Some characteristics of recurrent calcium stone formers in Puerto Rico.

We have studied 83 patients with recurrent calcium stone formation in an attempt to determine an approximate incidence of metabolic disturbances associated with stone disease. Male veterans (n = 42), male non-veterans (n = 13), and women (n = 28) composed the group. We divided the groups in such fashion because they represented generally two distinct socioeconomic groups. Primary hyperparathyroidism was present in 19 per cent of the subjects; a marked predominance of women (15/16) was noted. Hypercalciuria of renal or intestinal origin was present in 23 per cent of the group. Of interest was a group of male veterans (17/83) in whom normocalciuria, normocalcemia, and normal serum phosphate were associated with high values of immunoreactive parathyroid hormone. These subjects had low urine phosphate. This set of findings indicates that these patients may be a new subgroup of stone-forming patients. Metabolic abnormalities could not be detected in 38 per cent of the patients. Classification of stone subjects is essential for rational management.