Effect of switching from low-dose simvastatin to high-dose atorvastatin on glucose homeostasis and cognitive function in type 2 diabetes

Background: High-intensity statin is recommended in high-risk type 2 diabetes (T2D); however, statin dose dependently increases the risk of developing new-onset diabetes, can potentially worsen glycemic control in T2D, and may cause cognitive impairment. This study aimed to investigate the effect of statin intensification on glucose homeostasis and cognitive function in T2D. Materials and Methods: T2D patients who were taking simvastatin ≤20 mg/day were randomized to continue taking the same dosage of simvastatin (low-dose simvastatin group; LS, n=63) for 12 weeks, or to change to atorvastatin 40 mg/day for 6 weeks, and if tolerated, atorvastatin was increased to 80 mg/day for 6 weeks (high-dose atorvastatin group; HS, n=62). Fasting plasma glucose (FPG), glycated hemoglobin (HbA_1c ), plasma insulin, homeo-static model assessment of insulin resistance (HOMA-IR) and of β-cell function (HOMA-B), cognitive functions using Montreal Cognitive Assessment (MoCA), and Trail Making Test (TMT) were assessed at baseline, 6 weeks, and 12 weeks. Results: Mean age of patients was 58.8±8.9 years, and 72% were female. Mean baseline FPG and HbA_1c were 124.0±27.5 mg/dl and 6.9±0.8%, respectively. No differences in baseline characteristics between groups were observed. Change in HbA_1c from baseline in the LS and HS groups was −0.1% and +0.1% (p=0.03) at 6 weeks, and −0.1% and +0.1% (p=0.07) at 12 weeks. There were no significant differences in FPG, fasting plasma insulin, HOMA-B, HOMA-IR, MoCA score, or TMT between groups at 6 or 12 weeks. Conclusion: Switching from low-dose simvastatin to high-dose atorvastatin in T2D resulted in a slight increase in HbA_1c (0.1%) without causing cognitive decline.