There are 2 major types of osteodystrophy which occur in various combinations in dialysis patients. The first and most commonly predominant is secondary hyperparathyroidism. This appears to be preventable, or at least controllable, with a bath calcium concentration above 6 mg%. The second type is osteomalacia. In certain centers it has been the dominant lesion.
At the Ottawa General Hospital, osteomalacia unresponsive to recommended therapy was the predominant lesion in our patients prior to deionization. Subsequent to deionization, no patient has developed clinical renal osteodystrophy of any type, and in particular no osteomalacia. Patients who began the program with secondary hyperparathyroidism improved with standard dialysis treatment. A patient with non-responsive osteomalacia prior to deionization responded normally following deionization by healing her fractures and calcifying her osteoid. Hence we found that we could not only prevent symptomatic osteomalacia by deionization, but could also reverse its course.
This suggests that there was a factor in our tap water which prevented normal calcification of osteoid and that that this is removed by deionization.
We have previously reported high uptake of fluoride with an increase in the serum and bone levels of 11 fluoride in our patients dialyzed with ordinary tap water.
De Veber and Jowsey have observed an increase in osteoid similar to ours in their dialysis patients treated with high fluoride dialysate. High fluoride concentrations have also been shown experimentally to lead to a defect in osteoid calcification. These observations suggest a role for fluoride in the osteomalacic disease in dialysis patients. Against fluoride being the only factor are reports from other centers denying the presence of osteomalacia in their patients on fluoridated dialysate. We conclude that the osteomalacia that occurs in dialysis patients is due to multiple factors that are removed by deionization. Fluoride may be one of the contributing factors.