Objective
To evaluate medical treatments, in terms of adverse events (AEs) and therapeutic goals, in a large series of patients with cystinuria.
Patients and Methods
Data from 442 patients with cystinuria were recorded retrospectively. Crystalluria was studied in 89 patients. A mixedâeffects logistic regression model was used to estimate how urine pH, specific gravity and cysteineâbinding thiols (CBT) correlate with risk of cystine crystalluria.
Results
Alkalizing agents and CBT agents were given to 88.8% (n = 381) and 55.3% (n = 238) of patients, respectively. Gastrointestinal AEs were reported in 12.3%, 10.4% and 2.6% of patients treated with potassium bicarbonate, potassium citrate and sodium bicarbonate, respectively (P = 0.008). The percentages of patients who experienced at least one AE with tiopronin (24.6%) and with Dâpenicillamine (29.5%) were similar (P = 0.45). Increasing urine pH and decreasing urine specific gravity significantly reduced the risk of cystine crystalluria, whereas Dâpenicillamine and tiopronin treatments did not reduce this risk (odds ratio [OR] 1 for pH â€6.5; OR 0.52 [95% confidence interval {95% CI} 0.28â0.95] for 7.0 8.0, P <0.001).
Conclusion
Adverse events were frequent with Dâpenicillamine and tiopronin. Alkaline hyperdiuresis was well tolerated and reduced cystine crystalluria. Urine specific gravity â€1.005 and urine pH >7.5, while warning about calciumâphosphate crystallization, should be the goals of medical therapy.