PRS76 - DISEASE ADAPTATION AND PERCEIVED HEALTH STATUS: DOES IT EXIST AND CAN IT BE QUANTIFIED? INVESTIGATING EQ-5D IN SEVERE ASTHMA

Abstract

Patients may adapt their lifestyle because of long-term illness, and it could be hypothesised that these patients reach a new normal in terms of their perceived health status. We explore whether this adaptation in lifestyle phenomenon exists and how much it potentially can alter the perception of quality of life (QoL) improvement when using generic utility instruments such as EQ-5D. DREAM and MUSCA (GSK/ClinicalTrials.gov identifier: MEA112997/NCT01000506, 200862/NCT02281318) were randomised, double-blind, placebo-controlled trials of mepolizumab in severe eosinophilic asthma of 52 and 24 weeks duration, respectively. The EQ-5D-3L (DREAM) and EQ-5D-5L (MUSCA), respectively, were administered at baseline and select post-baseline visits. A stepwise selection model using Tobit regression was performed to overcome high levels of responses indicating a score of 1 or “perfect health” (i.e. ceiling effects) and high correlation between disease characteristics, duration, and health status. The average duration of disease was 19 and 20 years in DREAM and MENSA, respectively. Longer disease duration was associated with slightly higher values of EQ-5D at baseline after adjusting for age, gender, and asthma disease characteristics. Results reached statistical significance in DREAM. A logarithmic transformation of disease duration provided the best overall model fit. 5, 10, and 20 years since diagnosis was associated with higher utilities of 0.038, 0.054, and 0.070 in DREAM, and 0.013, 0.019, and 0.025 in MENSA, respectively. Results from this post-hoc analysis show that severe asthma patients with comparable disease severity perceive their health status differently the longer they have been diagnosed. Longer time since diagnosis was associated with better health status. This may indicate less potential for improvement following an intervention, which may in turn impact its cost-effectiveness. The impact of adaptation on perceived improvements in QoL should be investigated further, particularly in long-term diseases where patients progress at different rates. Funding: GSK