PON1 and diabetes mellitus: A subgroup analysis was performed in order to estimate the possible existence of a difference in PON-1 arylesterase activity in CAD patients having or not having DM; PON-1 arylesterase activity was significantly higher among CAD patients without DM compared to those with diabetes (SMD: 0.235, 95% CI: 0.014 to 0.456, p = 0.03, I2 = 0%) (Figure 3).