Does interval time between pulsed dye laser treatments for port-wine stains influence outcome? A systematic review and meta-analysis.

The pulsed dye laser (PDL) is the standard treatment for port-wine stains (PWS). Maximal improvement occurs after multiple treatment sessions; however, the optimal treatment interval has yet to be determined. The aim of this study was to review whether there is an association between PDL treatment interval and outcome of PWS. Six databases were searched by three reviewers for publications investigating treatment of PWS with PDL. The 75% improvement rates (75IR) were extracted for quantitative analysis. Meta-regression was used to investigate the association between treatment intervals and 75IR. The systematic review included 1 RCT and 33 cohort studies (7 prospective cohorts and 26 retrospective cohorts), with a total of 3777 patients. The pooled 75IR was 37% (95% CI 29-45%; I2 = 95%). Light Fitzpatrick skin type (p = 0.04), facial anatomic location (p = 0.01), and young age (p = 0.008) were associated with 75IR. In an unadjusted (p = 0.42) and multivariable adjusted (p = 0.98) meta-regression, no association was found between time interval between treatments and 75IR. These results persisted in a sensitivity analysis of studies with a mean patient age of ≤ 1. The majority of included studies were heterogeneous and retrospective. Based on cohort studies of low-to-moderate quality, time intervals between PDL treatments are not associated with PWS outcome.