Seven studies evaluated the association between serum Gd-IgA1 levels and risk of CKD progression [26, 31, 33, 34, 44, 51, 55], with six studies reporting the association between serum Gd-IgA1 levels and risk of kidney failure [21, 33, 34, 40, 47, 58]. Here, IGHA1 is linked to kidney failure.