In Stable COPD, Serum Amyloid A and Frequent Exacerbator Phenotype May Be Associated

Among patients with stable chronic obstructive pulmonary disease (COPD), serum amyloid A (SAA) is associated with the frequent exacerbator phenotype. The determination comes after new research showed that SAA is greater among those who experience frequent exacerbations than among those who had experienced 1 or fewer exacerbations in the previous year.

The research was released during the American Thoracic Society 2020 Virtual meeting.

“COPD exacerbations are associated with rapid decline in lung function, deterioration of quality-of-life, and increased mortality. These effects are worsened in those with frequent exacerbations (≥2 exacerbations per year),” the researchers wrote. “SAA is increased during the acute phase of a COPD exacerbation, induced by inflammatory mediators such as TNFa. SAA can be modestly elevated in the stable phase of COPD.”

To reach their conclusion, the researchers analyzed data on 88 patients with stable severe COPD. During a single visit, each patient had been assessed for demographics, medical and smoking history, exacerbation frequency, pulmonary function, and fractional concentration of expired nitric oxide (FeNO). Furthermore, the researchers collected the patients’ venous blood, assessed the patients’ serum for inflammatory variables, and measured the patients’ SAA via enzyme-linked immunosorbent assay.

The patients were aged 64.2±7.3 years with FEV₁ 37.8±9.4% predicted. In all, 10 patients (11.4%) were classified as frequent exacerbators.

Those who had frequent exacerbations had greater serum concentrations of SAA (129.7±67.7 ng/ml) and more surfactant protein D (16.5±11.5 ng/ml) than those with 1 or fewer exacerbations in the previous year (SAA serum concentration, 80.7±51.9 ng/ml; surfactant protein D, 10.5±8.5 ng/ml).

SAA remained independently associated with the frequent exacerbator phenotype even after adjusting for gender, age, body mass index, FEV₁/FVC, and smoking pack-years. However, surfactant protein D and other inflammatory variables—including IL-1β, IL-4, IL-6, IL-8, C-reactive protein, LTB4, GM-CSF, FeNO, MMP8, MMP9, and PRG4—were not associated with the frequent exacerbator phenotype.

According to the authors, SAA was not associated with FEV₁ % predicted or FVC % predicted.

—Colleen Murphy

Reference:

Zhao D, Rossiter HB, Abbasi A, et al. 815 - Serum amyloid A (SAA) in stable COPD patients is associated with the frequent exacerbator phenotype. Poster presented at: ATS Virtual 2020; August 5-10, 2020. https://cslide-us.ctimeetingtech.com/ats2020_eposter/attendee/eposter/poster/1986?q=COPD.