Table 4B.

Equation of the multivariate model with a high predictive value for the factors related to COPD in LC patients.^a

Pi = 1/1 + e–[–1.162 + (2.801 · protein carbonylation) + (1.796 · nitrotyrosine)]

^aExcluding patients with superoxide anion >3.56 nmol/L (because all of them are always LC-COPD, specificity 100%), a multivariate model with a high predictive value for the factors related to COPD in LC patients was obtained when protein carbonylation and nitrotyrosine were analyzed together. P_i is the probability of underlying COPD in patients with LC, e is the Euler’s number, protein carbonylation = 0, if levels of protein carbonylation are below 0.56 nmol/mg, or protein carbonylation = 1 when levels are equal or above 0.56 nmol/mg and nitrotyrosine = 0, if levels of nitrotyrosine are equal or below 42.88 nmol/L or nitrotyrosine = 1 if levels are above 42.88 nmol/L.