Abnormalities at three musculoskeletal sites on whole-body positron emission tomography/computed tomography can diagnose polymyalgia rheumatica with high sensitivity and specificity.

PURPOSE: To evaluate the sensitivity and specificity of PET/CT findings in PMR and generate a diagnostic algorithm utilizing a minimum number of musculoskeletal sites. METHODS: Steroid-naïve patients with newly diagnosed PMR (2012 EULAR/ACR classification criteria) were prospectively recruited to undergo whole-body 18F-FDG PET/CT. Each PMR case was age- and sex-matched to four PET/CT controls. Control scan indication, diagnosis and medical history were extracted from the clinical record. Qualitative and semi-quantitative scoring (maximum standardized uptake value [SUVmax]) of abnormal 18F-FDG uptake at 21 musculoskeletal sites was undertaken for cases and controls. Results informed the development of a novel PET/CT diagnostic algorithm using a classification and regression trees (CART) method. RESULTS: Thirty-three cases met the inclusion criteria and were matched to 132 controls. Mean age was 68.6 ± 7.4 years for cases compared with 68.2 ± 7.3 for controls, and 54.5% were male. Median CRP was 49 mg/L (32-65) and ESR 41.5 mm/h (24.6-64.4) in the PMR group. The predominant control indication for PET/CT was malignancy (63.6%). Individual musculoskeletal sites proved insufficient for diagnostic purposes. A novel algorithm comprising 18F-FDG uptake ≥ 2 adjacent to the ischial tuberosities in combination with either abnormalities at the peri-articular shoulder or interspinous bursa achieved a sensitivity of 90.9% and specificity of 92.4% for diagnosing PMR. CONCLUSIONS: The presence of abnormal 18F-FDG uptake adjacent to the ischial tuberosities together with findings at the peri-articular shoulder or interspinous bursa on whole-body PET/CT is highly sensitive and specific for a diagnosis of PMR. TRIAL REGISTRATION: Clinical Trial Registration: Australian New Zealand Clinical Trials Registry, http://www.anzctr.org.au , ACTRN1261400696695.

Characterising polymyalgia rheumatica on whole-body 18F-FDG PET/CT: an atlas.

The impact of modern imaging in uncovering the underlying pathology of PMR cannot be understated. Long dismissed as an inflammatory syndrome with links to the large vessel vasculitis giant cell arteritis (GCA), a pathognomonic pattern of musculotendinous inflammation is now attributed to PMR and may be used to confirm its diagnosis. Among the available modalities, 18F-fluorodeoxyglucose (18F-FDG) PET/CT is increasingly recognized for its high sensitivity and specificity, as well as added ability to detect concomitant large vessel GCA and exclude other relevant differentials like infection and malignancy. This atlas provides a contemporary depiction of PMR's pathology and outlines how this knowledge translates into a pattern of findings on whole body 18F-FDG PET/CT that can reliably confirm its diagnosis.

Exploring the patient experience in polymyalgia rheumatica.

Despite being the most common inflammatory rheumatic disease in the elderly (Partington et al., Ann Rheum Dis 77(12):1750-175, 2018), few studies to date have examined the patient experience of polymyalgia rheumatica (PMR). Our study explored patient perspectives in PMR by means of a survey and semi-structured group interviews. The results from this study highlight key aspects of the patient experience in PMR, including delays to diagnosis, complex attitudes toward glucocorticoid therapy, and a desire for alternate treatment strategies. Future trials should look to include physical function as a measured outcome. Finally, our results call attention to the chronicity of PMR symptoms, challenging the paradigm of PMR as a self-limiting condition.

Test-retest reliability of pain VAS/NRS, stiffness VAS/NRS, HAQ-DI and mHAQ in polymyalgia rheumatica: An OMERACT study.

