Objective: To systematically review the validity of serum uric acid (SUA) as a treatment target for patients with gout, and the clinimetric properties of the potential tools for monitoring these patients.
Methods: A search was performed in Medline, Embase and the Cochrane Library from inception to October 2011, and the 2010-2011 American College of Rheumatology and European League Against Rheumatism meeting abstracts. Studies evaluating different SUA levels or SUA reduction with the achievement of outcomes, and studies assessing clinimetric properties of instruments used to follow patients with gout were selected. Intervention studies were also included in order to estimate responsiveness. Titles and abstracts of the identified references were screened, and included articles were reviewed in detail and data collected using ad hoc standard forms.
Results: In total, 4575 articles were retrieved, 120 articles reviewed in detail, and 54 articles were included in the systematic literature review. SUA reduction was significantly associated with a reduction in acute attacks (6 studies), tophi regression (2 studies), and crystal clearance (3 studies). SUA 6.0 mg/dl was used as cutoff point in most of studies, but this level was found to be arbitrary. For followup of patients with gout, tophus measurement by caliper and ultrasound, the physical component of the Medical Outcomes Study Short Form-36 Survey, and Health Assessment Questionnaire have shown excellent clinimetric properties for this purpose.
Conclusion: Reducing SUA is a valid treatment target for patients with gout, but the target level of reduction (cutoff point) is not clear. Some tools were found suitable for following patients with gout.
Keywords: GOUT; IMAGING; PSYCHOMETRIC PROPERTIES; SERUM URIC ACID; VALIDITY.