Arthritis mutilans is often described as the most severe form of psoriatic arthritis. However, a widely agreed on definition of the disease has not been developed. At the 2012 annual meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA), members hoped to agree on a definition of arthritis mutilans and thus facilitate clinical and molecular epidemiological research into the disease. Members discussed the clinical features of arthritis mutilans and definitions used by researchers to date; reviewed data from the ClASsification for Psoriatic ARthritis study, the Nordic psoriatic arthritis mutilans study, and the results of a premeeting survey; and participated in breakout group discussions. Through this exercise, GRAPPA members developed a broad consensus on the features of arthritis mutilans, which will help us develop a GRAPPA-endorsed definition of arthritis mutilans.
A composite measure is one way of incorporating an assessment of all relevant clinical outcomes into one single measure. By definition it incorporates several dimensions of disease status often by combining these different domains into a single score. Such instruments are well established in rheumatoid arthritis (RA), and these RA-specific measures have successfully been adopted for use in clinical trials involving patients with psoriatic arthritis (PsA). However, the need for a more PsA-specific composite measure has led to a number of proposals, which, for the large part, incorporate only peripheral articular disease activity. New indices that combine the diverse clinical manifestations of PsA are now under development. These issues were discussed at the 2009 annual meeting of GRAPPA (Group for Research and Assessment of Psoriasis and Psoriatic Arthritis) in Stockholm, Sweden, and are summarized here.
Several screening tools for early identification of psoriatic arthritis (PsA) have been developed. While these tools had high sensitivity and specificity during their development and initial validation, it remained to be determined how they would function with widespread use. At the 2012 annual meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) in Stockholm, Sweden, these tools were compared for their utility when used to screen patients for PsA in clinics other than those in which they were developed. The screening tools did not perform as well as previously published, and members suggested new tools may need to be developed. An additional study of the prevalence of PsA in a large cohort of psoriasis patients, the PREPARE study, which investigated the use of screening questionnaires, was also presented.
Dermatologist and primary care clinicians are in an ideal position to identify the emergence of psoriatic arthritis (PsA) in patients with psoriasis. Yet these clinicians are not well trained to distinguish inflammatory musculoskeletal disease from other more common problems such as osteoarthritis, traumatic or degenerative tendonitis and back pain, or fibromyalgia. A simple set of clinical criteria to identify inflammatory disease would aid recognition of PsA. At its 2012 annual meeting, the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) discussed development of evidence-based, practical, and reliable definitions of inflammatory arthritis, enthesitis, dactylitis, and spondylitis. This project will be a sequential process of expert clinician nominal-group technique, patient surveys and focus groups, and Delphi exercises to identify core features of inflammatory disease, testing these in a small group of patients with and without inflammatory disease, and finally validating these criteria in larger groups of patients.
Patients with psoriasis attending general practitioner and dermatology clinics may complain about their joints, but it may be difficult for the nonrheumatologist to distinguish psoriatic arthritis (PsA) from other forms of arthritis. A screening tool for PsA would therefore be useful to both general practitioners and dermatologists and help identify patients for further evaluation by a rheumatologist. Although several screening tools have been developed, the Psoriasis Epidemiology Screening Tool (PEST) has the advantage of simplicity and ease of use. This new instrument consists of 5 simple questions supported by the addition of a manikin for patient markup. During development, the questionnaire has shown a sensitivity of 0.94 and a specificity of 0.78. Further validation of this and the other questionnaires is now required. A "head to head" study of the PEST, ToPAS (Toronto Psoriatic Arthritis Screening questionnaire), and PASE (Psoriatic Arthritis Screening and Evaluation) tools is planned in a secondary-care population with psoriasis. This study is important not only to confirm the comparative performance of the instruments, but also to confirm the high figures for sensitivity in a secondary-care population.