Background:Inflammatory back pain (IBP) is an important entry criterion for identifying patients with axial spondyloarthritis. Due to the very frequent prevalence of chronic non-inflammatory back pain (CBP), IBP is difficult to differentiate and recognize in many clinical practices. CBP is a frequent diagnosis in populations with low socioeconomic status.Objectives:To investigate whether IBP ASAS definition help discriminate from CBP in a low-income population.Methods:A total of 202 consecutive individuals were directly interviewed in Fortaleza/Brazil, for the prevalence of IBP (ASAS definition), monthly family income (US$), school education [>/≤ 8 school-years(SY)], and smoking habit (present/absent). People from all social levels were included.Results:Mean age was 38.9±12.9 years, 100 (49.5%) were male and 36 (17.8%) were smokers; 135 (66.8%) declared less than 730US$ family earnings per month and 71 (35.1%) had less than 8 SY. Although 122 (60.3%) declared lumbar pain, in comparison, 29 (14.3%), 22 (10.9%) and 59 (29.2%) fulfilled ASAS, Berlin, and Calin’s IBP criteria, respectively. There were 39 (58.02%) vs. 83 (61.5%) with vs. without CBP and 9 (13.4%) vs. 20 (14.8%) fulfilling vs. not fulfilling the ASAS IBP definition among those with more or less than 730US$ earnings (P>0.05), respectively.Conclusion:This is the first report on the prevalence of IBP in a very low-income population. Over one-third had less than 8SY, revealing very low literacy. Smoking prevalence was also low if compared to 28% smoking prevalence WHO estimates across Europe*. These IBP prevalence data are similar to those reported in wealthier populations, living in higher latitude. Data suggest that ASAS IBP definition may be used to discriminate patients with IBP from those with CBP, regardless of income and literacy.References:This is the first report on the prevalence of IBP in a very low-income population. Over one-third had less than 8SY, revealing very low literacy. Smoking prevalence (17.8%) was also low if compared to 28% smoking prevalence WHO estimates across Europe*. These IBP prevalence data are similar to those reported in wealthier populations, living in higher latitude. Data suggest that ASAS IBP definition may be used to discriminate patients with IBP from those with CBP, regardless of income and literacy.Disclosure of Interests:Jobson Oliveira: None declared, Rodolfo Nunes: None declared, Guilherme da Silva: None declared, Igor Nogueira: None declared, Artur Azevedo: None declared, Xenofon Baraliakos Grant/research support from: Grant/research support from: AbbVie, BMS, Celgene, Chugai, Merck, Novartis, Pfizer, UCB and Werfen, Consultant of: AbbVie, BMS, Celgene, Chugai, Merck, Novartis, Pfizer, UCB and Werfen, Speakers bureau: AbbVie, BMS, Celgene, Chugai, Merck, Novartis, Pfizer, UCB and Werfen, Airton Rocha Speakers bureau: Not related to the present work