title: Predictors and outcome of pain-related avoidance of activities in persons with early symptomatic knee osteoarthritis: a five-year followup study.
abstract: OBJECTIVE
  It has been hypothesized that pain and low vitality lead to an increase in avoidance of activities in persons with early symptomatic knee osteoarthritis (OA), and that avoidance of activities leads to an increase in activity limitations. The present study aimed to evaluate these hypotheses.
  
  
  METHODS
  Baseline, 2-year, and 5-year followup data of 828 participants from the Cohort Hip and Cohort Knee Study with early symptomatic knee OA were used. Autoregressive generalized estimating equations and linear regression models were used to analyze the longitudinal and cross-sectional associations between self-reported knee pain, vitality, pain-related avoidance of activities, and activity limitations. The models were adjusted for the covariates age, sex, education level, body mass index, comorbidity, radiographic severity, and hip pain.
  
  
  RESULTS
  In longitudinal analyses, knee pain and vitality predicted a subsequent increase in avoidance of activities. Pain-related avoidance of activities predicted a subsequent increase in activity limitations; however, this relationship lost statistical significance (P = 0.089) after adjustment for covariates. Cross-sectional analyses showed strong relationships between knee pain, low vitality, pain-related avoidance of activities, and activity limitations at all time points.
  
  
  CONCLUSIONS
  In persons with early symptomatic knee OA, knee pain and low vitality lead to a subsequent increase in avoidance of activities. Pain-related avoidance of activities is related to activity limitations at inception of symptoms, but also years later. Therefore, it can be recommended to monitor and target avoidance of activities at various stages of the disease.
authors.affiliation: Amsterdam Rehabilitation Research Center/Reade, Amsterdam, The Netherlands.
authors.forename: Jasmijn F M
authors.initials: JF
authors.lastname: Holla
authors.forename: Marike
authors.initials: M
authors.lastname: van der Leeden
authors.forename: Dirk L
authors.initials: DL
authors.lastname: Knol
authors.forename: Leo D
authors.initials: LD
authors.lastname: Roorda
authors.forename: Wim K H A
authors.initials: WK
authors.lastname: Hilberdink
authors.forename: Willem F
authors.initials: WF
authors.lastname: Lems
authors.forename: Martijn P M
authors.initials: MP
authors.lastname: Steultjens
authors.forename: Joost
authors.initials: J
authors.lastname: Dekker
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology*; D001362:Avoidance Learning / Q000502:physiology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D042241:Early Diagnosis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology*; D010147:Pain Measurement / Q000379:methods* / Q000639:trends; D011237:Predictive Value of Tests; D013997:Time Factors; D016896:Treatment Outcome