Real-world Effectiveness and Cost-effectiveness of Qvar Versus FP, a US Study
Real-world Effectiveness and Cost-effectiveness of Qvar Versus FP, a US Study
This study will compare the absolute and relative effectiveness and cost-effectiveness of
 asthma management in patients in the USA on inhaled corticosteroid (ICS) maintenance therapy
 as HFA-BDP (Qvar®) pressurised metered dose inhaler (pMDI) compared with fluticasone
 propionate (FP) pMDI. .
Current asthma guidelines are underpinned by evidence derived from randomised controlled
 trials (RCTs). Although RCT data are considered the gold standard, patients recruited to
 asthma RCTs are estimated to represent only a small percentage of the real-world asthma
 population. The poor representation of the asthma population is due to a number of factors,
 such as tightly-controlled inclusion criteria for RCTs. There is, therefore, a need to carry
 out real-world observational studies to inform existing guidelines on the effectiveness of
 available treatments as used in every-day clinical practice in the heterogeneous asthma
 population.

 Asthma management guidelines recommend long-term, daily anti-inflammatory controller therapy
 to attenuate the chronic airway inflammation of persistent asthma. The choice of inhaled
 corticosteroid can be guided by practical considerations (e.g., cost factors) as RCTs have so
 far failed to identify consistent, significant differences in outcomes among the available
 inhaled corticosteroids, and data from observational studies are lacking.

 FP and HFA-BDP are the two main ICS therapies prescribed in the US for the management of
 asthma. FP is approximately twice as potent and efficacious, on a microgram basis, as BDP. In
 clinical trials, however, the extra-fine hydrofluoroalkane (HFA) formulation of BDP has
 demonstrated potency similar to that of FP. This is felt to be because HFA-BDP shows higher
 and more even lung deposition than FP, with HFA-BDP, unlike FP, having distribution to both
 large and small airways.

 Owing to similarity of effectiveness of extra-fine HFA-BDP and FP suggested by clinical trial
 data, and the even lung distribution afforded by the smaller HFA aerosol particles, we
 hypothesises that extra-fine HFA-BDP may be at least as effective as FP in real-world
 clinical practice. This hypothesis was supported by a retrospective database study of HFA-BDP
 versus FP using the UK's General Practice Research Database (GPRD). The study found
 significantly lower odds for achieving the composite proxy measure for asthma control with FP
 in both patients initiating ICS therapy (0.77, 95%CI 0.61-0.98) and stepping-up ICS therapy
 (0.82, 95%CI 0.44-1.52) relative to HFA-BDP. The analysis also revealed that FP was
 prescribed at significantly higher doses than extra-fine HFA-BDP yet had lower associated
 odds of achieving asthma control.

 In addition to significant health benefits, delivering effective asthma control is critical
 to reducing the substantial economic burden of asthma, with research indicating annual costs
 are disproportionately attributable to patients with poorly controlled disease. Recent
 estimates place the annual figure at 56 billion dollars ($) in the US alone, consisting of
 direct costs and productivity losses.It is therefore of particular importance to consider
 outcomes achieved in relation to costs incurred when assessing overall benefit of asthma
 therapies, with a cost-effectiveness analysis of HFA BDP and FP planned as part of the
 current study.

 The aim of this study is to compare the absolute and relative effectiveness and
 cost-effectiveness of asthma management in patients in the US on inhaled corticosteroid (ICS)
 maintenance therapy as extra-fine HFA-BDP (Qvar®) pressurised metered dose inhaler (pMDI)
 compared with fluticasone propionate (FP) pMDI to further examine the findings of the UK
 study, and to identify similarities or differences in effectiveness and cost-effectiveness
 outcomes and prescribing practice between the two countries.
Inclusion Criteria:

 -  Aged: 5-80 years:

 -  Paediatric cohort (aged 5-11 years), and

 -  Adult cohort (aged 12-60 years)

 -  Non-smokers aged 61-80 years

 -  Evidence of asthma:

 -  a diagnostic code for asthma, (ICD 9 codes: 493xx) or

 -  ≥2 prescriptions for asthma at different points at any time

 -  Be on current asthma therapy

 -  ≥1 other asthma prescription during the outcome period

 -  Have at least one year of baseline data (prior to the IPD) and at least one year of
 outcome data (following the IPD).

 Exclusion Criteria:

 -  had been diagnosed with any chronic respiratory disease at any time other than asthma

 -  received maintenance oral steroid therapy during baseline.

 Updated inclusion criteria - used in the latest analysis:

 -  Aged 12-60 years (paediatrics included in original study - removed to make comparable
 with USA data)

 -  Evidence of asthma: a diagnostic code of asthma or ≥2 scripts for asthma in baseline
 year at different points in time

 -  Have definite dosing instructions

 -  Have at least 1 year of up-to-standard (UTS) baseline data before IPD

 -  Have at least 1 year of UTS outcome data after IPD. Index dates from 1998 onwards were
 accepted in the study.

 Updated exclusion criteria - used in the latest analysis:

 -  Had a diagnostic read code for chronic obstructive pulmonary disease (COPD) at any
 time

 -  Had a diagnostic read code for chronic respiratory disease at any time

 -  Were on maintenance oral steroid therapy at baseline