title: Factors that predict relapse of calcium nephrolithiasis during treatment: a prospective study.
abstract: We evaluated 522 patients with idiopathic, recurrent calcium nephrolithiasis using a comprehensive clinical and laboratory protocol, and obtained additional laboratory measurements during their subsequent years of treatment in our program. In 57 patients, a new calcium stone ultimately formed during treatment (relapse), whereas 189 others have been free of recurrence during at least two years (average 4.3 +/- 2.2 [SD] years) of follow-up. Compared with the patients who remained stone-free, the patients with relapse (1) had a shorter interval between the time they entered our program and the time their last recurrent, pretreatment stone formed; (2) excreted more calcium *in mg/kg of body weight pr 24 hours) in their urine during treatment (2.79 +/- 1.08 versus 2.39 +/- 0.98 [SD] for relapse and stone-free); and (3) increased their urine volume less during treatment compared with pretreatment values (delta in liters per 24 hours was -0.02 +/- 0.48 versus 0.23 +/- 0.54 for relapse and stone-free). The two groups were otherwise the same. All comparisons used only data obtained prior to relapse. A discriminant function using only these three characteristics correctly identified 72 percent of patients with relapse and 67 percent of those who remained stone-free.
mesh_terms: D000493:Allopurinol / Q000627:therapeutic use; D001581:Benzothiadiazines; D002118:Calcium / Q000652:urine; D004232:Diuretics; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000188:drug therapy* / Q000209:etiology / Q000652:urine; D008297:Male; D011446:Prospective Studies; D012008:Recurrence; D012306:Risk; D049993:Sodium Chloride Symporter Inhibitors / Q000627:therapeutic use; D014527:Uric Acid / Q000652:urine
chemical_list: D001581:Benzothiadiazines; D004232:Diuretics; D049993:Sodium Chloride Symporter Inhibitors; D014527:Uric Acid; D000493:Allopurinol; D002118:Calcium