Adverse events associated with currently used medical treatments for cystinuria and treatment goals: results from a series of 442 patients in France

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 mixed‐effects logistic regression model was used to estimate how urine pH , specific gravity and cysteine‐binding 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 D‐penicillamine (29.5%) were similar ( P = 0.45). Increasing urine pH and decreasing urine specific gravity significantly reduced the risk of cystine crystalluria, whereas D‐penicillamine and tiopronin treatments did not reduce this risk (odds ratio [ OR ] 1 for pH ≤6.5; OR 0.52 [95% confidence interval {95% CI } 0.28–0.95] for 7.0 < pH ≤7.5, P = 0.03; OR 0.26 [95% CI 0.13–0.53] for 7.5 < pH ≤8.0, P 8.0, P 7.5, while warning about calcium‐phosphate crystallization, should be the goals of medical therapy.