Lifetime prevalence of Type 2 comorbidities in patients with COPD: especially those with higher eosinophilic counts

Study type

• Study topic:
  Disease /health condition
• Study type:
  Non-interventional study
• Scope of the study:
  Disease epidemiology
• Data collection methods:
  Secondary use of data

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Medical condition to be studied:
  Asthma

  Chronic obstructive pulmonary disease

Population studied

• Short description of the study population:
  All the COPD-patients with confirmed diagnosis FEVC1/FVC ratio <70% and who do not have recorded history of asthma at any time either previous or concurrent and ; ; 2) All the asthma patients only regardless of their spirometry results and who do not have history of COPD at any time either previous or concurrent ; ; 3) COPD comorbid asthma previous or concurrent ; ; 4) For COPD-only and asthma-only patients the first ever recorded date of diagnosis will be their index date. For COPD comorbid asthma group, the index date will be the date when COPD was first diagnosed or when both COPD and asthma were first documented together. The timing of asthma diagnosis (whether before or after COPD) does not change the fact that the index date is based on the first COPD diagnosis as COPD is the primary condition and focus of the study. ; ; 5) To be eligible for inclusion, individuals must be 18 years or older at the index date ; ; 6) All of these people will be limited to those diagnosed within the last 10 years with at least 1 year of follow-up, i.e. patients diagnosed between 01/01/2013-01/01/2024. This would ensure that only patients diagnosed on or before 01/01/2024 will be included to have at least 1 year of follow-up. ; ; 7) All of these COPD-only, asthma-only and COPD-comorbid asthma patients should be registered at the OPCRD surgery during diagnosis. ; ; 8) At least 12 months of registration at participating GP surgery prior to index date
• Age groups:
  • Adult and elderly population (≥18 years)

    • Adults (18 to < 65 years)

      • Adults (18 to < 46 years)
      • Adults (46 to < 65 years)
• Special population of interest, other:
  Patients with COPD, Patients with asthma, patients with COPD with comorbid asthma
• Estimated number of subjects:
  228143

Study design details

• Study design:
  Retrospective cohort study using the Optimum Patient Care Research Database (OPCRD).
• Main study objective:
  • Compare the lifetime prevalence of T2-related comorbidities (e.g., allergic rhinitis, nasal polyps, atopic dermatitis) among patients with COPD (with and without T2 inflammation) and those with asthma. ; ; • Assess the prevalence of T2-related comorbidities in individuals before the diagnosis of COPD or asthma. ; ; • Evaluate the incidence of T2-related comorbidities within a fixed 5-year period following the diagnosis of COPD or asthma. ; ; • Stratify the study population based on blood eosinophil, count categories and examine trends in T2 comorbidities across these strata. ; ; • Perform sensitivity analyses addressing the rounding biases in blood eosinophil counts.
• Setting:
  This is a retrospective cohort study using the Optimum Patient Care Research Database (OPCRD). The OPCRD is an electronic primary care record database covering more than 1,000 GP surgeries across England, Scotland, Wales and Northern Ireland.
• Comparators:
  The patients with COPD having type 2 related comorbidities such as allergic rhinitis and atopic dermatitis will be compared with asthma patients with type 2 inflammation.
• Outcomes:
  T2-related comorbidities included in this study will encompass a range of conditions that have been associated with T2 inflammation, including ; ; • allergic rhinitis, ; ; • atopic dermatitis, ; ; • chronic rhinosinusitis, ; ; • nasal polyps, ; ; • allergic rhinitis, ; ; • eosinophilic esophagitis, ; ; • ulcerative colitis
• Data analysis plan:
  The first step will be to summarize the demographic and clinical characteristics of the study population. This will include means, medians and frequencies for continuous and categorical variables, stratified by the three groups: COPD only, asthma only, and COPD-asthma comorbid, to help us understand the distribution of the data or imbalances across the groups.; The lifetime prevalence of Type 2-related comorbidities (e.g., atopic dermatitis, allergic rhinitis, etc.) will be analyzed using Poisson regression with robust variance. ; Prevalence prior to COPD/Asthma diagnosis: For assessing prevalence prior to diagnosis, we will examine records of Type 2 comorbidities before the first diagnosis of COPD or asthma. The prevalence rate ratio will be calculated using Poisson regression with robust variance, both unadjusted and adjusted for potential confounders. ; Cumulative incidence: Kaplan-Meier curves will be used to estimate the cumulative incidence of Type 2 comorbidities over time, stratified by the three groups (COPD only, asthma only, and COPD-asthma comorbid). The analysis will focus on the incidence 5 years post-diagnosis as specified, and Kaplan-Meier survival functions will be estimated for each group. The log-rank test will be used to compare the survival curves between the groups. ; Age standardization: Since the three groups may differ in terms of age distribution, age standardization will be performed to adjust for these differences. The standardization will involve creating an age-standardized rate by weighing the incidence rates in each group according to a reference population (e.g., the overall study population). This process will help to eliminate any age-related biases and provide a fairer comparison between the groups. After age standardization, we will run the entire analysis again to ensure that any observed differences in prevalence, incidence, or comorbidity rates are not due to age adjustment on the observed results.
• Summary results:
  The work will be published in a peer-reviewed journal.