Serum isthmin-1 levels are positively and independently correlated with albuminuria in patients with type 2 diabetes mellitus

Introduction: Isthmin-1 (Ism-1), as a novel adipokine, plays a role in glucose homeostasis and lipid metabolism. However, the relationship between Ism-1 and type 2 diabetes mellitus (T2DM) remains unclear. This study aims to investigate the association of serum Ism-1 levels with albuminuria and insulin resistance in patients with T2DM and preserved renal function.

Research design and methods: A total of 150 patients with T2DM were recruited. The presence of albuminuria was evaluated by urinary albumin:creatinine ratio (UACR) in first morning urine sample. Serum Ism-1 levels were tested by ELISA. Homeostasis model assessments were used to evaluate insulin resistance. Binary logistic regression and multivariable linear regression analyses were used to assess the association of serum Ism-1 levels with albuminuria. Multivariable linear regression analyses were performed to explore the correlation of serum Ism-1 levels with insulin resistance.

Results: Compared with the normal-albuminuria and microalbuminuria groups, serum Ism-1 levels were significantly higher in the macroalbuminuria group (p<0.01). Binary logistic regression analyses showed that serum Ism-1 was positively associated with odds of albuminuria even after multiple adjustments (OR=4.766, p=0.013). Serum Ism-1 was positively associated with log10-transformed UACR (β=0.625, p<0.001). However, the associations between serum Ism-1 levels and insulin resistance were not observed in patients with T2DM.

Conclusions: Serum Ism-1 levels were positively and independently correlated with the severity of albuminuria in patients with T2DM but not with insulin resistance.