Fig. 1

PRISMA diagram representing the studies included in different stages of the SLR and current NMA. The SLR was first run in April 2018, and updated in May 2020 and December 2020. A more recent search of the literature, conducted on 31 August 2021, identified no additional studies. *Applies only to abstracts screened for full-text articles. A few prespecified specific conference abstracts and years were screened separately; therefore, conference abstracts and articles for which only information in abstract form were excluded from the main screening. **Abstract was a multiple attack study for which information was available only in aggregated form. ***Crossover study was a conference abstract for which aggregated data only were available. ^†No data were extracted from secondary publications. NMA, network meta-analysis; PICOS, population, intervention, comparator and outcome selection; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses; SLR, systematic literature review