Effectiveness of N-acetylcysteine for preserving residual renal function in patients undergoing maintenance hemodialysis: multicenter randomized clinical trial.

BACKGROUND: To investigate the efficacy and safety of oral N-acetylcysteine (NAC) for preserving residual renal function in patients undergoing hemodialysis. METHODS: Randomized, multi-center, parallel-group, open-label clinical trial (Registration No. IRCT 2014071418482N1). 54 patients who have been undergoing hemodialysis for at least 3 months and had residual urine volume >100 ml/24 h were randomly allocated to NAC or no medication. Residual renal function evaluated by (1) estimated glomerular filtration rate (GFR), (2) 24 h urine volume, and (3) renal Kt/V. GFR and Kt/V was determined at baseline and after 3 months. 24 h urine volume was measured at baseline, after 1, 2, and 3 months. RESULTS: Intention-to-treat analysis was performed on 47 patients (NAC = 26, control = 21). GFR in patients receiving NAC improved, whereas in the control arm a decline of 1.0 ml/min/1.73 m2 was recorded (3.59 vs. 2.11 ml/min/1.73 m2, effect size = 17.0 %, p = 0.004). For 24 h urine volume, the between-group difference after 1 month was significant (669 vs. 533 ml/24 h, effect size = 15.4 %, p = 0.004). After 3 months, 24 h urine volume in the NAC arm was on average 137 ml higher than in the control group, and the difference reached near significance (673 vs. 536 ml/24 h, p = 0.072). In the follow-up visit, Kt/V was higher in the NAC arm but the difference did not reach statistical significance (0.81 vs. 0.54, p = 0.152). CONCLUSION: Three months treatment with NAC appears to be effective in preserving renal function in patients undergoing hemodialysis and the medication is generally well-tolerated.

The relationship between total mass and blood supply of parathyroid glands and their secretion of parathyroid hormone in hemodialysis patients with secondary hyperparathyroidism.

Characteristics of parathyroid glands usually determined by ultrasonography such as its total weight or volume might be a good indicator for the induction or suppression of parathyroid hormone (PTH) secretion from these glands. In the present study, we investigated the relationship between the volume and blood supply grade of the parathyroid glands, and its PTH secretion. Study subjects included 52 consecutive patients with the secondary hyperparathyroidism undergoing maintenance hemodialysis therapy referred to dialysis wards of the Imam Khomeini and Amiralam University Hospitals in Tehran. Serum intact PTH (i-PTH) was measured by an ELISA assay. The parathyroid glands characteristics were identified by ultrasonography that was performed simultaneously with blood collection. Parathyroid blood flows were evaluated by power-Doppler color imaging. There was no significant correlation between the total mass of the glands and serum concentration of i-PTH. No significant correlations were also observed between both total central and peripheral parathyroid glands blood flow and serum i-PTH level. Dialysis duration and serum alkaline phosphatase were significantly correlated in a positive manner with i-PTH level. Furthermore, serum level of i-PTH was not correlated with the total signals of glands blood flow in a multivariable linear regression analysis. Serum secreted i-PTH level might not be predictable by a total mass of parathyroid glands as well as their blood supply.

Association of low vitamin D levels with metabolic syndrome in hemodialysis patients.

Low vitamin D levels have been linked to metabolic syndrome in the general population. In the present study, the relationship between inadequate serum concentrations of vitamin D and metabolic syndrome in patients with end-stage renal disease undergoing hemodialysis was explored. In a cross-sectional setting, 145 patients undergoing maintenance hemodialysis were enrolled. Metabolic syndrome was defined using the International Diabetes Federation criteria. Serum concentration of 25(OH) vitamin D was determined by a commercially available enzyme immunosorbent assay method. The prevalence of metabolic syndrome was 53.1%. The prevalence rate of severe vitamin D deficiency (<5 ng/mL) was 3.4%, mild vitamin D deficiency (5-15 ng/mL) 31.0%, vitamin D insufficiency (16-30 ng/mL) 36.6%, and vitamin D sufficiency (>30 ng/mL) 29.0%. With the increasing number of metabolic abnormalities, vitamin D levels significantly decreased (P for trend = 0.028). Among the components of metabolic syndrome, vitamin D deficiency was significantly associated with central obesity (odds ratio [OR], 95% confident interval [CI] = 2.80, 1.11-7.04, P = 0.028). A positive, but nonsignificant association between vitamin D deficiency and raised fasting plasma glucose was noted (OR, 95% CI = 2.40, 0.94-6.11, P = 0.067). Both vitamin D deficiency and insufficiency were significantly associated with an increased likelihood of having metabolic syndrome (P < 0.05). In a final model controlling for age, sex, and parathyroid hormone levels, vitamin D deficiency increased the odds of having metabolic syndrome by more than threefold (OR, 95% CI = 3.26, 1.30-8.20, P = 0.012). Low levels of vitamin D are frequent among hemodialysis patients and are associated with the metabolic syndrome.

