesis of the disease, and predict prognosis. Materials and methods Paraffin-embedded kidney biopsy samples of 128 IgAN patients were immuno-histochemically treated with C4d and ADAM10/WT1 dual stain. Results were evaluated according to Oxford classification parameters, epidemiologic features, laboratory findings at presentation and clinical follow-up. Results We observed C4d positivity in 40.6% of our patients, 25% of which was mesangial/peri-mesangial (m/pm) staining. Only m/pmC4d positivity statistically correlated with progression to end-stage renal disease (ESRD). M/pmC4d positive patients had statistically significantly higher baseline proteinuria levels, presence of crescents and > 25% segmental sclerosis of glomeruli. There was cytoplasmic staining of WT1 in 11.2% of cases. Presence of cWT1 correlated with m/pmC4d positivity and progression to ESRD. There was no glomerular ADAM10 detected and tubular expression of this protein did not relate to amount of tubular damage or other parameters. Conclusion This study is the first to show that cWT1is involved in IgAN and appears as an independent variable for worse prognosis.

Background: Seroepidemiology, risk factors to hepatitis E virus exposure, and prevalence of hepatitis E virus viremia have not yet been investigated among patients under immunosuppression or with liver disease that are high risk for infection in Turkey. Methods: In this cross-sectional study, 292 consecutive serum samples from renal transplant recipients, allogeneic hematopoietic stem cell transplant recipients, patients with acute hepatitis, and patients with chronic hepatitis C were prospectively collected in a ter- tiary university hospital. Sera were tested for hepatitis E virus immunoglobulin G/immunoglobulin M and hepatitis E virus ribonucleic acid using commercial enzyme-linked immunosorbent assay and in-house nested polymerase chain reaction with Sanger sequencing, respectively. Sociodemographic, clinical, laboratory data, and risk factors were collected using a questionnaire and hospital database. Multiple logistic regression analysis was employed to identify independent predictors for anti-hepatitis E virus seropositivity. Results: Among all patients, only 2 patients (1 renal transplant recipient and 1 patient with acute hepatitis) were identified as having hepatitis E virus genotype 3 viremia. Hepatitis E virus viremia rate was 0.6% in whole group. These patients showed no signs of chronic hepatitis E virus infection for 6 months and were spontaneously seroconverted 6 months after enrollment. Anti-hepatitis E virus IgG was positive in 29 patients yielding a hepatitis E virus seroprevalence of 9.9%. Older age (adjusted odds ratio: 1.03, 95% CI, 1.00-1.06; P = .022) and eating undercooked meat (adjusted odds ratio: 3.11, 95% CI, 1.08-8.92; P = .034) were independent risk factors to anti- hepatitis E virus seropositivity in all patients. Similarly, multiple logistic regression analysis demonstrated that age (adjusted odds ratio: 1.03, 95% CI, 0.99-1.07, P = .058) and eating undercooked meat (adjusted odds ratio: 5.77, 95% CI, 1.49-22.25, P = .011) were indepen- dent risk factors for anti-hepatitis E virus IgG positivity in the liver disease subgroup consisting of acute hepatitis and chronic hepatitis C patients. Conclusion: The hepatitis E virus seroprevalence rate was high (9.9%), despite low viremia rate (0.6%) in high-risk patients. The emer- gence of hepatitis E virus genotype 3 might indicate a serious problem for these patients. Future investigations are needed to elucidate foodborne transmission routes of hepatitis E virus in Turkey. Cite this article as: Balaban HY, Aslan AT, Akdoğan-Kittana FN, et al. Hepatitis E virus prevalence and associated risk factors in high-risk groups: A cross-sectional study. Turk J Gastroenterol. 2022;33(7):615-624.

The effect of hypertension (HT) and antihypertensive therapies such as renin-angiotensin-aldosterone system (RAAS) blockers on the disease course in COVID-19 patients is controversial. The purpose of this study was to evaluate the effect of HT and antihypertensive therapies on the course of COVID-19 disease. The age, sex, comorbid diseases, and antihypertensive therapies of 132,790 patients with positive COVID-19 real-time transcriptase polymerase chain reaction (RT-PCR) tests in the Turkish Health Ministry National COVID-19 database between 11 March and 31 May 2020, were examined and analyzed. Forty-one percent of the 132,790 patients in this study (median age: 40, 47.3% female) were hospitalized for treatment, and 4.5% were followed-up in the intensive care unit (ICU). The most frequent comorbid disease, at 19.5%, was HT (n = 25,863). Mortality was determined in 4.9% of HT patients and 1.9% of non-HT patients (p < .001). HT, age, and male gender emerged as independent predictors of hospitalization and admission to the ICU, while HT was not a predictor of mortality. In addition, no adverse effect of any antihypertensive treatment, including RAAS inhibitors, on mortality was detected. Based on Turkish national data, HT is common in COVID-19 patients, but does not appear to be an independent predictor of mortality, and no adverse effect of RAAS inhibitors on COVID-19-related mortality was observed.

Introduction: We aimed to investigate the effect of a standard hemodialysis prescription in hyponatremic patients requiring hemodialysis on the development of osmotic demyelination syndrome.Methods: Ninety‐nine patients who were treated with hemodialysis for the first time and had a pre‐dialysis sodium value of ≤125 meq/L included in the study. Standard hemodialysis treatment was applied to all patients. Biochemical data before, immediately after and 24 h after hemodialysis were recorded retrospectively. All patients followed up for 2 weeks and magnetic resonance imaging was performed in patients with neurological symptoms.Results: Eight patients had a sodium increase of more than 12 meq/L at 24‐h after hemodialysis. Although hyponatremia was corrected rapidly with hemodialysis, none of the 99 azotemic patients developed osmotic demyelination syndrome.Conclusion: We did not observe osmotic demyelination syndrome in hyponatremic patients with azotemia treated with standard protocol hemodialysis. However, caution should still be exercised in high‐risk patients for osmotic demyelination.

Compared to healthy controls, mean platelet volume (MPV) is frequently higher in patients with Familial Mediterranean fever (FMF) but lower in AA amyloidosis patients. The reason for the difference in MPV levels in FMF patients with and without AA amyloidosis is unclear. The aim of the study was to determine whether low MPV is unique to AA amyloidosis or MPV is similarly low in all glomerular diseases as a result of proteinuria and/or renal dysfunction. We compared pre-biopsy MPV levels of patients with AA amyloidosis secondary to FMF, to MPV levels of patients with membranous glomerulonephritis, focal segmental glomerulosclerosis (FSGS) and IgA nephropathy that all present with proteinuria and renal dysfunction. 703 patients (411 male, 292 female) were included in the study. Mean age was 42.6?14.3 years. There were 124 patients with AA amyloidosis, 224 patients with IgA nephropathy, 188 patients with membranous glomerulonephritis and 167 patients with FSGS. Patients with AA amyloidosis had lower MPV levels compared to patients without AA amyloidosis (7.9?1.2 fL vs. 8.2?0.9 fL respectively, p=0.008). Patients with AA amyloidosis had significantly lower MPV compared to patients with each of the other diagnoses. Independent predictors of MPV were platelet count (ß= - 0.321, p < 0.001) and CRP (ß= - 0.134, p < 0.03). This study is the largest study of MPV in patients with biopsy proven AA amyloidosis and confirms previous studies reporting low MPV in AA amyloidosis. This study indicates that low MPV in AA amyloidosis cannot be explained with proteinuria and renal dysfunction.