Statins are independently associated with increased HbA1c in type 1 diabetes--The Thousand & 1 Study.

Aims: Statin use has been associated with increased risk of developing type 2 diabetes (T2DM), and with impaired glycemic control in T2DM patients. The association between statin use and glycemic control in type 1 diabetes (T1DM) is unknown. The association between use of statins and glycemic control in T1DM patients without known heart disease was examined.

Methods: Cross-sectional study of 1093 T1DM patients from the outpatient clinic at Steno Diabetes Center. Physical examination, questionnaires, and echocardiography were performed in all patients. Investigators were blinded to all laboratory measurements. Data were analyzed in uni-and multivariable models.

Results: Mean age 49.6 years, 53% men, mean diabetes duration 25.5 years, 475 (43.5%) received statins. In baseline analyses statin users tended to be older, have longer diabetes duration, and have more severe kidney disease. Left ventricular ejection fraction was not associated with statin use. In multivariable models including age, gender, diabetes duration, BMI, blood pressure, physical activity, family history of cardiovascular disease, physical activity, albuminuria, eGFR, retinopathy, smoking, cholesterol, ejection fraction, triglycerides, and use of ACE/ATII-antagonists, aspirin, calcium-antagonists, betablockers or diuretics, statin use was independently and significantly associated with higher HbA1c (0.2% (95%CI: 0.1; 0.4) (2.0 mmol/mol (0.2; 3.8)), p=0.029).

Conclusions: In T1DM, use of statins is independently associated with impaired glycemic control. A causal relationship cannot be determined from this study. Given the benefit on cardiovascular outcome, this should not cause patients to stop statin treatment, but may indicate a need to revisit dose of insulin when starting statin treatment.