Introduction After a safety warning was issued for a risk of muscular injury associated with dipeptidyl peptidase-4 (DPP-4) inhibitor use, especially when co-prescribed with statins, spontaneous reporting analyses provided conflicting results. Objective The aim of this study was to investigate the association between DPP-4 inhibitor use and the risk of muscular injury in individuals with type 2 diabetes mellitus using statins or fibrates. Methods We conducted a nested case-control study amongst a cohort of individuals with type 2 diabetes using statins or fibrates, identified from a nationwide French health insurance database (2009–2014). Cases of serious muscular injury were defined as subjects hospitalized for rhabdomyolysis or myopathy, or for whom testing for myoglobin or creatine phosphokinase followed by a change in statin or fibrate prescription (dose decrease, treatment switch, or stop) was identified. Up to ten controls were matched to each case according to sex, age, and type of lipid-lowering agent. Associations between DPP-4 inhibitor use and serious muscular injury were estimated using a multivariate conditional logistic regression model, providing odds ratios (ORs) adjusted for alcoholism, chronic renal failure, hypothyroidism, and number of concomitant drugs. Results Within the 35,117 individuals with type 2 diabetes mellitus constituting the source cohort, 437 statin-user cases were identified who were matched to 4358 statin-user controls. Similarly, 54 fibrate-user cases were identified who were matched to 540 fibrate-user controls. The adjusted OR for DPP-4 inhibitor use and serious muscular injury was estimated at 1.0 (95% confidence interval [CI] 0.7–1.2) in statin users and 0.8 (95% CI 0.4–1.9) in fibrate users. Conclusion In this study, DPP-4 inhibitor use was not associated with an increased risk of serious muscular injury among patients with type 2 diabetes mellitus using statins or fibrates.Read less <