General considerations for recurrence prevention

All stone formers, independent of their individual risk, should follow the preventive measures in Table 11.5. The main focus of these is normalisation of dietary habits and lifestyle risks. Stone formers at high risk need specific prophylaxis for recurrence, which is usually pharmacological treatment and based on stone analysis.

Table 11.5: General preventive measures

Fluid intake (drinking advice) Fluid amount: 2.5-3.0 L/day Circadian drinking

Neutral pH beverages Diuresis: 2.0-2.5 L/day

Specific weight of urine: < 1010 Nutritional advice for a balanced diet Balanced diet*

Rich in vegetable and fibre

Normal calcium content: 1-1.2 g/day Limited NaCl content: 4-5 g/day

Lifestyle advice to normalise general risk factors BMI: 18-25 kg/m2 _{(target adult value, not applicable}

to children)

Stress limitation measures Adequate physical activity Balancing of excessive fluid loss

Caution: The protein need is age-group dependent, therefore protein restriction in childhood should be handled carefully.

* Avoid excessive consumption of vitamin supplements.

11.2.1 Fluid intake

An inverse relationship between high fluid intake and stone formation has been repeatedly demonstrated (1-3). The effect of fruit juices is mainly determined by the presence of citrate or bicarbonate (4). If hydrogen ions are present, the net result is neutralisation. However, if potassium is present, both pH and citrate are increased (5,6). One large fair-quality RCT showed that soft drink consumption significantly reduced the risk for symptomatic recurrences in men with more than one past kidney stone of any type (3,7).

11.2.2 Diet

A common sense approach to diet should be taken, that is, a mixed balanced diet with contributions from all food groups, but without any excesses (3,8,9).

Fruits, vegetables and fibres: fruit and vegetable intake should be encouraged because of the beneficial effects of fibre, although the role of the later in preventing stone recurrences is debatable (10-12). The alkaline content of a vegetarian diet also increases urinary pH.

Oxalate: excessive intake of oxalate-rich products should be limited or avoided to prevent high oxalate load (4), particularly in patients who have high oxalate excretion.

Vitamin C: although vitamin C is a precursor of oxalate, its role as a risk factor in calcium oxalate stone formation remains controversial (13). However, it seems wise to advise calcium oxalate stone formers to avoid excessive intake.

Animal protein: should not be taken in excess (14,15) and limited to 0.8-1.0 g/kg body weight. Excessive consumption of animal protein has several effects that favour stone formation, including hypocitraturia, low urine pH, hyperoxaluria and hyperuricosuria.

Calcium intake: should not be restricted unless there are strong reasons because of the inverse relationship between dietary calcium and stone formation (11,16). The daily requirement for calcium is 1000 to 1200 mg (17). Calcium supplements are not recommended except in enteric hyperoxaluria, when additional calcium should be taken with meals to bind intestinal oxalate (3,15,18).

Sodium: the daily sodium (NaCl) intake should not exceed 3-5 g (17). High intake adversely affects urine composition:

• calcium excretion is increased by reduced tubular reabsorption; • urinary citrate is reduced due to loss of bicarbonate;

• increased risk of sodium urate crystal formation.

Calcium stone formation can be reduced by restricting sodium and animal protein (14,15). A positive correlation between sodium consumption and risk of first-time stone formation has been confirmed only in women (16,19). There have been no prospective clinical trials on the role of sodium restriction as an independent variable in reducing the risk of stone formation.

Urate: intake of urate-rich food should be restricted in patients with hyperuricosuric calcium oxalate (20,21) and uric acid stones. Intake should not exceed 500 mg/day (17).

11.2.3 Lifestyle

Lifestyle factors may influence the risk of stone formation, for example, obesity (22) and arterial hypertension (23,24).

11.2.4 Recommendations for recurrence prevention

Recommendations LE GR

The aim should be to obtain a 24-h urine volume > 2.5 L. 1b A

Hyperoxaluria Oxalate restriction 2b B

High sodium excretion Restricted intake of salt 1b A

Small urine volume Increased fluid intake 1b A

Urea level indicating a high intake of animal protein

Avoid excessive intake of animal protein 1b A

11.2.5 References

1. Borghi L, Meschi T, Amato F, et al. Urinary volume, water and recurrences in idiopathic calcium nephrolithiasis: a 5-year randomized prospective study. J Urol 1996 Mar;155(3):839-43. http://www.ncbi.nlm.nih.gov/pubmed/8583588

2. Sarica K, Inal Y, Erturhan S, et al. The effect of calcium channel blockers on stone regrowth and recurrence after shock wave lithotripsy. Urol Res 2006 Jun;34(3):184-9.

http://www.ncbi.nlm.nih.gov/pubmed/16463053

3. Fink HA, Wilt TW, Eidman KE, et al. Medical Management to prevent recurrent nephrolithiasis in adults: a systematic review fora n American College of Physicians clinical guideline. Ann Intern Med 2013 Apr;158(7):535-43.

http://www.ncbi.nlm.nih.gov/pubmed/23546565

4. Siener R, Ebert D, Nicolay C, et al. Dietary risk factors for hyperoxaluria in calcium oxalate stone formers. Kidney Int 2003 Mar;63(3):1037-43.

