The relationship between spot urine sodium and metabolic syndrome, hypertension, graft function in kidney transplantation patients

Chronic kidney disease (CKD) can be divided into five stages according to the GFR level. Stage 5 renal failure is GFR <15 mL/min/1.73 m² and the phase that renal replacement therapy (RRT) is needed. Renal replacement therapies are hemodialysis, peritoneal dialysis and transplantation. Metabolic syndrome is a constellation of classic risk factors, including abdominal obesity, hypertension, dyslipidemia, and glucose intolerance for the development of atherosclerotic cardiovascular disease. Hypertension is defined as systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg. It is common cardiovascular disease and the World Health Organization (WHO) report is stated to be the leading cause of death in the world. Hypertension is not only a major risk for cardiovascular (cv) complications but also it is associated with a significant graduated increase of graft failure when systolic blood pressure is 140 mmHg or higher. The aim of this study is to evaluate the relationship between spot urine sodium and metabolic syndrome, HT and graft function in kidney transplantation patients. In this study, we included 152 patients with kidney transplantation and kidney function is stable adults aged 18 and older. Patients gender, age, body weight, height, body mass index, transverse waist circumference, antihyperlipidemic medications, tacrolimus, sirolimus ve cyclosporine use evaluated as 'yes/no' and was recorded. Body mass index was calculated by the formula of weight (kg)/height² (m²) with measured height and weight of the patients. During policlinic check-up, patients systolic and diastolic blood pressure (mmHg) were recorded. Blood pressure ≥140/90 mmHg was admitted for diagnostic criteria of hypertension. And also for the evaluation of cardiac functions, reports of transthoracic echocardiography in last 1 year were analyzed and left ventricular hypertrophy was considered as 'yes/ no'. BUN, creatinine, sodium, spot urine sodium, spot urine protein, eGFR, fasting blood glucose, insulin, LDL-cholesterol, HDL-cholesterol, triglycerides, albumin were measured by the enzymatic method. Women in low sodium group (spot urine sodium ≤57), serume creatinine was significantly low (p<0,001) and eGFR was significantly high (p=0.03). Mean protein in spot urine in women was statistically low (p=0.03). Serum HDL level in women was significantly high (p=0.04), and also serume triglycerides level was statistically lower in women than in men (p=0.02). In high sodium group (spot urine sodium ≥58) if we compare BUN and serum creatinine level by gender, in men they were significantly high [(p=0.04), (p=0.02)]. Serum HDL levels were significantly high in women (p=0.003), in contrast serum triglycerides levels were statistically higher in men than women (p=0.01). And also serum insulin levels were significantly higher in men than women (p=0.009). Men's EF measurements were significantly lower than women (p=0.008). When groups were independent from gender, there was no difference between evaluation of serum sodium levels (p>0.05). Patients with and without MS were compared to their spot urine sodium excretion and in both groups mean value of spot urine sodium was found 57 and there was no difference between in two groups (p=0.99). %63.6 of patients taking statins, and %45.4 of patients who don't take statins were in low sodium group and this difference was statistically significant (p=0.04). If we compare spot urine sodium excretion in patients with controlled and uncontrolled blood pressure, there was high significant difference between two groups (p=0). Spot urine sodium excretion, can be seen as an effective and relatively inexpensive screening method that can be used to evaluate the sodium intake in a special group of patients with renal transplantation as in the general population. Especially, kidney transplant recipients with male gender, renal function impairment and high blood pressure it can be considered more valuable as a follow-up procedure. Key words: Kidney transplantation, spot urine sodium, hypertension, metabolic syndrome, graft function