Abstract
Objective. To investigate the association between circulating betatrophin level and type 2 diabetes mellitus (T2DM) in human.

Methods. A comprehensive literature search was performed in PubMed and Embase databases to identify eligible studies assessing the circulating levels of betatrophin in both T2DM patients and nondiabetic adults.

Results. A total of nine eligible studies with twelve comparisons were included for the final meta-analysis. Circulating betatrophin levels in T2DM patients were higher than those in the nondiabetic controls (random-effect SMD 0.53; 95% CI 0.13 to 0.94; P=0.010). In the subgroup of nonobese population but not the obese population, the overall betatrophin level in T2DM patients was much higher than that in the nondiabetic controls (nonobese: random-effect SMD, 0.82; 95% CI 0.42 to 1.21; P<0.001; obese: random-effect SMD, −0.39; 95% CI, −0.95 to 0.18;P=0.18 ). Metaregression indicated that body mass index of T2DM patients was associated with mean difference of betatrophin level between T2DM and nondiabetic adults (slope, −578.8; t=-2.7; P=0.02).

Conclusion. Based on the findings of our meta-analysis, circulating betatrophin level of T2DM patients is higher than that of nondiabetic adults in the nonobese population, but not in the obese population.