Background Patients who are at risk for atherosclerotic cardiovascular diseases will start statin therapy as primary prevention to lower the low-density lipoprotein (LDL) level. However, the use of statins may induce new-onset diabetes and increase the HbA1c level. A meta-analysis of nine randomized clinical trials concluded that statins cause a modest increase in HbA1c levels by 0.12%. Different statins exert different effects. A cohort study aimed to examine the effect of different statins on the risk of new-onset diabetes, and concluded that atorvastatin, rosuvastatin, and simvastatin were associated with significantly higher risks of incident diabetes compared with pravastatin. Additionally, a randomized trial assessing the effect of high-dose statins on fasting plasma glucose (FPG) levels and HbA1c levels compared atorvastatin 80 mg with rosuvastatin 40 mg and found that atorvastatin 80 mg was associated with a significant increase in HbA1c level by 4 units. This study aimed to assess the effect of statins on HbA1c levels and to determine which statin exerts most of the effect.

Methods This was a subgroup analysis of a retrospective chart review study including patients who were admitted to King Abdulaziz Cardiac Center, National Guard Hospital in Riyadh, KSA, during January 2015 until September 2017. A total of 500 cases represent the sample size of the study. The inclusion criteria included adults older than 18 years who used either rosuvastatin or atorvastatin, while the exclusion criteria included patients on simvastatin, and patients who had a contraindication for high-intensity statins or who cannot tolerate them.

Results Our results showed the opposite to previous studies. The use of statins was not associated with a significant increase in HbA1c levels in patients with diabetes (p=0.870). This could be because of good glycemic control in these patients because they had already been diagnosed as diabetic patients and were on antidiabetic medications. The impact of statins on HbA1c level in non-diabetic patients demonstrated an increased level of HbA1c (p=0.004). We identified which type of statin and which dose exerted most of the effect. Atorvastatin 80 mg and rosuvastatin 20 mg were associated with a higher rate of HbA1c disturbances in patients with diabetes only (p=0.000 and p=0.022, respectively).

Conclusion This study along with previous studies showed that statins significantly affect the glycemic profile in non-diabetic patients only and showed no effect in diabetic population. The effect was significant only with high intensity statins. Therefore, careful monitoring in non-diabetic statin users is warranted.