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. χ(2) tests showed a significant association between high P and DM, hypertension, receiving vitD, smoking and eGFR stage (χ(2) = 6.3, P = 0.01, χ(2) = 3.9, P = 0.03, χ(2) = 6.9, P = 0.009, χ(2) = 7.04, P = 0.01 and χ(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.