Outcomes among patients with chronic obstructive pulmonary disease after recovery from COVID-19 infection of different severity.

While studies have suggested increased risks of severe COVID-19 infection in chronic obstructive pulmonary disease (COPD), the persistent and delayed consequences of COVID-19 infection on patients with COPD upon recovery remain unknown. A prospective clinical study was conducted in Hong Kong to investigate the persistent and delayed outcomes of patients with COPD who had COVID-19 infection of different severity (mild-moderate COVID-19 and severe COVID-19), compared with those who did not. Chinese patients with COPD ≥ 40 years old were recruited from March to September 2021. They were prospectively followed up for 24.9 ± 5.0 months until 31st August 2023. The primary outcome was the deterioration in COPD control defined as the change in mMRC dyspnea scale. The secondary outcomes included the change in exacerbation frequency and non-COVID-19 respiratory mortality (including death from COPD exacerbation or bacterial pneumonia). 328 patients were included in the analysis. Patients with mild-moderate and severe COVID-19 infection had statistically significant increased risks of worsening of mMRC dyspnoea scale by increase in 1 score from baseline to follow-up with adjusted odds ratios of 4.44 (95% CI = 1.95-10.15, p < 0.001) and 6.77 (95% CI = 2.08-22.00, p = 0.001) respectively. Patients with severe COVID-19 infection had significantly increased risks of increase in severe COPD exacerbation frequency with adjusted odds ratios of 4.73 (95% CI = 1.55-14.41, p = 0.006) non-COVID-19 respiratory mortality from COPD exacerbation or pneumonia with adjusted hazard ratio of 11.25 (95% CI = 2.98-42.45, p < 0.001). After recovery from COVID-19, worsening of COPD control from worsening of dyspnea, increase in severe exacerbation frequency to non-COVID-19 respiratory mortality (COPD exacerbation and pneumonia) was observed among patients with severe COVID-19. Mild to moderate COVID-19 was also associated with symptomatic deterioration.

Variability of Blood Eosinophil Count at Stable-State in Predicting Exacerbation Risk of Chronic Obstructive Pulmonary Disease.

Background: Chronic obstructive pulmonary disease (COPD) phenotyping using stable-state blood eosinophil level was shown to have prognostic implication in terms of exacerbation risk. However, using a single cut-off of blood eosinophil level to predict clinical outcome has been challenged. There have been suggestions that variability of blood eosinophil count at stable-state could provide additional information on exacerbation risk. Methods: A retrospective cohort study was conducted in a major regional hospital and a tertiary respiratory referral centre in Hong Kong, including 275 Chinese patients with COPD, to investigate the possible role of variability of blood eosinophil count at stable-state to predict COPD exacerbation risk in one year. Results: Higher variability of baseline eosinophil count, which is defined as the difference of the minimal and maximal eosinophil count at stable-state, was associated with increased risk of COPD exacerbation in the follow-up period with adjusted OR (aOR) of 1.001 (95% CI = 1.000-1.003, p-value = 0.050) for 1 unit (cells/µL) increase in variability of baseline eosinophil count, aOR of 1.72 (95% CI = 1.00-3.58, p-value = 0.050) for 1 SD increase in variability of baseline eosinophil count and aOR of 1.06 (95% CI = 1.00-1.13) for 50 cells/µL increase in variability of baseline eosinophil count. The AUC by ROC analysis was 0.862 (95% CI = 0.817-0.907, p-value < 0.001). The cut-off for variability of baseline eosinophil count identified was 50 cells/µL, with sensitivity of 82.9% and specificity of 79.3%. Similar findings were also shown in the subgroup with stable-state baseline eosinophil count below 300 cells/µL. Conclusion: Variability of baseline eosinophil count at stable-state might predict the exacerbation risk of COPD, exclusively among patients with baseline eosinophil count below 300 cells/µL. The cut-off value for variability was 50 cells/µValidation of the study findings in large scale prospective study would be meaningful.