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). To develop 2012 provisional classification criteria, adding interspinous bursitis evaluation by US. We reported the usefulness of interspinous bursitis evaluation by US at 2015 American college of rheumatology annual meeting.
Objectives In this time, we compared 2012 provisonal classification criteria to adding interspinous bursitis evaluation by US, and checked the association between US evaluation of conventional (shoulder and hip) bursitis and interspinous bursitis.
Methods This is a prospective cohort study. Candidate criteria were evaluated 161 patients with new onset untreated PMR, and 174 patients non-PMR comparison subjects with conditions mimicking PMR. We compared the diagnosis ability of 2012 provisional classification criteria with 2012 provisional classification criteria, adding interspinous bursitis evaluation by US. US evaluation was checked cervical and lumbar spine added conventional shoulder and hip. In PMR patients, we evaluated the prevalance of interspinous bursitis without hip or shoulder bursitis, the association between interspinous bursitis and shoulder or hip bursitis.
Results 2012 provisional classification criteria scoring system had 66% sensitivity and 82% specificity. Adding interspinous bursitis by US had significantly increased sensitivity to 89%,and not significantly decreased specificity to 77%.(ROC anaylysis: p<0.05)
PMR patients without hip or shoulder bursitis were 56 patients. Surprisingly, PMR patients without hip or shoulder bursitis had interspinous bursitis with high prevalence. (85%, 48 patients) No correlation was found between interspinous bursitis and shoulder or hip bursitis (r=0.09, P=0.36).
Conclusions Interspinous bursitis by US is important evalution in patients with PMR. Interspinous bursitis by US should be added classification criteria for PMR. If patients were suspected of PMR, interspinous bursitis by US might be performed despite hip and shoulder bursitis.
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]
Disclosure of Interest None declared