Annual recollection of exacerbations in patients with COPD: Impact on physical activity

Rationale The number of exacerbations in the previous year has shown to be the best predictor of new exacerbations. The ability to recall exacerbations may lead to misclassification of patients and may have consequences on patients’ phenotype.

Methods 47 patients with COPD (FEV1 65±21%pred) reported on a monthly basis all health care contacts and changes in medication. After 12 months they were asked to report the number of exacerbations they had experienced. At this timepoint the daily amount of steps was measured for 1 week with the ActiGraph. High exacerbation rate (HER) was defined as having 2 or more exacerbations per year.

Results Annual reporting resulted in less exacerbations compared to monthly reports (1.1 ±1.5 vs. 1.6±1.5, p<0.01). Based on monthly reports (set as golden standard) 21 patients were defined as HER, 26 as low. One year recollection has a sensitivity of 43% and specificity of 100% in identifying patients with HER. Corrected for lung function, the amount of steps was lower in the low, compared to the high exacerbators (p=0.03). There was no difference in the high exacerbation group between patients with a high or low 1 year recall (p=0.70).

Conclusion Annual recollection underestimates the exacerbation rate. This underestimation may have implications as patients with HER on monthly reporting have low PA levels regardless of their classification based on annual recall.