ADIPOQ and type 2 diabetes mellitus: Total patients (non-T2D and T2D groups) had HRV correlated positively with serum adiponectin (r = 0.37 [95% CI -0.04 - 1.00] p = 0.03) and negatively with HbA1c levels (r = -0.58 [95% CI -1.00 - -0.3] p = 0.00).