Undifferentiated spondyloarthropathies: A 2-year follow-up study

The aim of the study was to analyse the 2-year follow-up of a series of pat ients with the diagnosis of undifferentiated spondyloarthropathy (uSpA). A prospective study was carried out analysing 68 patients with symptomatic uS pA who fulfilled the European Spondylarthropathy Study Group (ESSG) criteri a for seronegative spondyloarthropathies (SpA) and were aged between 18 and 50 years. Inclusion criteria included inflammatory low back pain (ILBP) (w ithout radiographic sacroiliitis), asymmetric oligoarthritis (predominantly affecting large joints in the lower limbs) and heel enthesopathies (Achill es tendinitis and/or plantar fasciitis). Imaging methods included pelvic ra diography (at study entry and after 2 years) and calcaneal radiography (at study entry). There was a predominance of male gender (78%), caucasoid race (72%) and positive HLA-B27 (54%), with a mean age of 31 years and mean dis ease duration of 5 years. The first disease manifestations were ILBP (49%), asymmetric oligoarthritis (35%) and heel enthesopathies (16%), A positive family history of a definite SpA was mentioned by 9% of the patients. Seven teen patients (25%) scored 5 points in the Amor set of SpA criteria; logist ic regression analysis showed that HLA-B27, heel enthesopathy and asymmetri c oligoarthritis were significantly associated with Amor criteria greater t han or equal to6, whereas ILBP was associated with Amor criteria <6. Male s ex was associated with heel enthesopathies (p = 0.041) and ankle involvemen t (p = 0.015). Caucasoid race was associated with ILBP (p = 0.015) and butt ock pain (p = 0.047). Positive HLA-B27 was associated with wrist involvemen t (p = 0.019) and Amor criteria greater than or equal to6 (p = 0.001). Afte r a 2-year follow-up the following outcomes were observed: uSpA 75%; diseas e remission 13%; ankylosing spondylitis 10%; psoriatic arthritis 2%. Logist ic regression analysis showed that buttock pain and positive HLA-B27 (trend ) were statistically associated with progression to a definite SpA. In conc lusion, uSpA can represent a provisional diagnosis in the group of SpA and a systematic follow-up is necessary in order to better establish the differ ent patterns of the disease.