Exacerbation risk factors identified in patients with COPD, no recent exacerbations

Key takeaways:

• Exacerbation risk factors in this population included GERD, chronic bronchitis, high symptom burden and decreased FEV₁ percent predicted.
• These factors were included in a graduated risk score.

Four variables, including chronic bronchitis and high symptom burden, heightened the rate of exacerbations among patients with COPD and no recent exacerbations, according to results published in Annals of the American Thoracic Society.

“In patients with COPD but without a recent history of exacerbations, risk factors such as GERD, chronic bronchitis, high symptom burden and lower lung function are associated with an increased risk of future exacerbation,” Michael C. Ferrera, MD, of the division of pulmonary and critical care medicine at Beth Israel Deaconess Medical Center and instructor of medicine at Harvard Medical School, and colleagues wrote.

Using data from the COPDGene study, Ferrera and colleagues assessed 1,528 patients (mean age, 69 years; 58.1% men; 80.7% white; 66.3% former tobacco users; mean FEV₁, 65.5% predicted) with COPD, a smoking history and no exacerbations in the prior year to determine what variables raise the risk for exacerbations.

Of the total cohort, 27.4% had Global Initiative for Chronic Obstructive Lung Disease (GOLD) grade 1 COPD, 46.7% had grade 2 COPD, 20.4% had grade 3 COPD and 5.5% had grade 4 COPD.

All patients filled out a minimum of one follow-up questionnaire during the studied 36 months (median, 32 months), and within this period, 508 patients (33.2%) experienced a moderate or severe exacerbation.

Following adjustment for age, sex and smoking status, researchers observed a significantly heightened moderate/severe exacerbation rate among those with self-reported gastroesophageal reflux disease (GERD; rate ratio [RR] = 1.3; 95% CI, 1.05-1.6), chronic bronchitis (RR = 1.62; 95% CI, 1.27-2.05) and high symptom burden signaled by Modified Medical Research Council (mMRC) Dyspnea Scale scores of two (RR = 1.39; 95% CI, 1.04-1.88) and greater than two (RR = 2.16; 95% CI, 1.72-2.72).

A model further adjusted for GERD, chronic bronchitis and mMRC revealed two more factors significantly linked to a higher exacerbation rate: COPD Assessment Test (CAT) score of 10 or higher (RR = 1.59; 95% CI, 1.25-2.05) and reduced FEV₁ percent predicted (RR = 1.25 per –20%; 95% CI, 1.08-1.43).

After rounding each of the above risk factors’ regression coefficient to the nearest 0.25, researchers included them in a graduated risk score and found an elevated exacerbation rate of 29% in the studied time period with each 1-point rise in the score factoring in GERD, chronic bronchitis and mMRC scores of 2, 3 or 4.

Researchers continued to find a heightened exacerbation rate with each 1-point rise in the score factoring in the three variables above plus CAT scores of at least 10 (RR = 1.34; 95% CI, 1.27-1.41) and in the score factoring in all the observed risk factors (RR = 1.3; 95% CI, 1.25-1.36).

“The variables listed in our first risk score, mMRC, history of chronic bronchitis and history of GERD, are easily obtainable in the setting of a routine clinic visit and do not require a significant amount of time or resources,” Ferrera and colleagues wrote.