Triglycerides and risk of cardiovascular events in statin-treated patients with newly diagnosed type 2 diabetes: a Danish cohort study

BACKGROUND: Elevated triglyceride levels are a clinically useful marker of remnant cholesterol. It is unknown whether triglycerides are associated with residual cardiovascular risk in CVD-naïve patients with newly diagnosed type 2 diabetes mellitus (T2DM), who are already on statin therapy. We aimed to assess the association between triglyceride levels and risk of major cardiovascular events (MACE) in statin-treated patients with newly diagnosed T2DM managed in routine clinical care. METHODS: This cohort study included newly diagnosed T2DM patients without a previous diagnosis of cardiovascular disease in Northern Denmark during 2005–2017. Individual triglyceride levels while on statin treatment were assessed within 1 year after T2DM diagnosis. The primary outcome was a composite of myocardial infarction, ischemic stroke, or cardiac death (MACE). Patients were followed from one year after T2DM diagnosis until 30 April 2021, MACE, emigration, or death. We used Cox regression to compute hazard ratios (HRs) controlling for confounding factors. RESULTS: Among 27,080 statin-treated patients with T2DM (median age 63 years; 53% males), triglyceride levels were < 1.0 mmol/L in 17%, 1.0–1.9 mmol/L in 52%, 2.0–2.9 mmol/L in 20%, and ≥ 3.0 mmol/L in 11%. During follow-up, 1,957 incident MACE events occurred (11.0 per 1000 person-years). Compared with triglyceride levels < 1.0 mmol/L, confounder-adjusted HRs for incident MACE were 1.14 (95% CI 1.00–1.29) for levels between 1.0 and 1.9 mmol/L, 1.30 (95% CI 1.12–1.51) for levels between 2.0 and 2.9 mmol/L, and 1.44 (95% CI 1.20–1.73) for levels ≥ 3.0 mmol/L. This association was primarily driven by higher rates of myocardial infarction and cardiac death and attenuated only slightly after additional adjustment for LDL cholesterol. Spline analyses confirmed a linearly increasing risk of MACE with higher triglyceride levels. Stratified analyses showed that the associations between triglyceride levels and MACE were stronger among women. CONCLUSIONS: In statin-treated patients with newly diagnosed T2DM, triglyceride levels are associated with MACE already from 1.0 mmol/L. This suggests that high triglyceride levels are a predictor of residual cardiovascular risk in early T2DM and could be used to guide allocation of additional lipid-lowering therapies for CVD prevention. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12933-023-01921-5.