Avaliação longitudinal de pacientes com espondiloartrite indiferenciada: oito anos de seguimento

Abstract

Introduction: Undifferentiated spondyloarthritis (USpA) is used to describe patients with symptoms suggestive of a spondyloarthritis (SpA), but who do not fulfill the classification criteria for the currently established diseases of the group, e.g., ankylosing spondylitis (AS), psoriatic arthritis (PsA), reactive arthritis and arthritis of the inflammatory bowel diseases. It is known that the incidence and clinical spectrum of SpA show different patterns around world, which are related to the affected ethnic group. Brazilian studies including patients with USpA were performed at only one medical center. In a continental country like Brazil, considering the intense miscegenation, it is important to describe USpA features and outcomes in different regions, with distinct subgroups of patients. Objectives: The aim of the present study was to describe the manifestations and outcomes of Brazilian patients with USpA during an eight-year follow-up period. Methods: Patients fulfilling the European Study Group Classification Criteria for SpA, but who did not fulfill the criteria for any established diseases of the group were enrolled. Clinical, laboratorial e radiological data were collected using a standard protocol at the baseline, after 2.5 years and after 7.7 years of follow-up. Sacroiliac joints radiographies were taken at each time of evaluation. Results: Forty patients were seen at baseline, and 36 participated in the follow-up study. Twenty-three (58%) were female, there were 16 (40%) whites and 24 (60%) African Brazilians enrolled. HLA-B27 was positive in 18 (45%) patients. At disease onset, the predominant symptom was peripheral arthritis (20/55.6%), which was followed by heel pain (13/36.1%). Inflammatory low back pain (ILBP) was the onset symptom in 8 (22.2%) patients, and buttock pain was the onset symptom in 3 (8.3%) patients. After the study period, heel pain occurred in 34 (94.5%) patients, peripheral arthritis occurred in 24 (66.7%) patients, ILBP occurred in 26 (72.2%) patients and buttock pain occurred in 14 (39%) patients. The Assessment of SpA international Society (ASAS) classification criteria for axial SpA were fulfilled by 77% of patients and the ASAS criteria for peripheral SpA were fulfilled by 59% of patients. After 2.5 years, 6 (16.7%) of the 36 patients fulfilled the modified New York Criteria for AS, and 1 (2.7%) patient fulfilled the criteria for PsA. Twenty-six patients were followed over 7.7 years, and 3 new cases of AS were classified. A total of 10 (27.8%) patients progressed to definite SpA over the study period. Six (16.7%) patients entered disease remission. Buttock pain (p = 0.006, OR = 10.55; 95% CI: 2.00 65.90) and low-grade radiographic sacroiliitis (p = 0.025, OR = 11.50; 95% CI: 1.33 83.39) at baseline were associated with definite SpA. Conclusion: Thus, in this Brazilian cohort, which had a predominance of female African Brazilian patients, prevalent peripheral onset symptoms were followed by a high frequency of axial manifestations during the follow-up period. Evidence of clinical or radiological sacroiliitis, at baseline, was associated with progression to definite SpA.