Risk factors of developing irreversible cranial ischemic complications in giant cell arteritis. A prospective study of 178 cases

Purpose. - To search for risk factors of developing irreversible cranial is chemic complications (ICIC) in patients with giant cell arteritis (GCA) and to explore whether two subsets of patients (high risk and low risk of deve loping ICIC) can be defined. Methods. - One-hundred seventy-eight consecutive patients with temporal art eritis (149 biopsy-proven) were diagnosed and followed up in a department o f Internal Medicine between 1976 and 1999. The patients were separated into two groups, according to the presence or absence of ICIC, with comparison of 17 clinical and biological parameters prospectively recorded for each pa tient using a pre-established comprehensive questionnaire. Results. - ICIC occurred in 25 patients (14%), with amaurosis in 22 cases. Suggestive symptoms and/or signs of temporal arteritis were present in 92% of the patients, lasting 50 days (median) before the onset of ICIC. Forty-t hree patients (24%) complained of transient visual ischemic symptoms (TVIS) , which preceded acute blindness in 11 cases. A multivariate logistic regre ssion, from which 28 cases with upper limb artery involvement were excluded for technical reasons (no CCII in any case, thus predicting perfectly the lack of ischemic risk, P = 0.02), indicated that the only independent varia bles associated with the ischemic risk were: a history of TVIS (P = 0.05), the lack of signs of polymyalgia rheumatica (PMR; P = 0.02), lower blood le vels of fibrinogen (P = 0.024) and higher mean blood platelets levels (P = 0.006). However, these five variables predicted only 30% of the variability of the model. Sensitivity, specificity, positive and negative predictive v alues of the model reached respectively 36, 96, 64 and 88%. Overall, 86% of the cases were correctly classified with respect to the ischemic risk. Conclusion. - The rate of ICIC should be reduced by an earlier recognition of the usual signs of temporal arteritis. Several independent risk factors of ICIC have been identified. However, the logistic model failed to predict accurately the ischemic risk in 14% of the cases, indicating that as yet u nrecognised factors probably exist that play a role in the occurrence of IC IC. Nevertheless, regarding the strong association between platelet levels and ICIC, patients with thrombocytosis should receive initially both cortic osteroids and antiplatelet agents. (C) 2001 Editions scientifiques et medic ales Elsevier SAS.