COPD patient exacerbation recall ‘reliable’
MedWire News: Patients with chronic obstructive pulmonary disease (COPD) can reliably estimate the number of exacerbations they have had in the preceding year, and this can be used to accurately stratify them into frequent and infrequent exacerbator groups in subsequent years, UK researchers report.
"Knowledge of exacerbation frequency is important for assessment of clinical risk and stratification into trials, especially where exacerbation interventions are being evaluated," explain Jadwiga Wedzicha (University College London) and team.
"However, in order to determine an accurate exacerbation frequency, patients ideally need to be prospectively followed for at least 12 months to allow for effects of seasonality on exacerbations," they add. "In most situations when recruiting for clinical trials this is not practical."
To investigate whether patients can accurately recall the number of exacerbations they have recently suffered, and whether there are significant year-on-year differences in exacerbation frequency, the team studied 267 COPD patients who had a mean FEV1 of 1.14 l.
All the participants were asked to recall the number of exacerbations they had suffered in the year prior to recruitment, and to record the number of exacerbations suffered in the subsequent year on diary cards. The patients were also asked to recall the number of exacerbations they had suffered at the end of this subsequent year.
Exacerbations were defined by the presence of two COPD symptoms, of which one needed to be a major symptom, for 2 consecutive days. Major symptoms included significantly increased dyspnea, sputum volume, or sputum purulence, and minor symptoms included cough, wheeze, and sore throat.
The researchers found that there was no significant difference between the number of exacerbations recalled by patients in the year before recruitment and the number recorded on diary cards in the following year, at a median of two in each year, and at an actual agreement of 84.6%. The expected agreement would have been 76.4% if the patient estimates and actual exacerbation numbers were random, the researchers note.
There was also no difference between the number of exacerbations recalled by the patients and the number recorded on diary cards over the subsequent year, at a median of two exacerbations, and at an expected and actual agreement of 74.9% and 93.3%, respectively.
Wedzicha and team conclude: "This study using daily patient exacerbation monitoring shows for the first time that COPD patients can accurately recall the number of exacerbations they have experienced in the past year, and that this recall is sufficiently robust for stratification of COPD patients into frequent and infrequent exacerbator groups."
They add: "This finding has important implications for the performance of clinical trials in COPD patients and also in clinical practice when stratification of COPD patients at risk of exacerbation is required."
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By Mark Cowen