Aim: The number of patients with hyperuricemia has steadily risen every year. However, it remains unclear whether the prevalence of urinary stones with uric acid (UA) origin is on the same trend. Therefore, we carried out a survey on UA stones in outpatients with urolithiasis.
Methods: A retrospective survey was performed in a single municipal hospital. We enrolled a total of 312 patients diagnosed with urolithiasis during the 8 years observation period. All urinary stones underwent chemical component analysis and were divided into two groups: stones of UA component (UA group), and stones of non-UA component (non-UA group).
Results: Component analysis revealed the following; calcium oxalate stones 45.5% (n = 142), calcium phosphate stones 1.9% (n = 6), mixed stones without UA component 46.2% (n = 144), magnesium ammonium phosphate stones 1.6% (n = 5), ammonium urate stones 0.32% (n = 1), pure UA stones 2.6% (n = 8) and mixed UA stones 1.9% (n = 6). Stones with UA origin account for 4.5% (n = 14). Urinary pH was lower in the UA vs. the non-UA group (5.6 ± 0.6 vs. 6.5 ± 0.7, p < 0.01). Furthermore, HbA1c and age were higher in the UA vs. the non-UA group.A male patient in the UA group showed substantially low serum UA level (2.5 mg/dL) with multiple bladder stones, casting a suspicion of hereditary renal hypouricemia.
Conclusion: Calcium oxalate and mixed stones constitute approximately 90%. The prevalence of UA stones was 4.5%. The rate appears to remain unchanged over a past decade in Japan.
結果：SGLT2阻害薬投与後，HbA1c，食後血糖値，1,5-AG，血圧，体重，BMI，TGなど糖尿病関連マーカーの改善と同時に血清UA値低下作用が確認された．この効果は，4週目から認められ48週間以上にわたり持続した．また，血清UA値低下は糖排泄増加と関連し，Fractional Excretion of UA（FEUA）の増加を伴った．さらに，尿中アルブミン排泄量（ACR）は低下，微量あるいは顕性アルブミン尿群に改善効果が確認され，一部にACRの正常化例の出現も認めた．SGLT2阻害薬6剤間の比較では，血清UA値低下作用を含めた各測定項目の変化に群間差異は認められず，これらの効果は一律の「Class Effect」と思われた．本剤の痛風発症抑制効果に関しては不明であった．