Measurement properties of instruments assessing psoriatic arthritis symptoms for psoriasis clinical trials: a systematic literature review

Abstract

ABSTRACTIntroduction: The International Dermatology Outcome Measures (IDEOM) identified ‘Psoriatic Arthritis (PsA) Symptoms’ as a core domain to be measured in psoriasis clinical trials. This domain includes the measurement of pain, patient global and physical function. Herein, we evaluated the quality (i.e. measurement properties) of five candidate ‘PsA Symptoms’ measures: Patient Global Assessment (PGA) for Joints, PGA for PsA, the Routine Assessment Patient Index 3 (RAPID3), the PsA Impact of Disease 9 (PsAID9) and PsAID12.Areas covered: We searched MEDLINE and EMBASE (inception-to-March 2018) for studies assessing the measurement properties of candidate instruments. Two reviewers independently assessed the risk of bias of 12 eligible articles using the COSMIN checklist. For each measurement property, we rated the quality of the evidence as ‘high,’ ‘moderate,’ ‘low,’ or ‘very low’ (GRADE approach) and classified the results as ‘sufficient,’ ‘insufficient,’ or ‘inconsistent.’ Finally, we provided recommendations.Expert opinion: In PsA, RAPID3 had ‘very low’ quality evidence for ‘sufficient’ content validity and no evidence of internal structure. Global assessment instruments had ‘very low’ quality evidence for ‘inconsistent’ content validity. PsAID9 and PsAID12 had ‘low’ evidence for ‘sufficient’ content validity and were recommended to measure ‘PsA Symptoms.’ Further validation studies will improve the level of evidence of this recommendation.