Patients taking high-dose atorvastatin (Lipitor) were more likely to developed new onset diabetes than those taking lower doses of the drug, but only if they had at least two risk factors for elevated blood glucose, an analysis of two randomized trials indicates.
Patients with only one risk factor who were taking atorvastatin 80 mg did not have higher rates of new onset diabetes than patients taking atorvastatin 10 mg or simvastatin 20 mg to 40 mg (3.22% vs. 3.35%; HR 0.97, 95% CI 0.77-1.22), David Waters, MD, of the University of California San Francisco, and colleagues reported in the Journal of the American College of Cardiology.
However, those with two to four risk factors who took higher dose atorvastatin had significantly higher rates of new onset diabetes compared with patients taking lower doses (14.3% vs.11.9%; HR 1.24, 95% CI 1.08 to 1.42).
“These results should reassure physicians treating patients at low risk for diabetes,” the researchers wrote.
Similar to previous findings, the analysis showed that higher dose atorvastatin significantly reduced cardiovascular events across the diabetes spectrum, which some have argued outweighs the risk for diabetes.
The study involved 15,056 participants in the Treating to New Targets (TNT) Trial and Incremental Decrease in End Points Through Aggressive Lipid Lowering (IDEAL) Trial, who had coronary disease but not diabetes at baseline assessment.
TNT patients with stable coronary disease were randomly assigned to atorvastatin 10 mg or 80 mg daily. IDEAL patients who had had an MI were randomly assigned to atorvastatin 80 mg or simvastatin 20 mg to 40 mg daily.
The majority of patients in the TNT (53.7%) and IDEAL (63.6%) trials had only one of the following four characteristics considered risk factors for new-onset diabetes:
- Fasting blood glucose greater than 100 mg/dL
- Fasting triglycerides greater than 150 mg/dL
- Body mass index greater than 30 kg/m2
- History of hypertension
The remainder of participants had at least two risk factors and were considered high risk for new onset diabetes.
Atorvastatin 80 mg reduced cardiovascular events in both the low-risk (8.5% vs. 9.8%; HR 0.87, 95% CI 0.755 to 0.995) and high-risk (10.1% versus 12%; HR 0.82, 95% CI 0.71 to 0.96) groups, the researchers found, but only increased the risk for new onset diabetes in high-risk patients
Among those with two or more risk factors taking atorvastatin 80 mg, there were 80 cases of new-onset diabetes and 94 fewer major cardiovascular events compared with lower-dose statin therapy.
“In considering the balance between new-onset diabetes and cardiovascular event prevention, it is worth noting that the microvascular and macrovascular complications of diabetes occur relatively uncommonly during the first decade after diagnosis,” the researchers wrote. “Many patients with established vascular disease, such as those in this study, will die from an atherosclerotic event before they develop complications from diabetes.”