Platelet-Rich Plasma Monotherapies for Androgenetic Alopecia: A Network Meta-Analysis and Meta-Regression Study

Introduction: Platelet-rich plasma (PRP) is a commonly used therapeutic option for androgenetic alopecia (AGA). Evidence syntheses for the impact of PRP on AGA has been handicapped by non-standardized protocols for its administration. We quantitatively synthesized the evidence base to determine the relative efficacy of PRP regimens with different frequencies of administration. We defined frequency as a vector of the (i) number of sessions and Op time interval between the sessions. Methods: We systematically reviewed the peer-reviewed literature to obtain relevant data; we then conducted a multivariable meta regression and network meta-analyses (NMAs). Results: Twenty-five trials met our eligibility criteria; 10 unique PRP regimens were ultimately identified for use in our analyses. Our NMAs produced surface under the cumulative ranking curve (SUCRA) values that corroborated the findings of our multivariable meta regression. The frequency of PRP sessions, chemical activation, number of centrifugations, the age and sex of the patient, and the design of PRP administration (ie, whole-head vs split-scalp) are correlated with the efficacy of PRP insofar as the mean change in total hair density at 6 months from baseline. Conclusions: For the most part, regimens' SUCRA rankings and relative effects support that the efficacy of PRP administration increases when: (i) the number of sessions increases and (ii) the time interval between sessions decreases; we found that chemically-activated PRP (vs inactivated), double centrifugation (vs single), younger (vs older) age of treated patients, female (vs male) sex, and whole-head (vs split-scalp) administration is associated with improved PRP efficacy. Our approach rules out much confounding as the analysis of our outcome was exclusive to monotherapy at a singular timepoint. Our results may reconcile discrepant findings among previous studies and may be helpful in updating clinical practice guidelines.