Metformin therapy was not associated with improvement in central arterial stiffness among adults with T2DM. In a systematic review and meta-analysis published in Diabetes Research and Clinical Practice, pooled data showed no significant difference in PWV between metformin-treated groups and comparison groups, while cSBP was modestly higher with metformin.

Systematic searches of PubMed, MEDLINE, ScienceDirect, Cochrane, and Google Scholar identified controlled studies comparing metformin with placebo or non-metformin therapies. Three reviewers independently performed data extraction and quality assessment. Pooled analyses were conducted using RevMan version 5.4.1 under a registered protocol (PROSPERO 1135002).

PWV ranged from 8.9 to 11.2 m/s in metformin-treated groups and from 8.0 to 11.8 m/s in comparison groups. The pooled mean difference was 0.09 m/s (95 % CI −0.06 to 0.25; P = 0.23), indicating no statistically significant effect. No heterogeneity was observed across studies (I² = 0 %).

In contrast, cSBP was significantly higher in metformin-treated groups. The pooled mean difference was 3.30 mmHg (95 % CI 0.60 to 6.00; P = 0.02), with no observed heterogeneity (I² = 0 %).

These findings indicate that metformin does not reduce central arterial stiffness in T2DM and is associated with a small increase in cSBP. Further studies with larger sample sizes are required to clarify the clinical relevance of these vascular findings.