A relationship between serum potassium concentration and insulin resistance in patients with type 2 diabetes mellitus

In patients with type 2 diabetes mellitus (DM), insulin-stimulated glucose uptake is impaired. However, the relationship between serum potassium concentration and insulin resistance is poorly defined. This study aimed to investigate the association between serum potassium concentration and insulin resistance in these patients. Between April 2009 and October 2012, 180 patients with type 2 DM were analyzed. Insulin resistance was estimated using the homeostasis model and assessment (HOMA) index; resistance was defined as an index value of >2. The association between serum potassium concentration and insulin resistance was analyzed using linear regression methods. The incidence of hyperkalemia was also evaluated during follow-up. Mean serum potassium concentration was 4.12 ± 0.47 mEq/l. The median HOMA index score was 2.1 (interquartile range 1.1–3.4). When the patients were compared based on insulin resistance, serum potassium concentration was higher in the patients with insulin resistance compared with the patients without (4.25 ± 0.48 vs. 4.09 ± 0.44 mEq/l, p = 0.015). The variables found to be the determinants of serum potassium concentration included female, renal function, serum sodium level, log aldosterone-to-plasma renin activity ratio, glycosylated hemoglobin, and log HOMA index. Over a mean follow-up period of 2.6 ± 1.1 years, 37 of 180 patients (21 %) experienced episodic hyperkalemia. Patients with insulin resistance experienced episodic hyperkalemia more frequently than those without. Serum potassium concentration is likely to be increased in the patients with poorly controlled type 2 DM with insulin resistance than in those without insulin resistance.