Factors in COPD Exacerbation Variations Identified

The number of exacerbations experienced by patients with chronic obstructive pulmonary disease (COPD) tends to vary from year to year, a recent study showed.

Current treatment strategies used to assess exacerbation risk in COPD patients rely on a history of 2 or more events within the previous year. Therefore, a better understanding of trends in exacerbations is needed.
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From November 12, 2010, to July 21, 2015, the researchers assessed the cohort participating in the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS). They evaluated 2981 patients aged 40 to 80 years, 1105 of which had both COPD and 3 years of complete, prospective follow-up data.

Patients were categorized according to annual frequency of exacerbations: no exacerbations in any year, 1 exacerbation in every year during 3 years of follow-up, and inconsistent exacerbations (patients who had both years with and without exacerbations during the 3-year follow-up).

Additionally, participants were classified in accordance with the Global Initiative for Chronic Obstructive Lung Disease (GOLD) spirometric category (1-4) on the basis of post-bronchodilator forced expiratory volume in 1 second (FEV₁).

Results showed that 538 of 1105 patients (49%) had experienced at least 1 acute exacerbation over the 3-year follow-up period, while 567 (51%) had no exacerbations. A total of 82 of 1105 patients (7%) had at least 1 acute exacerbation each year, whereas 23 (2%) had 2 or more acute exacerbations each year. An inconsistent pattern was common among patients, especially among those at GOLD stages 3 and 4.

Logistic regression indicated that consistent acute exacerbations were related to higher baseline symptom burden, previous exacerbations, greater evidence of small airway abnormality on computed tomography (CT) scan, lower interleukin-15 concentrations, and higher interleukin-8 concentrations, compared with no acute exacerbations.

“Although acute exacerbations are common, the exacerbation status of most individuals varies markedly from year to year,” the researchers concluded. “In addition to symptoms and history of exacerbations in the year before study enrollment, we identified several novel biomarkers associated with consistent exacerbations, including CT-defined small airway abnormality, and interleukin-15 and interleukin-8 concentrations.”

—Christina Vogt

Reference:

Han MLK, Quibrera PM, Carretta EE, et al. Frequency of exacerbations in patients with chronic obstructive pulmonary disease: an analysis of SPIROMICS cohort [Published online June 28, 2017]. Lancet Respir Med. doi:10.1016/S2213-2600(17)30207-2.