Abstract
INTRODUCTION: dyslipidemia and obesity frequently accompany type 2 diabetes, contributing to cardiovascular risk. Metformin, beyond its effects on glycemic control, can also influence lipid metabolism and weight. Immediate-release (IR) and extended-release (XR) metformin may have differential effects on lipid profile and anthropometric measures. The study aimed to compare the effects of metformin IR versus XR on lipid parameters and body measurements in patients with type 2 diabetes in Saudi Arabia. METHODS: a prospective 6-month cohort study included 119 newly diagnosed type 2 diabetes patients (62 on metformin IR and 57 on metformin XR) at a Saudi hospital. Fasting lipid profile (T-Chol, TGs, HDL-C, and LDL-C) and body weight/BMI were measured at baseline and after 6 months of metformin treatment. Within-group changes and between-group differences were analysed. RESULTS: both groups showed modest improvements in their lipid profile. Metformin XR use was associated with a greater reduction in total cholesterol (-7.8% vs. -5.8% with IR) and LDL-C (-8.7% vs. -5.7% with IR). After 6 months, mean LDL-C was significantly lower in the XR group (102.3 ± 37.5 mg/dL) compared to the IR group (116.9 ± 36.0 mg/dL, p=0.032). Triglyceride and HDL-C levels changed minimally and were similar between groups. Neither IR nor XR had a significant impact on body weight or BMI: both groups remained essentially weight-neutral (average weight change <1 kg over 6 months). Final mean BMI was 30.4 ± 5.9 kg/m(2) in IR vs. 29.8 ± 4.7 kg/m(2) in XR (no significant difference). CONCLUSION: metformin XR was associated with short-term benefits in reducing total and LDL cholesterol levels compared to IR, likely attributable to more stable plasma drug concentrations that enhance lipid metabolism. Both formulations exhibited similar effects on triglycerides, HDL cholesterol, and body weight, reaffirming metformin's overall neutral impact on weight. These findings suggest that metformin XR may offer a marginal reduction in cardiovascular risk through superior LDL cholesterol lowering, while preserving the weight-neutral profile characteristic of metformin therapy.