Bone histology in CAPD patients: a comparison with hemodialysis and conservatively treated chronic uremics.

Thirteen patients treated with CAPD, 22 patients maintained on hemodialysis (HD) using aluminium-free water and matched for duration of treatment and 15 conservatively treated uremic patients (CONS) were evaluated by iliac bone biopsy to analyse the influence of CAPD on bone histomorphometry. CAPD patients were significantly (p less than 0.05) older (63.1 +/- 14.0, HD 52.7 +/- 13.3, CONS 53.3 +/- 11.7). Compared to HD the results were as follows: CAPD patients required significantly less aluminium to control hyperphosphatemia (0.16 vs. 0.49 g, p less than 0.005). They had a significantly lower incidence of symptomatic bone disease (p less than 0.05). Histomorphometry showed significantly lower osteoid volume (4.3 + 2.8% vs. 8.6 + 5.5%, p less than 0.05) and aluminium labelling intensity (0.15 vs. 1.0, p less than 0.05). Apart from bone mass indices, other histomorphometric variables showed an insignificantly more favourable trend in CAPD patients compared to HD. CONS patients had a significantly lower bone formation rate than CAPD (p less than 0.05), but otherwise no histomorphometric differences were observed. We conclude that CAPD patients require less aluminium therapy, have a lower risk of aluminium bone contamination, and may have a lower risk of developing uremic osteodystrophy.