Plasma homocysteine is associated with low diffusion capacity (DLCO) in COPD patients

Abstract

Introduction:

Chronic obstructive pulmonary disease (COPD) is associated with cardiovascular events, however, its underlying pathophysiological mechanism is unknown. Elevated total plasma homocysteine (tHCY) levels is considered to be a cardiovascular risk factor. Several studies show that COPD may be associated with high tHCY.

Objective:

To identify possible clinical variables associated with high tHCY in COPD patients.

Methods:

We performed an observational study of 88 consecutive smokers or ex-smokers older than fifty years and with more than 10 pack-years smoking history. We used Mann Whitney test to compare COPD with controls. Step wais logistic regression analysis was used to determine the association between tHCY and different clinical, analytical and physiological variables in COPD patients.

Results:

Of the subjects evaluated, 62 had COPD (70,5%) and 26 (29,5%) did not, and served as controls. COPD patients had higher tHCY than controls: median (±SD) 14.2 ± 6.5 vs 11.7 ± 4.5 μmol/L; p 0.025). In COPD patients, using tHCY >14 μmol/L as an independent variable, logistic regression analysis including age, gender, smoking history, creatinine clearance, FEV₁, DLCO and daily alcohol intake, only lung diffusion capacity for carbon monoxide (DLCO) was inversely associated [Odds Ratio (95% confidence intervals) 0.947 (0.904 – 0.992); p 0.023].

Conclusions:COPD patients had higher tHCY than controls and they were associated with a lower DLCO. Therefore, we conclude that COPD patients with low DLCO may have a higher risk of cardiovascular events; however, further studies are needed to confirm this hypothesis.