Given the lack of dedicated randomised controlled trials, a consensus on using statins for the primary prevention of cardiovascular disease (CVD) and all-cause mortality in adults with type 1 diabetes mellitus (T1DM) has been elusive.¹˒² A new study emulating a target trial sought to evaluate the long-term risks and benefits of this intervention in this specific patient population.

This sequential target trial emulation compared statin initiation versus non-initiation using UK primary care data from the IQVIA Medical Research Data database between 2005 and 2016. The cohort included adults aged 25–84 years with a T1DM diagnosis and an insulin prescription. Eligibility required a baseline low-density lipoprotein-cholesterol (LDL-C) of ≥2.6 mmol/L or non-high-density lipoprotein cholesterol of ≥3.4 mmol/L. Individuals with pre-existing CVD, myopathy, or liver disease were excluded.

The study analysed 4,176 statin initiators and 16,704 non-initiators over a median follow-up of 6 years. The primary outcome measures were all-cause mortality and major CVD. Safety endpoints included adverse events such as myopathy and liver dysfunction. Researchers estimated 10-year absolute risk differences (RDs) for both intention-to-treat (ITT) and per-protocol (PP) effects.

Statin initiation was associated with significant reductions in key outcomes compared to non-initiation. For all-cause mortality, the 10-year absolute risk difference was -1.66% (95% CI: -2.79% to -0.45%) in the ITT analysis and -3.48% (95% CI: -4.68% to -2.07%) in the PP analysis.

Similarly, for major CVD events, the ITT analysis revealed an absolute risk difference of -1.63% (95% CI: -2.57% to -0.53%), while the PP analysis showed a difference of -2.69% (95% CI: -4.00% to -1.22%).

Regarding safety, there was no association found with myopathy. Some analyses suggested a slight association with an increased risk of liver dysfunction.

Subgroup analyses indicated that absolute risk reductions were generally larger in women, individuals aged 40 years or older, those with a baseline LDL-C ≥3.4 mmol/L, and patients with a higher predicted cardiovascular risk.

The study's authors concluded that, "among adults with T1DM, statin initiation for primary prevention was associated with reductions in all-cause mortality and major CVD with a very low risk of adverse effects." They also noted that, "the differences in absolute risk reductions can help guide personalized statin treatment decisions in T1DM."

References

1. Blais JE, Yan VKC, Chan EWY, et al. Safety and Effectiveness of Statins for Primary Prevention in Adults With Type 1 Diabetes: An Emulation. J Am Coll Cardiol. 2025;86(11):797-809. https://doi.org/10.1016/j.jacc.2025.07.013

2. Soedamah-Muthu SS, Fuller JH, Mulnier HE, et al. High risk of cardiovascular disease in patients with type 1 diabetes in the U.K.: a cohort study using the general practice research database. Diabetes Care. 2006;29:798-804. https://doi.org/10.2337/diacare.29.04.06.dc05-1433

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