title: Exercise in knee osteoarthritis--preliminary findings: Exercise-induced pain and health status differs between drop-outs and retainers.
abstract: BACKGROUND
  Exercise effectiveness is related to adherence, compliance and drop-out. The aim of this study is to investigate if exercise-induced pain and health status are related to these outcomes during two exercise programs in knee osteoarthritis patients.
  
  
  METHODS
  Symptomatic knee osteoarthritis patients were randomly allocated to a walking or strengthening program (N=19/group). At baseline, patients were categorized according to their health status. Exercise adherence and compliance were calculated and drop-out rate was registered. For exercise-induced pain, patients rated their pain on an 11-point numeric rating scale (NRS) before and after each training session. Before each session the maximal perceived pain of the last 24h (NRSmax24) was assessed. Patients rated their global self-perceived effect (GPE) on a 7-point ordinal scale after the intervention period.
  
  
  RESULTS
  53% of the participants felt they improved after the program, 6 patients dropped out. The mean adherence and compliance rates were higher than .83 in both groups. Worse health and higher exercise-induced pain were seen in drop-outs. NRSmax24 during the first 3 weeks did not significantly increase compared to baseline, but correlated negatively with adherence during the home sessions (-.56, p<.05). Lower adherence during supervised sessions was significantly related with higher pre-exercise pain scores (ρ=-.35, p<.05).
  
  
  CONCLUSIONS
  Patients who drop-out show a worse health condition and higher exercise-induced pain levels compared to patients that retained the program.
authors.affiliation: Frailty in Ageing Research Department, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium; Frailty in Ageing Research Department, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium. Electronic address: david.beckwee@vub.ac.be.
authors.forename: David
authors.initials: D
authors.lastname: Beckwée
authors.affiliation: Frailty in Ageing Research Department, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
authors.forename: Ivan
authors.initials: I
authors.lastname: Bautmans
authors.affiliation: Department of Orthopaedic Surgery & Traumatology, UZ Brussel, Laarbeeklaan 101, B-1090 Brussels, Belgium.
authors.forename: Thierry
authors.initials: T
authors.lastname: Scheerlinck
authors.affiliation: Rehabilitation Sciences Research Department, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Vaes
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000534:rehabilitation*; D010146:Pain / Q000534:rehabilitation*; D010147:Pain Measurement; D010349:Patient Compliance; D010352:Patient Dropouts / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D016138:Walking
keywords: Aging; Drop-out; Exercise; Knee; Osteoarthritis