Six trials were included in the review (20,079 patients, sample sizes ranged from 164 to 9,795); 11,590 patients had type II diabetes mellitus (range across trials from 138 to 9,795). Three trials enrolled only patients with type II diabetes mellitus; in the remaining three trials, only small numbers of patients had type II diabetes. Follow-up in the trials ranged between three and 6.2 years.
There was a 21% statistically significant reduction in the risk of non-fatal myocardial infarction observed with the use of fibrates (RR 0.79, 95% CI 0.67 to 0.93; four RCTs). There was also a statistically non significant trend observed in decrease in the risk of stroke (RR 0.88, 95% CI 0.73 to 1.05;, four RCTs).
The risk of unstable angina was found to be slightly higher for the patients who received fibrates, but the increase in risk was not statistically significant (RR 1.16, 95% CI 0.98 tyo 1.37; four RCTs).
There were no statistically significant differences observed with the use of fibrates compared with placebo for the risks of all-cause mortality (four RCTs), cardiac mortality (five RCTs), fatal myocardial infarction (three RCTs), cancer (four RCTs) or cancer-related death (three RCTs). There was also no difference observed in the risk of invasive coronary revascularisation (two RCTs).
Moderate heterogeneity was observed across the trials for all-cause mortality (I2=55.9%), cardiac mortality (I2=57.7%), fatal myocardial infarction (I2=45.3%). Significant heterogeneity was found the risk of invasive coronary revascularisation (I2=82.6%).
All the trials reported reductions in total cholesterol levels (4 to 10%) and triglyceride levels (21 to 36%).