Changes of calcium and phosphorus levels and the correlation analysis in patients with type 2 diabetes mellitus and diabetic nephropathy

Abstract

Objective To analyze serum calcium and phosphorus levels and its related factors of clinical type 2 diabetes mellitus(T2DM) with overt diabetic kidney disease(T2-dDKD). Methods Ninety cases of T2DM patients according to K/DOQI Recommendations in 2007 were selected as the study subjects.Based on the patients’ 2 times mean urinary albumin/creatinine ratio(ACR), these people were divided into three groups, namely Normal albuminuria group(30 patients, ACR 300 mg/gCr). Thirty cases of healthy at the same period were selected as the Control group.Serum calcium, phosphorus, hs-CRP, IL-6, HbA1c were detected.And glomerular filtration rate(eGFR) was calculated. Results The eGFR in Normal albuminuria group was more higher than other groups(P<0.05), the eGFR of Microalbuminuria group was significantly lower than other groups(P<0.05). Subgroups of T2DM with different albuminuria presence and severity, duration was also different between the groups, the more albumin in urine, the longer its duration.The contents of HbA1c in the groups of varying degrees of albuminuria increased as urinary albumin aggravation(HbA1c was (8.87±2.44)%, (9.27±2.74)%, (11.04±2.86)% respectively, P<0.05), but there was not statistically significant between Microalbuminuria group((9.27±2.74)%) and Normal albuminuria group((8.87±2.44)%). Compared with Control group, in subgroups of T2DM, serum calcium was decreased((2.22±0.19) mmol/L, (2.16±0.14) mmol/L, (2.13±0.18) mmol/L, and the Contorl group was (2.32±0.11) mmol/L, P<0.05), and serum phosphorus((1.16±0.31) mmol/L, (1.42±0.52) mmol/L, (1.98±0.58) mmol/L, and the Control group was (1.08±0.28) mmol/L), hs-CRP((4.82±0.89) mmol/L, (8.46±2.85) mmol/L, (13.09±3.49) mmol/L, and the Control group was (2.46±0.48) mmol/L), IL-6((10.32±4.19) pg/L, (14.78±4.34) pg/L, (16.67±6.62) pg/L, and the Control group was (7.03±2.15) pg/L) were increased(P<0.05). In subgroups of T2DM, hs-CRP was significantly increased with the increase of the serum albumin((4.82±0.89) mmol/L, (8.46±2.85) mmol/L, (13.09±3.49) mmol/L, P<0.05), there were no statistical significance about blood phosphorus among Macroalbuminuria group(1.98±0.58) mmol/L), control group((1.08±0.28) mmol/L), normal albuminuria group((1.16±0.31) mmol/L) and albumin urinary group(1.42±0.52) mmol/L). Serum phosphorus in Microalbuminuria group were positively correlated with hs-CRP, IL-6, HbA1c(r=0.431, 0.384, 0.517 respectively, P<0.05). Serum phosphorus in Macroalbuminuria group were positively correlated with hs-CRP, IL-6, HbA1c(r=0.825, 0.622, 0.683 respectively, P<0.01), but negatively with eGFR(r=0.600, P<0.01). Conclusion Serum phosphorus metabolism is abnormal in patients with diabetic nephropathy, hs-CRP, IL-6, and HbA1c are the related factors influencing the progression of serum phosphorus in patients with diabetic nephropathy. Key words: Diabetic kidney disease; Calcium; Phosphorus; High sensitive C reactive protein; Interleukin 6