Overall, the Proportion of Uric Acid Stones Was 2.2 Times

higher in diabetic than in non-diabetic stone formers, but the difference was strikingly more marked in women than in men with a ratio of 3.8 vs 1.7 (P1⁄4 0.003). It was shown recently that the metabolic syndrome presently affects >40% of the population aged 60 years in the US [4], which is in keeping with the observation that uric acid nephrolithiasis was highly prevalent in our diabetic stone formers who were aged 60 years as a mean. Of note, the increased proportion of uric acid stones with diabetes mellitus was especially marked in women who spontaneously form stones less frequently in general, and uric acid stones in particular, than do males; however, the reasons for this gender difference are still unexplained. In view of the relentlessly growing ‘epidemic’ of type 2 diabetes in Western countries, uric acid nephrolithiasis may become of clinical concern in diabetic patients, thus justifying preventive measures. In clinical practice, patients with diabetes type 2 or the metabolic syndrome should be checked for nephrolithiasis by abdominal ultrasound, especially if urine pH is 5.5. Conversely, onset of uric acid nephrolithiasis, especially if the subject is overweight, should prompt a check for diabetes type 2. In short, we propose searching for uric acid nephrolithiasis in diabetics and searching for diabetes in uric acid stone formers, especially women.