Impact of urometabolic evaluation on prevention of urolithiasis: a retrospective study

To obtain information on compliance to therapy and study its effect on recurrences. Over the past 20 years, a selective therapy protocol has been formed for prevention of urolithiasis recurrence. Many studies have been performed on the effectiveness of this therapy, but compliance has never been examined.

Data were abstracted from 177 medical records of patients who were seen at the outpatient clinic between 1985 and 1994. At that time, they were advised to follow a specific therapy regimen (high fluid intake, medication, and/or specific diet) on the basis of the outcome of a standardized metabolic evaluation.

Thirty-six percent of the study population was still compliant to the prescribed therapy after a mean period of 5.3 years of follow-up. Therapy-compliant patients were older and had had more treatments, more lithiasis-related complaints, and more frequent follow-up visits. These characteristics suggest that patients' awareness of their disease might improve compliance. Survival analyses showed that patients can be classified into two groups characterized by the frequency of stone formation: a single stone episode versus frequent periods of stone formation. It appeared that the stone recurrence rate was twice as high among patients with a history of frequent stones compared with patients with a single stone episode, even though compliance to therapy seemed lower in the latter group.

The usefulness of urometabolic evaluation and subsequent therapy advice seems questionable. Compliance to a life-long therapy is very low after a relatively short follow-up period. This study also suggests a prognostic classification based on stone rate.