title: Can we use enthesis ultrasound as an outcome measure of disease activity in spondyloarthritis? A study at the Achilles level.
abstract: OBJECTIVE
  The aim of this study was to evaluate the construct validity of enthesis US in the assessment of disease activity in SpA.
  
  
  METHODS
  A longitudinal Achilles enthesis US study in patients with early SpA was undertaken. Achilles US examinations were performed at baseline, 6 and 12 months and compared with clinical outcome measures collected at the baseline visit.
  
  
  RESULTS
  Bilateral Achilles enthesis of 146 early SpA patients (68 women) were analysed. Basal mean BASFI, BASRI-spine, BASDAI and Ankylosing Spondylitis Disease Activity Score (ASDAS) were 2.44 (s.d. 2.05, range 0-8), 0.67 (s.d. 0.74, range 0-3), 4.60 (s.d. 2.07, range 0-9.5) and 2.51 (s.d. 1.16, range 0-5), respectively. The mean ESR was 15.0 mm/h (s.d. 16.99, range 0-109) and the mean CRP was 8.67 mg/l (s.d. 16.98, range 1-90). At baseline, the Achilles Doppler signal and US structure alteration were significantly associated with higher CRP and ESR levels. Patients who had very high disease activity at baseline, as assessed by the ASDAS (>3.5), had a significantly higher Achilles total US score at baseline (P = 0.04), and ASDAS <1.3 predicted no Doppler signal at 6 and 12 months. Overall, the Achilles total US score was significantly higher in patients with higher levels of CRP (baseline P = 0.04, 6 months P = 0.006, 12 months P = 0.03) and ESR (baseline P = 0.02, 6 months P = 0.04, 12 months P = 0.005) at baseline. The Doppler signal at the baseline visit predicted a higher total US score at 6 and 12 months.
  
  
  CONCLUSIONS
  Doppler US has significant associations with other commonly accepted disease activity measures, such as ESR, CRP and ASDAS, and seems to be an objective outcome measure for enthesitis.
authors.affiliation: Rheumatology Department, CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal and sfalcao76@gmail.com.
authors.forename: Sandra
authors.initials: S
authors.lastname: Falcao
authors.affiliation: Rheumatology Department, La Paz University Hospital, Madrid, Spain.
authors.forename: Concepción
authors.initials: C
authors.lastname: Castillo-Gallego
authors.affiliation: Rheumatology Department, La Paz University Hospital, Madrid, Spain.
authors.forename: Diana
authors.initials: D
authors.lastname: Peiteado
authors.affiliation: Rheumatology Department, CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal and.
authors.forename: Jaime
authors.initials: J
authors.lastname: Branco
authors.affiliation: Rheumatology Department, La Paz University Hospital, Madrid, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Martín Mola
authors.affiliation: Rheumatology Department, La Paz University Hospital, Madrid, Spain.
authors.forename: Eugenio
authors.initials: E
authors.lastname: de Miguel
mesh_terms: D000125:Achilles Tendon / Q000000981:diagnostic imaging*; D000293:Adolescent; D000328:Adult; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000378:metabolism; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D025241:Spondylarthritis / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D018608:Ultrasonography, Doppler / Q000379:methods*; D055815:Young Adult
chemical_list: D002097:C-Reactive Protein
keywords: disease activity; spondyloarthritis; ultrasonography