Relationships between iron dose, hospitalizations and mortality in incident haemodialysis patients: a propensity-score matched approach

Investigating the relationship between erythropoiesis-stimulating agents and mortality in hemodialysis patients: A systematic review and meta-analysis

BACKGROUND

In recent years, various studies have been conducted to investigate the relationship between erythropoiesis-stimulating agents (ESAs) and mortality in hemodialysis patients, who showed contradictory results. Therefore, this study aimed to investigate the relationship between ESAs and mortality in hemodialysis patients.

METHODS

The current study is a systematic review and meta-analysis based on observational and interventional studies published in the Web of Science, Cochrane Library, Science Direct, PubMed, Scopus, and Google Scholar databases between 1980 and the end of 2022. Jadad scale checklist and Newcastle Ottawa scale were used to evaluate the quality of articles. The study data were analyzed using Stata 15 software.

RESULTS

In the initial search, 3933 articles were extracted, and by screening and considering the research criteria, 68 studies were finally included in the meta-analysis. According to the meta-analysis results, the risk ratio (RR) of overall mortality in hemodialysis patients receiving ESAs was equal to 1.19 (95% CI: 1.16-1.23, P ≤ 0.001). The RR of mortality in patients aged 60 years and under was equal to 1.33 (1.15-1.55, P ≤ 0.001), in the age group over 60 years was equal to 1.13 (1.10-1.16, P ≤ 0.001), in randomized clinical trial studies was equal to 1.06 (0.80-1.40, P = 0.701), in cohort studies was equal to 1.20 (1.16-1.25, P ≤ 0.001), in American countries was equal to 1.19 (1.10-1.29, P ≤ 0.001), in Asian countries was equal to 1.15 (1.10-1.19, P ≤ 0.001), and in European countries was equal to 1.18 (1.05-1.34, P = 0.007).

CONCLUSION

The results of the study show that receiving ESAs is associated with a 19% increase in the risk of overall mortality in hemodialysis patients.

The Impact of CKD Anaemia on Patients: Incidence, Risk Factors, and Clinical Outcomes-A Systematic Literature Review

Anaemia is a common consequence of chronic kidney disease (CKD); however, the risk factors for its development and its impact on outcomes have not been well synthesised. Therefore, we undertook a systematic review to fully characterise the risk factors associated with the presence of anaemia in patients with CKD and a contemporary synthesis of the risks of adverse outcomes in patients with CKD and anaemia. We searched MEDLINE, EMBASE, and the Cochrane Library from 2002 until 2018 for studies reporting the incidence or prevalence of anaemia and associated risk factors and/or associations between haemoglobin (Hb) or anaemia and mortality, major adverse cardiac events (MACE), hospitalisation, or CKD progression in adult patients with CKD. Extracted data were summarised as risk factors related to the incidence or prevalence of anaemia or the risk (hazard ratio (HR)) of outcome by Hb level (<10, 10-12, >12 g/dL) in patients not on dialysis and in those receiving dialysis. 191 studies met the predefined inclusion criteria. The risk factor most associated with the prevalence of anaemia was CKD stage, followed by age and sex. Mean HRs (95% CI) for all-cause mortality in patients with CKD on dialysis with Hb <10, 10-12, and >12 g/dL were 1.56 (1.43-1.71), 1.17 (1.09-1.26), and 0.91 (0.87-0.96), respectively. Similar patterns were observed for nondialysis patients and for the risks of hospitalisation, MACE, and CKD progression. This is the first known systematic review to quantify the risk of adverse clinical outcomes based on Hb level in patients with CKD. Anaemia was consistently associated with greater mortality, hospitalisation, MACE, and CKD progression in patients with CKD, and risk increased with anaemia severity. Effective treatments that not only treat the anaemia but also reduce the risk of adverse clinical outcomes are essential to help reduce the burden of anaemia and its management in CKD.

Infectious complications and mortality associated with the use of IV iron therapy: a systematic review and meta-analysis

BACKGROUND

Parental iron is used to optimize hemoglobin and enhance erythropoiesis in end-stage renal disease along with erythropoietin-stimulating agents. Safety of iron has been debated extensively and there is no definite evidence whether parenteral iron increases the risk of infections and mortality. We performed this meta-analysis to evaluate the incidence of infectious complications, hospitalizations and mortality with use of parenteral iron.

METHODS

Medical electronic databases [PubMed, EMBASE, Scopus, Web of Science, and cochrane central register for controlled clinical trials (CENTRAL)] were queried for studies that investigated the association between intravenous iron administration and infection in hemodialysis patients. 24 studies (8 Randomized control trials (RCTs) and 16 observational studies) were considered for qualitative and quantitative analysis.

