Backgrounds: Although there are several metaanalyses showing that the risk of new onset diabetes mellitus (NODM) is more increased in statin or higher dose statin users than placebos or lower dose statin users, a small increase in the risk of NODM would be outweighed by the improved cardiovascular outcomes. However, these metaanalyses are accompanied by limitations of the inclusion of the studies with confounders. The aim of this study is to elucidate the risk-benefit balance by investigating the number needed to treat (NNT) and number needed to harm (NNH) in a simultaneous comparison according to the individual trial-based criteria of NODM and cardiovascular events.
Methods: A systematic review of the literature retrieves 6 randomized controlled trials (RCTs) comparing statins vs. placebos and 5 RCTs comparing higher vs. moderate doses of statin. Only RCTs which documented the number of patients who developed DM and who experienced cardiovascular events are included.
Results: NNH is consistently larger than NNT in trials of statin use vs. placebos, or in trials of higher vs. moderate dose. Furthermore, the benefit-risk ratios are consistently greater than 1 in most trial.
Conclusions: These results suggest that the absolute risk of NODM by statin is offset by the benefit for reducing cardiovascular events. The evaluation of an individual trial-based risk-benefit balance could resolve the limitations of previous studies as well as provide further reinforced evidence that the merit of statin use for the purpose of lowdensity lipoprotein cholesterol lowering outweighs the NODM risk.