COPD: Pathogenesis, Epidemiology, and the Role of Cigarette Smoke

Most patients with GOLD Stages I or II disease will not die of respiratory failure but are likely to die of non-respiratory causes before ever reaching GOLD Stage IV.

Generally, survival even in severe COPD is fairly long, so significant disability and morbidity may occur before palliative care decisions are entertained. Although survival predictions can be estimated using rules based on selected parameters, such as the BODE index (discussed previously), a realistic, patient-specific prediction regarding survival is not possible. Clearly, although the presence of hypoxemia or hypercarbia offers additional prognostic information, a formulaic application that incorporates these parameters to predict survival does not exist.

The outcome in COPD may be best viewed with respect to symptomatic improvement in treated versus untreated disease. Most of the single-drug and combination therapies previously discussed provide a clinically significant improvement in quality of life. A discussion of the improvement achieved using pharmacologic agents constitutes an important aspect of patient care, as a patient's lack of perceived benefit may not only limit the use of medications but also interfere with smoking abstinence. Studies that incorporate longer time frames for evaluating the effect of medications on survival suggest a survival benefit.

_{Reposted with permission from Decision Support in Medicine, LLC.}