Objective: To evaluate associations linking glucocorticoid dose changes in patients with polymyalgia rheumatica (PMR) to the PMR activity score (PMR-AS) and its components.
Methods: Nine clinical vignettes of PMR were written by a panel of experts and submitted to 35 rheumatologists, who were asked to assess disease activity using a visual analog scale (VASph) and to determine whether there was a relapse of PMR requiring an increase in the glucocorticoid dose. In 7 vignettes, >80% of the rheumatologists agreed on the diagnosis of relapse justifying the glucocorticoid dose decision. A total of 243 vignette-physician combinations were obtained. Using these vignettes, we evaluated statistical associations linking a decision to increase the glucocorticoid dose to the value of PMR-AS, of its components (VASph, visual analog scale for pain [VASp], C-reactive protein level [CRP], morning stiffness [MST], and elevation of upper limbs [EUL]), or to the difference in these variables between the last 2 visits (dPMR-AS, dVASph, dVASp, dCRP, dMST, and dEUL).
Results: The strongest associations with a decision to increase the glucocorticoid dose occurred with dPMR-AS >4.2, dMST >10 minutes, dVASph >1.55, and dCRP >4 mg/dl (99.3% sensitivity, 100% specificity for all 4 variables); MST >or=10 minutes (100% sensitivity, 99.3% specificity); PMR-AS >or=7 (98.1% sensitivity, 94.3% specificity); VASph >or=2.25 (94.2% sensitivity, 83.6% specificity); and CRP level >or=14.5 mg/liter (66.3% sensitivity, 99.3% specificity).
Conclusion: Despite inter-individual variations in VASph, PMR-AS was a good indicator of disease activity. However, MST, dMST, dVASph, dPMR-AS, and dCRP performed better than PMR-AS. These variables may be useful in tailoring the glucocorticoid dose to the individual needs of each patient.