CRP and chronic bronchitis: In the other model 4, (corresponding to model 2 but also adjusted for preoperative CRP levels), the independent factors were: FEV1% class (p = 0.000018), GOLD category (p = 0.0025), chronic bronchitis (p = 0.012), age (0.0075), stage of disease (p = 0.019), and CRP levels (p = 0.037).