Recurrent urolithiasis: a general-practice study of risk factors and clinical consequences.

In 93 consecutive outpatients with verified recurrent urolithiasis a clinical and biochemical investigation was performed. In 25 patients with uric acid disorder, the median values for number of stones formed and frequencies of hospital admission and surgical treatment were about twice those in the remainder of the series. No correlation was found between the number of stones or the number of renal colic episodes and the urinary calcium level or Ca/Mg ratio. Stone formation showed numerical increase with increasing 24-hour output of urine, possibly as a result of the observed positive correlation between excretion of uric acid and 24-hour urine volume. Sixty per cent of all the stones were spontaneously excreted. The urolithiasis was associated with increased frequency of urinary tract infection, particularly in men. In about one-third of the patients more than one etiologic factor was present.