Fig. 1.

PRISMA flow diagram of search results. ^aSanyal et al., 2010 [16] (from an excluded paper). ^bSayiner et al. 2016 [13] (from gray searches). ^cPalsgrove et al. 2016 [17] (conference abstract from ISPOR 2016). HRQoL, health-related quality of life; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses