Guideline for anti-TNF-α therapy in psoriatic arthritis

Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy with a prevalence between 0.1 and 1% and an equal sex distribution [1]. Psoriasis affects 1–3% of the population, with approximately a third of patients developing PsA [2]. The course of PsA is variable and unpredictable ranging from a mild nondestructive disease to a severe debilitating erosive arthropathy. Erosive and deforming arthritis occurs in 40–60% of PsA patients (followed at hospital clinics), and is progressive from within the first year of diagnosis [3, 4]. The classification of PsA is an area of ongoing international discussion. The five subgroups proposed by Moll and Wright [5] are still frequently used, although considerable overlap between these groups is now recognized. For the purpose of these guidelines we have differentiated between peripheral joint disease in PsA and axial disease alone. Psoriatic spondylitis is similar to ankylosing spondylitis (AS), although it is often less symptomatic, less limiting and radiologically tends to be asymmetrical and less severe [6]. However, despite these differences, until such time as there is evidence that psoriatic spondylitis responds in a different manner from AS to TNFblockade, we recommend that AS guidelines for anti-TNFtreatment are used for the management of psoriatic spondylitis [7]. Much like rheumatoid arthritis (RA), PsA can lead to chronic joint damage, increased disability [8, 9] and increased mortality [10, 11]. Social and financial implications are also important, both in terms of personal loss and the impact of direct (e.g. medical care) and indirect (e.g. inability to work) costs to the state. It is recognized that psoriasis is associated with an increased risk of non-melanoma skin cancers [12], most probably a result of excessive exposure to sunlight and enhanced by use of psoralen and ultraviolet A (PUVA) therapy [13]. The guidelines recognize that these risks that may be potentiated by anti-TNFtreatment and specific recommendations have been made accordingly (see sections headed Exclusion criteria and Monitoring and Toxicity). Need for guideline