Predictors of symptomatic response to glucosamine in knee osteoarthritis: an exploratory study

Alexander N Bennett ^1*, Kay M Crossley ², Peter D Brukner ² and Rana S Hinman ²

¹ Academic Unit of Musculoskeletal Disease, United Kingdom
² University of Melbourne, Australia

^* To whom correspondence should be addressed. E-mail: alexander.n.bennett{at}btinternet.com.

Accepted 6 January 2007

Abstract

Objective: To evaluate whether patient characteristics and/or radiographic disease patterns predict symptomatic response to treatment with glucosamine in knee osteoarthritis.

Design: Exploratory prospective correlational study.

Setting: Institutional

Patients: Thirty-nine participants with chronic knee pain from the local community

Interventions: Glucosamine sulphate (1.5g daily) for 12 weeks.

Main outcome measures: Pain and physical function were assessed with visual analogue scales (VAS) and participant-perceived global change scores (GCS). Regression modelling evaluated the relationship between treatment outcome and age, body mass index (BMI), pain and function self-efficacy and presence/absence of osteophytes in the medial and lateral tibiofemoral joint (TFJ) and patellofemoral joint (PFJ) compartments.

Results: Thirteen (33%) participants were male. The mean (SD) age and BMI were 53.6 (13.1) yrs and 27.9 (4.6) kg/m2 respectively. Thirteen (33%), 19 (49%) and 24 (62%) had medial TFJ, lateral TFJ, and PFJ osteophytes. Glucosamine significantly improved pain (mean change VAS= -1.4, 95% C.I [-0.6, -2.2], p=0.002) and activity restriction (- 1.9, [-1.0, -2.8], p<0.001). At 12 weeks, 30 (77%) and 27 (69%) participants reported improvement in pain and physical function respectively. Regression modelling showed no evaluated variables predicted change in pain on VAS. Decreased function self-efficacy, presence of PFJ osteophytes, and absence of medial TFJ osteophytes predicted functional improvement on VAS. BMI, pain self- efficacy and function self-efficacy predicted pain improvement by GCS.

Conclusions: Although glucosamine significantly improved symptoms, most of the variance in outcome at 12 weeks was unexplained by the predictors evaluated. However glucosamine may be more effective at improving symptoms in knee OA patients with a lower BMI, PFJ ostophytes and lower functional self-efficacy.

Key Words: Correlation, Glucosamine, Knee Pain, Osteoarthitis, Predictors

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