Iron storage indices and risk of bacterial infections in hemodialysis patients

Association of Abnormal Iron Status with the Occurrence and Prognosis of Peritoneal Dialysis-Related Peritonitis: A Longitudinal Data-Based 10-Year Retrospective Study

This retrospective study investigated the effect of iron status on peritonitis by analyzing longitudinal iron parameters in peritoneal dialysis (PD) patients. Patients who received PD at our center from 1 January 2006 to 31 December 2015 were included and followed up until 31 December 2017. According to the joint quartiles of baseline transferrin saturation and ferritin, iron status was categorized as reference iron status (RIS), absolute iron deficiency (AID), functional iron deficiency (FID), and high iron status (HIS). Generalized estimating equations and Cox regression models with time-dependent covariates were used. A total of 1258 PD patients were included; 752 (59.8%) were male, with a mean (±standard deviation) age of 47.4 (±14.9) years. During a median follow-up period of 35.5 (interquartile range, 18.4–60.0) months, 450 (34.3%) patients had 650 episodes of peritonitis. By analyzing longitudinal data, patients with AID were independently positively associated with the occurrence (adjusted odds ratio (AOR) = 1.45) and treatment failure of peritonitis (adjusted hazard ratio (AHR) = 1.85). Patients with HIS were positively associated with the treatment failure of peritonitis (AHR = 2.70). Longitudinal AID and HIS were associated with the episodes and poor prognosis of peritonitis. Active clinical monitoring and correction of iron imbalance in patients with PD are needed.

Description of the Etiologies, Clinical Characteristics, and Outcomes in Patients with Hyperferritinemia in a Colombian Tertiary Hospital

BACKGROUND

This study analyzes the clinical characteristics, outcomes, and conditions associated with hyperferritinemia (≥5000 ng/mL) in a high-complexity center in Colombia.

METHODS

This retrospective and descriptive study was performed between 2011 and 2020, at the Fundación Valle del Lili, Cali, Colombia, by reviewing medical charts from patients who had serum ferritin measurements equal to or greater than 5000 ng/mL.

RESULTS

We found 350 reports of ferritin values ≥5000 ng/mL, corresponding to 317 patients, with a median ferritin value of 8789 (6001-15 373)  ng/mL. The most frequent etiologies were infection (n = 198, 56.57%), hematologic disorders (n = 104, 29.71%), and blood transfusion (n = 98, 28.00%). These last 2 etiologies cooccurred in 37 (10.57%) cases. The main clinical signs accompanying hyperferritinemia were fever in 199 (56.86%) cases, multiorgan involvement in 125 (35.71%), and hepatomegaly in 95 (27.14%) cases. Ninety-four (29.65%) patients died in the hospital, and 11 (3.47%) died within 30 days after medical discharge, mainly due to infection (n = 51, 48.57%). Intrahospital mortality was associated with significantly higher ferritin levels (10 846, IQR: 6425-23 459) than survival (8452, IQR: 5980-13 932) (P = 0.018).

CONCLUSIONS

Hyperferritinemia is related to many underlying causes, with infection being the principal cause in our cohort, followed by hematologic disorders. Additionally, in-hospital mortality was related to higher ferritin levels.

Association between Dialysis Modality and Infectious Diseases: Peritoneal Dialysis versus Hemodialysis

INTRODUCTION

For dialysis patients with end-stage kidney disease, infectious diseases (IDs) are the most common causes of hospitalization and death. However, the association between dialysis modality and IDs remains unclear. We aimed to determine the association between the dialysis modality and IDs.

METHODS

This retrospective observational cohort study compared the emergency hospitalization and mortality for IDs between peritoneal dialysis (PD) and hemodialysis (HD) patients. After propensity score matching, the risk factors were evaluated by the Cox proportional hazard regression models.

