Prevention of renal stones by a high fluid intake?

From the physiochemical view on the formation of urolithiasis a high fluid intake, provided it resulted in a high urine volume, should reduce the propensity of crystallization, crystal growth and stone formation. This critical review of the literature, however, demonstrates that there is little epidemiologic support for the hypothesis that a low urine volume is an important risk factor for renal stones in temperate climates. Few clinical studies have attempted to elucidate if a large diuresis can prevent further stone formation in a recurrent renal stone former. In the present study 115 recurrent stone formers were followed for an average period of 6 years without any other treatment than advice about a high fluid intake. The annual recurrence rate was around 23% but there was no difference between those who maintained a high urine volume and those who did not. Thus, the available evidence does not indicate that variations of fluid intake markedly affect stone formation.