Relationship between serum leptin levels and bone mineral density and bone metabolic markers in patients on hemodialysis.

Leptin is the protein product of the obesity gene, which is produced in fat tissue. It was originally thought to be involved only in the regulation of food intake and energy balance. We aimed to investigate the relationship of serum leptin levels with bone mineral density (BMD) and biochemical markers of bone turnover in patients on hemodialysis (HD). This study included 72 patients (43 males and 29 females), whose mean age was 55.1 ± 11.4 years, mean body mass index was 23.13 ± 2.75 kg/m 2 and mean duration on HD was 5 ± 3.4 years. The BMD values were calculated using dual-energy X-ray absorptiometry (DEXA) at the femoral neck and lumbar spine. Blood samples were taken for leptin, intact parathyroid hormone (I-PTH), bone alkaline phosphatase (BAP), calcium (Ca), phosphate (P) and albumin. The leptin levels were higher in females than in males (22.3 ± 19.6 vs 20.8 ± 23), but this difference was not significant. The serum leptin level had a strong positive correlation with Ca levels in the female patients (r = 0.659 and P = 0.01) and a negative correlation with albumin levels (r = -0.461 and P = 0.01). No correlation was found with age, BMI, duration on dialysis, BMD and serum levels of PTH, BAP and P for the entire patient group or either gender separately. The serum leptin level was significantly lower in females with PTH >300 pg/mL when compared with patients with PTH = 100-300 pg/mL (86 ± 85 vs 47 ± 48) (P = 0.011).Women with BAP <300 IU/L had significantly higher serum leptin than those with BAP 300-600 IU/L (P = 0.024). Women with Ca <8.5 mg/dL had significantly lower serum leptin levels compared with those with Ca levels of 8.5-10.5 mg/dL (P = 0.011). There was no significant difference between the two genders among variables such as age, BMI, duration on dialysis, serum leptin, I-PTH, Ca, P, BAP, albumin and BMD of the femoral neck and lumbar spine.

Chronic inflammation increases risk in hemodialysis patients.

Chronic inflammation is the cause of malnutrition and cardiovascular disease in hemodialysis patients. The purpose of this study was to assess C Reactive Protein (CRP) as an inflammatory marker and to define the relationship between CRP and other inflammatory and nutritional factors in this group of patients. One hundred and fourteen hemodialysis patients undergoing chronic dialysis (3 times a week for at least 4 hours) in two hemodialysis centers were enrolled in this cross-sectional study. Anthropometric and laboratory data including CRP, Il-6, hemoglobin, serum ferritin, triglyceride, cholesterol, albumin, total protein and transferrin were measured. The Kt/V for adequacy of dialysis was also calculated. There was a statistically significant correlation between the mean CRP and albumin, hemoglobin, and transferrin; while such relation was not found with BMI, ferritin, the length of dialysis, triceps skin fold thickness, mid arm circumference, mid arm muscle circumference, and Kt/V. We conclude that the negative relationship between CRP and albumin, transferrin, and hemoglobin suggests a correlation between inflammatory and nutritional factors.

Persistence of hepatitis B vaccine immunity in hemodialysis patients.

Although the efficacy of hepatitis B vaccines in patients undergoing chronic hemodialysis (HD) treatment has been documented, the persistence of immunity in this population remains largely unknown. In this study we evaluated the persistence of hepatitis B vaccine immunity in HD patients. We followed 37 hepatitis B vaccinated HD patients (following a four-dose vaccination schedule of 40 mug injections intramuscularly in the deltoid muscle at 0, 1, 2, and 6 months) for up to one year to evaluate the persistence of immunity (as indicated by serum levels of hepatitis B surface antibody (anti-HBs) equal to or higher than 10 IU/L). One year after vaccination, 18.9% of patients had lost their anti-HBs (transient responders), while 81.1% still had detectable antibodies in the serum (persistent responders). From 81.1% of persistent responders 11.5% and 88.5% were weak and high responders, respectively. There was no significant difference between persistent and transient responders regarding age, sex, or nutritional factors. We did not find any factors that related to maintaining protective levels of anti-HBs in HD patients. It seems that an antibody titer above 100 IU/L following vaccination is necessary in order to maintain that level of antibody one year later.

Infertility among kidney transplant recipients.

We studied 122 women with a transplanted kidney to evaluate their reproductive performance. 15 of the patients were either post-menopausal or underwent hysterectomy and 33 were unmarried. Of the 76 married reproductive age women, 10 (13.1%) were infertile. Three had male factor infertility, three had ovulatory problems and in four cases, the cause was uncertain. Six of these patients were actively treated by ovulation induction with or without IUI and two of these patients became pregnant. The remaining four patients refused treatment for infertility. We conclude that the incidence of infertility among kidney transplant recipients is similar to the general population, but they are less motivated to be treated for infertility.