What is the best approach to prevent recurrent kidney stones?
Increased fluid intake or decreased soft drink intake may prevent further kidney stones in patients with a single episode of a calcium stone, but other dietary interventions are not effective. Thiazides and citrates with increased fluid intake decrease recurrence in patients with multiple past stones, as does allopurinol (Zyloprim) in patients with high uric acid levels. Combinations—allopurinol and citrates with a thiazide—are no more effective than thiazides alone. (Level of Evidence = 1a)
The researchers conducting this systematic review searched several databases, including the Cochrane library, and identified 28 English-language randomized trials that compared approaches to prevent recurrent kidney stones. The studies primarily evaluated patients with calcium stones, and included patients with a single incidence or with multiple recurrences. One reviewer abstracted the data and a second author checked for accuracy. Two reviewers independently rated the quality of the identified research. For patients with a single recurrence, low-quality evidence showed that increased fluid intake (greater than 2 to 2.5 L per day) or reduced soft drink consumption halved the recurrence of stones compared with no treatment. Decreased-protein diets or high-fiber diets and multicomponent diet changes (high fiber, low purine, and low protein) were all ineffective. In patients with recurrent calcium stones, six moderate-quality studies showed that thiazide treatment, combined with high fluid and decreased oxalate intake, decreased stone recurrence by one-half (relative risk = 0.52; 95% confidence interval, 0.39 to 0.69) and decreased rates of lithotripsy. Treatment with citrates (potassium citrate, potassium-magnesium citrate, or potassium-sodium citrate) and increased fluid intake also decreased composite stone recurrence (relative risk = 0.25; 95% confidence interval, 0.14 to 0.44). Allopurinol decreases composite stone recurrence in patients with baseline hyperuricemia or hyperuricosuria. Combinations with thiazides were no more effective than a thiazide alone.
Study design: Systematic review
Setting: Outpatient (any)
Funding source: Government
Reference:FinkHAWiltTJEidmanKEet alMedical management to prevent recurrent nephrolithiasis in adults: a systematic review for an American College of Physicians clinical guideline [published correction appears in Ann Intern Med. 2013;159(3):230–232]. Ann Intern Med. 2013; 158( 7): 535– 543.