Introduction: Psoriatic Arthritis (PsA) is a multifaceted disease in which various musculoskeletal and skin manifestations are involved. Beyond these features, PsA is associated with comorbidities that might increase the burden of the disease.
Areas covered: In the last years a growing interest has come out for the concept of multimorbidity in rheumatology. Multimorbidity was defined as the 'co-existence of two or more chronic diseases in the same individual.' In the multimorbidity concept, the patient is of central concern and all coexisting diseases are of equal importance. Comorbidity was defined as the 'occurrence of any distinct additional entity during the clinical course of patient who has the index disease under study.' In PsA, comorbidity and multimorbidity have often been confusingly used interchangeably, showing that there is an unmet need on this topic.
Expert opinion: This perspective article dealt with these different visions of the co-existence of other diseases in PsA, providing a distinction between them, not only for the impact on the treatment decision but also in how this concept might be incorporated into clinical trials design, choosing the right outcome measures for the patient-centric concept of multimorbidity. For this perspective, the authors searched PubMed and the Cochrane library for articles published.
Keywords: Psoriatic Arthritis; assessment; comorbidity; management; multimorbidity.