Additional Relevant Details Results: At 6 months, the survival curves for persistence of treatment for the 2 product groups started to separate (Figure 1). The survival probability estimates at 12 months were 0.229 (0.02 standard error) for AirFluSal Forspiro versus 0.105 (0.025 standard error) for Seretide Diskus (Figure 1). The Renyi family of tests demonstrated a statistically significant difference (P = .01) in persistence to AirFluSal Forspiro compared with Seretide Diskus in the overall survival experience of the 2 populations (Table III). The mean persistence in days was longer for AirFluSal Forspiro, 149.926 versus 134.228 for AirFluSal Forspiro and Seretide Diskus, respectively (Table IV). A higher proportion of patients using Seretide Diskus were prescribed 60 days' treatment than for AirFluSal Forspiro; the proportion of 30-day prescriptions was 62.12% for AirFluSal Forspiro compared with 50.23% for Seretide Diskus. This difference in dispensing patterns may explain the apparent difference in persistence seen between Seretide Diskus and AirFluSal Forspiro in the first 90 days. The aim of this study was to explore persistence to treatment, to provide an indicator of overall persistence of treatment over the long term.