[Lithogenic risk index in urinary lithiasis patients and their evolution after treatment.].

Objective: To determine the lithogenic risk index and its evolution after treatment of paraguayan lithiasic patients.

Methods: This experimental study of temporal series included 28 lithiasic patients of both sexes that attended to the Instituto de Prevision Social in 2012. Basal evaluation included metabolic study and urinary saturation indexes determined by EQUIL software. With this data, a specific treatment was selected for each patient. The follow up included a medical consultation monthly and the metabolic evaluation after 6 month. The study was approved by an ethical committee.

Results: Basal evaluation showed hypocitraturia, hypercalciuria and hyperoxaluria in 50%, 46.4% and 14.3% of patients, whereas 42.9% showed diuresis lower than 2 L/day. Crystallization risk for calcium oxalate, sodium urate, hidroxiapatite and uric acid was observed in 1,3, 12 and 12 patients respectively. After treatment, a decrease in the frequency of hypercalciuria and hypocitraturia was observed, just like the urinary saturation risk for all types of crystals studied. Statistical analysis showed a significant variation of diuresis (p 0,0001) and uric acid urinary saturation (p 0,002) after treatment.

Conclusions: The lithogenic risk factors more frequently detected were hipocitraturia and hypercalciuria. Therapeutic measures achieved the decrease of saturation risk indexes for all the crystals analyzed, registering significant effects in the increase of diuresis and uric acid saturation decrease. The use of software tools for the calculation of crystallization risk is an important innovation in Paraguay.