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Evidence summaries

Haemoglobin and Haematocrit Targets for the Anaemia of Chronic Kidney Disease

Low haemoglobin (Hb) concentrations (< 120 g/l) in patients with chronic kidney disease appear not to be associated with increased mortality as compared to higher Hb concentrations (> 133 g/l). Lower Hb targets appear to be associated with an increased risk for seizures but a reduced risk of hypertension. Level of evidence: "B"

A Cochrane review [Abstract] 1 included 22 studies with a total of 3 707 subjects. Hb ≥ 133 g/l was not associated with a reduction in the risk of all-cause mortality compared with 120 g/l in dialysis and pre-dialysis patients. In pre-dialysis patients, there was a significantly lower end of treatment creatinine clearance with Hb < 120 g/l compared to > 130 g/l (MD -4.17, 95% CI -6.33 to -2.02) but no significant difference in the risk of end-stage kidney disease (ESKD; RR 1.05, 95% CI 0.50 to 2.22). Lower Hb targets resulted in an increased risk for seizures (RR 5.25, 95% CI 1.13 to 24.34) and a reduced risk of hypertensive episodes (RR 0.50, 95% CI 0.33 to 0.76). There were no significant differences in the risk of vascular access thrombosis.

A meta-analysis 3 included 9 RCTs involving 3228 dialysis-dependent patients. In the studies, lower haemoglobin targets varied between 9 to 12 g/dL (hematocrit 23-33) and higher Hb targets between 13-16 g/dL (Hct 30-45).There was a significantly higher risk of fistula thrombosis without heterogeneity (RR 1.34, 95% CI 1.15 to 1.55; p < 0.05) in the higher Hb target group than in the lower Hb target group. However, no significant difference was found in all-cause (RR 1.09, 95% CI 0.93 to 1.27; p = 0.30), cardiovascular events (RR 0.77, 95% CI 0.31 to 1.92; p = 0.58), infectious diseases (RR 0.69, 95% CI 0.24 to 1.96; p = 0.49) and transfusion (RR 0.92, 95% CI 0.42 to 1.99; p = 0.82) between the higher Hb target group and the lower Hb target group.

Another meta-analysis 2 by the same group of investigators included 13 RCTs involving 7606 predialysis patients. There was a significantly lower risk of transfusion (RR 0.59, 95% CI 0.52 to 0.67; p<0.00001) in the higher hemoglobin group than in the lower one. However, no significant difference was found in all-cause mortality (RR 1.10, 95% CI 0.98 to 1.23; p=0.11), stroke (RR 1.32, 95% CI 0.82 to 2.10; p=0.25) and treatment of renal replacement including hemodialysis, peritoneal dialysis and renal transplant (RR 1.08, 95% CI 0.95 to 1.22; p= 0.23) between the higher hemoglobin group and the lower one.

Comment: The quality of evidence is downgraded by limitations in study quality (inadequate or unclear allocation concealment, lack of blinding, more than 20% loss to follow up).

    References

    • Strippoli GF, Navaneethan SD, Craig JC. Haemoglobin and haematocrit targets for the anaemia of chronic kidney disease. Cochrane Database Syst Rev 2006;(4):CD003967. [PubMed]
    • Liu H, Ye Y, Chen Y et al. Therapeutic targets for the anemia of predialysis chronic kidney disease: a meta-analysis of randomized, controlled trials. J Investig Med 2019. [PubMed]
    • Ye Y, Liu H, Chen Y et al. Hemoglobin targets for the anemia in patients with dialysis-dependent chronic kidney disease: a meta-analysis of randomized, controlled trials. Ren Fail 2018;40(1):671-679. [PubMed]

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