Statin-Related New-Onset Diabetes Appears Driven by Increased Insulin Resistance: Are There Clinical Implications?

Risk and effect modifiers for poor glycemic control among the chinese diabetic adults on statin therapy: the kailuan study

BACKGROUND

Limited studies have investigated the association between statin therapy and poor glycemic control, especially in the Chinese diabetic population.

METHODS

Two prospective diabetes cohorts were drawn from the Kailuan Cohort. In Cohort 1, linear regression models were used to evaluate the association between statin therapy and glycated hemoglobin (HbA1c) level change. In Cohort 2, new user design and conditional logistic models were used to assess associations between statin initiation and poor glycemic control which was a composite outcome comprised of hypoglycemic agent escalation and new-onset hyperglycemia.

RESULTS

Among 11,755 diabetic patients with medication information, 1400 statin users and 1767 statin nonusers with repeated HbA1c measurements were included in Cohort 1 (mean age: 64.6 ± 10.0 years). After a median follow-up of 3.02 (1.44, 5.00) years, statin therapy was associated with higher HbA1c levels (β: 0.20%; 95%CI: 0.05% to 0.34%). In Cohort 2, 1319 pairs of matched cases/controls were included (mean age: 61.6 ± 9.75 years). After a median follow-up of 4.87 (2.51, 8.42) years, poor glycemic control occurred in 43.0% of statin new users and 31.8% of statin nonusers (OR: 1.69; 95% CI: 1.32 to 2.17; P < 0.001). The statin-associated poor glycemic control risk was significantly higher among patients with lower body mass index (Pint = 0.089). Furthermore, a nonlinear association was observed between statin therapy duration and poor glycemic control (P = 0.003).

CONCLUSIONS

Among Chinese diabetic adults, statin therapy was associated with a higher level of HbA1c, and a higher risk of hypoglycemic agent escalation and new-onset hyperglycemia, especially among those who had lower body mass index levels and longer statin therapy duration.

Side effects of statins: from pathophysiology and epidemiology to diagnostic and therapeutic implications

Treatment with statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, has proven beneficial preventive effects on cardiovascular events. However, discontinuation due to intolerance and non-adherence remain two of the major gaps in both primary and secondary prevention. This leads many patients with high-risk of atherosclerotic cardiovascular disease (ASCVD) to be inadequately treated or not to achieve target lipid level goals, and as consequence they undergo an increased risk of cardiovascular events. The aim of this review is thus to give an overview of the reasons for discontinuation and on the possible mechanisms behind them. Although statins, as a class, are generally safe, they are associated with an increased risk of diabetes mellitus and hepatic transaminase elevations. Incidence of cataracts or cognitive dysfunction and others presented in the literature (e.g. proteinuria and haematuria) have been never confirmed to have a causal link. Conversely, debated remains the effect on myalgia. Muscle side effects are the most commonly reported, although myalgia is still believed by some to be the result of a nocebo/drucebo effect. Concerning mechanisms behind muscular side effects, no clear conclusions have been reached. Thus, if on one side it is important to identify individuals either at higher risk to develop a side effect, or with confirmed risk factors and conditions of statin intolerance, on the other side alternative strategies should be identified to avoid an increased ASCVD risk.

Statins Aggravate the Risk of Insulin Resistance in Human Muscle

Beside their beneficial effects on cardiovascular events, statins are thought to contribute to insulin resistance and type-2 diabetes. It is not known whether these effects are long-term events from statin-treatment or already triggered with the first statin-intake. Skeletal muscle is considered the main site for insulin-stimulated glucose uptake and therefore, a primary target for insulin resistance in the human body. We analyzed localization and expression of proteins related to GLUT4 mediated glucose uptake via AMPKα or AKT in human skeletal muscle tissue from patients with statin-intake >6 months and in primary human myotubes after 96 h statin treatment. The ratio for AMPKα activity significantly increased in human skeletal muscle cells treated with statins for long- and short-term. Furthermore, the insulin-stimulated counterpart, AKT, significantly decreased in activity and protein level, while GSK3ß and mTOR protein expression reduced in statin-treated primary human myotubes, only. However, GLUT4 was normally distributed whereas CAV3 was internalized from plasma membrane around the nucleus in statin-treated primary human myotubes. Statin-treatment activates AMPKα-dependent glucose uptake and remains active after long-term statin treatment. Permanent blocking of its insulin-dependent counterpart AKT activation may lead to metabolic inflexibility and insulin resistance in the long run and may be a direct consequence of statin-treatment.