Low urine pH Is a predictor of chronic kidney disease

A variety of risk factors for chronic kidney disease (CKD), including the metabolic syndrome, were recently reported. It has been suggested that a low urine pH is another characteristic of the metabolic syndrome. However, the relationship between urine pH and CKD remains to be elucidated.

A cohort study was performed on 1,811 subjects who underwent a health check-up, and we examined whether low urine pH could be a predictor of CKD. The following risk factors for CKD were evaluated: age, gender, history of alcohol intake and smoking, BMI, systolic blood pressure, fasting plasma glucose, total cholesterol, uric acid, total leukocyte count, CKD stage, fasting urine pH, and protein at baseline.

We followed 1,811 subjects for a median period of 7.7 years. Three hundred and thirty-nine subjects developed stage 3 CKD defined as progression to estimated glomerular filtration rate < 60 ml/min/1.73 m(2). Multiple Cox regression analysis revealed that the adjusted HR (95% CI) for stage 3 CKD was 1.32 (1.06-1.65; p = 0.0129) in subjects with fasting urine pH 5.0-5.5 compared to subjects with pH 6.5-7.0.

Our study suggests that low urine pH is an independent predictor of stage 3 CKD.