“…Regarding the SRH assessment, 72.5% of the studies ( n = 37) [5, 21, 22, 30, 33, 37, 39, 43–46, 49–52, 59–64, 66, 68–71, 73–77] used general direct questions ( n = 21, 67.7%) [5, 30, 33, 37, 39, 43, 46, 49, 51, 59–61, 64, 68–71, 73, 74, 76, 77] or comparative direct questions ( n = 15, 48.4%) [5, 21, 22, 30, 44, 45, 50–52, 62, 63, 66, 69, 73, 75]. Comparative SRH referred to patients’ current health status in comparison to an earlier period [5, 37, 43, 51, 54–56, 66] or to people of the same age [21, 22, 38, 43, 50, 56, 66, 69, 73, 75].…”