This Study Evaluates the Superiority of Daily Self-pH Monitorization of Lit-control®pH Meter Compared to the Monitorization of Reactive Strips (Standard of Care).

This Study Evaluates the Superiority of Daily Self-pH Monitorization of Lit-control®pH Meter Compared to the Monitorization of Reactive Strips (Standard of Care).

Randomized, Controlled and Opened Trial on the Impact of the Use of a pH-Meter on the Domiciliary Control of the Urinary pH as Adjuvant to the Treatment of Cystinuric Patients

This study evaluates the superiority of daily self-pH monitorization of Lit-control®pH meter compared to the monitorization of reactive strips (standard of care).

Cystinuria is a disease of autosomal recessive inheritance. This disease belongs to the so-called orphan diseases although its prevalence may change depending on the country. It is known that urinary pH is a risk factor for the formation of cystine crystals because their solubility is pH-dependent. In different studies it has been shown that the solubility of cystine in urine increases when alkalinizing urinary pH, thus reducing the likelihood of crystal formation. Therefore, the control of urinary pH along with hygienic-dietetic measures that alkalize the urine or decrease the urinary concentration of cystine (abundant intake of water, food, etc.) are highly recommended as a preventive method to prevent the formation of cystine crystals whose retention and growth results in the formation of stones. The Lit-control®pH Meter is a pH meter that allows a patient to self-monitor its urinary pH in a comfortable and simple way. With this tool the patient is able to know if his urinary pH is within the recommended limits. In other medical fields it has been observed that home monitoring of clinically relevant physiological parameters is a way of empowering the patient that can positively affect their attitudes and behaviors (adherence to received treatment, quality of life) and potentially improve their medical condition. Specifically, in patients with chronic diseases, the self-monitoring has been associated with a significant reduction in hospitalizations and hospital readmissions.

Patients will receive the product for home pH monitoring, but they will keep following the doctor's recommendations indicated in the usual clinical practice. The proportion of patients will be 1: 1 between the study group (Lit-control®pH Meter) and the control group (test strips).

The process of randomization, either device use or use of strips, will be masked until the moment it is delivered to the patient. The random assignment to each product will be made through lists created by an ad hoc computer program.

The control of the urinary pH will be carried out twice a day: with the first urine in the morning and in the evening-night (approximately every 12h and at the same time). Measurements will be performed using the Lit-control®pH Meter device.

The control of the urinary pH will be carried out twice a day: with the first urine in the morning and in the evening-night (approximately every 12h and at the same time). Measurements will be performed using the reactive strips.

Alkalinization products will be used as standard clinical practice together with the pH monitoring through the Lit-control®pH Meter.

Alkalinization products will be used as standard clinical practice together with the pH monitoring through the reactive strips.

Blood Analysis. Estimated Glomolecular Filtration Chronic Kidney Disease Epidemiology Collaboration (FG CKD-EPI)

cystatin in mg/L (to be measured only if estimated FG> 45 or <ml /min / 1.73 m2 and albumin / creatinine in the urine <3 mg / mmol)

First urine of the morning (totality) for the study of crystalluria. Patient will provide the last hour of urination and hour of urine obtention in the morning.

Inclusion Criteria: Age ≥18 years old. Cystinuric patients, with or without urinary lithiasis at the time of inclusion. Patients who accept their participation in the study and give their informed consent. Exclusion Criteria: Patients with pathologies that require pH control other than the one established in the study protocol to avoid the formation of kidney stones.