Study type

Study topic

Disease /health condition
Medical procedure

Study type

Non-interventional study

Scope of the study

Effectiveness study (incl. comparative)

Data collection methods

Secondary use of data
Non-interventional study

Non-interventional study design

Cross-sectional
Population studied

Short description of the study population

Patients with a COPD diagnostic Read code, with blood eosinophil counts recorded on an exacerbation date with no OCS and antibiotic use during the 2 weeks before the event and registered at general practices providing data to OPCRD (or CPRD) across the United Kingdom.

Age groups

Adults (18 to < 46 years)
Adults (46 to < 65 years)
Adults (65 to < 75 years)
Adults (75 to < 85 years)
Adults (85 years and over)

Special population of interest

Other

Special population of interest, other

Chronic obstructive pulmonary disease (COPD) patients

Estimated number of subjects

2500
Study design details

Main study objective

To study whether COPD patients with high blood eosinophil counts at the time of exacerbation prescribed oral corticosteroids with/without antibiotics experience decreased treatment failure as compared to those not prescribed oral corticosteroids.

Outcomes

The primary outcome is treatment failure (to be studied for 6 weeks outcome period), defined as additional prescription of antibiotic or oral corticosteroids course or respiratory-related accident and emergency (A&E) attendance or respiratory-related hospital attendance / admission. The secondary outcome is healthcare resource utilisation in the outcome period of 6 weeks and additionally at a 1 year outcome period for both high blood eosinophil and non-high blood eosinophil patients treated with and without oral corticosteroids.

Data analysis plan

Exact matching for categorical variables and matching within a maximum calliper for continuous variables will be used to match patients using nearest neighbour variable mixed matching with a match maximum of 3:1 on the variables predictive of outcomes, without replacement. Multiple observations can exist for the same patient, but each observation will only be used once during the matching process.The odds of experiencing treatment failure as defined above in patients prescribed oral corticosteroids with/without antibiotics will be compared to those not prescribed oral corticosteroids. A conditional logistic regression analysis in the matched cohorts will be performed to study whether the association between therapy option and outcomes is modified by the blood eosinophil level, adjusted for variables causing residual confounding. In addition, conditional cox proportional hazard regression will be used to assess how therapy option is associated with time to hospital admission.