THE ABNORMAL RED-CELL OXALATE TRANSPORT IS A RISK FACTOR FOR IDIOPATHIC CALCIUM NEPHROLITHIASIS - A PROSPECTIVE-STUDY

An abnormal erythrocyte transmembrane oxalate flux was described in re current idiopathic calcium nephrolithiasis, To verify whether it might represent a risk marker of renal stone disease, two prospective studi es were carried out, One hundred ninety patients with idiopathic calci um nephrolithiasis who were enrolled at their first episode of lithias is during the period 1984 to 1986, form the basis of the first prospec tive study. The impact of erythrocyte oxalate transport anomaly, gende r, familial occurrence of nephrolithiasis, hypercalciuria, hyperoxalur ia, and hyperuricosuria on stone recurrence by both bivariate and mult ivariate analysis of frequencies was assessed. The predictive value of the erythrocyte anomaly for a patient's becoming a stone former was a lso assessed in five nephrolithiasic families. Recurrence occurred in 57.9% of patients; this was significantly associated with the erythroc yte anomaly, hyperoxaluria, and male gender, However, when using multi variate analysis, only gender and the erythrocyte anomaly were statist ically significant and were independent predictors of recurrency, The probability of stone recurrency predicted by the logistic model ranged from 30.1% for women with normal erythrocyte oxalate transport, to 73 .4% for men with the erythrocyte anomaly, The family follow-up showed that only subjects with the erythrocyte abnormality become renal stone -formers in the 8-yr survey. By showing the predictive value of the er ythrocyte oxalate anomaly for recurrent calcium nephrolithiasis, our f indings support the notion that this anomaly is a risk factor in renal stone disease.