M. Agaliotis

Glucosamine and chondroitin for knee osteoarthritis: a double-blind randomised placebo-controlled clinical trial evaluating single and combination regimens

Objective To determine if the dietary supplements, glucosamine and/or chondroitin, result in reduced joint space narrowing (JSN) and pain among people with symptomatic knee osteoarthritis. Methods A double-blind randomised placebo-controlled clinical trial with 2-year follow-up. 605 participants, aged 45–75 years, reporting chronic knee pain and with evidence of medial tibio-femoral compartment narrowing (but retaining >2 mm medial joint space width) were randomised to once daily: glucosamine sulfate 1500 mg (n=152), chondroitin sulfate 800 mg (n=151), both dietary supplements (n=151) or matching placebo capsules (n=151). JSN (mm) over 2 years was measured from digitised knee radiographs. Maximum knee pain (0–10) was self-reported in a participant diary for 7 days every 2 months over 1 year. Results After adjusting for factors associated with structural disease progression (gender, body mass index (BMI), baseline structural disease severity and Heberdens nodes), allocation to the dietary supplement combination (glucosamine–chondroitin) resulted in a statistically significant (p=0.046) reduction of 2-year JSN compared to placebo: mean difference 0.10 mm (95% CI 0.002 mm to 0.20 mm); no significant structural effect for the single treatment allocations was detected. All four allocation groups demonstrated reduced knee pain over the first year, but no significant between-group differences (p=0.93) were detected. 34 (6%) participants reported possibly-related adverse medical events over the 2-year follow-up period. Conclusions Allocation to the glucosamine–chondroitin combination resulted in a statistically significant reduction in JSN at 2 years. While all allocation groups demonstrated reduced knee pain over the study period, none of the treatment allocation groups demonstrated significant symptomatic benefit above placebo. Trial Registration ClinicalTrials.gov identifier: NCT00513422; http://www.clinicaltrials.gov

Hip and knee pain: Role of occupational factors

Many people rely economically on occupations involving high loading of the hip or knee joints for lengthy periods, possibly placing them at increased risk of developing chronic pain in these joints. There is a growing body of evidence from large longitudinal cohort studies, case-control studies and population-based surveys that certain occupations, or having work involving considerable heavy lifting, kneeling or squatting, may be associated with increased risk of symptomatic hip or knee osteoarthritis and joint replacement surgery. Only a few studies have evaluated the effectiveness of specific workplace strategies to reduce this risk. Identifying modifiable workplace risk factors and implementing feasible and accessible preventative strategies will be of great public health significance in the next decade.

AB1255-HPR Personal and Workplace Environmental Factors Associated with Reduced Worker Productivity Among People with Chronic Knee Pain

Background Globally, with an ageing population, an increase in obesity and a tendency to delay retirement, the absolute numbers and prevalence of people affected by chronic knee pain in the workforce will increase1. A more recent review found strong evidence to indicate a positive association between knee pain or knee osteoarthritis and absenteeism from work. However, data were lacking to demonstrate a clear association with presenteeism2. Also few studies have examined, the influence of the physical or psychological workplace environment or individual or personal factors that may significant influences worker productivity or the decision making process of whether to go to or forgo work among people with knee pain3. Objectives The aims of this study were to evaluate the burden of absenteeism, presenteeism and work transitions and explore the personal and workplace environmental risk factors associated with reduced worker productivity among people with chronic knee pain. Methods A survey containing several validated measures of absenteeism, presenteeism and work transitions as well as individual, disease and work-related demographics was mailed to 496 people who had completed participation in the Long-term Evaluation of Glucosamine Sulfate (LEGS) study. Results A total of 296 (60%) people provided a completed survey with 129 currently in paid employment. Only six (5%) reported absenteeism in the past two months, however 63 (49%) reported presenteeism over a seven day period and 31 (24%) reported making one or more work transitions in the last six months due to knee problems. In multivariate analysis, presenteeism was associated with moderate to severe knee pain (≥3/10) (odds ratio (OR) 2.77, 95% CI 1.30 – 5.8) and reporting problems with other joints (OR 2.32, 95% CI 1.04 – 5.17) while job instability reduced the likelihood (OR 0.40, 95% CI 0.19 – 0.86). Reporting one or more work transitions was associated with moderate to severe knee pain (OR 4.09, 95% CI 1.53 – 10.95), a high co-morbidity score (OR 4.44, 95% CI: 1.02 – 19.32) and low co-worker support (OR 2.79, 95% CI 1.04 – 7.46) while having an occupation involving sitting >30% of the working day reduced the likelihood (OR 0.35, 95% CI 0.12 – 0.97). Conclusions This survey demonstrates the high prevalence of reduced worker productivity among people with chronic knee pain. Allowing access to sitting and promoting positive affiliations between co-workers are likely to provide an enabling workplace environment for these workers. References Woolf AD, Pfleger B. Burden of major musculoskeletal conditions. Bull World Health Organ 2003;81(9):646-56. Agaliotis M, Mackey MG, Jan S, et al. Burden of reduced work productivity among people with chronic knee pain: a systematic review. Occupational and Environmental Medicine 2014. Tang K, Escorpizo R, Beaton DE, et al. Measuring the impact of arthritis on worker productivity: perspectives, methodologic issues, and contextual factors. J Rheumatol 2011;38(8):1776-90. Acknowledgements We thank the LEGS participants for their contributions to our research. This work was supported by Arthritis Australia (The Kevin R James Grant) awarded to Ms Maria Agaliotis. Disclosure of Interest None declared

