Effects of non-pharmacological interventions on urinary citrate levels: a systematic review and meta-analysis.

BACKGROUND: Hypocitraturia is a known risk factor for nephrolithiasis, present in 20-60% of stone-forming patients. The administration of citrate or other alkali preparations has been demonstrated to benefit hypocitraturic stone formers. Dietary modifications that include citrate-containing fluids can be an alternative option to pharmacological agents. We aimed to systematically review, summarize and quantify available evidence on the effects of non-pharmacological interventions on urinary citrate and nephrolithiasis. METHODS: Manual and electronic database searches (MEDLINE/PubMed, Embase, Cochrane Library, Scopus, Scielo, LILACS) were performed for studies published up to July 2014. Two reviewers independently identified studies for inclusion and extracted data on study characteristics, outcomes and quality assessments. We included controlled studies with non-pharmacological interventions that assessed urinary citrate levels or nephrolithiasis pre- and post-intervention. Meta-analysis was performed by random effects and subgrouped by the type of intervention, and heterogeneity was analysed by I(2). RESULTS: Of the 427 studies identified, 13 studies were included (18 samples), involving 358 participants with a mean age of 43 ± 11.0 years across the studies. Interventions were grouped as commercial fruit juices, soft drinks, calcium-/magnesium-rich mineral water, high-fiber diet, low-animal-protein diet and plant extract. Almost half of the studies (6/13; 8/18 samples) reported effects in non-stone formers. Two studies included stone formers and non-stone formers. Commercial fruit juice interventions showed high I(2) (88.1%, P = 0.000) and an increase in citraturia levels ( 95% confidence interval) of 167.2 (65.4; 269) mg/day. Other types of intervention did not show important heterogeneity; however, pooled estimates were not significant. CONCLUSION: Our review indicates that further larger scale trials are required to analyze whether non-pharmacological interventions can increase urinary citrate levels and act in kidney stone prevention.

Interleukin-6 is a better predictor of mortality as compared to C-reactive protein, homocysteine, pentosidine and advanced oxidation protein products in hemodialysis patients.

Inflammatory markers predict mortality in hemodialysis (HD) patients, whereas a possible association between oxidative stress (OS) markers and survival is less clear. We assessed the impact on all-cause mortality of baseline inflammatory [high-sensitivity C-reactive protein and interleukin-6 (IL-6)] and OS markers (advanced oxidation protein products, pentosidine, homocysteine) in 112 HD patients. We found no significant correlations between inflammatory and OS markers. During the 5.5 years of follow-up, 51 patients died. In a Kaplan-Meier analysis, the survival rate was reduced in patients with IL-6 higher than the median (IL-6 >4.2 pg/ml) (log- rank = 6.47; p = 0.01), in diabetics (log-rank = 12.26; p = 0.0005) and in older patients (log-rank = 11.22; p = 0.0008). Moreover, in Cox analysis only IL-6 and age were independently associated with mortality. We conclude that in this group of prevalent Brazilian HD patients, IL-6 was a better predictor of survival than other inflammatory and OS markers.

The prognostic impact of fluctuating levels of C-reactive protein in Brazilian haemodialysis patients: a prospective study.

BACKGROUND: A single elevated C-reactive protein (CRP) value predicts mortality in haemodialysis (HD) patients, but the relative importance of repeated vs occasional positive systemic inflammatory response findings is not known. METHODS: To assess the influence on survival of occasional inflammation, CRP, serum albumin (S-Alb) and fibrinogen were analysed bimonthly in 180 HD patients (54% male, 49+/-14 years). Clinically significant inflammation was defined as CRP >5.1 mg/l, based on the receiver operating characteristics curve for CRP as predictor of death. Based on four consecutive measurements of CRP, patients were assigned into three groups: group 1 (n = 74; 41%), no inflammation (CRP < or = 5.1 mg/l in all measurements); group 2 (n = 65; 36%), occasional inflammation (1-3 measurements of CRP > 5.1 mg/l); and group 3 (n = 41; 23%), persistent inflammation (all measurements of CRP >5.1 mg/l). The nutritional status was evaluated by subjective global assessment (SGA) and body mass index (BMI), and the survival (21 months of follow-up) by Kaplan-Meier curve and Cox model. RESULTS: The median and range of CRP values (mg/l) for group 1, 2 and 3 were: 3.2 (3.2-5.1), 3.6 (3.2-54.9) and 13.8 (5.2-82), respectively (P<0.001), whereas the prevalence of malnutrition, assessed by SGA and BMI, did not differ significantly between the groups. The survival rate by Kaplan-Meier analysis was significantly different among the groups (chi2 = 12.34; P = 0.0004). Patients in group 3 showed the highest mortality (34%; P = 0.001), compared with group 1 (8%) and group 2 (14%; P = 0.01), respectively, whereas there was no significant difference in mortality between groups 1 and 2. Age, CRP, S-Alb level and SGA were independent predictors of mortality. CONCLUSION: The patients with a persistent elevation of CRP had a higher mortality rate than the patients with occasional CRP elevation. Thus, persistent, rather than occasional, inflammation is an important predictor of death in HD patients.

