Importance of serum phosphate in elderly patients with diabetes mellitus

BACKGROUND Metabolic disturbances including changes in serum calcium, magnesium or phosphate (P) influence the prevalence of type 2 diabetes mellitus (DM). We assessed the importance of serum P in elderly patients with type 2 DM vs non-diabetes mellitus (non-DM) in relation to renal function. AIM To determine the association between serum P and serum glucose or insulin resistance in diabetic and non-diabetic patients. METHODS One hundred-ten subjects with a mean age of 69.02 14.3 years were enrolled. Twenty-nine of the participants had type 2 DM (26.4%). The incidence of hypertension, smoking and receiving vitamin D (vitD) derivates were recorded. The participants were classified by both estimated glomerular filtration rate (eGFR) and albuminuria categories according to the Kidney Disease Improving Global Outcomes 2012 criteria. RESULTS We divided the patients in two groups according to the P cut-off point related to DM value. A comparison between high and low P showed that body mass index 30.2 +/- 6.3 vs 28.1 +/- 4.6 (P = 0.04), mean glucose 63.6 vs 50.2 (P = 0.03), uric acid 6.7 +/- 1.6 vs 6.09 +/- 1.7 (P = 0.05), mean intact-parathyroid hormone 68.06 vs 47.4 (P = 0.001), systolic blood pressure 147.4 +/- 16.7 vs 140.2 +/- 16.1 (P = 0.02), mean albuminuria 63.2 vs 50.6 (P = 0.04) and eGFR 45.6 +/- 22.1 vs 55.4 +/- 21.5 (P = 0.02) were significantly different. chi(2) tests showed a significant association between high P and DM, hypertension, receiving vitD, smoking and eGFR stage (chi(2) = 6.3, P = 0.01, chi(2) = 3.9, P = 0.03, chi(2) = 6.9, P = 0.009, chi(2) = 7.04, P = 0.01 and chi(2) = 7.36, P = 0.04, respectively). The adjusted model showed that older age, female gender and increased body mass index were significant predictors of type 2 DM when entering the covariates. CONCLUSION High serum P contributes to vascular and metabolic disturbances in elderly patients with type 2 DM and renal impairment.