Abstract
BACKGROUND: Patient-reported outcome measures (PROMs) are crucial to capture patients' health and illness status. Selecting the most suitable PROM to measure self-reported health in a specific study population is essential. Shortcomings of much used generic instruments have been identified in certain populations, and more investigation is needed to clarify the extent to which the generic instruments capture the aspects of health that really matter to patients. Therefore, the aim of this study was to determine floor and ceiling effects of a generic health utility instrument (EQ-5D-5L) in an international multi-centre cohort of patients after percutaneous coronary intervention (PCI) and further explore those with perfect health scores by using a disease-specific instrument. METHODS: The CONCARD(PCI) study was conducted at seven large referral PCI centres in Norway and Denmark between June 2017 and May 2020. In all, 2574 unique patients were available for this analysis. The generic EQ-5D-5L descriptive system and visual analogue scale, and the disease-specific Myocardial Infarction Dimensional Assessment Scale (MIDAS) comprising 35 items measuring seven areas of health status and daily life challenges were used to scrutinize the aims. Latent class analyses were conducted to identify classes with similar patterns of daily life challenges based on MIDAS item scores within the group of patients with best possible EQ-5D-5L score ('perfect scorers'). RESULTS: There was a large ceiling effect on the EQ-5D-5L score in patients with coronary artery disease (CAD) with 32% scoring the best possible EQ-5D-5L score, suggesting perfect health. Latent class analysis on the MIDAS revealed, however, four classes where 17-46% of the perfect scorers did perceive challenges in health, particularly related to symptoms of fatigue, and worries about risk factors and side effects of medication. CONCLUSION: To obtain an accurate picture of patients' health status, these results emphasize that both generic and disease-specific patient-reported outcomes measures are needed to capture the distinct problems that patients with CAD experience after PCI. Caution should be made when using the EQ-5D-5L as the sole measure, particularly in priority settings, due to its potential ceiling effect and the fact that important aspects of patient health may be neglected. TRIAL REGISTRATION: NCT03810612.