METHODS: The Promoting Independence in Seniors with Arthritis (PISA) study is a longitudinal observational study of individuals with and without knee pain and knee OA recruited from the orthopaedics clinic of the Universiti Malaya Medical Centre and the local hospital catchment. Patients were diagnosed with OA based on the American College of Rheumatology (ACR) criteria, the presence of knee pain, and a history of physician-diagnosed knee OA. Psychosocial parameters were measured using validated measures for social participation, independence, and ability to perform activities of daily living, and life satisfaction.
RESULTS: Of the 230 included participants, mean age was 66.9 years (standard deviation: 7.2) and 166 (72.2%) were women. Kappa agreement between ACR criteria and knee pain was 0.525 and for ACR and physician-diagnosed OA it was 0.325. Binomial logistic regression analysis showed that weight, anxiety, and handgrip strength (HGS) were predictive of ACR OA. Knee pain was only predicted by HGS but not weight and anxiety. Physician-diagnosed OA was predicted by weight and HGS but not anxiety. HGS was predictive of ACR OA, knee pain, and physician-diagnosed OA.
CONCLUSION: Our study showed that the characteristics of patients with OA are different, physically and psychosocially, depending on the criteria used. Poor agreement was observed between radiological diagnosis and the other diagnostic criteria. Our findings have important implications for the interpretation and comparison of published studies using different OA criteria.
METHODS: The Promoting Independence in our Seniors with Arthritis study recruited participants aged 65 years and over from orthopedic outpatients and community engagement events. Participants were invited to annual visits during which knee OA symptoms were assessed with the Knee Injury and Osteoarthritis Outcome Score (KOOS), social network using the 6-item Lubben Social Network Scale and anxiety and depression using the Hospital Anxiety and Depression scale. Knee OA worsening was defined by a 5% reduction in mean KOOS scores at the last visit compared to the first visit.
RESULTS: Data were available from 148 participants, mean age 66.2±6.5 years and 74.1% female, of whom 28 (18.9%) experienced OA worsening over a median follow-up period of 29 months. Univariate analyses revealed that age, sex, height, grip strength, and social network were associated with OA worsening. Social network remained statistically significantly associated with OA worsening after adjustment for age and sex difference (odds ratio=0.924; 95% confidence interval, 0.857-0.997). The relationship between social network and OA worsening were attenuated by both depression and handgrip strength at baseline.
CONCLUSION: Psychological status and muscle strength may be modifiable risk factors for social network which may in turn prevent knee OA worsening and should be targeted in future intervention studies.