Discolored phlegm linked to exacerbations, death in patients with bronchiectasis

Key takeaways:

• Patients with more purulent sputum had a higher frequency of exacerbations and hospitalizations over 5 years.
• Producing discolored sputum also raised the risk for death.

Patients with bronchiectasis who produced discolored sputum appeared more likely to experience exacerbations, hospitalization and death, according to a poster presented at the European Respiratory Society International Congress.

“Sputum sampling is noninvasive for patients, and they are actively encouraged to cough up sputum whenever possible to improve their lung function,” Megan Crichton, BSc, postdoctoral researcher at University of Dundee, U.K., said in a press release. “Knowing that [patients can look at] their sputum color as a means of self-monitoring and self-management can empower [them] and gives them some control over their condition, which we know is important for improving patient quality of life.”

Using data from the EMBARC registry, Crichton and colleagues evaluated 13,484 patients with bronchiectasis from 31 countries for 5 years to determine whether the color of their phlegm/sputum is a biomarker for exacerbations and mortality.

Patients’ sputum was assessed on a 4-point color chart at baseline. According to the press release, mucoid sputum (n = 5,541; 40.4%) appears clear and frothy, mucopurulent sputum (n = 5,380; 39.9%) appears creamy yellow, purulent sputum (n = 2,486; 18.4%) appears a dirty yellow/green color with a thick texture and severe purulent (n = 177; 1.3%) appears a dark green/brown color.

Within the study population, researchers found elevated bronchiectasis severity index scores, worse lung function (FEV₁) and a higher prevalence of chronic infection among those classified as having more purulent-colored sputum.

Exacerbations also occurred more frequently among patients with more purulent sputum vs. mucoid sputum over 5 years, as demonstrated by incidence rate ratios (IRRs) of 1.26 (95% CI, 1.19-1.33) among those with mucopurulent sputum, 1.45 (95% CI, 1.36-1.55) among those with purulent sputum and 1.54 (95% CI, 1.26-1.89) among those with severe purulent sputum.

When assessing the prevalence of severe exacerbations that resulted in hospitalization, researchers continued to see high rates in patients with mucopurulent sputum (IRR = 1.29; 95% CI, 1.19-1.39), patients with purulent sputum (IRR = 1.73; 95% CI, 1.58-1.9) and patients with severe purulent sputum (IRR = 2.01; 95% CI, 1.54-2.63) compared with patients with mucoid sputum.

Sputum color was also observed to be a biomarker for death. Each rise in sputum purulence by one point signaled a 12% (HR = 1.12; 95% CI, 1.01-1.24) higher mortality risk, according to researchers.

“As this is a large study conducted across multiple countries and with 5 years of follow-up data, it provides the evidence that sputum color reflects prognosis,” Crichton said in the release. “Sputum samples can be easily collected from most patients, and the color has shown to be a useful indicator, thereby making sputum a readily available and easy-to-interpret clinical biomarker for disease progression. We believe that implementation of this biomarker into clinical practice will improve treatment and monitoring of bronchiectasis patients.”

According to the press release, future research will focus on the use of the sputum color chart among patients and how this tool can be introduced into clinical practice.

Reference:

• Colour of phlegm can predict outcomes for patients with the lung disease, bronchiectasis. https://www.ersnet.org/news-and-features/news/colour-of-phlegm-can-predict-outcomes-for-patients-with-bronchiectasis/. Published Sept. 10, 2023. Accessed Sept. 11, 2023.