The selection of hyaluronic acid when treating with the nasolabial fold: A meta-analysis.

BACKGROUND: Hyaluronic acid (HA) gel is a widely used dermal filler for the correction of facial volume loss. The relationship between the characteristics of HA and clinical efficacy remains unclear. The aim of this systematic review and meta-analysis was to compare the efficacy and safety of monophasic and biphasic HA in the treatment of nasolabial folds (NLFs). METHODS: Studies were identified by searching the electronic databases PubMed, Embase, and Web of Science from inception to May 2021. Randomized controlled trials (RCTs) were selected according to the inclusion criteria. Outcomes included the Wrinkle Severity Rating Scale (WSRS) score, Global Aesthetic Improvement Scale score, and incidence of adverse events. RESULTS: A total of 1190 patients from 14 RCTs were included in the meta-analysis. The mean WSRS score improvement in the biphasic HA group was much lower than that in the monophasic HA group (MD = 0.18, 95% CI: 0.16-0.20, p < 0.00001). The subject satisfaction percentage was significantly higher for monophasic than biphasic HA (RR = 1.95, 95% CI: 1.09-3.48, p = 0.02). There was no significant difference in the adverse event rate between the monophasic and biphasic HA groups (RR = 0.96, 95% CI: 0.75-1.24, p = 0.77). CONCLUSIONS: Regardless of whether improvement in NLFs or patient satisfaction is considered, monophasic HA is better than biphasic HA. Regarding the adverse event rate, there is no difference between monophasic and biphasic HA.