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Preventing Recurrent Nephrolithiasis in Adults



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Am Fam Physician. 2014 Mar 15;89(6):461-463.

See the full review, clinician summary, consumer summary, and CME activity.

This clinical content conforms to AAFP criteria for continuing medical education (CME). See CME Quiz Questions.

Author disclosure: No relevant financial affiliations

Key Clinical Issue

What are the potential benefits and adverse effects associated with dietary and pharmacologic interventions to prevent recurrence of kidney stones in adults 18 years and older?

Evidence-Based Answer

There is limited evidence that fluid intake to maintain urine output greater than 2 L per day; eliminating soft drinks containing only phosphoric acid (i.e., no citric acid); or consuming a normal-calcium (1,200 mg per day), low-sodium, low–animal protein, decreased-oxalate, and increased-water diet may each reduce the risk of calcium stone recurrence. (Strength of Recommendation [SOR]: C, based on disease-oriented evidence.) Diets with high fiber or reduced animal protein as solitary interventions may not help prevent stone recurrence. The effectiveness of other dietary interventions is not clear. When added to increased fluid intake, thiazide diuretics, citrate, and allopurinol (in patients with elevated blood or urine uric acid levels) each reduce the risk of recurrent calcium stones more than increased fluid intake alone. (SOR: C, based on disease-oriented evidence.) Patients receiving pharmacologic interventions (particularly thiazide diuretics and citrate) may experience adverse effects, such as gastrointestinal problems, that lead to stopping treatment. The evidence is too limited to determine the role of baseline or follow-up laboratory testing in predicting stone recurrence.

Clinical Bottom Line: Preventing Recurrent Nephrolithiasis in Adults

Dietary interventions
Intervention Comparator Mode of detection ARR (%) NNT RR (95% CI) Strength of evidence

Limited evidence suggests that the following dietary interventions may reduce the risk of stone recurrence:

Increasing fluids to maintain urine output greater than 2 L per day (for persons with a single previous calcium stone episode)

No increase in fluids

Composite*

15

7

0.45 (0.24 to 0.84)

●○○

Eliminating soft drinks (based on a single study in men)

No advice to reduce intake of soft drinks

Symptomatic

7

14

0.83 (0.71 to 0.98)

●○○

Eliminating soft drinks acidified solely with phosphoric acid, but not citric acid (subgroup analysis of participants who frequently consumed such soft drinks)

No advice to reduce intake of soft drinks

Symptomatic

16

6

0.65 (0.49 to 0.87)

●○○

Normal-calcium,† low-sodium, low–animal protein, decreased-oxalate, and increased-water diet

Low calcium, decreased oxalate, and increased water intake

Composite

18

6

0.52 (0.29 to 0.95)

●○○

Limited evidence suggests that the following dietary intervention may increase the risk of stone recurrence:

Low–animal protein, high-fiber, increased-bran, low-purine, adequate-calcium, and increased-fluid diet

Adequate calcium and increased fluid

Composite

–20

5

5.88 (1.39 to 24.92)

●○○

Neither a high-fiber diet nor a reduced–animal protein diet as an isolated intervention had a statistically significant effect on stone recurrence. ●○○

Adverse effects (reflected by withdrawals for any cause) were high in long-term trials; however, there were no significant differences in withdrawals between intervention and control groups.

Pharmacologic interventions (NOTE: Trials evaluated effects of pharmacologic agents given in addition to standard dietary recommendations)

Thiazide diuretics, citrate, and allopurinol each reduce the risk of calcium stone recurrence. ●●○

Thiazide diuretics: ARR = 29%, NNT = 3, RR = 0.53 (95% CI, 0.41 to 0.68)

Citrate: ARR = 41%, NNT = 3, RR = 0.25 (95% CI, 0.14 to 0.44)

Allopurinol (in patients with elevated blood or urine uric acid levels): ARR = 22%, NNT = 5, RR = 0.59 (95% CI, 0.42 to 0.84)

Patients given thiazide diuretics or citrate, but not allopurinol, are more likely to withdraw from trials because of adverse effects compared with patients in the control group.

Baseline and follow-up biochemical evaluations to predict stone recurrence

The evidence is too limited to determine the role of baseline or follow-up biochemical measures in predicting stone recurrence outcomes.


Strength of evidence scale

High: ●●● There are consistent results from good-quality studies. Further research is very unlikely to change the conclusions.

Moderate: ●●○ Findings are supported, but further research could change the conclusions.

Low: ●○○ There are very few studies, or existing studies are flawed.

Insufficient: ○○○ Research is either unavailable or does not permit estimation of a treatment effect.


ARR = absolute risk reduction (the difference in risk between the control group and the treatment group); CI = confidence interval; NNT = number needed to treat (the number of patients to be treated to find the benefit in one patient more than in the control group); RR = relative risk.

*—Composite end point refers to stones detected by either symptoms or scheduled radiography.

†—The recommended level of dietary calcium intake in this study was 1,200 mg per day.

Adapted from the Agency for Healthcare Research and Quality, Effective Health Care Program. Recurrent

Address correspondence to Janelle Guirguis-Blake, MD, at jguirgui@u.washington.edu. Reprints are not available from the author.

EDITOR'S NOTE: American Family Physician SOR ratings are different from the AHRQ Strength of Evidence (SOE) ratings.

 

REFERENCES

1. Fink HA, Wilt TJ, Eidman KE, et al. Recurrent nephrolithiasis in adults: comparative effectiveness of preventive medical strategies. Rockville, Md.: Agency for Healthcare Research and Quality; July 2012 (revised March 2013 and May 2013). http://www.effectivehealthcare.ahrq.gov/search-for-guides-reviews-and-reports/?pageaction=displayproduct&productID=1035. Accessed January 9, 2014.

2. Strohmaier WL. Course of calcium stone disease without treatment. What can we expect? Eur Urol. 2000;37(3):339–344.

3. Borghi L, Meschi T, Amato F, Briganti A, Novarini A, Giannini A. Urinary volume, water and recurrences in idiopathic calcium nephrolithiasis: a 5-year randomized prospective study. J Urol. 1996;155(3):839–843.

4. Sarica K, Inal Y, Erturhan S, Yağci F. The effect of calcium channel blockers on stone regrowth and recurrence after shock wave lithotripsy. Urol Res. 2006;34(3):184–189.

5. Shuster J, Jenkins A, Logan C, et al. Soft drink consumption and urinary stone recurrence: a randomized prevention trial. J Clin Epidemiol. 1992;45(8):911–916.

6. Ettinger B, Tang A, Citron JT, Livemore B, William T. Randomized trial of allopurinol in the prevention of calcium oxalate calculi. N Engl J Med. 1986;315(22):1386–1389.

7. Smith MJ. Placebo versus allopurinol for renal calculi. J Urol. 1977;117(6):690–692.

8. Türk C, Knoll T, Petrik A, et al. European Association of Urology. Guidelines on urolithiasis. 2013. http://www.uroweb.org/gls/pdf/21_Urolithiasis_LRV4.pdf. Accessed January 9, 2014.

The Agency for Healthcare Research and Quality (AHRQ) conducts the Effective Health Care Program as part of its mission to organize knowledge and make it available to inform decisions about health care. A key clinical question based on the AHRQ Effective Health Care Program review is presented, followed by an evidence-based answer and an interpretation that will help guide clinicians in making treatment decisions.

A collection of Implementing AHRQ Effective Health Care Reviews published in AFP is available at http://www.aafp.org/afp/ahrq.


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