Mm. Couttenye et al., HIGH PREVALENCE OF ADYNAMIC BONE-DISEASE DIAGNOSED BY BIOCHEMICAL MARKERS IN A WIDE SAMPLE OF THE EUROPEAN CAPD POPULATION, Nephrology, dialysis, transplantation, 12(10), 1997, pp. 2144-2150
Background. Adynamic bone disease (ABD) has been described in the curr
ent dialysis population to have an unexpectedly high prevalence. Moreo
ver, it is clearly more prevalent in CAPD patients, compared to haemod
ialysis patients. Recently we demonstrated that both a low (less than
or equal to 27 U/l) level of bone alkaline phosphatase (BAP) as determ
ined by an optimized agarose gel electrophoretic technique and a low (
less than or equal to 150 pg/ml) level of iPTH are good markers of AED
with sensitivities of 78.1% and 80.6% and specificities of 86.4% and
76.2% respectively. Methods. In this study (n = 212), the prevalence o
f ABD in the European CAPD population was evaluated by means of these
biochemical markers. Clinical data on the patients included were recor
ded at the moment of blood sampling. In patients under CARD treatment
for longer than 9 months, we calculated an index of calcium exposure t
hrough PD fluid. Results. In this population with a low exposure to al
uminium, the prevalence of ABD as indicated by either a low level of B
AP or PTH was 43%. The following risk factors could be identified: adv
anced age, shorter time on renal replacement therapy, male gender, and
high calcium content of PD fluid. The index of calcium exposure was s
ignificantly higher in the patients with low BAP and low iPTH levels c
ompared to those with either BAP >27 U/l or iPTH >150 pg/ml. The latte
r finding gives further support to the hypothesis that a high calcium
load administered to renal failure patients may lead to 'oversuppresse
d' parathyroids in ABD. In a subgroup of patients with a high level of
BAP associated with a low iPTH level a profile previously shown to be
associated in the presence of aluminium overload, significantly highe
r serum aluminium levels were noted, suggesting that even in patients
with low exposure to aluminium, this element still can affect bone met
abolism. Conclusion. A high prevalence of ABD - as diagnosed by bioche
mical markers - was observed in the European CAPD population. A number
of risk factors could be put forward. The aetiology and pathogenesis
of this type of renal osteodystrophy remain to be elucidated, but appe
ar, however, to be multifactorial.