Retrospective review of delayed adverse events secondary to treatment with a smooth, cohesive

Abstract Background Recent publications have suggested an increased risk of delayed adverse events (DAE) with a smooth, cohesive 20 mg/mL hyaluronic acid filler (HA-V). Objective To examine the occurrence of HA-V DAEs and identify patterns and characteristics. Methods Charts from patients who received HA-V between February 1, 2009 and February 28, 2018 from two clinics were analyzed. Results In 4500 patients who received 9324 treatments with HA-V, 44 DAE’s were identified, for a combined incidence of 0.98% per patient, 0.47% per treatment, and 0.23% per syringe. Patients with DAEs received a slightly larger cumulative amount of HA-V than those who did not. Delayed swelling and nodule formation were the most common reactions and occurred a median of 4 months after treatment, with an increase in frequency between October and January. About a third were preceded by an identifiable immunologic stimulus. DAEs were transient and resolved without incident. Limitations Retrospective nature made it difficult to capture time to resolution or remember potential triggers. Conclusion In this large, long-term retrospective review, HA-V DAEs occurred at a rate of 0.98% per patient. Although the exact cause has yet to be elucidated, the authors hypothesize an increase in fragmentation during the HA-V degradation process may trigger an inflammatory response following an immunologic trigger.