Statins provided primary prevention benefit in younger patients with type 1 diabetes

Statin initiation was associated with a reduction in all-cause mortality and major cardiovascular disease (CVD) among adults with type 1 diabetes, a British study showed.

To evaluate the long-term risks and benefits of statins for primary prevention in adults with type 1 diabetes, researchers in the United Kingdom used a database to perform a sequential target-trial emulation. All included patients were ages 25 to 84 years, had a prescription for insulin between January 2005 and December 2016, and had baseline low-density lipoprotein (LDL) cholesterol levels of at least 2.6 mmol/L (100 mg/dL) or non-high-density lipoprotein cholesterol levels of at least 3.4 mmol/L (130 mg/dL). Any individual with pre-existing coronary artery disease, myocardial infarction, stroke, heart failure, myopathy, liver disease, rheumatic heart disease, schizophrenia, or cancer was excluded. Findings were published by the Journal of the American College of Cardiology on Sept. 8.

A total of 4,176 statin initiators (mean age, 45 years; 40.6% women) were compared to 16,704 noninitiators. Statin initiation was associated with a 1.66% (95% CI, 0.45% to 2.79%) reduction in the 10-year absolute risk of all-cause mortality, with a hazard ratio (HR) of 0.74 (95% CI, 0.64 to 0.86). Statin initiation was also associated with a 10-year absolute risk reduction of 1.63% (95% CI, 0.53% to 2.57%) in major CVD (HR, 0.84; 95% CI, 0.73 to 0.97). Statin use was linked with a slight increase in liver dysfunction (HR, 1.29 [95% CI, 1.00 to 1.67]; risk difference, 0.45% [95% CI, −0.20% to 1.08%]), but there was no association with myopathy. Subgroup analyses showed absolute risk reductions were generally larger in women, individuals ages 40 years or older, those with baseline LDL cholesterol levels of at least 3.4 mmol/L (130 mg/dL), and anyone with a higher predicted cardiovascular risk.

“The implication for clinical decision making is that statins should not be delayed until an arbitrary age of 40 years or development of other CVD risk factors,” the authors wrote, noting that one-third of the emulated patients in their study were under 40 years of age.

Limitations include a lack of data on cause of death and that the use of electronic health records may have introduced information bias.

The CVD risks of type 1 diabetes were highlighted by another recent study, published by The Lancet Diabetes & Endocrinology on Aug. 25. Investigators followed 38,3510 Swedish adults with type 1 diabetes and 365,675 with type 2 diabetes for five years and compared incidence of myocardial infarction, heart failure onset or exacerbation, stroke, and CVD death. They found that at ages younger than 50, years, patients with type 2 diabetes had a higher risk than individuals with type 1 diabetes for the composite end point of any CVD event (HR, 1.23; 95% CI, 1.07 to 1.41), but at ages older than 60 years, they had a lower risk (HR, 0.87; 95% CI, 0.82 to 0.92).

After adjustment for CV risk factors, the whole cohort with type 2 diabetes had a greater risk for incident CVD and mortality compared with those who had type 1 diabetes, but when researchers excluded diabetes duration from the model, type 1 diabetes was associated with higher risk. “Longer diabetes duration seems to be a main contributing factor for higher risk found in people with type 1 diabetes versus those with type 2 diabetes in this age group,” the authors wrote.

An editorial accompanying the Swedish study speculated on the possible pathophysiology for these findings and advocated for better integrated management of all CVD risk factors in any patient with diabetes. It also called for more research on pharmacological treatments that can be used with insulin in patients with type 1 diabetes.