http://www.ncbi.nlm.nih.gov/pubmed/12631085

5. Wabner CL, Pak CY. Effect of orange juice consumption on urinary stone risk factors. J Urol 1993 Jun;149(6):1405-8.

http://www.ncbi.nlm.nih.gov/pubmed/8501777

6. Gettman MT, Ogan K, Brinkley LJ, et al. Effect of cranberry juice consumption on urinary stone risk factors. J Urol 2005 Aug;174(2):590-4.

http://www.ncbi.nlm.nih.gov/pubmed/16006907

7. Shuster J, Jenkins A, Logan C, et al. Soft drink consumption and urinary stone recurrence: a randomized prevention trial. J Clin Epidemiol 1992 Aug;45:911-6.

http://www.ncbi.nlm.nih.gov/pubmed/1624973

8. Kocvara R, Plasgura P, Petrik A, et al. A prospective study of nonmedical prophylaxis after a first kidney stone. BJU Int 1999 Sep;84:393-8.

http://www.ncbi.nlm.nih.gov/pubmed/10468751

9. Hess B, Mauron H, Ackermann D, et al. Effects of a ‘common sense diet’ on urinary composition and supersaturation in patients with idiopathic calcium urolithiasis. Eur Urol 1999 Aug;36(2):136-43. http://www.ncbi.nlm.nih.gov/pubmed/10420035

10. Ebisuno S, Morimoto S, Yasukawa S, et al. Results of long-term rice bran treatment on stone recurrence in hypercalciuric patients. Br J Urol 1991 Mar;67(3):237-40.

http://www.ncbi.nlm.nih.gov/pubmed/1902388

11. Hiatt RA, Ettinger B, Caan B, et al. Randomized controlled trial of a low animal protein, high fiber diet in the pre- vention of recurrent calcium oxalate kidney stones. Am J Epidemiol 1996 Jul;144: 25-33. http://www.ncbi.nlm.nih.gov/pubmed/8659482

12. Dussol B, Iovanna C, Rotily M, et al. A randomized trial of low-animal-protein or high-fiber diets for secondary prevention of calcium nephrolithiasis. Nephron Clin Pract 2008;110:c185-94.

http://www.ncbi.nlm.nih.gov/pubmed/18957869

13. Auer BL, Auer D, Rodger AL. The effects of ascorbic acid ingestion on the biochemical and

physicochemical risk factors associated with calcium oxalate kidney stone formation. Clin Chem Lab Med 1998 Mar;36(3):143-7.

http://www.ncbi.nlm.nih.gov/pubmed/9589801

14. Borghi L, Schianchi T, Meschi T, et al. Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria. N Engl J Med 2002 Jan;346(2):77-84.

http://www.ncbi.nlm.nih.gov/pubmed/11784873

15. Fink HA, Akornor JW, Garimella PS, et al. Diet, fluid, or supplements for secondary prevention of nephrolithiasis: a systematic review and meta-analysis of randomized trials. Eur Urol 2009 Jul; 56(1):72-80.

16. Curhan GC, Willett WC, Speizer FE, et al. Comparison of dietary calcium with supplemental calcium and other nutrients as factors affecting the risk for kidney stones in women. Ann Intern Med 1997 Apr;126(7):497-504.

http://www.ncbi.nlm.nih.gov/pubmed/9092314

17. Hesse AT, Tiselius H-G. Siener R, Hoppe B. (Eds). Urinary Stones, Diagnosis, Treatment and Prevention of Recurrence. 3rd edn. Basel, S. Karger AG, 2009. ISBN 978-3-8055-9149-2.

18. von Unruh GE, Voss S, Sauerbruch T, et al. Dependence of oxalate absorption on the daily calcium intake. J Am Soc Nephrol 2004 Jun;15(6):1567-73.

http://www.ncbi.nlm.nih.gov/pubmed/15153567

19. Curhan GC, Willett WC, Rimm EB, et al. A prospective study of dietary calcium and other nutrients and the risk of symptomatic kidney stones. N Engl J Med 1993 Mar;328(12):833-8.

http://www.ncbi.nlm.nih.gov/pubmed/8441427

20. Coe FL. Hyperuricosuric calcium oxalate nephrolithiasis. Adv Exp Med Biol 1980;128:439-50. http://www.ncbi.nlm.nih.gov/pubmed/7424690

21. Ettinger B. Hyperuricosuric calcium stone disease. In: Coe FL, Favus MJ, Pak CYC, Parks JH, Preminger GM, eds. Kidney Stones: Medical and Surgical Management. Lippincott-Raven: Philadelphia, 1996, pp. 851-858.

22. Siener R, Glatz S, Nicolay C, et al. The role of overweight and obesity in calcium oxalate stone formation. Obes Res 2004 Jan;12(1):106-113.

http://www.ncbi.nlm.nih.gov/pubmed/14742848

23. Madore F, Stampfer MJ, Rimm EB, et al. Nephrolithiasis and risk of hypertension. Am J Hypertens 1998 Jan;11(1 Pt 1):46-53.

http://www.ncbi.nlm.nih.gov/pubmed/9504449

24. Madore F, Stampfer MJ, Willett WC, et al. Nephrolithiasis and risk of hypertension in women. Am J Kidney Dis 1998 Nov;32(5):802-7.

http://www.ncbi.nlm.nih.gov/pubmed/9820450