By Kurt Ullman
Recent studies have suggested an increased risk of type 2 diabetes mellitus (T2DM) in patients taking statin medications. A new look at the results of three major trials finds a slightly increased incidence of new-onset T2DM in those using high dose atorvastatin, but baseline fasting glucose and features of the metabolic syndrome are better predictors.
“A recent meta-analysis had indicated that statins increase the risk of developing new-onset diabetes by 9%, but only one of the studies included in that analysis used atorvastatin,” said author David D. Waters, MD, from the division of Cardiology at San Francisco General Hospital. “I am involved in Treating to New Targets (TNT), a large study using atorvastatin, and I obtained access to the data from 2 other large trials, Incremental Decrease in End Points Through Aggressive Lipid Lowering (IDEAL) and Stroke Prevention by Aggressive Reduction in Cholesterol Levels (SPARCL). We thought it important to examine which types of patients were more at risk for developing new-onset diabetes while taking a statin.”
In the TNT trial, 351 of 3,798 patients randomized to 80 mg of atorvastatin and 308 of 3,797 randomized to a 10 mg dose developed new-onset T2DM (9.24% vs. 8.11%, adjusted hazard ratio [HR]: 1.10, 95% confidence interval [CI]; 0.94 to 1.20; P = 0.226). In IDEAL, the results were 239 of 3,737 randomized to atorvastatin 80 mg/day and 208 of 3,724 randomized to simvastatin 20 mg/day developed new cases of T2DM (6.40% vs. 5.59%, adjusted HR 1.19; 95% CI: 0.98 to 1.43; P = 0.072). The data from SPARCL showed new-onset type 2 diabetes was seen in 166 of 1905 patients randomized to atorvastatin 80 mg/day and in 115 of 1,898 who were randomized to take a placebo (8.71% vs. 6.06%, adjusted HR: 1.37, 95% CI: 1.08 to 1.75; P = 0.011). Major cardiac events occurred in 11.3% of patients with new-onset diabetes and in 10.8% of those without (adjusted HR: 1.02, 95% CI: 0.77 to 1.35, P = 0.69).
“Atorvastatin increased the risk of new-onset diabetes in SPARCL, the only trial of the 3 with a placebo-control group,” said Dr. Waters. “The increase was within the range reported in the statin meta-analysis.”
In the other 2 trials, there was a non-significant trend toward an increase in the high-dose atorvastatin group. In Dr. Waters’ view, the risk of developing new-onset diabetes was linked to fasting blood sugar at baseline, the presence of hypertension, a high body mass index, and fasting triglyceride levels at baseline. “These findings show that the benefits of taking a statin (in terms of preventing heart attack, stroke and other cardiovascular events) far outweigh any risk of new-onset diabetes,” said Dr Waters.
Author Disclosures: One or more of the authors report that they have consulted, received honoraria, or participated in clinical trials involving multiple pharmaceutical companies.
Source: Waters DD, et al., Predictors of new-onset diabetes in patients treated with atorvastatin: Results from 3 large randomized clinical trials. JACC. 2011;57:1535-1545.