The healthcare costs associated with comorbidities of refractory asthma and systemic steroid exposure in the UK (Refractory Asthma & Steroid Exposure)

Study type

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

  Other
• If ‘other’, further details on the scope of the study:
  Cost effectiveness modelling

Non-interventional study

• Non-interventional study design:
  Case-control

  Cohort

  Cross-sectional

Study drug and medical condition

• Anatomical Therapeutic Chemical (ATC) code:
  (H02AB06) prednisolone
• Medical condition to be studied:
  Asthma

Population studied

• Age groups:
  Adolescents (12 to < 18 years)

  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)
• Estimated number of subjects:
  30000

Study design details

• Main study objective:
  To provide best morbidity prevalence estimates for the UK’s refractory asthma populations to inform models to estimate the burden of steroid-induced morbidity.
• Data analysis plan:
  For both Phase 1 and 2 of the study, well-controlled asthma patients and non-asthmatic controls will be matched to refractory asthma patients. To increase the power of the analysis matching will be on a 5-to-1 basis, with five randomly selected well-controlled asthma patients and five non-asthmatic control patients matched to each refractory asthma patients.Matching criteria will be patients’: age, gender, year of birth.Phase 1: cross-sectional evaluation: Frequency of existing morbidities in the 2 year period (2011-2013) will be evaluated and reported separately for each group. Rate ratios will be evaluated for each morbidity with 95% confidence intervals. Phase 2: longitudinal evaluation: incidence of new morbidities in the period 1 April 2006–present day will be evaluated for each patient group.Survival analyses will be conducted, patients who are lost to follow up (e.g. through leaving the practice or through death) will be censored.