Impact of biologic initiation on steroid burden and new-onset of potentially OCS-related outcomes in patients with severe asthma (SOLAR)

Study type

• Study type:
  Non-interventional study
• Scope of the study:
  Disease epidemiology

Non-interventional study

• Non-interventional study design:
  Other
• Non-interventional study design, other:
  Historic-cohort design

Study drug and medical condition

• Medical condition to be studied:
  Asthma

Population studied

• Age groups:
  • Adult and elderly population (≥18 years)

    • Adults (18 to < 65 years)

      • Adults (18 to < 46 years)
      • Adults (46 to < 65 years)
    • Elderly (≥ 65 years)

      • Adults (65 to < 75 years)
      • Adults (75 to < 85 years)
      • Adults (85 years and over)
• Estimated number of subjects:
  12814

Study design details

• Main study objective:
  1) To assess the change in OCS intake in the full follow-up period in biologic initiator patients and non-biologic patients. 2) To quantify the association between change in OCS intake and subsequent new onset of potentially OCS-related adverse outcomes all patients, AND/OR 3) To compare the risk of potentially OCS-related adverse outcomes between biologic and non-biologic patients.
• Outcomes:
  The total OCS dose at follow-up (which is the sum of long-term OCS dose and rescue steroid dose) will be measured. All three types of OCS dose will be categorized as: increased dose (<0% reduction), low dose reduction (0% to ≤50%), moderate dose reduction (>50% to ≤75%) and optimal dose reduction (>75% to ≤100%). It will also be determined if a patient reached ≤5mg total or long-term OCS dose. Occurrence of potential OCS related outcomes (Anxiety, Depression, Cerebrovascular accident, Osteoporosis and/or related fractures, Type II diabetes mellitus, progression of diabetes, Cataract/Glaucoma, Obesity (BMI≥30 kg/m3), Peptic Ulcer, Pneumonia, Obstructive Sleep Apnea, Renal Failure, Heart Failure, Myocardial Infarction, Thromboembolism, Pulmonary Embolism) will be determined.
• Data analysis plan:
  Descriptive statistics of the baseline (pre-index date) demographic and clinical variables will be conducted and compared for each exposure groups (change in OCS or biologic vs non-biologic groups) as well as by data source (ISAR vs OPCRD). Continuous variables will be summarised using means, standard deviations, medians, ranges and interquartile ranges. Categorical variables will be presented as counts and percentages. Logistic regression with IPTW-matching will be used to assess the likelihood of attaining low total OCS or LTOCS dose. Low OCS dose will be defined as ≤5mg of total OCS dose or LTOCS. Univariate and multivariable analyses will be performed for acute and chronic outcomes that are and are not recurrent. All analyses will be conducted with R version 4.1.0.