Relationships between Botulinum Toxin type, administer, and location with odds of adverse events.

[BACKGROUND] Given the rising demand for cosmetic Botulinum Toxins (BoNT) procedures in the UK, the potential for adverse outcomes, and a notable gap in evidence regarding how injector type, treatment location, and product choice influence risk, this study aims to investigate these associations in a large UK patient sample.

[METHODS] A cross-sectional observational survey was designed to gather data on individuals' (aged ≥18 years) experiences and adverse events with cosmetic BoNT injections across Great Britain and Northern Ireland. Data were collected on participants age, gender, injector role, treatment location, BoNT type, adverse events (AEs) and satisfaction. Binary logistic regression models were fitted for each adverse event to examine the association between the occurrence of the symptom (Yes/No) and injector role, treatment location and BoNT type. Ethical approval for the study was granted by Anglia Ruskin University Research Ethics Panel (Ethics ID: ETH2425-1930).

[RESULTS] The present sample included 919 participants. Receiving BoNT injections from a beautician was significantly associated with increased odds of some AEs, including pain, and eyelid ptosis. Interestingly, BoNT administered by pharmacists, was significantly associated with bruising and swelling, whereas BoNT administered by a doctor was associated with increased odds of nerve damage. Medical clinics outperformed all other environments, with patients reporting lower odds of complications across multiple AEs. By contrast, home-based injections carried significantly elevated odds of bruising and swelling. Participant reported unknown or undisclosed BoNT-A products had markedly poorer outcomes across multiple AEs.

[CONCLUSION] Findings from this cross-sectional study suggest that injectors operating from informal settings, particularly without disclosing the product used, pose a potential measurable and preventable risk. As public demand grows, safeguarding patient outcomes requires further legislative action.