Questionable Reliability of Homocysteine As the Metabolic Marker for Folate and Vitamin B12 Deficiency in Patients with Chronic Obstructive Pulmonary Disease

Abstract

Background: An increased homocysteine (Hcy) concentration may represent a metabolic marker of folate and vitamin B-12 deficiency, both significant public health problems. For different reasons, patients with chronic obstructive pulmonary disease (COPD) are prone to these deficiencies. The study evaluates the reliability of Hcy concentration in predicting folate or vitamin B-12 deficiency in these patients. Methods: A group of 50 COPD patients (28 males/22 females, age ((X) over bar +/- SD=49.0 +/- 14.5) years was enrolled. A chemiluminescent microparticle immunoassay was applied for homocysteine, folate and vitamin B-12 concentration. Kolmogorov-Smirnov, Mann-Whitney U and chi(2) tests, Spearman's correlation and ROC analysis were included in the statistical analysis, with the level of significance set at 0.05. Results: Average (SD) concentrations of folate and vitamin B-12 were 4.13 (2.16) mu g/L and 463.6 (271.0) ng/L, whereas only vitamin B-12 correlated with the Hcy level (P=-0.310 (R=0.029)). Gender related differences were not significant and only a borderline significant correlation between age and folate was confirmed (R=0.279 (P=0.047)). The incidence of folate and vitamin B-12 deficiency differed significantly (P=0.000 and P lt 0.000 for folate and vitamin B12 respectively), depending on the cutoff used for classification (4.4, 6.6 and 8.0 mu g/L folate; 203 and 473 ng/L - vitamin B-12). ROC analyses failed to show any significance of hyperhomocysteinemia as a predictor of folate or vitamin B-12 deficiency. Conclusion: Reliability of the Hcy concentration as a biomarker of folate or vitamin B-12 depletion in COPD patients is not satisfactory, so their deficiency cannot be predicted by the occurrence of HHcy.