[Metaphylaxis in the first occurrence of urolithiasis]

Abstract

Background: Urolithiasis is a socially important disease with a high tendency to recurrences. By specific medicamentous metaphylaxis it is possible to achieve an as high as tenfold reduction of recurrences, however, regular check-ups focussed on possible side-effects are required. The objective of the project was to assess prospectively the effectiveness of non-medicamentous metaphylaxis in patients with the first kidney stone. In 113 patients, a fluid and specific dietary regimen were recommended based on a comprehensive diagnosis of metabolic disorders (Table 1) and the regimen was modified with regard to results of metabolic check-up examinations after 6, 18, and 36 months (group 1). Ninety-four patients were recommended a fluid and non-specific dietary regimen after a limited metabolic evaluation with a subsequent check-up after 36 months (group 2). The two groups were clinically comparable. A stone recurrence developed in 7 (6%) patients of the group 1 and in 18 (19%) of the group 2 (p < 0.01). The difference was even greater after including the growth of the concrement (7% and 23%). The patients with a recurrence or growth of a stone had more frequently weddellite in the concrement and had also more frequently a bilateral residual or conservatively managed urolithiasis (p < 0.0001). Half the recurrencies were asymptomatic. The development of metabolic disorders in the group 1 indicated a gradual decrease of uric acid in serum and urine (p < 0.01) although it was not yet significant after 6 months. There was also a significant increase of calciuria (p < 0.01), most probably in conjunction with a regular calcium intake.

Conclusion: Specific non-medicamentous metaphylaxis with an adequate calcium intake leads to a lower incidence of stone recurrences than a non-specific fluid and dietary regimen. It is justified to introduce the specific metaphylaxis in all patients after the first diagnosis of a kidney stone. It ensures subsequent adjustment of the individual diet which the patient is more likely to adhere to than to general non-specific instructions.