Resistant Anemia in CKD Patients

Resistant Anemia
in CKD Patients
Kamal Okasha MD.
Prof of Internal Medicine & Nephrology, Tanta University, Egypt.
Fellowship of Nephrology, Sask University, Canada.

Agenda
•Overview.
•Definitions.
•Causes of ESA Hyporesponsiveness.
•KDIGO Guideline.
•NICE Guideline.
•New Anemia Therapies.

Overview
• The anemia of CKD is principally due to reduced renal
erythropoietin (EPO) production and, to a lesser degree, to
shortened red cell survival.
• Anemia can develop well before the onset of uremic
symptoms due to ESRD.
• Some patients are relatively resistant to ESAs and require large
doses.
• The poor response to ESA therapy may be associated with
increased mortality.
Bradbury BD, Danese MD, Gleeson M, Critchlow CW. Effect of Epoetin alfa dose changes on hemoglobin and
mortality in hemodialysis patients with hemoglobin levels persistently below 11 g/dL. Clin J Am Soc Nephrol 2009;
4:630.

Overview
•A large ESA requirement is defined as
either :
the requirement of excessive doses during
initiation of therapy, or
inability to achieve or maintain target
hemoglobin levels despite the large dose in
the iron-replete patient.

Erythropoiesis – stimulating agents

Erythropoiesis – stimulating agents
FDA – Food and Drug Administration;
EMA – European Medicines Agency

Definitions
• According to the European best practice
guidelines (EBPG):
The resistance to ESAs is defined as a failure to
achieve target Hb levels (11– 12 g/dl) with doses
lower than 300 IU/kg/ week of epoetin or 1.5
μg/kg/ week of darbopoietin-α.
Locatelli, F, Aljama, P, Barany, P, et al. Revised European best practice guidelines for the
management of anaemia in patients with chronic renal failure. Nephrol Dial Transplant (2004).
Suppl 2:ii, 1-47.

Definitions
• According to NKF KDOQI guidelines,
Hyporesponsiveness to ESAs therapy is defined by, at
least, one of these situations:
1. a significant increase in the ESA dose required to
maintain a certain Hb level,
2. a significant decrease in Hb level at a constant ESA
dose or
3. a failure to increase the Hb level to higher values than
11 g/dL, despite the administration of an ESA dose
equivalent to epoetin higher than 500 IU/kg/week.
KDOQI Clinical Practice Guidelines and Clinical Practice Recommendations for Anemia
in Chronic Kidney DiseaseAm J Kidney Dis (2006). S, 11-145.

Definitions
• KDIGO defines :
initial hyporesponsiveness as having no increase
in hemoglobin concentration after the first
month of appropriate weight-based dosing.
acquired hyporesponsiveness as requiring two
increases in ESA doses up to 50 percent beyond
the dose at which the patient had originally been
stable.
 KDIGO clinical practice guidelines for anemia in chronic kidney disease. Kidney Int Suppl 2012;
2:288.

The ESA Resistance Index
(ERI),
• defined as the weekly weight-adjusted ESA dose (U/kg/week)
divided by hemoglobin level (g/dl).
• By means of the ERI values (baseline data), patients were
divided into quartiles:
• The cut-off values were Quartile 1 < 4.19.
• Quartile 2 (4.20 – 6.64).
• Quartile 3 (6.65 – 10.11).
• Quartile 4 > 10.11.
• Patients in the upper quartile were defined as ESA resistant.

Causes of
ESA Hyporesponsiveness
1) Iron deficiency.
2) Bone disease due to secondary hyperparathyroidism.
3) Occult malignancy and unsuspected hematologic
disorders (eg; vitamin B12 and folate deficiency,
Hemoglobinopathies and Multiple myeloma/
myelofibrosis/ myelodysplastic syndrome).
4) Chronic inflammation.
5) Although now rare, the accumulation of aluminum
(Aluminum overload). !!!

Causes of
ESA Hyporesponsiveness
6) Inadequate dialysis.
7) ACE inhibitors and ARBs. may result in relative ESA
resistance.
8) Development of pure red cell aplasia associated with
the presence of neutralizing anti-EPO antibodies in
patients treated with particular brands of ESA by the
subcutaneous route.
9) Presence of human immunodeficiency virus (HIV)
infection.

Iron deficiency
• Iron deficiency: The most common cause, which may be due to
external blood losses and/or exhaustion of iron stores due to an
increase in erythropoiesis caused by ESA treatment.
• Iron-restricted erythropoiesis is frequent in CKD patients and is due
to absolute or functional iron deficiency.
• It is important to distinguish between absolute and functional iron
deficiency.
• Indeed, there is a controversy about iron supplementation when
TSAT is lower than 20-30% and ferritin is higher than 500ng/mL
(functional deficiency).
• In this situation, probably associated with an inflammatory
response, an excess of iron can be potentially harmful to these
patients.
Johnson, D. W, Pollock, C. A, & Macdougall, I. C. Erythropoiesis-stimulating agent hyporesponsiveness. Nephrology
(Carlton) (2007). , 12, 321-330.

