Fig. 5

Co-occurrence analysis of the titles and abstracts among the medication adherence studies selected. a Mapping and clustering of keywords; three clusters: “Perceptions” (yellow), “interventions” (green and blue), Preferences and needs (red cluster). b Mapping and clustering of titles and abstract keywords according to the mean frequency of appearance between 2014 and 2018; keywords in blue appeared earlier (2014) than those in yellow which appeared later (2018)