Modulators of urinary pH in the context of urinary stone disease: a literature review.

Background and objective: Urinary pH is an important factor in the preventative management of kidney stones. A variety of options are available for modulating urinary pH, including pharmaceuticals, over the counter (OTC) formulations [such as stone specific OTCs, complementary and alternative medicines (CAMs), and home remedies], and dietary modifications. These options can be overwhelming for both providers and patients and vary with regards to cost, convenience, and efficacy. In the absence of a consolidated central source of information for patients and physicians to reference, our study aims to summarize and analyze the effectiveness of these various treatment approaches to provide a more comprehensive understanding of how common interventions alter urinary pH.

Methods: The PubMed database was used to identify human clinical trials related to pharmacologic and dietary interventions to modify urinary pH. Eligible studies were selected based on the following criteria: (I) observational or interventional study; (II) urinary pH as a reported outcome of the study intervention; (III) inclusion baseline or control urinary pH data; (IV) sufficient presentation of data for analytical purposes. Data was abstracted, and the mean changes in urinary pH for each intervention were compiled and grouped.

Key content and findings: A total of 86 studies met inclusion criteria: 61 were randomized clinical trials, 20 were crossover or prospective studies, and 5 were observational cohort reports. In total, 150 individual experiments with a combined sample size of 2,895 were included. For urinary alkalinization, the most effective pharmaceutical, OTC formulation, and dietary change were sodium bicarbonate, Citro-Soda^®, and lacto-ovo-vegetarian diet, respectively. For urinary acidification, the most effective interventions were ammonium chloride, methionine, and high protein diet, respectively.

Conclusions: Our study found that pharmaceuticals are not the only effective options for altering urine pH; select dietary changes and OTC options are also viable for patients. When considering cost, accessibility and side effects, these alternative options may be more appealing to some patients, potentially improving adherence compared to pharmaceuticals.