Real-world Comparative Effectiveness in Patients with Asthma Newly Initiating Fluticasone Furoate/Vilanterol or Budesonide/Formoterol: A United Kingdom General Practice Cohort Study

It is important that treatment recommendations reflect real-world data when available, as randomised controlled trials have stringent eligibility criteria and do not represent the entire asthma population or their usual ecosystem of care. Limited real-world evidence has compared the effectiveness of fluticasone furoate/vilanterol (FF/VI) and budesonide/formoterol (BUD/FOR) to date in asthma; we explored this in England using patients from general practice. We retrospectively compared new FF/VI users and new BUD/FOR users from 1 December 2015 to 28 February 2019, based on de-identified data from the Clinical Practice Research Datalink. The baseline period pre-index was ≥ 1 year; the follow-up period was 1 year. At index, eligible adults (≥ 18 years) with diagnosed asthma had ≥ 1 prescription for FF/VI or BUD/FOR, ≥ 1 years' general practitioner registration and records eligible for linkage to Hospital Episode Statistics. Chronic obstructive pulmonary disease was an exclusion criterion. The primary study outcome assessed the overall asthma exacerbation rate in new FF/VI or BUD/FOR users. Secondary outcomes included oral corticosteroid (OCS) use and medication persistence (analysed using Kaplan-Meier curves). For each treatment comparison, propensity scores were generated and confounding between baseline group characteristics was adjusted via inverse probability of treatment weighting, separately carried out for each study outcome. Intercurrent events (ICEs) were considered for analyses, such as death, loss to follow-up, rescue-medication use, treatment discontinuation or switching. Between groups, baseline attributes were well balanced. Annual per-person rates of exacerbation were numerically similar in the while on-treatment population (measuring outcome until ICE; FF/VI, 0.1356; BUD/FOR, 0.1583 P = 0.3023). Patients who continued initiation treatment for 1 year without interruption had significantly lower annual per-person exacerbation rates with FF/VI (0.0722 n = 425) versus BUD/FOR (0.2258 n = 546) (rate ratio 0.3197 P = 0.0003). Patients indexed on FF/VI had significantly fewer OCS prescriptions and lower OCS dosage versus BUD/FOR (respective coefficients: - 0.29 P = 0.0352; 0.41 P = 0.0004) and improved treatment persistence (hazard ratio: 0.62 P < 0.0001). Patients who continued initiation treatment for a year without interruption had reduced exacerbation rates with FF/VI versus BUD/FOR. The FF/VI group also had reduced treatment discontinuation and OCS use.