Anaemia of Chronic Kidney Disease

Explanation

This is anaemia of chronic kidney disease, and because the patient is already iron replete the appropriate next step is an erythropoiesis-stimulating agent such as erythropoietin. As functioning renal mass is lost, peritubular interstitial fibroblasts produce less erythropoietin, and the result is a normocytic normochromic anaemia whose severity tracks the fall in glomerular filtration rate; it becomes common once eGFR drops below 30 mL/min/1.73 m². Before attributing anaemia to the kidneys, other causes must be excluded, which is why B12, folate, and iron indices are checked; a ferritin of 480 µg/L with a transferrin saturation of 32% excludes both absolute and functional iron deficiency. Current guidance is to consider an erythropoiesis-stimulating agent in non-dialysis chronic kidney disease when haemoglobin falls below 10 g/dL in a symptomatic patient whose iron stores have been repleted and whose other reversible causes have been addressed. The aim is to raise and maintain haemoglobin around 10 to 11.5 g/dL and never to normalise it, because the CHOIR, CREATE, and TREAT trials showed excess stroke, vascular access thrombosis, and cardiovascular events at higher targets. Blood pressure must be monitored during therapy since accelerated hypertension is a recognised adverse effect, and iron indices need rechecking because stimulated erythropoiesis rapidly consumes iron. Oral hypoxia-inducible factor prolyl hydroxylase inhibitors such as daprodustat are an accepted alternative to injectable agents in some health systems. Transfusion is avoided in potential transplant candidates because allosensitisation reduces future graft options.

Why each option

A.

Watchful waiting suits a mild asymptomatic anaemia, but this man is symptomatic with a haemoglobin below 10 g/dL, which is the accepted threshold for starting an erythropoiesis-stimulating agent.

B.

Iron is first-line only when absolute or functional iron deficiency is present. A ferritin of 480 µg/L with a transferrin saturation of 32% shows he is already iron replete.

C.

Correct. Erythropoietin replaces the hormone the failing kidney no longer makes, and it is indicated for symptomatic anaemia below 10 g/dL once iron stores are adequate and other causes excluded.

D.

Transfusion is reserved for severe symptomatic anaemia, haemodynamic compromise, or acute bleeding, and carries a risk of allosensitisation that jeopardises future kidney transplantation.

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