RESULTS

All-cause mortality Data from 6 RCTs show that high-dose IV iron conferred 17% less all-cause mortality compared to controls; however, this outcome was not statistically significant (OR = 0.83, CI [0.7, 1.01], p = 0.07). Nine observational studies were pooled under the random effects model due to significant heterogeneity (I² = 83%, p < 0.001). The overall HR showed increased risk of all-cause mortality in the high-dose group but was statistically non-significant (HR = 1.1, CI [1, 1.22], p = 0.06). Infections Four RCTs with no heterogeneity among their data (I² = 0%, p = 0.61). Under the fixed effect model, there was no difference in the infection rate between high-dose iron and control group (OR = 0.97, CI [0.82, 1.16], p = 0.77); eight observational studies with significant heterogeneity and utilizing random effects model. Summary HR showed increased yet non-significant risk of infection in the high-dose group (HR = 1.13, CI [0.99, 1.28], p = 0.07) Hospitalization 1 RCT and six observational studies provided data for the rate of all-cause hospitalization. There was marked heterogeneity among observational studies. RCT showed no significant difference between high-dose iron and controls in the rate of hospitalization (OR = 1.03, CI [0.87, 1.23], p = 0.71). Summary HR for observational data showed increased rate of hospitalization in the high-dose group; however, this effect was not statistically significant (HR = 1.11, CI [0.99, 1.24], p = 0.07). Cardiovascular events One RCT compared the rate of adverse cardiovascular events between high-dose and low-dose iron. No significant difference was observed between the two groups (22.3% vs 25.6%, p = 0.12). Six heterogeneous observational studies (I² = 65%, p < 0.001) reported on the rate of cardiovascular events. No significant difference was observed between high-dose iron and controls (HR = 1.18, CI [0.89, 1.57], p = 0.24).

CONCLUSION

High-dose parenteral iron does not seem to be associated with higher risk of infection, all-cause mortality, increased hospitalization or increased cardiovascular events on analysis of RCTs. Observational studies show increased risk for all-cause mortality, infections and hospitalizations that were not statistically significant and were associated with significant heterogeneity.

Achievement of renal anemia KDIGO targets by two different clinical strategies - a European hemodialysis multicenter analysis

Background

The optimal treatment algorithm for iron therapy and the use of erythropoiesis-stimulating agents (ESA) in anemic hemodialysis (HD) patients has not been established. Hemoglobin (Hb) target levels can be achieved through more frequent intravenous (IV) iron use with lower ESA dose, or with less iron dosing but higher ESA. ESA therapy to correct anemia may result in severe arterial and venous thrombotic complications and the evidence base evaluating hard clinical outcomes related to the use of IV iron is sparse.

Methods

A total of 1247 maintenance HD patients from 12 dialysis centers in Portugal (n = 730) and Poland (n = 517) were considered. We assessed achievement of KDIGO renal anemia targets with focus on treatment strategies, which typically differ between countries. In Poland the use and dose of IV iron was 35–72% higher than that in Portugal (p <  0.001) during three consecutive months; use and dose of ESA was 61% higher in Portugal (5034 vs 3133 IU (adjusted)/week, p <  0.001).

Results

Mean Hb concentration was similar (11.0 vs 11.0 g/dL) in patients treated in both countries and the proportion of patients within KDIGO anemia target was 69.5% in Poland vs 65.8% in Portugal (NS). Ferritin and TSAT levels and the proportion of patients with TSAT > 20 and > 50% were both significantly higher in patients in Poland (88.8 and 14.6%) than in Portugal (76.3 and 5.7% respectively, p <  0.001). Significantly more patients in Poland had a ferritin concentration > 800 μg/L (35.6%) compared to Portugal (15.8%, p <  0.001). The ESA resistance index (ERI) was significantly higher in patients treated in Portugal (p <  0.001). Correlation analyses showed confounding by treatment indication in unadjusted models. Multiple and logistic regression analyses showed that with ferritin within KDIGO recommended range of 200–800 μg/L the odds for Hb within guidelines increased significantly. Annual gross mortality was 16% in Poland and 13% in Portugal (NS); there were no differences in cause-specific mortality.

Conclusions

Administration of high doses of IV iron in routine clinical HD practice may not be associated with considerable harm. However, large randomized controlled trials are needed to provide absolute evidence of iron safety.

Measurement of iron status in chronic kidney disease

Anemia is a common complication of chronic kidney disease (CKD) in children, and dysregulation of iron homeostasis plays a central role in its pathogenesis. Optimizing iron status is a prerequisite for effective treatment of anemia. Insufficient iron can lead to inappropriate escalation of the erythropoiesis-stimulating agent (ESA) dose, which is associated with adverse outcomes. Excess iron supplementation also has negative sequelae including free radical tissue damage and increased risk of systemic infection. Notwithstanding the importance of optimizing bioavailable iron for erythropoiesis for children with advanced CKD, achieving this remains challenging for pediatric nephrologists due to the historical lack of practical and robust measures of iron status. In recent years, novel techniques have come to the fore to facilitate accurate and practical assessment of iron balance. These measures are the focus of this review, with emphasis on their relevance to the pediatric CKD population.