Psychometric benefits of adding bolt-ons to the EQ-5D-5L in populations undergoing minimally invasive cosmetic procedures

Objectives There is growing interest in measuring health outcomes associated with minimally invasive cosmetic procedures (MICPs), such as botulinum toxin and hyaluronic acid injections. However, the EQ-5D may have limited content validity for this purpose. This study aims to psychometrically test five additional dimensions (‘bolt-ons’) for the EQ-5D-5L in individuals planning or undergoing MICPs. Methods In 2023, a cross-sectional, online survey was conducted with 149 women planning MICPs and 215 who had recently undergone them. Respondents completed the EQ-5D-5L, five bolt-ons (skin irritation, self-confidence, sleep, social relationships, tiredness), the Rosenberg Self-Esteem Scale (RSES) and the Brief Fear of Negative Evaluation Scale-Straightforward Items (BFNE-S). The following psychometric properties were tested for the EQ-5D-5L + bolt-on(s): ceiling, convergent and divergent validity, explanatory power and known-groups validity. Results Adding tiredness (22%), self-confidence (23%) or sleep bolt-ons (27%) substantially reduced the ceiling of the EQ-5D-5L (47%). The self-confidence and social relationships bolt-ons showed a moderate or strong correlation with the RSES and BFNE-S total scores (-0.462 to -0.679). The tiredness and self-confidence bolt-ons improved the EQ-5D-5L’s explained variance in EQ VAS scores from 37% to 45%. The self-confidence and social relationships bolt-ons improved the EQ-5D-5L’s discrimination between known groups based on self-esteem and bodily appearance (relative efficiency: 2.72 to 2.82). Conclusions Relevant bolt-ons substantially enhance the psychometric performance of the EQ-5D-5L in MICP populations. The self-confidence and tiredness bolt-ons may be recommended as primary choices for use alongside the EQ-5D-5L, both in clinical studies and as part of sensitivity analyses in economic evaluations of MICPs.