Objective. Evaluation of the relationship between homocysteine (HC) and folic acid (FA) concentration with the presence and severity of renal failure in patients with chronic kidney disease (CKD).
Material and methods. A cross-sectional study with the inclusion of 388 people aged 18 to 89 years was carried out. The main group consisted of 216 patients with an established diagnosis of CKD. The control group included 172 patients who had no signs of CKD according to the results of clinical and laboratory examination. Serum HC, FA, total cholesterol, sodium, calcium and creatinine level were analyzed in all study participants. Kidney function was assessed by glomerular filtration rate (GFR) using the CKD-EPI formula.
Results. There were no significant differences in age, anthropometric and hemodynamic parameters between the patients of the studied groups. In the group of patients with CKD, the incidence of arterial hypertension (63.8%), type 2 diabetes mellitus (31.0%), coronary artery disease (29.1%), chronic cerebral ischemia (10.1%) and comorbid pathology (42.1%) were significantly higher, and the serum calcium level was significantly lower (2.105±0.348 versus 2.313±0.360 mmol/L; P<0.05) compared with the group without CKD. Among all study participants (n=388), hyperhomocysteinemia was detected in 196 (50.5%) patients. The serum homocysteine (HC) level was significantly higher in patients with CKD. The frequency of hyperhomocysteinemia among the examined patients with CKD was 175 (81.0%), in the control group – 21 (12.2%). Hyperhomocysteinemia was most often detected among male patients with CKD – 58 (58.5%). As the renal function decreased, the blood serum HC level increased significantly. Among the examined individuals, FA deficiency was detected in 108 (27.8%) patients. A decrease in the FA level below the optimal value was found in 67 (31.0%) patients with CKD, and in the control group – in 41 (23.8%) (P>0.05). In patients with CKD, significantly low FA levels were recorded at the C3A stage of the disease. A positive strong correlation between HC and creatinine levels (r=0.6267; P<0.005) and a negative correlation with GFR (r=-0.5963; P<0.05) and serum calcium level (r=-0.2094; P<0.05) were demonstrated.
Conclusion. In patients with CKD, significantly high serum HC level was observed. With a decrease in renal function, the blood serum HC level increased significantly. Hyperhomocysteinemia was found significantly more frequently among male patients with CKD. A decrease in the FA level was observed among patients with CKD at the C3A stage of the disease. In CKD, the serum HC level not only determines the severity of renal failure and the risk of cardiovascular complications, but, possibly, is a marker of mineral bone disorders. In this regard, the determination of the blood serum HC and FA levels is of certain scientific and practical interest.

Keywords: osteoporosis, calcium, cardiovascular complications, creatinine, glomerular filtration rate, chronic kidney disease, folic acid, homocysteine