“…Four studies were designed as prospective cohort studies [15,23,28,31], and rest were case series [12-14,16-22,24-27,29,30,32,33]. Three studies by Metcalfe et al [16,17,19], two studies by Brandberg et al [23,28], two studies by Gahm et al [21,25] and another three studies by Gahm et al [26,27,32] were each based on same patient populations. Eight studies were from Sweden [21,23-28,32], 5 from the US [12-14,20,22], 3 each from Canada [16,17,19] and the Netherlands [18,30,31], and 1 each from UK [15], Turkey [29] and Norway [33].…”