1996 年 20 巻 1 号 p. 9-16
We investigated circadian changes in urine pH in 157 gouty patients. The urine pH of each patients was measured 3 times a day for 2 weeks: the first urine specimen immediately after rising, and diurnal and nocturnal urine specimens, regard of meal times. All patients were divided into the following four groups according to the pH of the morning urine specimen and subsequent changes: Type aA: pH<5.8 throughout the day. Type bB: pH>5.8 throughout the day. Type aB: pH<5.8 only in the morning urine. Type C: pH varied irregularly or patient did not belong to any of the above 3 groups. Type aA was found in 39% of 157 patients, type bB in 24%, type aB in 13% and type C in 24%. To evaluate the role of acidic urine in gouty patients, we compared some laboratory data between the aA type and the bB type. The serum uric acid value in the aA type was significantly higher than that in the bB type (p<0.005). The incidence of abnormal value of creatinine clearance and serum creatinine levels were higher in the aA type than in the bB type (p>0.05). The incidence of complicated urolithiasis was also higher in the aA type than in the bB type (p>0.05). These data imply that gouty patients with acidic urine have more severe stage than those without acidic urine. Determination of the presence or absence of acidic urine has commonly been based on the pH of morning urine, but determination should be based on the circadian changes in urine pH. In this paper, we propose a simple method for classifying urinary pH type. This method seemed to be useful for assessing acidic urine and will also facilitate the alkalization of urine in gouty patients.