Journal Article

Idiopathic Pulmonary Fibrosis: Outcome in Relation to Smoking Status

Hansell, David M, Desai, Sujal R, Antoniou, Katerina M, Marten, Katharina, Wells, Athol U, Siafakas, Nikolaos M, Rubens, Michael B, Nicholson, Andrew G, du Bois, Roland M

2008

Overview

The pathogenic importance of smoking status in idiopathic pulmonary fibrosis (IPF) is uncertain. In theory, increased oxidative stress in current and former smokers might promote disease progression. However, better survival has been reported for current smokers with IPF, although this might reflect less severe disease at presentation (a \"healthy smoker effect\"). To determine whether smoking status is associated with survival differences in IPF. A total of 249 patients with IPF were studied (current smokers, n = 20; former smokers, n = 166; never-smokers, n = 63). Survival was evaluated against smoking status, using proportional hazards analysis, adjusting for sex, age, disease severity (extent of the disease on high-resolution computed tomography, composite physiologic index [CPI], percentage predicted diffusing capacity for carbon monoxide in separate models), and the degree of honeycombing. Current smokers had milder disease than did former smokers, with lower CPI scores (P < 0.0001), less extensive disease on high-resolution computed tomography (P < 0.005), and higher unadjusted survival (hazard ratio = 0.44; 95% confidence interval = 0.24, 0.80; P = 0.007). However, survival did not differ between current and former smokers (P = 0.39) after adjustment for CPI levels. By contrast, the increase in survival seen in nonsmokers than in former smokers (hazard ratio = 0.51; 95% confidence interval = 0.41, 0.83; P = 0.008) was amplified (P < 0.0005) by adjustment for CPI levels. In IPF, survival and severity-adjusted survival are higher in nonsmokers than in former smokers or the combined group of former and current smokers. By contrast, a better outcome in current smokers, compared with former smokers, reflects less severe disease at presentation and may represent a healthy smoker effect.

• Publisher: Am Thoracic Soc,American Lung Association,Oxford University Press
• Subject: Aged / Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy / Biological and medical sciences / Carbon monoxide / Confidence intervals / Emergency and intensive cardiocirculatory care. Cardiogenic shock. Coronary intensive care / Female / Follow-Up Studies / Forced Expiratory Volume / Humans / Intensive care medicine / Male / Medical sciences / Middle Aged / Oxidative stress / Pneumology / Proportional Hazards Models / Pulmonary fibrosis / Pulmonary Fibrosis - etiology / Pulmonary Fibrosis - mortality / Pulmonary Fibrosis - physiopathology / Pulmonary hypertension. Acute cor pulmonale. Pulmonary embolism. Pulmonary vascular diseases / Severity of Illness Index / Smoking - adverse effects / Smoking cessation / Survival Analysis / Tomography / Vital Capacity