Recently, I have been asked about statins and diabetes by several patients at my practice site – a family medicine clinic. Some patients have asked if he or she should stop their prescribed statin or seek legal advice. Over the past year, there have been news reports about statins and the risk of diabetes. A patient may interpret the reports differently than another, as well as how it is presented in a newspaper or on the television. Based on these inquiries, I wanted to provide an unbiased opinion related to statins and diabetes.
There were two meta-analyses regarding the incidence of statins and new-onset diabetes. In the first analysis, statins were found to have a 1.09 increased risk of diabetes, resulting in a numbers needed to harm of 255 patients. This number meant that 1 case of diabetes would occur if 255 patients took a statin for 4 years. In the second analysis, moderate and intensive (i.e., high) doses of statin were evaluated and both doses showed a higher risk of new-onset of diabetes. With a moderate statin dose, 1 case of diabetes would occur if 498 patients took this dose for 1 year. An additional 2 cases would occur with an intensive statin dose. These numbers can be scary to a patient considering the number of patients in the United States requiring statins as primary or secondary cardiovascular prevention. There is a greater benefit with statin as a moderate or intensive statin dose can prevent 1 cardiovascular event among every 155 patients treated for 1 year, indicating the benefits of a statin definitely outweigh the risk. (JAMA 2011; 305:2556-2564 and Lancet 2010;375:735-742)
New evidence was published in the British Medical Journal in June 2013 regarding individual statins and new-onset diabetes. This trial was a population-based cohort in a time-to-event analysis. Confounders were adjusted, such as cardiovascular medications, but the authors did not control for other influences (i.e., atypical antipsychotics and corticosteroids). Pravastatin was used as a reference statin in the analysis. Based on the evidence, atorvastatin had the highest risk of new-onset diabetes (22 percent), compared to rosuvastatin (18 percent) and simvastatin (10 percent), respectively. In addition, moderate to high doses of statins had a higher risk of causing diabetes, compared to low doses (i.e., atorvastatin 20 to 80 mg versus atorvastatin 10 mg). It should be added that a majority of the patients in this trial were taking atorvastatin, rosuvastatin, and simvastatin, compared to lovastatin and fluvastatin.
In conclusion, there is evidence to show statins can cause new-onset diabetes. Our patients most likely had other risk factors for developing diabetes in his or her lifetime. Therefore, there is a greater benefit with the statin in preventing a heart attack or stroke and should be continued among our patients.