Inflammation
Chronic inflammation (possibly due to enhanced cytokine
production).
• This is also consistent with the observation that an increased
number of vascular access-related infections and dialysis catheter
insertions are associated with higher ESA requirements.
• The anemia of CKD is often referred as an inflammatory anemia.
• Inflammation is a common feature in CKD patients, mainly, in those
under HD.
Costa, E, Lima, M, Alves, J. M, et al. Inflammation, T-cell phenotype, and inflammatory cytokines in chronic kidney
disease patients under hemodialysis and its relationship to resistance to recombinant human erythropoietin
therapy. J Clin Immunol (2008). , 28, 268-275.

Inflammation
Inflammation contributes to anemia through several ways:
• Suppression of erythropoiesis:
directly, by the inhibitory effects of pro-inflammatory
cytokines: IL-1β and TNF-α
indirectly as IL-1β and TNF-α stimulate the production of
INF-γ, known to mediate erythropoiesis suppression.
• Accelerated destruction of erythrocytes by the reticulo-
endothelial macrophages activated by the inflammatory
state.

Inflammation
Inflammation contributes to anemia through several ways:
• Reduction of EPO production: IL-1β and TNF-α increase
the expression NF-κB, inhibitory of the transcriptional
factors of EPO gene.
• Impaired iron availability for erythropoiesis: transferrin
receptors in erythroid and non erythroid cells can be
down-regulated by inflammatory cytokines reducing iron
uptake

Decreased hepcidin excretion
• An increase of hepcidin levels leads to a decrease in iron
absorption and an inhibition of iron release from its
storages (macrophages and hepatocytes),
• As hepcidin binds to ferroportin (the only known iron
exporter in the cells) promoting its internalization and
degradation in lysosomes.
Mena, N. P, Esparza, A, Tapia, V, Valdes, P, & Nunez, M. T. Hepcidin inhibits apical iron uptake in intestinal
cells. Am J Physiol Gastrointest Liver Physiol (2008). G, 192-198.

Decreased hepcidin excretion
• Hepcidin is increased in HD patients, and it is regulated
by inflammation and linked to ESA resistance.
• Hepcidin correlates with IL-6, the cytokine that stimulate
its production, and with ferritin reflecting high
inflammation and high levels of iron stores.
• Hepcidin could be a marker of functional iron deficiency
and that ESA therapy can decrease hepcidin levels.
Won, H. S, Kim, H. G, Yun, Y. S, et al. IL-6 is an independent risk factor for resistance
to erythropoiesis-stimulating agents in hemodialysis patients without iron deficiency.
Hemodial Int (2012). , 16, 31-37.

Secondary hyperparathyroidism
• Bone disease due to secondary hyperparathyroidism; this
should be suspected when ESA resistance occurs in iron-
replete patients in the setting of severe hyperparathyroidism.
• Several mechanisms have been proposed as
interference with RBC production as PTH causes bone marrow
fibrosis,
has an inhibitory effect on CFU-E and interferes with EPO
endogenous production ;
interference with RBC survival as PTH increases osmotic
fragility of erythrocytes.
Brancaccio, D, Cozzolino, M, & Gallieni, M. Hyperparathyroidism and anemia in
uremic subjects: a combined therapeutic approach. J Am Soc Nephrol (2004). Suppl1:S, 21-24

Inadequate dialysis
• Inadequate dialysis is associated with the need for higher
ESA doses.
• Some studies showed that convective treatments
present benefits in ESA response, as compared with
other treatments.
• High flux HD (HF-HD) and online hemodialfiltration (OL-
HDF) improve the response to ESAs, as compared to low
flux HD (LF-HD), probably due to a better removal of
middle and large molecules that impair erythropoiesis.
Johnson, D. W, Pollock, C. A, & Macdougall, I. C. Erythropoiesis-stimulating agent
hyporesponsiveness. Nephrology (Carlton) (2007). , 12, 321-330.

OL-HDF favorably impacts anemia by not only eliminating putative uremic
inhibitors that suppress erythropoiesis, reducing red cell destruction and
increasing iron availability, but also by mechanisms restricting underlying
inflammation and endothelial dysfunction that are crucial to both CKD and
anemia.

ACEI and ARBs
• They can act through several mechanisms, not well
understood, including inhibition of angiotensin-induced
EPO release and
• increased plasma levels of N-acetyl-serylaspartyl-lysil-
proline that impairs the recruitment of pluripotent
hemopoietic stem cells.
Priyadarshi, A, & Shapiro, J. I. Erythropoietin resistance in the treatment of the anemia
of chronic renal failure. Semin Dial (2006). , 19, 273-278.

• During the last few years, newer strategies for correcting
anemia have been investigated:

• None of the newer agents has outcomes data showing
superiority to existing ESAs.
• None has been tested in sufficient numbers of
hyporesponsive patients to know whether the outcomes
in these patients are different from those with
conventional ESAs.
• They therefore will need to be subjected to the same
degree of scientific investigation as the existing ESAs.
• Some of them were withdrawn from the market because
of their side effects.

Resistant Anemia in CKD Patients

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