ATORVASTATIN BUT NOT PITAVASTATIN SIGNIFICANTLY INCREASES FASTING PLASMA GLUCOSE IN PATIENTS WITH TYPE 2 DIABETES AND COMBINED DYSLIPIDEMIA

Drug-Induced Diabetes Mellitus: Evidence for Statins and Other Drugs Affecting Glucose Metabolism

Abnormalities of glucose metabolism and glucose tolerance, either because of a reduction in tissue sensitivity to insulin (e.g., in liver, skeletal muscle, and adipose tissues) and/or a reduction in pancreatic insulin secretion, are associated with a number of unwanted health outcomes. Even small increases in circulating glucose levels (often described as dysglycemia or prediabetes) may confer an increased risk of cardiovascular (CV) disease and progression to overt type 2 diabetes. A number of drug therapies, many of them used long term in chronic disease management, have adverse effects on glucose metabolism, diabetes risk, and glycemic control among patients with preexisting diabetes. In this study, we review the evidence, underlying mechanisms, and the clinical significance of drug-related adverse effects on glucose metabolism.

Is statin-induced diabetes clinically relevant? A comprehensive review of the literature

In those predisposed to the development of diabetes (the insulin resistant, obese and older patients) statins may increase the risk of developing diabetes. Despite the fact that the conversion to diabetes is generated from post hoc analyses, it seems to be a class effect with a dose-response relationship. However, statins have not been clearly shown to increase diabetic microvascular complications (retinopathy, nephropathy and neuropathy). Thus, the clinical significance of increased glucose levels in patients treated on statins is uncertain. While the exact mechanism for how statins increase the risk of diabetes is unknown, a possible explanation is through a reduction in adiponectin levels. Despite the fact that higher statin doses are more likely to lead to new-onset diabetes, for every case of diabetes caused, there are approximately three cardiovascular events reduced with high dose versus moderate dose statin therapy. Overall, the small risk of developing type 2 diabetes with statin therapy is far outweighed by the potential of statins to decrease cardiac events.

Statins are diabetogenic--myth or reality?

Multiple clinical trials have demonstrated the beneficial effects of statins in lowering levels of low-density lipoprotein and in the prevention of cardiovascular disease. However, although statins have a good safety profile, a debate has been ongoing as to whether use of statins increases risk of new-onset diabetes. Recent large scale meta-analyses of statin trials support the concept of a diabetogenic effect of statins, as do some other small trials assessing changes in glycaemia parameters and insulin levels. However, a definitive mechanism of action has not yet been elucidated. Nevertheless, the level of evidence has been sufficient to lead the FDA to make a change to the labelling of statins. This review assesses the current available evidence and offers a clinical perspective.

Comparative long-term efficacy and tolerability of pitavastatin 4 mg and atorvastatin 20-40 mg in patients with type 2 diabetes mellitus and combined (mixed) dyslipidaemia

AIM

To compare the long-term efficacy and safety of pitavastatin with atorvastatin in patients with type 2 diabetes and combined (mixed) dyslipidaemia.

METHODS

Randomised, double-blind, active-controlled, multinational non-inferiority study. Patients were randomised 2 : 1 to pitavastatin 4 mg (n = 279) or atorvastatin 20 mg (n = 139) daily for 12 weeks. Patients completing the core study could continue on pitavastatin 4 mg (n = 141) or atorvastatin 20 mg (n = 64) [40 mg (n = 7) if lipid targets not reached by week 8] for a further 44 weeks (extension study). The primary efficacy variable was the change in low-density lipoprotein cholesterol (LDL-C).

RESULTS

Reductions in LDL-C were not significantly different at week 12 between the pitavastatin (-41%) and atorvastatin (-43%) groups. Attainment of National Cholesterol Education Program and European Atherosclerosis Society targets for LDL-C and non-high-density lipoprotein cholesterol (non-HDL-C) was similarly high for both treatment groups. Changes in secondary lipid variables (e.g. HDL-C, apolipoprotein B and triglycerides) were similar between treatments. Post hoc analysis showed that adjusted mean treatment differences for pitavastatin vs. atorvastatin were within the non-inferiority margin at weeks 16 (+0.11%; 95% confidence interval (CI), -5.23 to 5.44) and 44 (-0.02%; 95% CI, -5.46 to 5.41) of the extension study. Both treatments were well tolerated; atorvastatin increased fasting blood glucose from baseline (+7.2%; p < 0.05), whereas pitavastatin had no significant effect (+2.1%).

CONCLUSIONS

Reductions in LDL-C and changes in other lipids were not significantly different in patients treated with pitavastatin 4 mg or atorvastatin 20 or 40 mg. Pitavastatin may, however, have a more favourable effect on the glycaemic status.