Drug treatments for high cholesterol blood levels, with Atorvastatin versus Simvastatin: A Systematic review and Meta-analysis

Abstract

Objectives: Diabetes mellitus is a strong risk factor for atherosclerosis and is often characterized by hyperlipidemia. This review was done to evaluate the effectiveness of pharmacological management of hyperlipidemia with atorvastatin versus simvastatin in lowering high cholesterol among diabetic and cardiac patients.

Sources: Trials were identified by searching four electronic databases (Medline, Cochrane, Pub Med, Scopus and Highwire) and the reference lists of eligible publications.

Keywords: Dyslipidemia, statins and diabetes, atheroscelerosis, statins, atorvastatin, simvastatin

Methods: We performed a systematic review of trials that randomly assigned participants to receive atorvastatins versus simvastatin or simvastatin versus placebo or atorvastatin versus placebo for a minimum of 6 week. A meta-analysis was performed using a fixed-effects model, and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate pooled treatment effects. All statistical tests were two sided. Revman 5.0 version have been used to assess the difference between two treatment group.

Result: Thirteen trials were included, involving a total of 20598 participants. Trials differed considerably in their inclusion criteria; outcomes measured, and type of lipid-lowering therapy used. The pooled results from all eligible trials indicated that atorvastatin therapy had no statistically significant effect than simvastatin on overall mortality (Risk Ratio (RR) 0.88; 95% confidence Interval (CI) 0.34 to 2.27; P = 0.78)) or on total cardiovascular events (RR 0.99; 95% CI 0.69 to 1.42, P = 0.95). However, analysis showed that atorvastatin significantly reduced the total blood cholesterol versus simvastatin (RR 0.74; CI 0.55 to 0.98). This was primarily due to a positive effect on total coronary events (RR 8.24; 95%CI 8.18 to 8.29; P < 0.00001). Greatest evidence of effectiveness came from the use of atorvastatin in people with blood cholesterol 3.5 mmol/litre.

Conclusion: The role of statin therapy as a main component of cardiovascular risk reduction in-patients with diabetes. Atorvastatin have significantly better outcomes in lowering blood cholesterol against simvastatin but there was no significant difference in the mortality and total cardiovascular events.