Relationship between Meteorin-like protein and type 2 diabetes mellitus: an update and meta-analysis.

Background: Meteorin-like protein (Metrnl) is considered a novel adipokine, which plays an important role in the occurrence and development of type 2 diabetes mellitus (T2DM). In a previous meta-analysis, no significant difference in circulating Metrnl levels was found between T2DM patients and normal glucose tolerance individuals. However, these meta-analyses included limited studies, and more studies about Metrnl and T2DM were published recently. Therefore, the association between Metrnl and T2DM remains uncertain.

Aim: This study aimed to systematically and comprehensively update the relationship between circulating Metrnl levels and T2DM.

Methods: A systematic search was conducted on the Web of Science, Wiley Online Library, PubMed, and Ovid databases using the terms 'type 2 diabetes mellitus' in combination with 'Metrnl'. Meta-analysis results were reported as standardized mean differences (SMDs) with corresponding 95% confidence intervals (CIs).

Results: In total, 17 studies, including 649 patients with T2DM and 396 healthy controls, were included in the meta-analysis. We found that circulating Metrnl levels were lower in patients with T2DM than in healthy individuals (SMD: -0.47, 95% CI: (-0.98, 0.05); prediction interval: (-3.66, 2.73)). Moreover, serum Metrnl levels in patients with T2DM were significantly lower than in healthy individuals (SMD: -0.91, 95% CI: (-1.60, -0.22); prediction interval: (-5.03, 3.21)).

Conclusions: This study aimed to systematically and comprehensively update the relationship between circulating Metrnl levels and T2DM. A clearer understanding of the role of Metrnl in T2DM could facilitate the development of effective treatments.