Population Pharmacokinetics of Bisoprolol in Hemodialysis Patients with Hypertension.

The aim of our study was to estimate clearance of bisoprolol and reveal the factors that could influence its pharmacokinetic (PK) variability in hypertensive patients on hemodialysis, using the population PK analysis. Parameters associated with plasma concentration of bisoprolol at steady state were analyzed in 63 patients (mean age 62.12 years, mean total weight 69.63 kg) who were hypertensive and on hemodialysis due to severe renal failure using non-linear mixed-effect modeling with ADVAN1 subroutine. The final regression model for the clearance of the drug included only creatinine clearance (CLcr) out of 12 tested covariates. The equation that describes CL of bisoprolol is the following: CL (l/h) = 0.12 + 6.33 * CLcr. These findings suggest that the routine measuring of serum creatinine level may be used to facilitate administration of bisoprolol in patients on hemodialysis.

Habitual coffee consumption enhances attention and vigilance in hemodialysis patients.

OBJECTIVE: Coffee drinking is the main source of caffeine intake among adult population in the western world. It has been reported that low to moderate caffeine intake has beneficial effect on alertness and cognitive functions in healthy subjects. The aim of this study is to evaluate the impact of habitual coffee consumption on cognitive function in hemodialysis patients. METHODS: In a cross-sectional study, 86 patients from a single-dialysis centre underwent assessment by the Montreal Cognitive Assessment tool and evaluation for symptoms of fatigue, mood, and sleep disorders by well-validated questionnaires. The habitual coffee use and the average daily caffeine intake were estimated by participants' response to a dietary questionnaire. RESULTS: Sixty-seven subjects (78%) consumed black coffee daily, mostly in low to moderate dose. Cognitive impairment was found in three-quarters of tested patients. Normal mental performance was more often in habitual coffee users (25% versus 16%). Regular coffee drinkers achieved higher mean scores on all tested cognitive domains, but a significant positive correlation was found only for items that measure attention and concentration (P = 0.024). CONCLUSIONS: Moderate caffeine intake by habitual coffee consumption could have beneficial impact on cognitive function in hemodialysis patients due to selective enhancement of attention and vigilance.

[Headache associated with haemodialysis].

INTRODUCTION: Haemodialysis (HD) is one of the most accessible methods for the treatment of the growing number of patients suffering from terminal-stage renal insufficiency. Although headache is the most frequently encountered neurological symptom during HD, there are few studies reporting its prevalence and clinical features. OBJECTIVE: The objective of this study was to examine the frequency, demographic and clinical features of headache during HD, and to compare these parameters among patients with and without headache. METHOD: The study involved 126 patients (48 female and 78 male) with chronic renal failure on regular HD for at least six months, at the Dialysis Unit of Nephrology Department, Krusevac. All patients were inquired about their possible problems with headache using the standardized questionnaire designed according to the diagnostic criteria of the International Headache Classification of Headache Disorders, second edition, published in 2004 (ICHD-II). Subsequently, the patients were clinically evaluated and patients with headaches were further subclassified by a neurologist with special interest in headache disorders. Patients with headache were compared to the patients without headache regarding age, sex, duration of HD, causes of end-stage renal disease, arterial diastolic and systolic blood pressure, and serum values of the most important blood parameters such as sodium, potassium, urea and creatinine. In the group of patients with headache we analyzed the characteristics of specific headache type according to ICHD-II classification. We also analyzed the most important clinical features of haemodialysis headache (HDH). RESULTS: In the group of 126 evaluated patients, 41 (32.5%) patients had headaches. There were no statistically significant differences between the patients with headaches and those without headaches regarding sex, age, BMI, duration of HD, causes of end-stage renal disease, arterial blood pressure, red blood cell count, serum concentration of haemoglobin, blood urea nitrogen, creatinine, glucose, MCHC, total protein, sodium and potassium. Fourteen patients (34% of those with headaches) experienced headache during the HD session and were subclassifled as HDH using diagnostic criteria of the International Headache Society. Tension type headache (41% of those with headaches) and migraine without aura (10%) were most common in the primary headache group and headache due to arterial hypertension (7%) was the most prevalent among the secondary headaches. Although there were some common clinical characteristics, we could not find a unifying clinical pattern in the patients with HDH. CONCLUSION: Haemodialysis headache is the most common headache in patients undergoing haemodialysis, and despite some common symptoms, it does not appear to be uniform in its clinical characteristics.

[Restless legs syndrome prevalence in patients on chronic hemodialysis in central Serbia].

BACKGROUND/AIM: Restless legs syndrome (RLS) is a sensorymotor disorder and the core feature of this syndrome is a distressing, irresistible need or urge to move the legs. RLS is one of the most troublesome conditions experienced by endstage renal disease patients treated with regular hemodialysis, and is significantly associated with their increased mortality. The aim of this study was to assess the prevalence of RLS in the patients with end-stage renal failure in the three dialysis centers in central Serbia, and to investigate the association of the syndrome with clinical characteristics and biochemical variables. METHODS: A cross-sectional multicentric study in which 166 consecutive hemodialysis patients were evaluated using a standard questionnaire based on diagnostic criteria elaborated by the International Restless Legs Syndrome Study Group was performed. All patients were reinterviewed and clinically examined by a qualified neurologist. The data on the patients with and without RLS were compared. RESULTS: The prevalence of RLS was 22.96% (95% CI, 16.57% to 29.35%). There was no significant difference in duration of hemodialysis and clinical characteristics when we compared the patients with RLS with those without RLS. We found significantly higher levels of blood urea nitrogen and creatinine and lower level of Kt/V index in the patients with RLS, which might point to inadequate dialysis in these patients. CONCLUSION: In our study the prevalence of RLS in the patients on the regular hemodialysis was 22.96%. The obtained results are similar to those of other studies using the same methodology in the white population on the regular hemodialysis.