Treatment of Anemia in Kidney Disease: Beyond Erythropoietin

Growing concerns about using hypoxia-inducible factor prolyl hydroxylase inhibitors for the treatment of renal anemia

Hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) have emerged as a novel therapeutic class for treating anemia in patients with chronic kidney disease. Small molecule analogs of α-ketoglutarate (AKG), an essential substrate for 2-oxoglutarate-dependent dioxygenases (2-OGDDs), including prolyl hydroxylase domain proteins (PHDs), inhibit PHDs pharmacologically and thereby prevent HIF degradation. HIF stabilization alleviates anemia through several stimulatory effects on erythropoiesis, but it also affects the expression of many anemia-unrelated genes whose protein products exert important functions in vivo. Therefore, the pleiotropic effects of HIF stabilization under normoxic conditions deserve to be examined in more detail. Specifically, we believe that particular attention should be given to epigenetic modifications among the various AKG-based metabolic systems that may be altered by HIF-PHIs. It is noteworthy that AKG has been reported to exert health-protective actions. AKG-based metabolic systems include enzymes associated with the tricarboxylic acid cycle and amino acid metabolism, as well as 2-OGDD-mediated processes, which play important roles in many biological reactions. In this review, we examine the multifaceted effects of HIF-PHIs, encompassing not only their on-target effect of HIF stabilization but also their off-target inhibitory effects on various AKG-based metabolic systems. Furthermore, we examine its potential relevance to cardiovascular complications, based on clinical and animal studies suggesting its involvement in vascular calcification, thrombogenesis and heart failure. In conclusion, although HIF-PHIs offer a promising avenue for anemia treatment in CKD patients, their broader impact on multiple biological systems raises substantial concerns. The intricate interplay between HIF stabilization, AKG competition and cardiovascular complications warrants extensive, long-term investigations to ensure the safety and usefulness of HIF-PHIs in clinical practice.

In blood we trust: anemia as a negative healing prognostic factor in diabetic foot patients

AIM

Anemia has been associated with severity of diabetic foot (DF) disease. Our study aimed to evaluate whether the presence of anemia could decrease the healing chances in DF.

METHODS

We retrospectively analyzed all patients admitted in our department in 2021 for DF, dividing them according to presence (Group A) or absence (Group B) of anemia. Groups were compared for clinical and demographic characteristics, procedures and outcomes: healing rate (HR) at 6 months, healing time (HT) and recurrence rate (RR) at 12 months.

RESULTS

We sorted out data from 196 consecutive patients: 114 (58%) in Group A and 82 (42%) in B. Group A had a higher male prevalence and a longer duration of disease. Group A showed lower hemoglobin concentration (10.3 ± 1.3 g/dL vs 13.1 ± 1.4 g/dL, p < 0.002) and red blood cells count (3.4 ± 0.5 × 106/mL vs 4.8 ± 0.6 × 106/mL, p = 0.004). Group A presented a lower HR (55.2% vs 76.8%, p = 0.0028), no differences in HT and a higher RR (23.6% vs 17.1%, p < 0.02). Cox's logistic regression on healing confirmed the negative impact of anemia: hazard ratio 2.8 (CI 95% 1.4-5.4, p = 0.0037).

CONCLUSIONS

Anemia is frequent in DF and associates to a reduction in healing chances and an increase in recurrences representing an independent predictor of healing failure.

Efficacy and safety of vadadustat compared to darbepoetin alfa on anemia in patients with chronic kidney disease: a meta-analysis

OBJECTIVE

As a novel oral agent in treating anemia of chronic kidney disease (CKD), several clinical trials of vadadustat have been conducted to compare with darbepoetin alfa. This study systematically reviews and investigates the efficacy and safety of vadadustat in the anemia treatment with different duration in both nondialysis-dependent CKD (NDD-CKD) and dialysis-dependent CKD (DD-CKD).

METHODS

Several main databases were searched for randomized controlled trials (RCTs) reporting vadadustat vs darbepoetin alfa for anemia patients with CKD. The outcome indicators were focused on hemoglobin (Hb), the percentage of patients within the target Hb, the need for RBC (Red Blood Cell) transfusions, and serious adverse events (SAEs).

RESULTS

Four eligible studies with 8,026 participants were included. The changes of Hb levels from the baseline in the darbepoetin alfa group were significantly higher than that in the vadadustat group with DD-CKD (mean difference (MD) - 0.19, [95% confidence interval (CI), - 0.21 to - 0.17], p < 0.0001). In NDD-CKD patients, the changes of Hb levels in the two groups are not significantly different (MD = - 0.06, [95% CI, - 0.18 to 0.05], p = 0.006), especially, during the treatment duration of 20-36 weeks (MD = 0.02, [95% CI, - 0.04 to 0.08], p = 0.51). The percentage of patients within the target Hb was significantly lower in the vadadustat group than that in the darbepoetin alfa group in DD-CKD patients (MD = 0.9, [95% CI, 0.86 to 0.94], p < 0.00001), while in NDD-CKD patients, there was no significant difference (MD = 1.05, [95% CI, 0.99 to 1.12], p < 0.00001). In terms of safety, the two agents had no significant difference in the incidence of RBC transfusions and SAEs (RR = 1.26 [95% CI, 0.99 to 1.61], p = 0.52; RR = 0.97, [95% CI, 0.94 to 1.01], p = 0.19; respectively).

CONCLUSION

Compared to darbepoetin alfa, vadadustat had the same effect in raising the hemoglobin level in NDD-CKD patients in the short term. Vadadustat may become an effective and safe alternative for the treatment of patients with anemia and CKD, especially in NDD-CKD patients. As the application of vadadustat is still under exploration, future research should compensate for the limitations of our study to estimate the vadadustat's value.