Characterization of viral infections in stable and exacerbated COPD

Viral respiratory tract infections have been implicated as the predominant risk factor for acute exacerbations of COPD (AECOPD). We aimed to investigate factors associated with viral infections in stable COPD and at AECOPD. We analysed the co-primary end-point of the PREVENT study, an investigator-initiated and driven, controlled, longitudinal trial, that included 450 COPD patients followed for 3 years. Detection of 18 viruses was performed in naso- and orοpharyngeal swabs at stable periods (n=1909) and at AECOPD (n=177) by multiplex PCR. At stable visits, positive viral PCR was observed in 5.3% of the patients (n=102). These patients were younger, had a higher BMI, higher values of FEV1, FEV1/VC, DLCO, and lower RV/TLC and BODE. In these cases, cough was more common (p=0.018), patients produced more sputum (p=0.041) and had a higher evidence of potentially pathogenic bacteria in sputum (p=0.026). An increase of 10 units in SGRQ impact score was associated with an increased chance of 11% of having any viral infection (p=0.032). At AECOPD, 38.4% of the cases (n=68) presented positive viral PCR. These patients had more severe symptoms as assessed by CAT score (p=0.007), more cough (p<0.001) and sputum production (p=0.002). An increase of 1 unit in CAT score was associated with an increased chance of 8.4% of having any viral infection (p=0.005). In contrast, the BODE score (p=0.008) was lower. Viral detection is associated with more productive cough at stable state and at AECOPD. At stable state, it is linked to a higher prevalence of pathogenic bacteria in sputum despite being found more commonly among younger patients with milder airflow obstruction, partial reversibility and less severe parenchymal destruction.