Bone disease in primary biliary cirrhosis: lack of association with distal renal tubular acidosis.
OBJECTIVE
Primary biliary cirrhosis (PBC) might be complicated by osteoporosis, whose etiology remains unknown but seems to be multifactorial. Prevalence rates of 30% to 60% for distal renal tubular acidosis (DRTA) have been reported in PBC patients, generally as incomplete DRTA. Although it is undisputed that a reduced bone mineral density (BMD) is the expected outcome among patients who have been suffering from longstanding chronic metabolic acidosis, it is unclear if incomplete DRTA is also associated with metabolic bone disease in PBC patients. The present study was undertaken to compare the BMD of PBC patients with and without DRTA.


METHODS
The BMD of 23 PBC patients (11 with DRTA and 12 without), all with normal clearance of creatinine, was assessed by dual energy radiograph absorptiometry. The diagnosis of DRTA was made if the urine pH was above 5.4 in all samples after the oral acid overload, showing tubular inability to acidify urine in the presence of test-induced systemic metabolic acidosis.


RESULTS
Densitometric signs of osteoporosis were found in 82% of DRTA cases and in 83% of patients without DRTA (difference not significant). There were no significant differences in BMD measurement, T and Z scores of patients with and without DRTA.


CONCLUSIONS
The present study could not support a correlation between the presence of DRTA and the bone loss observed in PBC patients.
Farias
Alberto Q
AQ
Department of Gastroenterology, Institute of Tropical Medicine, São Paulo University School of Medicine, São Paulo, Brazil. albertosp@bol.com.br
Gonçalves
Luciana L
LL
Cançado
Eduardo Lr
EL
Seguro
Antonio C
AC
Campos
Silvia B
SB
Abrantes-Lemos
Clarice P
CP
Carrilho
Flair J
FJ
D000141:Acidosis, Renal Tubular / Q000150:complications; D015519:Bone Density; D001847:Bone Diseases / Q000150:complications*; D005260:Female; D006801:Humans; D008105:Liver Cirrhosis, Biliary / Q000150:complications*; D008875:Middle Aged