Influencing factors of serum Ca/Mg ratio and its relation with nutritional status in patients with non-dialysis dependent diabetic kidney disease

Objective To analyze the relationship between nutritional status and serum Ca/Mg ratio in patients with non-dialysis-dependent diabetic kidney disease.

Methods A total of 139 patients with non-dialysis diabetic kidney disease who visited Shanghai Eighth People's Hospital from January 2017 to June 2019 were selected and divided into three groups according to serum Ca/Mg ratio: group A (≤ 3.5, n=32), group B (3.5-4.5, n=56) and group C (≥ 4.5, n=51). Biochemical indexes of patients in each group were detected, and the correlation between nutritional status and serum Ca/Mg ratio was analyzed.

Results With the increase of Ca/Mg ratio, the levels of albumin (Alb) and hemoglobin (Hb) significantly increased (P < 0.05), while the proportion of malnourished patients in the subjective global assessment of nutrition (SGA) score showed a decreasing trend (P < 0.05). Spearman correlation analysis showed that the serum Ca/Mg ratio was negatively correlated with age (r=-0.199), the level of high-sensitivity C-reactive protein (hsCRP, r=-0.294), blood urea nitrogen (BUN, r=-0.328) and serum creatinine (SCr, r=-0.366), and it was positively correlated with the level of eGFR (r=0.266), intact parathyroid hormone (iPTH, r=0.101), Alb (r=0.193) and Hb (r=0.266). The above correlations were all statistically significant (P < 0.05). However, the serum Ca/Mg ratio had no correlation with gender and the levels of albumin/creatinine ratio (ACR), total cholesterol (TC), or triglyceride (TG). The multivariate linear regression analysis result showed that serum Ca/Mg ratio was negatively correlated with hsCRP level and age, but positively correlated with Alb, Hb, and iPTH levels. Multivariate logistic regression showed that the Ca/Mg ratio was independently associated with the risk of malnutrition in non-dialysis patients with diabetic kidney disease (HR=0.506, 95%CI 0.267-0.961, P=0.038).

Conclusions Serum Ca/Mg ratio was correlated with nutritional status in non-dialysis patients with diabetic kidney disease, and it might be used for the assessment of nutritional status in patients with non-dialysis diabetic kidney disease.