Measuring and quantifying acute exacerbations of COPD: pitfalls and practicalities

Abstract

@ERSpublicationsIt is difficult to conclude that EXACT is effective at measuring COPD exacerbation events http://ow.ly/qynrG Pity the poor clinical researcher who is charged with identifying and quantifying chronic obstructive pulmonary disease (COPD) exacerbation events in clinical trials. An exacerbation of COPD is a clinical event that: 1) has no standard, consensus definition [1]; 2) often goes unreported and undetected if patients choose to stay at home instead of presenting to a healthcare provider [2]; 3) often occurs suddenly with little or no warning [3]; and 4) is subject to diagnostic uncertainty and is easily confused with pulmonary embolism, congestive heart failure or pneumonia [4][5][6].Given these inherent difficulties, much-needed efforts have been made towards developing better measurement tools for quantifying COPD exacerbation events [7]. One such new measurement tool is the Exacerbations of Chronic Pulmonary Disease Tool (EXACT), a 14-item, patient-reported daily symptom diary that attempts to accurately capture the frequency, severity, and duration of exacerbations, and which is meant to be used in clinical trials and cohort studies of COPD patients [8]. A tool such as EXACT is desperately needed by COPD clinical researchers [9], assuming that it works.In this issue of the European Respiratory Journal, MACKAY et al. [10] have attempted to test EXACT to see if it fulfils its expected functions. The investigators prospectively administered EXACT as well as their previously validated London COPD Cohort diary cards to 58 patients in their COPD cohort on a daily basis [10]. Clearly, the hope going into the study was that EXACT events and London diary card events would be concordant, and that EXACT would provide additional important information on the severity and duration of the exacerbation event that is currently not available from the London diary card.The results of the study are certainly mixed. The good news is that mean EXACT scores did increase, as expected, during exacerbation events relative to the stable state, and that the time taken for EXACT scores to return to baseline was significantly correlated to both diary-card symptom recovery time and lung function recovery. This information suggests that EXACT can be used to measure the duration of COPD exacerbation events.The bad news is that this study suggests that the EXACT seems to be relatively insensitive in detecting exacerbation events. Only 34 (27%) out of 128 of London diary card exacerbations exceeded the EXACT threshold for an exacerbation event (defined as a 12-point increase in EXACT score above baseline for two consecutive days or a 9-point increase for three days). Even more worryingly, of the 85 London COPD Cohort diary card-defined exacerbations that were treated with oral antibiotics and/or corticosteroids by the study team during the 2-year study period, only 34% were picked up using EXACT. The study results thus

“I just know”: exploring self-knowledge in chronic obstructive pulmonary disease

“…Among clinicians there is no consensus on how such exacerbations are identified, however most agree that these are related to a significant deterioration of at least two major respiratory symptoms, a change in medication and/or contact with health care services (Aaron, 2014;Pauwels et al, 2004) compared with people's normal health status. Since people living with COPD are arguably most knowledgeable about their symptoms and any variation of these, both during stable and acute phases of their condition, it seems imperative that we seek to understand both their experience and knowledge of their symptoms, and how they articulate these.…”

Updates in Chronic Obstructive Pulmonary Disease for the Year 2014

“…An exacerbation of COPD is a clinical event that 1) has no standard, consensus definition; 2) unreported events are common; 3) often occurs suddenly with little or no warning; and 4) is subject to diagnostic uncertainty and is easily confused with pulmonary embolism, congestive heart failure, or pneumonia [23].…”