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Table 2 Characteristics of included observational studies

From: Blood eosinophil count, a marker of inhaled corticosteroid effectiveness in preventing COPD exacerbations in post-hoc RCT and observational studies: systematic review and meta-analysis

StudyInclusion criteriaExclusion criteriaDisease severityExacerbation historyLAMA use at/prior to enrolmentICS use at/prior to enrolmentEosinophils measured
Song 2017 [35] 168 patients> 40 years. Smoked > 10 years. FEV1/FVC < 0.7Asthma. FEV1 reversibility > 12%. Hx atopy, allergic rhinitis. Blood eos > 5% IgE > 100FEV1% predicted 55.5 ± 18Mean 31.9% patients AECOPD in 12 months prior to study enrolment.
Recorded 6-monthly patient reviews
59%43%Not stated
Suissa 2018 [36]
24,732 patients
≥55 years.
COPD new users of LAMA or LABA+ICS from 1.1.02.
Blood eosinophil count before cohort entry
Initiated on LAMA & LABA+ICS at same time.
Asthma NOT excluded
Not knownRecord drawn from READ code.
Mean 33.6% patients had ≥1 AECOPD in 12 months prior to study enrolment
0%0%Prior to study entry.
Oshagbemi 2018 [37]
32,693 patients
≥40 year.
New diagnosis COPD from 1.1.05
Asthma.
Any previous AECOPD.
ICS use in past year
Not knownRecord drawn from READ code14%0%Single eosinophil measure at point closest to index date (start of follow-up)
Oshagbemi 2019 [38]
48,157 patients
≥40 year.
New diagnosis COPD from 1.1.05
Asthma.
AECOPD in 6 months prior to index date
Not knownRecord drawn from READ code18%28%Single eosinophil measure at point closest to index date (start of follow-up)
Suissa 2019 [39]
3954 patients
≥55 years.
new use LAMA or LABA+ICS from 1.1.02.
Blood eosinophil count before cohort entry
AsthmaFEV1% predicted
53.9% (LABA + LAMA)
52.7% (LABA + ICS)
Record drawn from READ code.
Mean 41% of patients had ≥1 AECOPD in 12 months prior to study enrolment
77% (LABA+LAMA)
49.1% (LABA + ICS)
37% (LABA+LAMA)
52.8% (LABA+ICS)
Baseline