OBJECTIVE: To examine the test-retest reliability of four measurement instruments in polymyalgia rheumatica (PMR): pain severity visual analogue scale (VAS) / numerical rating score (NRS), stiffness severity VAS/NRS, the Health Assessment Questionnaire-Disability Index (HAQ-DI) and the modified Health Assessment Questionnaire (mHAQ). METHOD: Two prospectively collected datasets were used. All participants had a diagnosis of PMR and only those with stable disease were included in analyses. Measurement instruments were administered twice, with a testing interval of two to six weeks. The intra-class correlation coefficient (ICC) was calculated using a two-way mixed effects model looking for absolute agreement. ICC values of 0.8-0.9 were deemed representative of good test-retest reliability, whilst values >0.9 were representative of excellent test-retest reliability. RESULTS: From the first dataset, 38 participants were analysed. The ICC between baseline and 2 weeks for pain VAS, stiffness VAS, HAQ-DI and mHAQ were 0.84, 0.82, 0.92 and 0.92 respectively. From the second dataset, 58 participants were included in the analysis for pain NRS, 59 for stiffness NRS and 78 for mHAQ. The ICC between baseline and follow-up for pain NRS, stiffness NRS and mHAQ were 0.80, 0.83 and 0.87 respectively. CONCLUSION: Pain severity VAS/NRS, stiffness severity VAS/NRS, HAQ-DI and mHAQ all demonstrate good to excellent test-retest reliability in a PMR patient population.

Neutrophil to lymphocyte ratio predicts glucocorticoid resistance in polymyalgia rheumatica.

AIM: Neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) correlate with disease activity in several rheumatic diseases; however, their utility in polymyalgia rheumatica (PMR) remains unclear. This study evaluated their relationship with disease activity and glucocorticoid resistance in PMR. METHOD: Data for disease activity (PMR-AS) and full blood examination was obtained from a prospective observational cohort comprising newly diagnosed, steroid-naïve PMR patients treated with low-dose glucocorticoid therapy. Glucocorticoid resistance was defined as non-response to prednisolone 15 mg/d or initial response followed by flare (PMR-AS ≥ 9.35 or ∆ ≥6.6) upon weaning to 5 mg/d. Univariable Bayesian linear regression analysis of the relationship between PMR-AS (baseline and mean) and NLR and PLR was performed. Predictors of glucocorticoid resistance were identified using a multivariable outcome model, with variables derived from Bayesian model selection. RESULTS: Of the 32 included patients, 16 (50%) fulfilled the primary outcome measure of glucocorticoid resistance. These participants were older, typically female, and had higher baseline C-reactive protein than their glucocorticoid-responsive counterparts. A statistically significant relationship was identified between PMR-AS and both NLR (odds ratio [OR] 28.1; 95% CI 1.6-54.7) and PLR (OR 40.6; 95% CI 10.1-71.4) at baseline, with PLR also found to correlate with disease activity during follow-up (OR 15.6; 95% CI 2.7-28.2). Baseline NLR proved a statistically significant predictor of glucocorticoid-resistant PMR (OR 14.01; 95% CI 1.49-278.06). CONCLUSION: Baseline NLR can predict glucocorticoid resistance in newly diagnosed PMR patients. Both NLR and PLR may be reliable biomarkers of disease activity in PMR.

Association of good oncological response to therapy with the development of rheumatic immune-related adverse events following PD-1 inhibitor therapy.

AIM: To investigate whether any patient or treatment characteristics are associated with the development of rheumatic immune-related adverse events (irAEs) following programmed cell death protein 1 (PD-1) inhibitor therapy for cancer. METHOD: This was a retrospective chart review of all patients who were dispensed nivolumab or pembrolizumab at a single center before 1 January, 2017, with follow-up until 1 July, 2017. Patients with any diagnosis of a non-cutaneous irAE were identified, regardless of severity, and rheumatic irAEs were characterized. RESULTS: Of 244 episodes of therapy, a non-cutaneous irAE occurred in 72 (29.5%). Rheumatic irAEs were diagnosed in 19 episodes of therapy (7.8%), with 12 de novo diagnoses (5.1% of episodes without a pre-existing autoimmune rheumatic disease) and 7 exacerbations of existing disease. Review by a rheumatologist occurred in only 11 of these. Rheumatic irAEs were more common in patients with a good oncological response to therapy (relative risk [RR] 11.16), those being treated for melanoma (RR 2.94) and those who developed another non-cutaneous irAE (RR 2.64). CONCLUSION: Rheumatic irAEs are relatively common with PD-1 inhibitor therapy, and appear to be associated with a good oncological response to therapy. Many rheumatic irAEs were not referred to rheumatological services. Prospective systematic investigation would be of benefit to explore these characteristics.