Anemia and iron deficiency among chronic kidney disease Stages 3-5ND patients in the Chronic Kidney Disease Outcomes and Practice Patterns Study: often unmeasured, variably treated

Abstract

Background: International variation in anemia assessment and management practices in chronic kidney disease (CKD) is poorly understood.

Methods: We performed a cross-sectional analysis of anemia laboratory monitoring, prevalence and management in the prospective Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps). A total of 6766 participants with CKD Stages 3a-5ND from nephrology clinics in Brazil, France, Germany and the USA were included.

Results: Among patients with anemia (hemoglobin <12 g/dL), 36-58% in Brazil, the USA and Germany had repeat hemoglobin measured and 40-61% had iron indices measured within 3 months of the index hemoglobin measurement. Anemia was more common in the USA and Brazil than in France and Germany across CKD stages. Higher ferritin and lower iron saturation (TSAT) levels were observed with lower hemoglobin levels, and higher ferritin with more advanced CKD. The proportion of anemic patients with ferritin <100 ng/mL or TSAT <20% ranged from 42% in Brazil to 53% in France and Germany, and of these patients, over 40% in Brazil, Germany and the USA, compared with 27% in France, were treated with oral or intravenous iron within 3 months after hemoglobin measurement. The proportion of patients with hemoglobin <10 g/dL treated with erythropoiesis-stimulating agents ranged from 28% in the USA to 57% in Germany.

Conclusions: Hemoglobin and iron stores are measured less frequently than per guidelines. Among all regions, there was a substantial proportion of anemic patients with iron deficiency who were not treated with iron, highlighting an area for practice improvement in CKD care.

Keywords: anemia; chronic kidney disease; erythropoiesis-stimulating agents; iron deficiency; iron supplementation.

FIGURE 1

Cumulative incidence of hemoglobin measurement. (a) By CKD stage. (b) By hemoglobin level. Graph by CKD stage allows patients to contribute once for each stage. French data are excluded from the graph as the laboratory measurements are collected according to a predefined study protocol. Time 0 is the first hemoglobin (Hgb) measurement. KDIGO 2012 anemia guidelines [21]: (i) for nondialysis CKD patients with anemia not being treated with an ESA, hemoglobin should be measured when clinically indicated and at least every 3 months in patients with CKD Stages 3–5ND; (ii) for nondialysis CKD patients being treated with an ESA, hemoglobin should be measured at least monthly during the initiation phase of ESA therapy, whereas hemoglobin should be measured at least every 3 months during the maintenance phase of ESA therapy.

FIGURE 2

Measurement of iron parameters, by country. (a) By CKD stage. (b) By hemoglobin level. Patients could contribute once for each CKD stage experienced during the study for (a). Measurement within ±3 months from hemoglobin (Hgb) value. French data are excluded from the graph as the laboratory measurements are collected according to a predefined study protocol.

FIGURE 3

Hemoglobin distribution, by country and CKD stage. Patients could contribute once for each CKD stage experienced during the study for (a). First hemoglobin (Hgb) for each stage was taken if there were multiple measures.

FIGURE 4

Serum ferritin distribution, by country. (a) By CKD stage. (b) By hemoglobin level. Patients could contribute once for each CKD stage experienced during the study for (a). Ferritin values within ±3 months from hemoglobin (Hgb) value.

FIGURE 5

TSAT distribution, by country. (a) By CKD stage. (b) By hemoglobin level. Patients could contribute once for each CKD stage experienced during the study for (a). TSAT values within ±3 months from hemoglobin (Hgb) value.

FIGURE 6

Iron (Fe) status, by country. (a) By CKD stage. (b) By hemoglobin level. Patients could contribute once for each CKD stage experienced during the study for (a). Ferritin and TSAT values within ±3 months from hemoglobin value in (b).

FIGURE 7

Prescription of ESAs and iron (oral or IV), by country. (a) By CKD stage. (b) By hemoglobin level. Patients could contribute once for each CKD stage experienced during the study for (a). Prescription within 3 months subsequent to hemoglobin measurement. Graph by CKD stage allows patients to contribute once for each stage. ESA = Erythropoiesis-stimulating agent.