24-Hour urinary sodium excretion in chronic kidney disease

Objective: To correlate urinary sodium excretion in isolated sample with 24-hour urine and glomerular filtration rate in patients with chronic kidney disease. Material and Methods: Cross-sectional study with 185 patients. Urinary sodium excretion was evaluated in 24-hour urine and in isolated sample. The statistics used the Student or Mann Whitney t tests and Pearson or Spearman’s correlation coefficients. Results: 58.9% were women, mean age of 59.8±12.1 years. The mean sodium excretion in 24-hour urine was 150.3±71.7 mmol/L and 108.8±51.2 mmol/L (p-value<0.001) in isolated sample were 82.5±43.6 mmol/L and 73.6±42.4 mmol/L (p-value=0213) for men and women, respectively. They correlated with 24-hour sodium excretion, urinary sodium in isolated sample (r=0.53; p<0.001), low-density lipoprotein (r=0.32; p=0.003), high-density lipoprotein (r=-0.22; p=0.048). Low-density lipoprotein correlated with sodium in isolated urine (r=0.22; p= 0.047). Conclusion: Men with glomerular filtration rate <60 mL/min/1.73m2 presented lower sodium excretion in 24-hour urine and isolated sample. Women with glomerular filtration rate <60 mL/min/1.73m2 showed higher albuminuria, lower sodium excretion in isolated urine and lower total cholesterol and low-density lipoprotein.