SAN FRANCISCO — All statins may not be created equal as far as diabetes patients are concerned, according to a recent study.
In patients with diabetes initiating statin therapy for the first time, those who took atorvastatin experienced 12% fewer cardiovascular events than those who took simvastatin, said Joshua Benner, Pharm.D., Sc.D., of IMS Health Care, Falls Church, Va. He spoke at the annual scientific sessions of the American Diabetes Association in place of the study's first author, Dr. Joanne M. Foody of Harvard Medical School, Boston.
The observational, comparative-effectiveness study used a large managed-care database including patient information from 92 health care plans in the United States, In all, the investigators identified 12,304 patients with diabetes initiating statin therapy with simvastatin and 33,772 initiating statin therapy with atorvastatin.
The researchers included only adult patients who were continuously enrolled in their health plan for 1 year prior to their first statin prescription and for at least 30 days after. Patients had to be taking either 10 mg or 20 mg of atorvastatin or 20 mg or 40 mg of simvastatin. The simvastatin group was followed for a mean of 591 days, and the atorvastatin group was followed for a mean of 556 days.
Among patients taking atorvastatin, the unadjusted rate of cardiovascular events requiring hospitalization was 3.35 per 100 person-years, significantly lower than the rate for simvastatin, which was 4.45 per 100 person-years.
After adjustment for age, gender, type of health plan, payer type, geographic region, calendar year of statin initiation, physician specialty, comorbidities, concomitant therapies, and prior health care cost, the hazard ratio for atorvastatin was 0.88 relative to simvastatin, indicating a 12% reduction in cardiovascular risk.
Atorvastatin and simvastatin were the two most commonly prescribed statins in the United States during the study period, which ran from January 2003 to September 2005, said Dr. Benner. “The comparison between these two statins is especially important given the recent trends in their utilization, where simvastatin recently became generic and is now preferred by many payers in the United States.”
Patients taking atorvastatin persisted with that prescription for a mean of 219 days, significantly longer than the 153 days for the patients taking simvastatin. Although the investigators did not compile data on adverse events, Dr. Benner said that this difference in persistence times suggests that there were fewer dose-limiting or a treatment-limiting side effects among those taking atorvastatin.
Future studies are needed to determine whether differences in “persistence, achieved LDL levels, or other factors may have contributed to the improved outcomes in diabetes patients taking atorvastatin,” he said.
The researchers have not yet concluded that atorvastatin's greater efficacy justifies its higher cost. “That's where a number of analyses are headed, because this raises the important policy question of what is the clinical and economic value of a marginal increase in effectiveness.”
Dr. Benner said the IMS Health Group conducts research and consulting projects supported by manufacturers of numerous lipid-lowering drugs.
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