Nearly half of newly detected antimitochondrial antibodies (AMAs) in clinical practice do not lead to a diagnosis of primary biliary cholangitis (PBC), according to a prospective study.
Geraldine Dahlqvist, MD, and her associates examined 720 patients whose AMA tests were registered during a 1-year census period. They were divided into groups according to whether they were newly diagnosed (275), were previously diagnosed (216), or had a nonestablished diagnosis (229) of PBC. Results showed the prevalence of AMA-positive patients without evidence of PBC was 16.1 per 100,000 inhabitants. It was four (all AMA-positive patients) to six (PBC patients) times higher in women than in men. The median age was 58 years, with the median AMA titer at 1:16. Normal serum alkaline phosphatases (ALP) were 74%, and were 1.5 times above the upper limit of normal in 13% of patients, while cirrhosis was found in 6%. Among the patients with normal ALP and no evidence of cirrhosis, the 5-year incidence rate of PBC was 16%.
It was noted that no patients died officially from PBC in this study. The 1-, 3-, and 5-year rates of survival were 95%, 90%, and 75% (95% CI, 63-87), respectively, compared with 90% in the control group.
“The younger age and lower autoantibody titer of these patients, together with the frequent mild abnormalities of their biochemical liver tests, supports a very early, presymptomatic precholestatic stage of the disease,” Dr. Dahlqvist, of Catholic University of Louvain (Belgium), and her colleagues noted. “The incidence of clinical manifestations of PBC seems, however, much lower than previously reported.”
Find the full story in Hepatology (doi: 10.1002/hep.28559).