LDL Reduction and Risk of Diabetes in Veteran Statin Users.

Background: While statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) reduce cardiovascular morbidity and mortality, there is controversy regarding a potentially causal link with incident diabetes mellitus (DM). This association may partially be due to confounding by indication; since prescription guidelines encourage statin use among those diagnosed with DM, this may encourage their prescription among those with elevated blood glucose in the absence of DM diagnosis.

Objective: The study examined the association between low-density lipoprotein (LDL) reduction following initiation of statin use and new-onset DM among veterans.

Methods: We conducted a retrospective cohort study using data from the James A. Haley Veteran's Hospital in Tampa, Florida. Patients with a visit between January 2007 and December 2011 were selected from the Veterans Information Systems and Technology Architecture system. Individuals were classified into categories of statin usage based on LDL reduction percentages and frequency-matched with controls. The primary outcome of interest was incident DM.

Results: There was a significant association between LDL reduction and DM which was higher in lower LDL reduction groups (low response hazard ratio [HR]: 2.12, 95% CI: 1.62, 2.79; moderate response HR: 1.85, 95% CI: 1.40, 2.45; high response HR: 1.24, 95% CI: 0.74, 2.07).

Conclusion And Relevance: This association may partially be explained by potential lifestyle modifications individuals may make when prescribed a statin which may reduce their risk of DM independent of the statin usage. This research has demonstrated a protective association between greater LDL reduction and DM at the individual level while reenforcing the evidence of an association between statin usage and DM.