Serum bilirubin: A prognostic factor in primary biliary cirrhosis

Abstract

We followed up 55 patients with proven primary biliary cirrhosis for several years or until death. A graph of the level of serum bilirubin versus time that was constructed for each patient shows an initial stable period of variable length in which the serum bilirubin level remained constant. This was followed by a period of rapid rise in serum bilirubin which culminated in the patient's death. Whenever two successive serum bilirubin values taken 6 mth apart exceeded 34 μmol/l (2.0 mg/dl), the patient had entered a late phase of disease and lived an average of 49 mth. Ninety-five per cent confidence limits on survival time were 32-74 mth. If two successive 6 mth bilirubin values exceeded 102 μmol/l (6.0 mg/dl), calculated survival time was 25 mth, and if two successive 6 mth bilirubin values exceeded 170 μmol/l (10.0 mg/dl), survival time was 17 months. Fifteen of the 41 living patients had two consecutive serum bilirubin levels greater than 34 μmol/l (2.0 mg/dl). However, the slope of the rising bilirubin in the living patients is only 25 μmol/l/yr (1.5 mg/dl/yr) compared with 42 μmol/l/yr (2.5 mg/dl/yr) in the dead patients. This means that patients with this disease now may be living considerably longer.