PSQI correlated rather weakly with DBP (r = −0.296, p = 0.035), Hb (r = −0.291, p = 0.042) and LDL-C (r = −0.334, p = 0.023), while sleep quality metrics calculated by CPC analysis were more significantly correlated with clinical indicators that were related to metabolic functions of T2DM patients. This evidence concerns the gene GSTM1 and type 2 diabetes mellitus.