Background. Both types of diabetes mellitus (DM) cause alterations in bone metabolism, which are more pronounced as the renal function declines. Renal transplantation, on the other hand, improves bone condition. However, less is known about the changes in patients with DM.
Aim. We aimed to evaluate the changes of biochemical factors playing crucial role in bone and mineral disorder and to compare them between diabeti cs and non-diabetics.
Material and methods. We conducted a retrospective analysis of demographic and clinical data of 421 patients who underwent kidney transplantation in Vilnius University Hospital Santaros clinics 2008-2016. 48 patients had diabetes and 273 were non-diabetics. We excluded patients who were younger than 18 years, underwent transplantectomy during early period, developed new onset diabetes after transplantation (NODAT) or were lost during follow up. Concentrations of ionized calcium, total calcium, inorganic phosphorus, potassium, PTH, creatinine and other factors were evaluated at five different times (1 week, 1 month, 6 months, 1 year and 5 years after transplantation). Creatinine values were needed to calculate glomerular filtration rate by using MDRD (Modification of Diet in Renal Disease) formula. Unpaired two-sided Student’s t-test was used to compare two groups. A p-value <0.05 was considered statistically significant. Statistical analysis was generated using Microsoft Excel 2016 and GraphPad Prism 5.
Results. The average age of diabetic group was 42.96±10.03 yrs. and 41.88±12.92 yrs. of non-diabetic group p>0.05. Gender ratio (male:female) was 1.09:1 and 1.28:1, in diabetics and non-diabetics respectively, p>0.05. Kidney function remained similar between the groups during study period. Starting the first week after transplantation, ionized calcium concentration was 1.11 ±0.03 mmol/L in diabetlcs, whereas in non-diabetics it was 1.28±0.016 mmol/L, p<0.05. Similar distribution was seen after six months (1.16±0.14 mmol/L vs 1.24±0.12 mmol/L, p<0.05). Later on, differences in inorganic phosphorus and PTH concentrations were observed (1.13±0.22 mmol/L vs 0.98±0.23 mmol/L and 13.94±2.14 pmol/L vs 22.70±4.06 pmol/L, p<0.05, in diabetics and non-diabetics, respectively). Corrected for GFR, these changes remained the same between two groups, excluding the effect of renal function deterioration.
Conclusions. Following renal transplantation diabetic patients had significantly lower calcium, PTH and higher phosphorus concentrations.