Are red blood cell indices good indicators of cobalamin,folate and iron satus in the elderly?

16.03.2013 / Risch C, Stanga Z, Medina Escobar P, Nydegger UE, Risch M, Risch L
Are red blood cell indices good indicators of cobalamin,folate and iron satus in the elderly?

Kurzbeschrieb für Probanden

Gewisse Eigenschaften von roten Blutkörperchen, nämlich deren mittleres Volumen und deren mittlere Hämoglobinkonzentration, werden in der Regel als wertvoll angesehen, um auf Mangelzustände für gewisse Vitamine (Folsäure und Vitamin B12) und Spurenelemente (Eisen) hinzuweisen. Diese Studie am gesunden Seniorenkollektiv hat untersucht, ob dies bei älteren Personen auch der Fall ist. Es konnte gezeigt werden, dass die Eigenschaften der roten Blutkörperchen wohl gut sind, um auf Eisenmangel hinzuweisen. Für einen Hinweis auf Vitaminmangel sind sie jedoch nicht geeignet. Dies dürfte den Grund darin haben, dass andere Ursachen, welche ähnliche Veränderungen wie die Vitaminmängel hervorrufen, im Alter gehäuft vorkommen. Die Resultate dieser Analyse wurden am internationalen IFCC-Euromedlab Kongress für Labormedizin, welcher vom 19. – 23. Mai 2013 in Milano stattgefunden hat, vorgestellt.

Kurzbeschrieb für Fachpersonen

Background:

Red blood cell (RBC) indices such as MCV, MCH, as well as the red cell distribution width (RDW) are commonly known to indicate nutritional deficiencies (i.e. vitamin B12, folate, and iron deficiency). Elderly patients show an increased prevalence of several circumstances influencing RBC indices, often with concomitant occurrence. This could affect the diagnostic characteristics of RBC indices in this patient group.

Aim:

To investigate the diagnostic characteristics of RBC indices to indicate nutritional deficiencies in a cohort of elderly individuals.

Methods:

This cross-sectional analysis was performed in subjectively healthy individuals aged >60 years. B12 status was investigated by holotranscobalamin (HoloTc) and total cobalamin (CBL), folate status was assessed with RBC folate and serum folate, whereas iron status was assessed with ferritin and reticulocyte hemoglobin (Ret-Hb) content. Diagnostic characteristics of RBC indices were evaluated by ROC-analysis.

Results:

A total of 1230 Caucasian participants (697 females; 533 males; mean age 72 + 8 years) were included in the study. MCV had a an area under the curve (AUC) of 0.86, 95% confidence interval [0.84,0.88], for recognizing ferritin <15 ng/mL, 0.91 [0.89,0.93] for recognizing Ret-Hb <30 pg, 0.50 [0.48,0.53] for recognizing HoloTC<30 pmol/L, 0.53 [0.50,0.56] for recognizing CBL <150 pmol/L, 0.62 [0.59,0.64] for recognizing folate <7 nmol/L and 0.52 [0.49,0.55] for recognizing RBC folate <370 nmol/L. The AUC for MCH were 0.89 [0.87,0.90] for ferritin <15 ng/mL, 0.96 [0.95,0.97] for Ret-Hb <30 pg, 0.50 [0.48,0.53] for HoloTC <30 pmol/L, 0.54 [0.51,0.56] for CBL <150 pmol/L, 0.59 [0.56,0.61] for folate <7 nmol/L and 0.57 [0.55,0.60] for RBC folate <370 nmol/L. The AUC for RDW were 0.74 [0.72,0.77] for ferritin <15 ng/mL, 0.79 [0.76,0.81] for Ret-Hb <30 pg, 0.50 [0.47,0.53] for HoloTC <30 pmol/L, 0.53 [0.50,0.56] for CBL <150 pmol/L, 0.60 [0.58,0.63] for folate <7 nmol/L, and 0.79 [0.76,0.81] for RBC folate <370 nmol/L.

Conclusions:

RBC indices exhibit satisfactory diagnostic characteristics in the recognition of iron deficiency in elderly Caucasians. However, they do not possess a discriminatory ability to recognize Vitamin B12 and folate deficiency.