Characterization of patients with chronic refractory gout who do and do not have clinically apparent tophi and their response to pegloticase

Objectives. To determine the characteristics and response to pegloticase of patients with chronic refractory gout with and without clinically apparent tophi. Methods. Results from two randomized controlled trials of pegloticase in patients with chronic refractory gout with clinically apparent tophi or without tophi were used to assess baseline and on-treatment between-group differences. Results. Patients with tophi were significantly older than those without tophi, had a significantly longer duration of disease, higher numbers of tender and swollen joints, higher Patient Global Assessment scores and Health Assessment Questionnaire-Disability Index scores, and lower Arthritis-Specific Health Index scores. Patients with tophaceous gout also had significantly lower scores for physical functioning, role physical, social functioning, and the physical component summary scores of the Short Form 36 vs patients without tophi. In addition, subjects with clinically apparent tophi had a significantly lower mean estimated glomerular filtration rate. Pegloticase treatment of tophaceous patients caused significant reductions in serum urate, flares, Patient Global Assessment, tender joints, swollen joints, Health Assessment Questionnaire-Disability Index, visual analogue scale pain and Short Form 36 Bodily Pain, whereas patients without tophi had significant improvement in serum urate, flares, Patient Global Assessment, tender joints, and Short Form 36 Bodily Pain, but not swollen joints, Health Assessment Questionnaire-Disability Index functional score or pain visual analogue scale. Treatment with pegloticase had no effect on estimated glomerular filtration rate despite significant lowering of the urinary uric acid: creatinine ratio. Conclusion. Patients with chronic refractory gout and clinically apparent tophi have more severe disease as well as reduced renal function. Both groups experienced significant clinical benefit with pegloticase treatment, although no change in renal function was noted.