Systematic review of the use of CRP in clinical trials for psoriatic arthritis: a concern for clinical practice?

CRP levels were inconsistently used as inclusion criterion in clinical trials, often limiting generalisability of the data. The use of composite scores such as ACR20 or Disease Activity Score-28-CRP is also limited since baseline levels of CRP affects their sensitivity to change. High CRP levels may be an individual predictor for disease progression and response to treatment, but the current conflicting findings and selective patient trial inclusions, do not allow CRP to play a very prominent role in treatment decision making.