Purpose: Urinary stones are heterogenous but often grouped together. The incidence of CaP abundant (≧50%) stone and Brushite stone has increased during the past 45 years in Taiwan. We reported here clinical finding and the potential effects of patient demographics on stone composition. Our purpose was to inform urologists and highlight area that seem to deserve further research.
Materials and Methods: The first stone submitted by patients for analysis to the National Taiwan University Hospital (NTUH, 1961–2010) and National Cheng-Kung University Hospital (NCKUH, 2010–2016) were studied. Totally, 13672 stone analysis were examined at NTUH and 1061 at NCKUH, respectively. Stone were classified in the following order: majority calcium oxalate (≧50%), majority (≧50%) hydroxyapatite, any brushite, any metabolic stone (including uric acid and cysteine), and any struvite.
Results: Though the most common stone component is CaOx, but its incidence decreased from 82.1% (1991–2000) to 53.3% (2010–2016). The incidence of CaP (Ca3(PO4)2) increased from 7.1% (2001–2010) to 27.9% (2010–2016), while brushite increased from 0.2% (1961–1980) to 1.8% (2010–2016). Mean age for patients with CaP stone is 56 ± 16 Y/O and male: female ratio = 1.7:1; whereas mean age is 48 ± 18 Y/O and male: female ration is 3.7:1 for brushite stone patients. Patient with CaP abundant stone has a larger stone size (747.5±135.8mmˆ2) and lower eGFR (65.4 ± 18.9 mL/min/1.73m2) than patients with CaOx stone (73.7 ± 66.4 mmˆ2, and 85.9 ± 31.8 mL/min/1.73m2, respectively). Patient with CaP stone has a lower stone free rate and received more surgical procedures than CaOx stone disease (35.9% vs. 64%; 1.24 vs. 0.92, respectively). Patient with CaP stones has normal 24h urine Ca and uric acid and lower 24h urine Mg than CaOx stones.
Conclusion: CaP has risen for recent four decades. Gender of CaP stone did not differ in this cohort, but they had decreased eGFR and larger stone size and received more procedures than CaOx. High urine pH (6.8) and low 24h urine Mg was the main metabolic abnormality.