Assessing the performance of the EQ-VAS in the NHS PROMs programme

OBJECTIVES: The study aims to increase knowledge about the performance of the EuroQol-visual analogue scales (EQ-VAS) in the UK NHS patient-reported outcome measures (PROMs) programme, which covers groin hernia, hip and knee replacement and varicose vein surgery, and make suggestions for improved collection, coding and analysis of data. METHODS: Four hundred scanned images of matched before-and-after EQ-VAS PROMs responses were selected at random. These were classified according to the different ways in which they were completed. Patient-level PROMs programme data linked to Hospital Episode Statistics for all patients from April 2009 to February 2011 were used to analyse the relationship between the EQ-VAS and the EQ-5D profile, index-weighted profile and condition-specific instruments. The linked PROMs and HES data comprise 331,951 anonymised patient records. RESULTS: A large majority (95 %) of EQ-VAS responses were completed in an unambiguous way, but only a minority (45 %) conformed strictly to the instructions given, posing challenges for data coding. The EQ-VAS data have a predictable and consistent relationship with the EQ-5D profile, although the correlations between the EQ-VAS and other measures of patient-reported health, both before and after surgery and in the change between them, are weak. CONCLUSIONS: EQ-VAS data might be improved by providing better guidance on collection and coding. It is argued that the observed differences in results from EQ-VAS and other measures of health reflect the fact that it measures a broader underlying construct of health, arguably providing a means of summarising overall health that is closer to the patient’s perspective.