Prevalence and factors associated with diagnosis of early rheumatoid arthritis in the south of Brazil

Background: Rheumatoid arthritis (RA) is an autoimmune inflammatory disease characterized by peripheral and symmetrical polyarthritis. It can be divided into Very Early Rheumatoid Arthritis (VERA) diagnosed up to 3 months of symptoms and late onset (Late Early Rheumatoid Arthritis - LERA), diagnosed between 3 and 12 months. Currently, it is recommended to evaluate the patient with joint symptoms as early as possible, and the first 12 weeks of manifestations represent the ideal phase for the diagnosis, favoring a better evolution of the treatment. The present study aimed to determine the prevalence of early diagnosis of rheumatoid arthritis, mean time of diagnosis and to determine possible associated factors in the municipality of Blumenau, Santa Catarina, Brazil. Methods: A cross-sectional study using the 1987 American College of Rheumatology diagnostic criteria to select patients attended at primary or secondary health care units in Blumenau, Santa Catarina, southern Brazil, in 2014. Diagnostic time was verified by self-report of the time elapsed between the onset of symptoms and the diagnosis made by a rheumatologist. To test the associations, the chi-square test, the Wald linear trend test and the Poisson regression analysis were used. Results: The mean time of diagnosis was 28 months. The prevalence of diagnosis up to 3 and 12 months was 27. 7% and 64.8%, respectively. Obesity was associated with time diagnosis in both periods. The 0-4 years category of the variable education was associated only with the period up to 12 months. Conclusion: The mean time of diagnosis was similar to the national context. Among socioeconomic factors, lower education was associated with the diagnosis of late onset RA. The anthropometric variable presented a progressive increase in the prevalence due to the longer time to diagnosis.