The Measurement and Influence of estimated Salt intake in 24-hour urine collection in chrOnic kidneY disease in Okayama Study - The MISOY-Okayama study

The median follow-up period was 36 months, during which time, sixteen of 159 patients reached the renal composite endpoint (10.1%). A significant correlation between the baseline systolic blood pressure and urinary sodium excretion was detected in both all individuals (r=0.2602; P=0.0009) and in female subjects (r=0.3308; P=0.0029). A similar correlation was found between log-transformed value of the baseline urinary protein excretion and urinary sodium excretion in the whole (r=0.1838; P=0.0239) and in the female (r=0.2766; P=0.0136) subjects. When the patients with CKD stage 4 and 5 were stratified according to the quartile levels of urinary sodium excretion of each gender, increase in urinary sodium excretion was a risk for the renal composite endpoint only in female subjects (P=0.0107, Log rank test). In the Cox regression analysis, the level of urinary sodium excretion was independently associated with the endpoint, but the risk was not independent of the urinary protein excretion.