Increased serum strontium levels in dialysis patients: An epidemiological survey

Background. We previously reported on increased bone strontium levels in di alysis patients with osteomalacia versus those presenting other types of re nal osteodystrophy. A causal role of strontium in the development of osteom alacia was established in a chronic renal failure rat model. Methods. To further elucidate the latter issue and to find out whether dial ysis patients from particular centers/countries are at an increased risk fo r strontium accumulation, a worldwide multicenter study was established In total, 834 patients from 34 dialysis centers in 23 countries were included. In each of the patients, a serum sample was taken for strontium determinat ion, and water and dialysate samples were taken at the various steps of the water purification process. For each patient clinical data and for each ce nter dialysis modalities were recorded. Results. Strontium levels in serum of dialysis patients showed major differ ences between the various centers, ranging from mean values of 25 +/- 8 mu g/liter in the center with the lowest Level up to 466 +/- 90 mu g/liter in the center with the highest concentration. It is of interest that these hig h levels were mainly found in developing countries. Furthermore, our data p oint toward a role of the final dialysate in the accumulation of the elemen t, as indicated by the strong correlation (r = 0.74, P < 0.001) between mea n serum and dialysate strontium levels. As the high tap water concentration of strontium was adequately reduced during the water purification process, contamination of the final dialysis fluid occurred by the addition of conc entrates contaminated with strontium. Besides the dialysate, other factors, such as duration of dialysis, vitamin D supplements, or types of phosphate binders, played a less important role in the accumulation of the element. Conclusions. Data of this multicenter study indicate patients of particular dialysis centers to be at an increased risk for strontium accumulation. th e clinical consequence of which is under current investigation.