Evaluation of the effects of hemodialysis on the accuracy of HbA1c and PTH tests in diabetic patients under hemodialysis and its comparison with non-dialysis patients based on fasting blood sugar and ionized calcium

Abstract

Parathyroid hormone (PTH) is very important for controlling calcium and phosphate homeostasis. PTH is responsible for regulating the normal level of ionized serum calcium by influencing the transport of calcium and phosphate in the kidneys, the transport of calcium from bones, and the renal synthesis of 1,25 dihydroxyvitamin D, the active form of vitamin D. On the other hand, HbA1c concentration as an indicator of long-term blood sugar control and predictor of risk is an essential part of routine diabetes management. Considering the high importance of determining the serum level of PTH and HbA1c and the correct interpretation and management of the patient based on them, and on the other hand, considering the possibility of different levels of PTH and HbA1c in dialysis patients compared to non-dialysis patients and probably the need to consider the cut-off different in dialysis patients for these two biomarkers, this study aims at the effect of hemodialysis on PTH and HbA1c levels, which was done by measuring and comparing the serum level of ionized calcium and fasting blood sugar in dialysis and non-dialysis patients. Materials and Methods: The present study was a cross-sectional study that was conducted in Sina Hospital (Tabriz-Iran) during 1401; Based on hemodialysis (for at least one year) or no history of hemodialysis, patients were divided into two groups with the same number of 88 people in case and control groups. The level of PTH, ionized calcium, as well as the level of FBS and HBA1C in dialysis patients were investigated in the sample taken from the peripheral vein of the forearm before and after the completion of dialysis. In non-dialysis patients, the aforementioned tests were checked once. Tests with special kits and solid-phase sandwich ELISA method and relevant standard laboratory method were performed by experienced staff with the same method for all patients under study. Results: HbA1c showed a significant relationship with FBS in diabetic patients before dialysis (r=+0.631and P=0.031); This relationship was not observed after dialysis, so a very weak and non-significant relationship between HbA1c and FBS levels was observed (r=+0.063 and P=0.412), while HbA1c has a significant relationship with FBS in non-dialysis patients ( r=+0.789 and P=0.014). Ionized calcium levels showed a significant relationship with PTH in diabetic patients before dialysis (r=+0.783and P=0.011); On the other hand, a minor and non-significant correlation was observed between ionized calcium and PTH levels after all dialysis (r=+0.015and P=0.697); Also, PTH had a significant relationship with ionized calcium levels in non-dialysis patients (r=+0.859 and P=0.009).