Predictors of disability among Filipinos with knee osteoarthritis


: Ester G. Penserga, Department of Medicine, University of the Philippines College of Medicine, Philippine General Hospital, Taft Avenue, Manila 1000, The Philippines. Email:


Aims:  This study aims to describe the level of disability of Filipino patients with knee osteoarthritis (OA) in relation to common risk factors.

Methodology:  This is a cross-sectional analytic study. Patients with knee osteoarthritis diagnosed using the American College of Rheumatology criteria for the classification of knee OA, seen at East Avenue Medical Center, using the Quezon City, Philippines, were entered by convenient sampling. The Western Ontario and McMaster Universities (WOMAC (va) 3.1 Tagalog Version) osteoarthritis index was used. Self-reported disability was measured by the function subscale of the WOMAC OA index and used as the dependent variable. Independent variables assessed as possible risk factors affecting disability were age, sex, weight, height, body mass index (BMI), education (in years), number of comorbidities present, smoking status (pack years), duration of knee OA, pain and stiffness. Categories of disability were identified as high, moderate and low. Analyses of the data were performed using Statistical Package for the Social Sciences (SPSS) version 13.

Results:  Eighty-five subjects were included in the study. The mean disability score was 674.1 ± 318.81 (moderate disability). Chi-square tests showed that the categories or levels of disability are not significantly dependent on the categorical variables. Significant direct correlations were seen between mean disability and weight (r = 0.260, P = 0.016), pain (r = 0.574, P = 0.000), and stiffness (r = 0.616, P = 0.000).

Conclusion:  This is the first study analysing the relationship between disability and specific risk factors among Filipino patients with knee OA. Self-reported disability of knee OA in the population studied was strongly related to pain scores, weight and joint stiffness scores.