A total of 431 publications were identified, of which 380 were retained for screening (51 duplicates were excluded). After initial screening of titles and abstracts, 311 publications were excluded. Full-text screening of the remaining 69 publications resulted in a total of 19 publications that met the inclusion criteria. The number of studies included and excluded at each stage of screening is shown in the PRISMA flow chart presented in Fig. 1. Of the 19 publications, 14 were conference abstracts and the remaining 5 were full papers (Table 1). Three of these publications (one letter to the editor and two abstracts) [26,27,28,29,30] report data from some of the same patients.

PRISMA flow chart. IBEC Índice Bibliográfico Español en Ciencias de la Salud, MEDES Medicina en Español, PRISMA Preferred Reporting Items for Systematic Reviews and Meta-Analyses; adapted from Moher et al. (2009) [62]

A total of 18 publications reported longitudinal data [26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43], 2 of which were prospective [38, 42] and 16 of which were retrospective [26,27,28,29,30,31,32,33,34,35,36,37, 39,40,41, 43] and one study had a cross-sectional, retrospective design [44]; 15 studies were single-centre studies [26,27,28,29,30,31, 33,34,35, 37, 38, 40, 42,43,44]. Most studies collected data on patient demographics [26, 28, 29, 31, 33,34,35,36,37,38, 40,41,42, 44], clinical characteristics [26, 28, 29, 31, 33,34,35,36, 38, 40, 41, 44] and treatment patterns [26, 28,29,30,31, 33,34,35,36,37,38, 40, 41, 43, 44]. Nine studies collected effectiveness data [26, 29, 34,35,36, 38, 40, 42], 11 collected persistence data [28, 30,31,32,