Characteristics of urinary sodium excretion in patients with chronic kidney disease in Jiangsu, China

The current study aimed to assess the dietary salt intake in patients with CKD in Jiangsu province and investigate the relationship of urinary sodium excretion with blood pressure. A total of 800 patients with CKD stages 1–4 were recruited. All enrolled patients were asked to collect complete 24‐h urine specimen. At the same time, patient's demographic and laboratory data were recorded. The mean age was 47.45 ± 15.25 years old, including 423 men and 377 women. There was no significant difference in urinary sodium excretion among different stages of CKD (p = .748). This study revealed that the median urinary sodium excretion of all patients was 127.20 mmol/d (IQR 91.03–172.06), corresponding to a salt intake of 7.4 g/d. Among them, only 167 (20.9%) cases had salt intake <5 g/d. Moreover, urinary sodium excretion in overweight group and obese group was higher than that in normal weight group (p = .001, p ˂ .001). Likewise, urinary sodium excretion in men was higher than that in women (p ˂ .001). Spearman correlation analysis indicated that urinary sodium excretion positively correlated with urinary protein excretion (r = .178, p ˂ .001), SBP (r = .109, p = .002), and DBP (r = .086, p = .015). After adjusting for age, gender, BMI, eGFR, urinary protein excretion, and history of taking antihypertensive drug, multivariate linear regression demonstrated that higher level of urinary sodium excretion associated with increased level of SBP, DBP, and MAP (β = 0.020, p = .049; β = 0.015, p = .040; β = 0.016, p = .025, respectively). In conclusion, the dietary salt intake in CKD patients, especially in male, overweight and obese subjects, remains high in Jiangsu province. It is vital to decline salt intake to control blood pressure in Jiangsu patients with CKD.