RESULTS

A total of 260 patients were compared - 130 of 135 PD and 130 of 706 HD patients. When the modality-specific ID (PD-catheter ID/peritonitis- and vascular access-related ID) was excluded, no significant differences in emergency hospitalization and mortality rates for overall IDs were observed between the PD and HD groups. Serum ferritin (HR, 2.17; CI, 1.06-4.43; p = 0.03) and Charlson Comorbidity Index (CCI) (HR, 1.24; CI, 1.01-1.52; p = 0.04) were significant predictors of emergency hospitalization for IDs, whereas age (HR, 1.12; CI, 1.05-1.19; p < 0.001), male (HR, 3.38; CI, 1.01-11.3; p = 0.048), serum alkaline phosphatase (ALP) (HR, 6.87; CI, 2.18-21.7; p = 0.001), C-reactive protein (CRP) (HR, 10.7; CI, 3.55-32.1; p < 0.001), and CCI (HR, 1.79; CI, 1.27-2.52; p < 0.001) were significant predictors of ID mortality. When modality-specific ID was included, the emergency hospitalization rate for overall IDs was higher in the PD groups, and PD was a significant predictor of emergency hospitalization for IDs, whereas no significant difference in mortality rate for overall IDs was found between the PD and HD groups.

CONCLUSIONS

ID events were not associated with dialysis modality when modality-specific ID was excluded, whereas the risk of modality-specific IDs was higher in PD than HD. Serum ferritin and ALP as well as age, male sex, CRP, and CCI were the risk factors for ID events.

Efficacy and safety of intravenous iron therapy for functional iron deficiency anemia in hemodialysis patients: a meta-analysis

BACKGROUND

Studies on benefits of intravenous iron therapy among hemodialysis patients with functional iron deficiency anemia have shown conflicting results. We conducted a meta-analysis to assess the efficacy and safety of intravenous iron in this subset of patients.

METHODS

We searched MEDLINE (through December 2012), the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov for single-arm studies and randomized controlled trials (RCT) that examined the effect of intravenous iron for functional iron deficiency anemia in hemodialysis patients on anemia parameters and markers of oxidative stress and inflammation. Studies of absolute iron deficiency were excluded. Random-effect model meta-analyses were used to compute changes in outcomes of interest.

RESULTS

We identified 34 studies (2,658 patients), representing 24 single-arm studies, and 10 parallel-arm RCT. In the analyses of the study arms, intravenous iron therapy resulted in a significant increase in hemoglobin, serum ferritin, transferrin saturation rate, serum iron, reticulocyte hemoglobin content as well as a significant decrease in the percentage of hypochromic erythrocytes and erythropoietin dose. There were significant increases in plasma malonyldialdehyde level and thiobarbituric acid-reactive substances, and a decrease in neutrophil respiratory burst. The analyses of the RCT revealed less robust net changes in these parameters, and there was no increased risk of adverse events including infections, cardiac events and mortality.

CONCLUSIONS

Intravenous iron therapy for functional iron deficiency anemia in hemodialysis patients improves anemia parameters but exerts some effects on markers of oxidative stress that are of unclear clinical significance. The long-term safety and efficacy of this treatment strategy requires further study.

Iron and infection in hemodialysis patients

Intravenous iron is an important component of the treatment of anemia of end-stage renal disease (ESRD), but it is biologically plausible that iron could increase the risk of infection through impairment of neutrophil and T-cell function and promotion of microbial growth. Any such increase in risk would be particularly important because infection is a significant cause of mortality and morbidity in dialysis patients. The overall evidence favors an association between iron and infection in hemodialysis patients, but the optimal iron management strategy to minimize infection risk has yet to be identified. There is a need for further research on this topic, particularly in light of increased utilization of intravenous iron following implementation of the bundled ESRD reimbursement system.

Hyperferritinemia and hyperuricemia may be associated with liver function abnormality in obese adolescents

BACKGROUND

The iron status in human body and its association with liver function in adolescents was rarely studied. The objective was to investigate the association among the levels of serum ferritin, uric acid and alanine aminotransferase (ALT) in adolescents.

