A new diagnostic sign for rheumatoid arthritis: Avicenna sign

Abstract

Aim: The status of a new sign for diagnosing rheumatoid arthritis is discussed for the first time in this study. It is defined as marked tenderness on the anterior surface of leg (shin) on pressure of about 4 kg by thumb. The sign has been denoted as 'Avicenna sign'. Methods: All cases were selected by convenient sampling from patients who were referred to two rheumatology clinics in Tabriz, Iran. Sample size was calculated as 618 using Cochran's sampling equation. Diagnosis of rheumatoid arthritis was made according to American Rheumatism Association criteria. Two physicians were asked to examine the sign on all of the selected patients separately. One of them (a general physician) was not informed about methodology and objectives of the study whereas a rheumatologist was well informed and he collected data using a written questionnaire. Test-retest method and discriminant analysis were used to test reliability and validity of the sign for diagnosing rheumatoid arthritis. The effects of intervening variables including osteoporosis and consumption of some medications were controlled employing Chi-square test. Results: When the general physician examined patients with Avicenna sign to diagnose rheumatoid arthritis, sensitivity and specificity of the sign were reported as 77.1% and 98.4%, respectively. The corresponding values were 81.3% and 98.4%, respectively, when the rheumatologist examined the patients. Conclusions: This study suggested considerable diagnostic value of the sign for rheumatoid arthritis. Consumption of acetaminophen or NSAIDs had no effect on the status of Avicenna sign while taking gluccocorticoids made it unreliable for diagnostic purposes. é Asia Pacific League of Associations for Rheumatology.