Traditional red cell indices are not suggestive of iron deficiency in children with chronic kidney disease

Abstract

Background. Iron deficiency (ID) contributes significantly to the chronic anaemia seen in chronic kidney disease (CKD). The use of traditional red cell indices such as mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC) and red cell distribution width (RCDW) in screening for ID has been recommended, because they are inexpensive and widely available, especially in low-income settings.

Objectives. To determine the prevalence of anaemia and ID, and the role of traditional red cell indices in screening for ID in children with CKD.

Methods. A sample of 130 children (aged 5 - 18 years) with various stages of CKD was recruited. Blood samples were taken and assessed for traditional red cell indices (MCV, MCH, MCHC and RCDW), serum haemoglobin, creatinine, C-reactive protein, iron, transferrin, transferrin saturation (TSAT) and ferritin.

Results. The mean (standard deviation) age was 10.7 (3.6) years, with a male-to-female ratio of 1.8:1. There was a high prevalence (32%) of anaemia among the patients. The median TSAT and ferritin were 19 (range 13 - 26)% and 50 (28 - 102) ng/mL, respectively. The prevalence of ID and ID with anaemia (IDA) was 43% and 11%, respectively. The majority of the patients (110/130; 85%) were iron deplete, and serum ferritin and RCDW were found to be independent predictors for anaemia, ID and IDA. There was no significant difference in the traditional red cell indices in iron-deplete and iron-replete patients.

Conclusion. The routine use of traditional red cell indices alone in screening for ID in children with CKD should be discouraged.