Background Polymyalgia rheumatica (PMR) is a common inflammatory disease of the elderly, and 2012 provisional classification criteria were suggested, however it is provisional and not meant for diagnosis purpose1. Ultrasound (US), MRI and other modalities were often detected interspinous bursitis in patients with PMR2.
Objectives To develop 2012 provisional classification criteria, adding interspinous bursitis evaluation by US.
Methods This is a prospective cohort study. Candidate criteria were evaluated 45 patients with new onset untreated PMR, and 67 patiens non-PMR comparison subjects with conditions mimicking PMR. We compared the sensitivity and specificity of 2012 provisional classification criteria with 2012 provisional classification criteria, adding interspinous bursitis evaluation by US. US evaluation was checked cervical and lumbar spine, and if at least one interspinous bursitis was detected, it was calculated 1 point. Total score (interspinous bursitis evaluation by US score plus 2012 provisional classification criteria with US score) was 5 or more, it is categorised as PMR.
Results 2012 provisional classification criteria scoring system had 71% sensitivity and 75% specificity. Adding interspinous bursitis by US had significantly increased sensitivity to 79% (p<0.05), and not significantly decreased specificity to 72% (p=0.47).
Conclusions Interspinous bursitis by US is very sensitive in patients with PMR. Interspinous bursitis by US should be added classification criteria for PMR.
Dasgupta B, et al. 2012 Provisional classification criteria for polymyalgia rheumatica: a European League Against Rheumatism/American College of Rheumatology collaborative initiative. Ann Rheum Dis. 2012 Apr;71(4):484-92. doi: 10.1136/annrheumdis-2011-200329.
Camellino D, et al. Interspinous bursitis is common in polymyalgia rheumatica, but is not associated with spinal pain. Arthritis Res Ther. 2014 Dec 1;16(6):492. [Epub ahead of print]
Acknowledgements We all thank Noriko Kuwaba for selecting and analysing data.
Disclosure of Interest None declared