Replacement of routine liver biopsy by procollagen III aminopeptide for monitoring patients with psoriasis receiving long-term methotrexate: a multicentre audit and health economic analysis

Background Patients receiving long-term methotrexate for psoriasis are at risk of developing hepatic fibrosis. Repeated liver biopsy has long been regarded as the only reliable method of detecting this and it is still recommended by the American Academy of Dermatology (AAD). More recently, monitoring by serum procollagen III aminopeptide (PIIINP) measurement (Orion Diagnostica, Espoo, Finland) has been advocated as a means of significantly reducing the need for liver biopsy. Objectives To assess the validity of guidelines developed in Manchester for the use of PIIINP to monitor patients with psoriasis receiving long-term methotrexate; to assess the anticipated benefits to patients of introducing this change in practice, including reduction in requirement for liver biopsy; and to determine the impact of its introduction on healthcare costs. Methods A multicentre audit was conducted over a 24-month period to compare the healthcare costs and outcomes of two intervention groups from centres where serial PIIINP measurement was employed with those of two control groups from centres in which AAD guidelines were followed. Results A sevenfold reduction in the need for liver biopsy was observed in the two intervention groups (n = 166; 0.04 and 0.02 biopsies/patient/year, respectively) compared with the two control groups (n = 87; 0.26 and 0.30 biopsies/patient/year, respectively). Abnormalities of sufficient severity to influence management were identified in one in five patients biopsied in the main intervention group compared with one in 16 in the control groups. The overwhelming majority of patients surveyed expressed a preference for being monitored by methods that would minimize the need for liver biopsy. The adoption of PIIINP for monitoring would result in significant cost savings. Conclusions This audit has shown that patients managed by the Manchester protocol using serial PIIINP measurement and selective liver biopsy were not disadvantaged in comparison with those managed according to AAD guidelines; they were subjected to sevenfold fewer liver biopsies without evidence that important liver toxicity was missed in the process. If PIIINP monitoring were widely adopted, methotrexate would become a more acceptable option for many patients who are dissuaded from considering it because of the threat of repeated liver biopsy; it would also result in significant savings to the healthcare budget.