title: Systemic and local factors are involved in the evolution of erosions in hand osteoarthritis.
abstract: OBJECTIVE
  In order to gain insight in the pathogenesis of erosive hand osteoarthritis (OA), the evolution of erosions in hand OA and risk factors involved were investigated.
  
  
  METHODS
  The 6-year evolution in radiographic Verbruggen-Veys anatomical phase was assessed in interphalangeal joints of 236 patients with hand OA (mean age 59 years, 83% women) from the GARP (for 'Genetics ARthrosis and Progression') sibling pair study. Erosive evolution comprised phase transitions from non-erosive to erosive phases and from active erosions to remodelling. Clustering of erosive evolution within patients was assessed using the χ² test. Familial aggregation was evaluated in sibling pairs by estimating ORs for siblings and probands sharing erosive evolution. Local baseline determinants and the effect of high sensitivity C reactive protein were assessed using generalised estimating equations.
  
  
  RESULTS
  Erosive evolution took place in 181 of 4120 interphalangeal joints at risk (4.4%), corresponding to 60 patients (25.4% of study sample). Erosive evolution was found more often in multiple interphalangeal joints in one patient than would be expected by chance (χ² 373.0, p < 0.001). The adjusted OR (95% CI) for a sibling having erosive evolution if the proband had erosive evolution was 4.7 (1.4 to 15.8). Systemic inflammation was not associated with erosive activity. Independent local determinants were joint space narrowing (OR (95% CI) 8.9 (4.8 to 16.4)) and self-reported pain (OR (95%CI) 2.3 (1.1 to 4.7)).
  
  
  CONCLUSIONS
  rosive evolution was clustered within patients and families. Local factors were also involved in the evolution. This increase in insight in the pathogenesis of erosive hand OA will contribute to the development of new treatments.
authors.affiliation: Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands. J.Bijsterbosch@lumc.nl
authors.forename: J
authors.initials: J
authors.lastname: Bijsterbosch
authors.forename: J M
authors.initials: JM
authors.lastname: van Bemmel
authors.forename: I
authors.initials: I
authors.lastname: Watt
authors.forename: I
authors.initials: I
authors.lastname: Meulenbelt
authors.forename: F R
authors.initials: FR
authors.lastname: Rosendaal
authors.forename: T W J
authors.initials: TW
authors.lastname: Huizinga
authors.forename: M
authors.initials: M
authors.lastname: Kloppenburg
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D018450:Disease Progression; D004812:Epidemiologic Methods; D005260:Female; D005384:Finger Joint / Q000000981:diagnostic imaging / Q000473:pathology*; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000209:etiology* / Q000235:genetics / Q000473:pathology; D011859:Radiography
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein