Patients with dilated cardiomyopathy possess insulin resistance independently of cardiac dysfunction or serum tumor necrosis factor-α

It has recently been reported that insulin resistance is prevalent in patients with dilated cardiomyopathy (DCM); however, it remains unclear whether insulin resistance is directly induced by DCM or if it is caused by congestive heart failure associated with DCM. We evaluated homeostasis model assessment insulin resistance (HOMA-R) in 14 patients with DCM in comparison with 9 patients with valvular heart diseases (VHD). We also measured the level of serum tumor necrosis factor (TNF)-α as a possible causative factor for inducing insulin resistance. Even after the adjustment for age, body mass index, and cardiac function, HOMA-R was significantly higher in patients with DCM than in those with VHD (P = 0.012) (mean ± SEM: 3.51 ± 0.59, and 0.80 ± 0.64, respectively). The serum TNF-α level tended to be higher in patients with DCM than in those with VHD; however, the difference was not significant. In conclusion, patients with DCM possess insulin resistance independently of the severity of cardiac dysfunction or serum TNF-α, suggesting that insulin resistance in patients with DCM may be closely associated with the pathogenic condition of DCM itself.