Risk factors for accelerated decline among patients with chronic obstructive pulmonary disease.

The interpretation of studies of decline of FEV1 in patients with established COPD is complicated by many methodologic problems, such as retrospective analyses, small patient groups, different patient selection, and differences in the mathematical models used. Nevertheless, it is clear that the rate of loss of lung function is above all determined by the smoking status and history. A more abnormal bronchoconstrictor response is predictive of a steeper decline of lung function. Other prognostic factors have not been consistently found in patients with established disease. The decline can be influenced favorably by smoking cessation, and probably by oxygen administration in hypoxemic patients. Long-term oral steroid use seems to be associated with a more favorable course of FEV1, but the value of inhaled corticosteroids has not yet been established. Maintenance therapy with bronchodilators only does not appear to improve the decline of FEV1.