de Zwart AH1, van der Leeden M1,2, Roorda LD1, van der Esch M1, Twisk JWR3, Lems WF1,4,5, Dekker J2,6
1Reade, Centre for Rehabilitation and Rheumatology, Amsterdam, Netherlands, 2VU University Medical Center Amsterdam, Rehabilitation Medicine, Amsterdam, Netherlands, 3VU University Medical Center Amsterdam, Epidemiology and Biostatistics, Amsterdam, Netherlands, 4VU University Medical Center Amsterdam, Rheumatology, Amsterdam, Netherlands, 5Jan van Breemen Research Institute, Reade, Amsterdam, Netherlands, 6VU University Medical Center Amsterdam, Psychiatry, Amsterdam, Netherlands
Background: Muscle weakness is common in patients with knee osteoarthritis (OA). Muscle weakness negatively impacts future functional and disease status in patients with knee OA and has been linked to symptomatic and radiographic progression of knee OA. Limited information is available on the course of muscle strength over time in patients with knee OA. Hence, upper leg muscle strength plays a vital role in the prognosis of patients with knee OA. Therefore, it is of major importance to describe the course of muscle strength and identify those knee OA patients at risk for a decline in muscle strength over time.
Purpose: The aim of the present study is
(i) to describe the course and
(ii) to identify baseline predictors for upper leg muscle strength over time in subjects with knee OA.
Methods: Data were obtained from the progression cohort of the Osteoarthritis Initiative (OAI) database. Upper leg muscle strength (in N/kg) was measured at baseline, 24 months and 48 months. The baseline predictors were age, gender, body height, body weight, body mass index (BMI), race, dietary protein intake, dietary energy intake, vitamin D use, glucosamine use, alcohol consumption, smoking, physical activity, KL grade, knee alignment, effusion, pain, pain medication use, comorbidities and depression. Univariate and multivariate mixed model analyses were performed to identify baseline predictors for muscle strength over time.
Results: A total of 1390 subjects with knee osteoarthritis were included. The majority of the subjects were female (57.1%), mean ± SD for age was 61.4 ± 9.1 and mean ± SD for body mass index was 30.2 ± 4.9. All subjects had frequent knee symptoms and radiographic tibiofemoral knee OA (Kellgren en Lawrence score ≥ 2) at baseline. Muscle strength was significant lower at 24 months and 48 months compared to baseline; but not between 24 and 48 months. Older age, being female, higher BMI, being non-Caucasian, lower protein intake (g/kg bodyweight), higher dietary energy intake, alcohol consumption, less physical activity valgus malalignment, higher score on the WOMAC pain subscale and the use of pain medication at baseline were associated with lower muscle strength over time.
Conclusion(s): Muscle strength decreased over time between baseline line and 24 months, but not between 24 and 48 months. In the present study a set of baseline factors, consisting of demographic, biomechanical, metabolic, nutrition, lifestyle and pain related factors, were found to be predictive for muscle strength over time. This set of baseline factors can be used to identify patients with knee OA at risk for decline of muscle strength over time. External validity of our model is needed to confirm our findings.
Implications: This set of baseline factors can be used to identify patients with knee OA at risk for decline of muscle strength over time. External validity of our model is needed to confirm our findings.
Keywords: Osteoarthritis, Knee joint, Muscle strength
Funding acknowledgements: This study was funded by the Dutch Arthritis Association.
Purpose: The aim of the present study is
(i) to describe the course and
(ii) to identify baseline predictors for upper leg muscle strength over time in subjects with knee OA.
Methods: Data were obtained from the progression cohort of the Osteoarthritis Initiative (OAI) database. Upper leg muscle strength (in N/kg) was measured at baseline, 24 months and 48 months. The baseline predictors were age, gender, body height, body weight, body mass index (BMI), race, dietary protein intake, dietary energy intake, vitamin D use, glucosamine use, alcohol consumption, smoking, physical activity, KL grade, knee alignment, effusion, pain, pain medication use, comorbidities and depression. Univariate and multivariate mixed model analyses were performed to identify baseline predictors for muscle strength over time.
Results: A total of 1390 subjects with knee osteoarthritis were included. The majority of the subjects were female (57.1%), mean ± SD for age was 61.4 ± 9.1 and mean ± SD for body mass index was 30.2 ± 4.9. All subjects had frequent knee symptoms and radiographic tibiofemoral knee OA (Kellgren en Lawrence score ≥ 2) at baseline. Muscle strength was significant lower at 24 months and 48 months compared to baseline; but not between 24 and 48 months. Older age, being female, higher BMI, being non-Caucasian, lower protein intake (g/kg bodyweight), higher dietary energy intake, alcohol consumption, less physical activity valgus malalignment, higher score on the WOMAC pain subscale and the use of pain medication at baseline were associated with lower muscle strength over time.
Conclusion(s): Muscle strength decreased over time between baseline line and 24 months, but not between 24 and 48 months. In the present study a set of baseline factors, consisting of demographic, biomechanical, metabolic, nutrition, lifestyle and pain related factors, were found to be predictive for muscle strength over time. This set of baseline factors can be used to identify patients with knee OA at risk for decline of muscle strength over time. External validity of our model is needed to confirm our findings.
Implications: This set of baseline factors can be used to identify patients with knee OA at risk for decline of muscle strength over time. External validity of our model is needed to confirm our findings.
Keywords: Osteoarthritis, Knee joint, Muscle strength
Funding acknowledgements: This study was funded by the Dutch Arthritis Association.
Topic: Musculoskeletal: lower limb; Rheumatology
Ethics approval required: Yes
Institution: University of California, San Francisco
Ethics committee: Committee on Human Research, Institutional Review Board
Ethics number: Approval Number: 10-00532
All authors, affiliations and abstracts have been published as submitted.
