Background: The importance of patient involvement in healthcare research is increasingly emphasized. Patients participate as research partners in designing studies and development of management recommendations, measurement tools and outcome measures. However, ensuring representation of the general patient population by specific patient groups may be challenging for multisystem diseases with heterogenous phenotype. Objectives: We aimed to evaluate whether patients with Behcet syndrome (BS) participating in a patient convention represent the actual patient population attending the clinic. Methods: A questionnaire was applied to 104 BS patients (Meeting group) attending the patient convention which was held during the Cerrahpasa Behcet Disease Symposium in Istanbul in February 2020. Patients had been invited to the convention through posters, advertisement on our website and social media. The questionnaire was conducted with a keypad given to the patients and it consisted of 21 items including age, gender, education level, working status, disease duration, BS manifestations, and treatment. The same questionnaire was filled by 97 consecutive patients (Clinic group) who attended our rheumatology outpatient clinic for their routine controls. Chi-square test was used to compare the groups. Results: Table 1 shows demographic and disease characteristics of the patient groups. The groups were similar in terms of sex and education level. There were more men in both groups, probably reflecting the more severe disease course among men in BS. There were significantly more patients who were >40 years of age and had a disease duration more than 20 years in the Meeting group. Although there were more patients who had a job in Clinic group, the difference was not significant. Central nervous system involvement, vascular involvement, genital ulcers, erythema nodosum, and arthritis were significantly more common in patients in the Meeting group compared with those in the Clinic group. The frequency of eye involvement, gastrointestinal involvement and papulopustular lesions were similar in the two groups. Cyclophosphamide use was significantly more common in Meeting group compared to the Clinic group. Table 1. Demographics, clinical characteristics, and treatments Meeting Group (n=104) (n/N, %) Clinic Group (n=97) (n, %) P Oral aphthous ulcers 88/97(91) 94(97) 0.13 Genital ulcers 86/104(83) 68(70) 0.045 Erythema nodosum 77/103(75) 47(48) 0.0003 Papulopustular skin lesions 69/103(67) 75(77) 0.09 Arthritis 78/102(77) 46(47) <0.0001 Eye involvement 51/103(50) 53(55) 0.48 Vascular involvement 42/98(43) 25(26) 0.036 CNS involvement 14/103(14) 2(2) 0.016 GI involvement 14/97(14) 6(6) 0.10 Prednisolone - still using 30/104(29) 34(35) 0.37 Prednisolone - ever used 88/104 (85) 72(74) 0.08 Colchicine - still using 43/100 (43) 46(47) 0.57 Colchicine - ever used 86/100(86) 74(76) 0.10 AZA - still using 45/100 (45) 41(42) 0.77 AZA - ever used 81/100 (81) 74(76) 0.49 CYC - still using 1/96(1) 0(0) NS CYC - ever used 16/96(17) 7(7) 0.048 bDMARDs - still using 20/101(20) 26(27) 0.31 bDMARDs - ever used 28/101(28) 32(33) 0.44 * Adjusted P -values by Bonferroni correction were <0.001. BS: Behcet Syndrome, CNS: Central nervous system, GI: Gastrointestinal, AZA: Azathioprine, CYC: Cyclophosphamide; bDMARDs: Biologic disease-modifying anti-rheumatic drugs; NS: non-significant Conclusion: Patients in the Meeting group had more severe disease compared to the Clinic group. Patients with all types of involvement were adequately represented in the Meeting group. Disclosure of Interests: None declared