Objective: To assess the responsiveness of ultrasound (US) inflammatory findings in the shoulder and hip of patients with polymyalgia rheumatica (PMR) who began treatment with corticosteroids (CST).
Methods: 53 patients with active PMR who started treatment with prednisone from 6 Spanish centres were prospectively studied. The patients underwent clinical, laboratory, and US assessment at baseline, 4 weeks, and 12 weeks. The US investigation consisted of detection and quantification of inflammatory findings in the shoulder and the hip. Responsiveness of clinical, laboratory and US parameters was tested by the standardized response mean (SRM). Intraobserver and interobserver reliability between US investigators were assessed.
Results: At baseline, 34 (69%) patients presented inflammation in at least a bilateral site. During the follow-up, clinical, laboratory, and US variables showed a parallel decrease. A significant decrease in US inflammatory parameters was found at week 4 (p<0.001). After 4 weeks and 12 weeks of CST therapy, US inflammatory findings showed similar or better sensitivity to change than clinical and laboratory markers of PMR activity. Intraobserver and interobserver intraclass correlation coefficients were 0.96 and 0.99, respectively (p<0.05).
Conclusion: US may be a responsive additional tool in monitoring CST response in PMR patients in daily practice and multicentre trials.