352 WORK DISABILITY AMONG PEOPLE WITH MILD TO MODERATE KNEE OSTEOARTHRITIS

open-ended free text question, which were coded into thematic groups. Ordered logistic regression modelling was used to look at the association between patients pre-operative expectations and baseline characteristics (age, sex, education, ASA status, K&L grade, obesity, medication use, WOMAC score, EQ5D score). The OMERACT-OARSI responder criteria were used to classify patients as improved/not improved 12-months after THR. Logistic regression modelling was used to explore whether pre-operative expectations predict response to THR, adjusting for baseline characteristics. Results: A greater number of recorded pre-operative expectations were associated with younger age, women, more education, lower ASA grade, obesity, greater medication use, and worse pre-operative pain and function (WOMAC score). Analyses identifying predictors of outcome, suggested that the more pre-operative expectations a patient had, the more likely they were to improve after surgery. Each individual expectation a patient had, was associated with a 26% increase in the probability of improvement (95%CI 1%-56%). Sensitivity analyses, using different methods to classify patients as responders to surgery, support this finding. Analyses within WOMAC subgroups suggest the association is strongest for stiffness and function. Other predictor variables were associated with improved patient outcomes. Educated people had greater improvement following surgery, as were those with worse baseline pain and function. Patients with less severe radiographic change had a better outcome. Patients with higher ASA grades were less likely to respond, as were obese patients. Age, sex and pre-operative medication use were not associated with outcome. Conclusions: This study demonstrates variability in patients’ pre-operative expectations of THR surgery. Patients with a larger number of pre-operative expectations are more likely to have a good clinically important outcome 12-months post-THR. This appears to be driven more by stiffness and function, rather than pain. The majority of patients described expectations regarding function which is likely an artefact of how the expectation question was worded, asking patients what they would be “able to do”. These findings have implications for informed patient-clinician decision-making. As unfulfilled expectations are related to patients reporting poor outcomes of surgery and lower levels of satisfaction, some have suggested surgeons should attempt to moderate patients hopes of surgery when discussing the likely outcomes of surgery given their individual characteristics. An alternative point of view is that the patients greater expectations contributed to outcome by acting as a psychological contextual factor, which ultimately influences pain and function post-op (unconditioned “placebo”). Further research should address these two different causes of action.

338 SCREENING, RECRUITMENT AND BASELINE CHARACTERISTICS OF THE LONG-TERM EVALUATION OF GLUCOSAMINE SULPHATE (LEGS) STUDY PARTICIPANTS

Clinical trials evaluating potential ’disease-modifying’ agents for osteoarthritis are required to demonstrate both symptomatic and structural benefit. Ideally, to reduce ceiling or floor effects, study participants are required to have at least moderate pain, yet retain sufficient tibiofemoral joint space to allow the measurement of narrowing over time. To describe study recruitment procedures and baseline demographics of people with symptomatic knee osteoarthritis participating in the Long-term Evaluation of Glucosamine Sulphate (LEGS) study (NCT00513422).