Quantitative liver function in patients with rheumatoid arthritis treated with low-dose methotrexate: a longitudinal study.

The objectives were to determine quantitative liver function prospectively in patients with rheumatoid arthritis (RA) treated with low-dose methotrexate (MTX), to search for risk factors for a loss of quantitative liver function and to assess the relationship between quantitative liver function and histological staging. A total of 117 patients with RA (ACR criteria, 85 women. mean age 59 yr) had measurements of galactose elimination capacity (GEC). aminopyrine breath test (ABT) and liver enzymes [aspartate amino transferase (AST). alanine amino transferase (ALT), alkaline phosphatase (AP), γ-glutamyl transferase (GGT). bile acids, bilirubin, albumin] before treatment with weekly i.m. MTX injections and every year thereafter. In 16 patients. liver biopsies were performed. Before the introduction of MTX, mean GEC was 6.6 mg/min/kg [5th to 95th percentile (5-95 PC) 5.1-8.5: reference range 6.0-9.1] and mean ABT was 0.80%kg/mmol (5-95 PC 0.42-1.30; reference range 0.6-1.0). During treatment with MTX [mean weekly dose 11.8 mg (5-95 PC 5.4-20.2), mean observation period 3,8 yr (5-95 PC 0.4-6.9)]. significant declines of GEC (-0.12 mg/min/kg per year, t = 3,30, P 30 g/week became evident. Two patients with Roenigk grade III had impaired quantitative liver function, while 14 patients with Roenigk grades I and II exhibited a high variability of GEC and ABT from normal to abnormal values. The continuous declines in GEC and ABT observed deserve attention in patients with prolonged treatment. Patients with a low GEC or ABT at baseline seem not to be at increased risk for a further loss of quantitative liver function. An impaired GEC or ABT does not necessarily concur with hepatic fibrosis on histological examination.