Metabolic characteristics of the elderly with recurrent calcium oxalate stones

Objective To determine the metabolic characteristics of elderly patients wi th recurrent calcium oxalate stones. Patients and methods Metabolic abnormalities were investigated in 88 patien ts with recurrent calcium oxalate stones, including 70 aged <60 years and 1 8 aged greater than or equal to 60 years. The frequency of each metabolic a bnormality and the value of each urinary constituent were compared among su bgroups of age and gender. Results Hyperoxaluria was the most common abnormality, present in 56% and 6 7% of patients aged <60 and greater than or equal to 60 years, respectively . Hyperuricosuria was significantly more common in older than in younger pa tients. There were no significant differences in the frequencies of hyperca lciuria and hypocitraturia between the age groups. The urinary excretion of oxalate and the ratio of oxalate to creatinine were significantly greater in older than in younger men. The frequency of low urine volume was lower i n older than in younger patients and the mean urinary volume was also great er in the older group. Conclusions Hyperuricosuria and hyperoxaluria seem to be essential risk fac tors for calcium oxalate stone formation in elderly patients. Urinary oxala te excretion is significantly greater in older than in younger stone former s and is more prominent in men.