METHODS AND RESULTS

A total of 2090 adolescents negative for hepatitis B surface antigen from one junior high school (786, 12-13 years), three senior high schools (973, 15-16 years) and one college (331, 18-19 years) participated in this survey. Anthropometric and biochemical measurements, including complete blood count, ALT, serum ferritin and uric acid were performed. An ALT>42 U/L was defined as elevated, a ferritin level >200 µg/L was defined as hyperferritinemia. A uric acid level >460 µmol/L in males and >340 µmol/L in females was defined as hyperuricemia. The chi-squared test, linear regression and multivariate logistic regression were used for the data analysis. Elevated ALT levels were detected in 76 (3.6%) students and were more prevalent in males than females (6.4% vs. 2.0%, p<0.001). The univariate analysis found gender, age group, body mass index, ferritin level, uric acid level and white blood cell count all to be significantly associated with elevated ALT. Linear regression showed a positive correlation among log(ferritin), uric acid level and ALT level. Elevated ALT occurred more frequently at ferritin level >100 µg/L. The logistic regression analysis found that body mass index, hyperferritinemia and hyperuricemia were significant factors associated with the ALT elevation, but gender, age, and white blood cell count were not.

CONCLUSIONS

Hyperferritinemia and hyperuricemia are two independently significant factors associated with ALT elevation among obese adolescents. More studies are needed to corroborate any hypothesis related to these phenomena.

Catheter-related infections in chronic hemodialysis: a clinical and economic perspective

PURPOSE

Central venous catheters emerged as a major risk factor for infectious complications in hemodialysis (HD) patients. We aimed to assess the incidence of bacteremia in catheter-dependent HD patients and to characterize its clinical and economic impact.

METHODS

We retrospectively collected clinical data and healthcare costs from 15 months for 75 admitted catheter-dependent HD patients, to document the type of bacteremia (complicated or not), pathogen and inflammation.

RESULTS

Bacteremia (97 % with Staphylococcus aureus, 33 % methicillin-resistant) was present in 51 % patients, with an overall infections incidence of 5.79 per 1,000 catheter-days. Metastatic complications occurred in 21 % of bacteremic patients and were associated with higher mortality (38 vs. 4 %; p = 0.001). Although, in patients starting dialysis on catheter (41 %) as compared to those using catheter as bridge angioaccess, inflammation (higher C-reactive protein; p = 0.006) and anemia (lower Hb; p = 0.008) were more pronounced, bacteremia occurred in a lower proportion (32 vs. 64 %, p = 0.007). The total medical costs were 47 % higher in patients with complicated bacteremia than in those without bacteremia (p = 0.008) and 45 % higher in patients starting HD on catheter than in those using catheter as bridge angioaccess (p = 0.002).

CONCLUSIONS

Despite the limitations resulting from retrospective cross-sectional single-center design, our study suggests that patients already on HD who required catheters as bridge angioaccess were more prone to bacteremia. This highlights the importance of close angioaccess monitoring to avoid unnecessary catheter usage. A similar increase in costs when initiating dialysis on catheter as in case of complicated bacteremia strongly supports the initial placement of a native arteriovenous fistula.

Plasma pharmacokinetics of two consecutive doses of ferumoxytol in healthy subjects

Intravenous (IV) iron is used to treat iron-deficiency anemia in patients with chronic kidney disease (CKD). Ferumoxytol is a novel iron formulation administered rapidly as two IV boluses of 510 mg each. In this placebo-controlled, double-blind, parallel-group study, 58 healthy volunteers received ferumoxytol in two 510 mg doses administered 24 h apart. Population pharmacokinetics (PK) analysis was conducted, and a two-compartment open model with zero-order input and Michaelis-Menten elimination was found to best describe the data. The population mean estimates for volume of distribution of the central compartment (V(1)), maximal elimination rate (V(max)), and ferumoxytol concentration at which rate of metabolism would be one-half of V(max) (K(m)) were 2.71 l, 14.3 mg/h, and 77.5 mg/l, respectively. When the effect of body weight on V(1) was added in the analysis, interindividual variability was found to be reduced. A noncompartmental analysis of two simulated 510-mg ferumoxytol doses was also performed to provide clinically interpretable data on half life and exposure. Ferumoxytol given as two consecutive 510-mg doses was well tolerated.