Construct validity of radiographs of the feet to assess joint damage in patients with gout

Abstract

Objective. To investigate construct validity of radiographic damage of the feet in gout. Methods. Radiographs of the feet were scored using the Sharp/van der Heijde method. Factors associated with damage were investigated by a negative binomial model, and contribution of damage to health by linear regressions. Results. Age, disease duration, serum uric acid, and tophi were associated with being erosive and erosion score. Tophi were associated with joint space narrowing. Erosions were associated (β 0.47, 95% CI 0.09-0.84) with physical function, but damage was not associated with overall physical health. Conclusion. Our results support construct validity for radiographs of the feet when assessing joint damage in gout.