ERS 2022: What Insights Do Studies Focused on COPD Biomarkers Bring?

FE_NO Variability and Prediction of COPD AE

Can the variability of fractionally exhaled nitric oxide (FE_NO) predict the risk and etiology of acute COPD exacerbations? This was investigated by a Swiss study, whose authors (Papakonstantinou et al.) based their research on the fact that COPD AE can be triggered by viral and bacterial respiratory infections.

FE_NO was measured during 2157 visits by 421 patients with COPD in stages 2-4 according to the Global Initiative for COPD (GOLD) classification, who participated in the longitudinal intervention study PREVENT. Long-term measurement of FE_NO revealed intra-individual variability of FE_NO, which was significantly higher in exacerbators compared to non-exacerbators and positively associated with the number of COPD AEs. As the variability of FE_NO increased in patients, the probability that they would remain free of acute exacerbations decreased – in subjects in the lowest quartile of FE_NO variability, it was 80%, while in the highest it was only 35%. The change in FE_NO from the last stable visit to a COPD AE was positively associated with the probability of viral infections, more strongly in active smokers than in ex-smokers, and inversely with the probability of bacterial infections in ex-smokers (this did not apply to active smokers).

The authors concluded that variability of FE_NO is associated with the risk of COPD AEs, its significance in predicting the etiology of COPD AEs is different for active and former smokers, and it is a non-invasive biomarker for etiological early diagnosis of COPD AEs. Stabilizing FE_NO variability in patients with COPD may form a potential target for personalized treatment.

What came out of the COHERENT-COPD study?

The retrospective Spanish study COHERENT-COPD was presented multiple times. The authors utilized electronic records of 2384 patients with COPD AE initially examined in 2018 at the emergency department of a tertiary hospital. The median age was 76 ± 13.2 years, and 60% were men. In one of the analyses presented during ERS 2022, using the already validated COHERENT model (Bueno et al., 2022), clinical trajectories and healthcare resource use in the study cohort were graphically and visually presented.

The model showed a high rate of readmissions (41.8%) and mortality (23.5%) within 1 year and also the proportions of patients per day in various clinical situations (at home, in the emergency department, hospitalization, death) after 7, 30, and 365 days. Another analysis of this study demonstrated that 1-year mortality is significantly influenced by the presence of congestive heart failure (p < 0.0001) and age, with a clear difference between the sexes in those younger than 67 years (12.1% men vs. 3.8% women; p = 0.002).

New findings on the role of microbiota in COPD

The authors of another Spanish study (Lopez-Aladid et al.) pointed out increasing evidence that the lung microbiota is crucial in COPD and that the sputum microbiome has potential significance in COPD phenotyping and risk stratification. According to them, lung microbiome studies have so far shown that with worsening lung function, there is a relative increase in the abundance of the Proteobacteria phylum, especially the Haemophilus genus. A decrease in microbial diversity could be associated with more severe disease and greater risk. They investigated the role of microbiota in their observational study that included 26 patients with acute COPD exacerbation. They isolated DNA from sputum samples and used the Illumina MiSeq platform for sequencing.

They found that patients with GOLD B and D COPD (symptomatic) had significantly lower richness and higher alpha and beta diversity. Furthermore, LDA scores revealed differences in bacterial composition between GOLD 1-3 and GOLD 4 COPD groups, with Haemophilus dominance repeating in GOLD 4 samples, while bacterial communities were more diverse in the other groups.

Eva Srbová
MeDitorial Editorial Team

Sources and References:
1. Papakonstantinou E., Schumann D., Kostikas K. et al. Variability of fractional exhaled nitric oxide can predict acute exacerbations of COPD. ERS International Congress, Barcelona, 2022 Sep 4–6. Available at: https://live.ersnet.org/ers/ers2022/en-GB/presentation/545506
2. Siesto López G., Sánchez-Covisa Hernández J., Goñi Echeverría C. et al. A visual and innovative representation of the clinical trajectory of patients after an acute exacerbation of COPD. Results of the COHERENT-COPD study. E-poster presentation. ERS International Congress, Barcelona, 2022 Sep 4–6. Available at: https://live.ersnet.org/ers/ers2022/en-GB/presentation/545508
3. Piñeiro Roncal M., Catalinas Muñoz E., Sánchez-Covisa Hernández J. et al. Mortality according to age, sex, or congestive heart failure after an acute COPD exacerbation. COHERENT-COPD study. E-poster presentation. ERS International Congress, Barcelona, 2022 Sep 4–6. Available at: https://live.ersnet.org/ers/ers2022/en-GB/presentation/545512
4. Bueno H., Bernal J. L., Jiménez-Jiménez V. et al.; ICA-SEMES ad hoc COHERENT study group. The clinical outcomes, healthcare resource utilization, and related costs (COHERENT) model. Application in heart failure patients. Rev Esp Cardiol 2022; 75 (7): 585–594, doi: 10.1016/j.rec.2021.08.009.
5. Lopez-Aladid R., Barat L. F., Bueno-Freire L. et al. Relationship between the microbiome and the GOLD Stage during exacerbations. E-poster presentation. ERS International Congress, Barcelona, 2022 Sep 4–6. Available at: https://live.ersnet.org/ers/ers2022/en-GB/presentation/545517