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

BACKGROUND An increased homocysteine (Hcy) concentration may represent a metabolic marker of folate and vitamin B12 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 B12 deficiency in these patients. METHODS A group of 50 COPD patients (28 males/22 females, age (χ̄±SD=49.0±14.5) years was enrolled. A chemiluminescent microparticle immunoassay was applied for homocysteine, folate and vitamin B12 concentration. Kolmogorov-Smirnov, Mann-Whitney U and χ2 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 B12 were 4.13 (2.16) μg/L and 463.6 (271.0) ng/L, whereas only vitamin B12 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 B12 deficiency differed significantly (P=0.000 and P<0.000 for folate and vitamin B12 respectively), depending on the cutoff used for classification (4.4, 6.6 and 8.0 μg/L - folate; 203 and 473 ng/L - vitamin B12). ROC analyses failed to show any significance of hyperhomocysteinemia as a predictor of folate or vitamin B12 deficiency. CONCLUSION Reliability of the Hcy concentration as a biomarker of folate or vitamin B12 depletion in COPD patients is not satisfactory, so their deficiency cannot be predicted by the occurrence of HHcy.