Table 2.
Summary of Studies on the Stability of Blood Eosinophil Count Measures for Patients with Chronic Obstructive Pulmonary Disease
| Study | N | Patient Group | Assessment Period | Type of Analysis | Main Results |
|---|---|---|---|---|---|
| Long et al., 2020 (72) | 255 | Patients with stable COPD | 1 yr | Spearman’s rank correlation; repeatability (ICC); Bland-Altman regression analysis; repeatability coefficient analysis | Spearman’s rank correlation at 12 mo: 0.71; P < 0.001 |
| ICC at 12 mo: 0.84 | |||||
| Bland-Altman regression at 12 mo: P < 0.001 | |||||
| Southworth et al., 2018 (73) | 82 | Patients with stable COPD (>4 wk from exacerbation) | 6 mo, >2 yr | Spearman’s rank correlation; repeatability (ICC); Bland-Altman regression | Spearman’s rank correlation at 6 mo: 0.80; P < 0.001 |
| ICC at 6 mo: 0.89 | |||||
| Spearman’s rank correlation at >2 yr: 0.74; P < 0.001 | |||||
| ICC at >2 yr: 0.87 | |||||
| Bland-Altman regression: 6 mo, P = 0.006; >2 yr, P = 0.015 | |||||
| Barker, 2012 (74) | 145 | Patients with stable COPD (over 3–6 mo) | 6 mo | Repeatability (ICC) | ICC at 3 mo: 0.66 |
| ICC at 6 mo: 0.73 | |||||
| Landis, 2017 (75) | 27,557 | Primary care cohort of patients with COPD with stable disease | 1 yr | Repeatability (ICC); sensitivity analysis excluded patients who had been prescribed OCS or antibiotics during follow-up | ICC at 1 yr full cohort: 0.64 |
| ICC at 1 yr sensitivity cohort: 0.70 | |||||
| Bafadhel et al., 2017 (71) | 1,483 | Patients receiving ICS | 1 yr | Repeated measures analysis of BEC once every 3 mo in a 12-mo minimum period (ICC) | ICC over 3 mo: 0.79; 65% of patients with COPD remained above or below the BEC cutoff of 400 cells/μl during the year |
| Singh et al., 2014 (28) | 1,483 | ECLIPSE study cohort | 3 yr | Four BEC measurements over 3 yr analyzed through BEC cutoffs | 37% of patients had persistent BEC ≥ 2% |
| Casanova et al., 2017 (57) | CHAIN, 424; BODE, 308 | Patients with COPD from the CHAIN study cohort and BODE study cohort | 2 yr | Analysis through a cutoff of BEC ≥ 300 cells/μl | Over 2 yr, 16% of patients in the CHAIN cohort and 12% of patients in the BODE cohort had persistent BEC ≥ 300 cells/μl |
Definition of abbreviations: BEC = blood eosinophil count; BODE = body mass index, degree of airflow obstruction, functional dyspnea, and exercise capacity; CHAIN = COPD History Assessment in Spain; COPD = chronic obstructive pulmonary disease; ECLIPSE = Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-points; ICC = intraclass coefficient; ICS = inhaled corticosteroids; OCS = oral corticosteroids.