The influence of hepatitis C and iron replacement therapy on plasma pentosidine levels in haemodialysis patients.

BACKGROUND: Chronic liver disease and intravenous (i.v.) iron therapy can enhance oxidative stress. The aim of this study was to assess the influence of hepatitis C virus (HCV) and i.v. iron administration on oxidative stress in chronic haemodialysis (HD) patients. METHODS: A total of 115 HD patients (47% males, age 47 +/- 13 years) were placed in two groups according to the presence (HCV(+)) or absence (HCV(-)) of serum antibodies against HCV. Plasma pentosidine, high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6) and alanine aminotransferase (ALT) levels were measured. The patients were also analysed according to the tertiles of serum levels of ferritin: group 1 (ferritin <380 ng/ml), group 2 (ferritin 380-750 ng/ml) and group 3 (ferritin >750 ng/ml). The cumulative iron dose was recorded during 6 months prior to the study. RESULTS: HCV(+) patients had significantly higher levels of plasma pentosidine and ALT than HCV(-) patients. Age, gender, serum albumin, IL-6 and hsCRP did not differ according to HCV serology. The levels of pentosidine were related to the ferritin levels and were significantly higher in group 3 compared with group 1. Moreover, the cumulative dose of iron was significantly higher in group 3 than in group 1. Plasma pentosidine showed a positive correlation with age, HCV and ferritin. In a stepwise backward multiple regression model, age and HCV were independent predictors of pentosidine levels. CONCLUSION: HCV in HD patients is associated with increased pentosidine levels, possibly reflecting increased oxidative stress. The association between pentosidine and ferritin levels may suggest an impact of i.v. iron therapy.

The recommendations from the International Society for Peritoneal Dialysis for Peritonitis Treatment: a single-center historical comparison.

The antibiotic treatment currently recommended by the International Society for Peritoneal Dialysis (ISPD) for peritonitis consists of a combination of a first- and a third-generation cephalosporin. The schedule formerly recommended combined a first-generation cephalosporin and an aminoglycoside. No comparison between the treatment schedules has been performed until now. We compared the effectiveness of these two regimens in peritoneal dialysis-related peritonitis at our center. From January 1999 to April 2000, we followed 107 patients in our PD clinic (period 1: 47% men; 32% with diabetes; mean age: 52 +/- 13 years). We followed a similar number of patients from January 2002 to July 2003 (period 2: 109 patients; 54% men; 51% with diabetes; mean age: 56 +/- 18 years). In each period, diagnosis and treatment of peritonitis were based on the recommendations of the ISPD as earlier described. Negative culture rates were similar in period 1 and period 2 (32% vs. 30%). In both study groups, the bacteria that most commonly caused peritonitis were Staphylococcus epidermidis (period 1: 41%; period 2: 39%) and S. aureus (period 1: 27%; period 2: 18%). Gram-positive infections occurred in 59% of patients during period 1 and in 57% during period 2. Gram-negative infections occurred in 16% of patients during period 1 and in 18% during period 2. We observed no significant difference in the peritonitis cure rate from period 1 to period 2 (78% vs. 83%; chi-square: 0.98; p = 0.3), but changes in the primary antibiotic schedule were necessary in 4 patients in period 1 as compared with 1 patient in period 2. The rates of catheter removal were not significantly different during the two periods (period 1: 14%; period 2: 5%; chi-square: 2.5; p = 0.11). Mortality was also not significantly different during the two periods (period 1: 7%; period 2: 5%; chi-square: 0.23; p = 0.62). The two antibiotic schedules were equally effective in the treatment of peritonitis. Cost-effectiveness, impact on residual renal function, and potential development of bacterial resistance must be considered when selecting the antibiotic schedule for peritonitis treatment.

Hemodiálise e síndrome de lise tumoral / Hemodialysis and tumor lysis syndrome

Determinadas neoplasias podem ter sua evoluçäo complicada por hiperuricemia, hiperfosfatemia, hipocalcemia, hiperpotassemia, acidose metabólica e insuficiência renal aguda, quadro este denominado de síndrome de lise tumoral, que ocorre espontaneamente ou após a açäo de quimioterápicos. Os autores apresentam a experiência com cinco casos de síndrome de lise tumoral que necessitaram de tratamento dialítico, ressaltando a importância de aspectos preventivos e terapêuticos nestes pacientes