The report, published in the online journal BMJ Open Diabetes Research & Care, suggests that the elevated risk is 30%. Those results are based on analysis of more than 3,000 participants in the Diabetes Prevention Program Outcomes Study (DPPOS) conducted in the United States.
Researchers from Albert Einstein College of Medicine conducted a long-term follow-up study of a randomized clinical trial designed to determine if modest weight loss through lifestyle changes or treatment with metformin could reduce or delay development of type 2 diabetes in people at high risk.
In that trial, participants were provided standard advice on healthy eating and exercise but were randomly assigned to either an intensive lifestyle program, treatment with metformin, or treatment with a placebo. At trial’s end, the study group was invited to join DPPOS, where a range of tests were performed. Initiation of statins was recorded during twice-yearly measurement of blood glucose.
The report notes that when DPPOS began, fewer than 4% of participants took statins, but that percentage mushroomed to 33% to 37% over a decade, especially with a diabetes diagnosis. Simvastatin (40%) and atorvastatin (37%) were prescribed most often, according
to the study.
Results indicated, however, that statin use was associated with a greater risk of diabetes diagnosis, with no difference among the treatment groups in the original trial. Overall, use of a statin was linked to a 36% increased risk of subsequently being diagnosed with type 2 diabetes, compared with those who had not been prescribed these drugs, although the percentage dropped to 30% when clinical criteria used to determine the need for statin treatment was added.
Study authors emphasize that, although participants who were prescribed statins had slightly higher levels of blood glucose at the beginning of the trial, that didn’t fully explain their higher rates of diabetes.
Potency of the statin didn’t seem to have an effect, nor did how much LDL cholesterol was reduced, according to the report. To determine that, researchers grouped statins into low- (pravastatin, lovastatin, fluvastatin) or high-potency (atorvastatin, simvastatin, rouvastatin, cerivastatin) categories.
Cautioning that causation can’t be determined from the observational study, the researchers suggest one factor might be that statins impair production of insulin, which has been determined in some experimental research. They also emphasize that a potentially modest increase in diabetes risk might not outweigh the need to take a statin to significantly reduce the risk of heart attack or stroke.
“Nonetheless, glucose status should be monitored and healthy lifestyle behaviors reinforced in high risk patients who are prescribed statins for [cardiovascular disease] prophylaxis,” study authors conclude.