ABSTRACT
As this volume demonstrates, exacerbations of chronic obstructive pulmonary disease (COPD) are important events that contribute to progressive ill health and mortality in these patients (1,2). A variety of increasingly robust definitions have been developed to allow us to capture information about when these events occur and how they relate to other aspects of the COPD patient’s life (1,3-5). Such definitions have considerable utility when collecting data in clinical trials but have not yet translated themselves into routine clinical practice where treatment for COPD, presently dictated by some identifiable symptomatic change, does not always match up with discreet step changes in predefined symptoms, physical findings, or laboratory measurements. The potential for diagnostic overlap is considerable, even in clinical trial populations. Thus, in the large multicenter TORCH study (TOwards a Revolution in COPD Health), which looked, among other things, at the occurrence of health care-defined exacerbations, all episodes treated with antibiotics and/or oral corticosteroids were classed as exacerbations (6). Hence, those episodes that the physician thought were due to, or were associated with, pneumonia were also counted as exacerbations, despite their presumably rather different clinical course and management. This highlights our neglect of issues related to the differential diagnosis of these episodes, and while it may be inevitable that operational definitions applied to clinical trial data produce this sort of confusion, it cannot be considered acceptable in clinical practice.
