Giovanni Manca Rizza

Anaemia and resistance to erythropoiesis-stimulating agents as prognostic factors in haemodialysis patients: results from the RISCAVID study

BACKGROUND Resistance to erythropoiesis-stimulating agents (ESAs) is often associated with chronic inflammation. Here, we investigated how anaemia, ESA resistance and the plasma levels of biological markers of inflammation could influence all-cause and cardiovascular disease morbidity and mortality. METHODS Seven hundred and fifty-three haemodialysis (HD) patients (mean age 66 ± 14.2 years, mean dialytic age 70 ± 77 months and diabetes 18.8%) were enrolled and followed-up for 36 months. Demographic, clinical and laboratory data, co-morbidity conditions, administered drugs, all-cause mortality and fatal/non-fatal cardiovascular (CV) events were recorded. We measured ESA resistance index, C-reactive protein (CRP) and interleukin-6 (IL-6). RESULTS Six hundred and fifty-one patients (86.4%) received ESAs. Patients with haemoglobin level <11 g/dL (n = 225) showed increased risk of CV [relative risk (RR) 1.415, 95% confidence interval (CI) 1.046-1.914] and overall mortality (RR 1.897, 95% CI 1.423-2.530) versus patients with haemoglobin levels >11 g/dL. ESA resistance values categorized into quartiles (Quartile I <5.6, Quartile II 5.7-9.6, Quartile III 9.7-15.4 and Quartile IV >15.4) correlated with all-cause mortality and fatal/non-fatal CV events (RR 1.97, 95% CI 1.392-2.786; RR 1.619, 95% CI 1.123-2.332, respectively). Furthermore, albumin was significantly reduced versus reference patients and correlated with all-cause mortality and CV events; CRP levels were higher in hyporesponders (Quartile IV) (P < 0.001) and predicted all-cause mortality and CV events. IL-6 but not CRP was a strong predictor of ESA resistance. CONCLUSIONS ESA responsiveness can be considered a strong prognostic factor in HD patients and seems to be tightly related to protein-energy wasting and inflammation.

A Vitamin E-Coated Polysulfone Membrane Reduces Serum Levels of Inflammatory Markers and Resistance to Erythropoietin-Stimulating Agents in Hemodialysis Patients: Results of a Randomized Cross-Over Multicenter Trial

Background: Oxidative stress is prevalent in dialysis patients and has been implicated in the pathogenesis of cardiovascular disease and anemia. Vitamin E is a fat-soluble antioxidant that plays a central role in reducing lipid peroxidation and inhibiting the generation of reactive oxygen species. The aim of this cross-over randomized study was to compare the effects of a vitamin E-coated polysulfone (Vit E PS) membrane and a non-vitamin E-coated polysulfone (PS) membrane on inflammatory markers and resistance to erythropoietin-stimulating agents (ESAs). Methods: After a 1-month run-in period of standard bicarbonate dialysis with a synthetic membrane, 62 patients of both genders, and older than 18 years, dialysis vintage 48 ± 27 months, BMI 22 ± 3 (from 13 different dialysis units) were randomized (A-B or B-A) in a cross-over design to Vit E PS (treatment A) and to PS (treatment B) both for 6 months. C-reactive protein (CRP) and interleukin-6 (IL-6) concentrations were determined by a sandwich enzyme immunoassay at baseline and every 2 months; red blood cell count, ESA dose and ESA resistance index (ERI) were assessed monthly. Results: Hemoglobin (Hb) levels significantly increased in the Vit E PS group from 11.1 ± 0.6 g/dl at baseline to 11.5 ± 0.7 at 6 months (p < 0.001) and remained unchanged in the PS group. Although ESA dosage remained stable during the observation periods in both groups, ERI was significantly reduced in the Vit E PS group from 10.3 ± 2.2 IU-dl/kg/g Hb week at baseline to 9.2 ± 1.7 at 6 months (p < 0.001). No significant variation of ERI was observed in the PS group. A significant reduction in plasma CRP and IL-6 levels was observed in the Vit E PS group: CRP from 6.7 ± 4.8 to 4.8 ± 2.2 mg/l (p < 0.001) and IL-6 from 12.1 ± 1.4 to 7.5 ± 0.4 pg/ml (p < 0.05). In the PS group, CRP varied from 6.2 ± 4.0 to 6.4 ± 3.7, and IL-6 from 10.6 ± 2.1 to 9.6 ± 3.5 (p = n.s.). Conclusions: Treatment with Vit E PS membranes seems to lead to a reduction in ESA dosage in HD patients; in addition, a low chronic inflammatory response may contribute to a sparing effect on exogenous ESA requirements.

Interleukin-8 is a powerful prognostic predictor of all-cause and cardiovascular mortality in dialytic patients.

Background: Cohort studies have demonstrated an association between C-reactive protein (CRP) and interleukin-6 (IL-6) and all-cause and cardiovascular mortality in end-stage renal disease (ESRD) patients. Interleukin-8 (IL-8) appears to be not only the plasma expression of the acute-phase response but also a direct pathogenetic mediator of the atherosclerotic process. Methods: To evaluate the role of IL-8 in predicting outcome, 76 chronic dialytic patients were prospectively followed for 18 months. At baseline, blood samples were taken for analysis of high-sensitivity CRP, IL-6, IL-8 and other standard laboratory analyses. Results: Median IL-8 was 5.2 mg/l, therefore near half of the patients had IL-8 values within the range of ‘normal limits’. IL-6 and CRP were significantly correlated (r = 0.45, p < 0.001) and a positive correlation was also found between IL-6 and IL-8 (r = 0.39, p < 0.001). The correlation coefficient between IL-6 and CRP was 0.43 (p < 0.001) and 0.50 (p < 0.001) in patients without and with history and/or clinical signs of cardiovascular disease, respectively. After a follow-up of 1.5 years, 8 patients had died from cardiovascular causes and another 7 patients for other reasons; furthermore 9 major nonfatal cardiovascular events were recorded. Stepwise regression analysis showed IL-8 as the strongest independent predictor of all-cause and cardiovascular events (p = 0.0025) even after adjustment for age and dialytic age, followed by IL-6 and CRP (p < 0.01). Conclusion: Despite a small population and a relatively short follow-up period, this study firstly demonstrated that IL-8 is a powerful independent predictive factor for cardiovascular and overall mortality cause in ESRD patients.

Severe Hypotension During Hemofiltration in an Uremic Patient with Metabolic Alkalosis

We describe a case of medication induced metabolic alkalosis in a maintenance dialysis patient who developed severe hypotension while undergoing a lactate hemofiltration procedure. A 73‐year‐old man with ESRD due to renovascular disease was used to ingesting up to 30 grams per day of a non‐prescription medication (Effervescent granulare 250 grams, CRASTAN™, Pisa Italy) consisting of sodium bicarbonate, citric acid, glucose and lemon flavor. For technical problem lactate hemofiltration was performed and thirty minutes after dialysis was started a severe symptomatic hypotension occurred (blood pressure 65/35 mmHg). Lactate hemofiltration was suspended and one‐hour later standard bicarbonate dialysis was performed without any clinical problem. The different mechanisms in acidosis buffering occurring in lactate and bicarbonate hemofiltration were discussed.