One hundred and ninety-five aged (mean age: 67+/-4.8 years), non-
insulin dependent diabetic patients underwent a randomised single-blind study for investigating the effect of
statin administration on
insulin resistance and respiratory quotient. After 4 weeks run-in period, all patients were randomised in three groups: placebo (n=67),
simvastatin (10 mg/day) (n=61) and
atorvastatin (5 mg/day) (n=67). Each treatment period lasted 8 weeks. At the beginning, after the run-in and at the end of the study,
insulin resistance was assessed by homeostasis model assessment (HOMA) index, while respiratory quotient (Rq) was evaluated by indirect calorimetry.
Statins versus placebo significantly lowered plasma total,
LDL-,
HDL-cholesterol and
triglyceride concentrations and improved
insulin resistance and Rq and metabolic control.
Atorvastatin had a greater effect than
simvastatin on plasma
triglyceride concentration (-26.3+/-3.1 vs. -19.7+/-2.8%, P<0.03), HOMA index (-13.1+/-0.6 vs. -9.1+/-0.9%, P<0.05), Rq (5.9+/-0.4 vs. 3.1+/-0.5%, P<0.05) and glycosylated haemoglobin (-11.2+/-0.3 vs. -7. 1+/-0.4%, P<0.05). In the whole group of subjects (n=195) and at the end of the study, changes in plasma
triglyceride concentrations were significantly correlated with the change in the HOMA index (r=0.44, P<0.001) and age and BMI adjusted-Rq (r=-0.32, P<0.005). Multivariate analyses demonstrated that decline in plasma
triglyceride concentration was a significant determinant for explaining the effect of
statin on
insulin resistance and Rq. In conclusion our study demonstrates that
statin administration is useful for controlling
dyslipidemia in
NIDDM patients and for improving the metabolic control. With regard to this latter aim,
atorvastatin seems to be more powerful than
simvastatin.