AB0355 THE VALUE OF PLATELET-TO-LYMPHOCYTE AND NEUTROPHIL-TO-LYMPHOCYTE RATIOS AS INFLAMMATORY MARKERS IN BIOPSY-PROVEN GIANT CELL ARTERITIS

Abstract

Background:Platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) have been shown to correlate with disease activity in various rheumatic diseases. High PLR and elevated platelet count are potentially useful in diagnosing some systemic vasculitides, eg. giant cell arteritis (GCA)1 and has been suggested predictive for diagnosing GCA, even in the absence of characteristic temporal artery involvement2.Objectives:To evaluate the role of PLR and NLR as inflammatory markers in the diagnosis of GCA in patients referred to temporal artery biopsy (TAB).Methods:During 10 months, all patients referred to TAB at the Department of Ophthalmology (Rigshospitalet, Copenhagen, Denmark) in suspected GCA were included. Immediately prior to TAB, ultrasound of bilateral temporal arteries was performed at the Center for Rheumatology and Spine Disease (Rigshospitalet, Copenhagen, Denmark) by rheumatologists experienced in vascular ultrasound. Ultrasound signs of GCA were a positive Halo sign or compression sign. Patients had C-reactive protein (CRP), erythrocyte sedimentation ratio (ESR), platelets, white blood cells with differential counts, hemoglobin and platelets measured. Final clinical diagnosis, based on rheumatological expert opinion, and fulfilment of ACR1990 classification criteria for temporal arteritis at six months was noted, with clinical diagnosis being the reference standard.Results:106 patients were included and had a TAB evaluated. Forty-five (42%) had a clinical diagnosis of GCA at 6 months of which 28 (62%) also were TAB positive. US was performed in 74 (70%), of these 20 (67%) of the GCA patients had a positive ultrasound for GCA (termed US GCA patients). There was no significant difference in mean age or gender distribution between GCA and non-GCA patients. ESR, CRP and platelets were significantly higher in GCA than non-GCA patients (p<0.001). PLR was significantly higher in GCA than non-GCA patients (p<0.007), while NLR was not (p=0.076). For US GCA patients vs. US non-GCA patients, platelets were significantly higher in the US GCA group (p=0.025). Both PLR and NLR were significantly higher in the US GCA group compared to the US non-GCA group (p= 0.003 and p=0.007, respectively).Conclusion:In this cohort of patients, suspected of GCA and referred to TAB, PLR but not NLR was significantly higher in GCA patients than in non-GCA patients. In patients with US findings of GCA, both PLR and NLR were significantly higher in GCA compared to non-GCA. An elevated PLR could be considered an additional feature in diagnosing GCA.