title: Risk factors associated with reduced work productivity among people with chronic knee pain.
abstract: OBJECTIVE
  To determine the burden and risk factors associated with reduced work productivity among people with chronic knee pain.
  
  
  METHODS
  A longitudinal study, nested within a randomised controlled trial (RCT) evaluating the long-term effects of dietary supplements, was conducted among people with chronic knee pain in paid employment (n = 360). Participants recorded days off work (absenteeism) and reduced productivity while at work (presenteeism) for seven days every two months over a 12-month period in a study specific diary. Examined risk factors included knee pain severity, occupational group, radiographic disease severity, physical activity, body mass index (BMI), health-related quality of life (SF-12) and co-morbidity.
  
  
  RESULTS
  Over the 12-month follow up period, 50 (14%) participants reported one or more days off work due to knee problems, while 283 (79%) reported reduced productivity while at work (presenteeism <100%). In multivariate analysis, the only significant risk factor for absenteeism was having an SF-12 Mental Component Summary (MCS) score <40 (OR: 2.49 [95% CI: 1.03-5.98]). Significant risk factors for presenteeism included; reporting an; SF-12 Physical Component Summary (PCS) score <50 (OR: 1.99 [95% CI: 1.05-3.76]), semi-manual labour (OR: 2.23 [1.09-4.59]) or manual labour (OR: 6.40 [1.44-28.35]) or a high maximum knee pain (4-6 out of 10) (OR: 2.29 [1.17-4.46]).
  
  
  CONCLUSIONS
  This longitudinal study found that among this cohort of people with chronic knee pain, the burden of reduced work productivity is mainly attributable to presenteeism rather absenteeism. This study demonstrated that effective strategies to increase work productivity should focus on reducing knee pain or physical disability especially among workers in manual or semi-manual labour.
authors: Faculty of Health Sciences, University of Sydney, Australia. maria.agaliotis@sydney.edu.au
authors: M
authors: M
authors: Agaliotis
authors: M
authors: M
authors: Fransen
authors: L
authors: L
authors: Bridgett
authors: L
authors: L
authors: Nairn
authors: M
authors: M
authors: Votrubec
authors: S
authors: S
authors: Jan
authors: R
authors: R
authors: Heard
authors: M
authors: M
authors: Mackey
mesh_terms: D000041:Absenteeism; D000368:Aged; D018771:Arthralgia / Q000188:drug therapy / Q000453:epidemiology*; D059350:Chronic Pain / Q000188:drug therapy / Q000453:epidemiology*; D015897:Comorbidity; D017281:Cost of Illness; D019587:Dietary Supplements; D004526:Efficiency; D004651:Employment / Q000706:statistics & numerical data*; D005260:Female; D006306:Health Surveys; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000188:drug therapy / Q000453:epidemiology*; D012307:Risk Factors; D012720:Severity of Illness Index
keywords: Absenteeism; Employment; Knee osteoarthritis; Longitudinal studies; Work productivity