Aims: In order to evaluate a hypothesized protective effect of the use of HMG Co-A reductase inhibitors (statins) on the development of Type 2 diabetes, we conducted a nested case-control study based on data from the UK-based General Practice Research Database (GPRD).
Methods: We identified a population of adults 30-79 years of age between 1 January 1991 and 31 March 2002, who were being treated with a statin or who were diagnosed with hyperlipidaemia but were not being treated with a lipid-lowering drug. From this population we identified all incident cases of Type 2 diabetes. We conducted a nested case-control study encompassing 588 cases and 2063 matched controls.
Findings: We observed an adjusted odds ratio (OR) of 1.1 [95% confidence interval (CI) 0.8, 1.4] for current statin users compared with non-exposed subjects and adjusted ORs for pravastatin use alone and simvastatin use alone compared with non-exposed of 0.7 (95% CI 0.4, 1.2) and 1.0 (95% CI 0.7, 1.3), respectively. There was little evidence for a duration effect for simvastatin in these data, though there is a slight suggestion of a long-term protective effect with pravastatin.
Conclusion: The current study results are most consistent with the conclusion that there is little if any protective effect of statins on the development of Type 2 diabetes.