Purpose: Given the paucity of large, real-world datasets for the investigation of knee osteoarthritis, the purpose of this study was to identify and describe the treatment patterns and effects of intra-articular hyaluronic acid (HA) on knee osteoarthritis pain and mobility in a large, Canadian, real-world population. Methods: This is an observational, retrospective cohort of patients 18 years and older who, between June 1, 1999 and December 31, 2012 had: 1) a diagnosis of knee osteoarthritis identified by ICD9-10 and/or text coding; 2) received at least 1 treatment cycle with intra-articular HA and; 3) complete pain and mobility data [i.e., pain Visual Analogue Scale (VAS) and 6-minute walk test measures] for each treatment cycle. Data came from the Southwestern Ontario (SWO) database, which is a representative primary care, researchable database of over 325,000 unique patient records in Ontario, Canada. The SWO has compiled data continuously beginning from 1999 until present. This database has shown similar prevalence to the Canadian population for several chronic diseases and includes demographic, biometric, laboratory, diagnostic and health resource measures as collected in a primary care setting. Treatments were provided as per usual care of the provider. In addition to demographic data, pain [VAS (0-10 cm) pre and post treatment at rest], and mobility (6-minute walk test in meters) were examined in this study. Differences within and between treatments were compared using paired and independent samples t-tests. Results: Among 325,000 patients in the SWO database, 20,187 patients had a diagnosis of osteoarthritis of the knee (6.2% prevalence) with 6,618 receiving at least 1 treatment cycle of any intra-articular HA product (33% prevalence). Treatments included Hylan G-F 20 (Synvisc, Genzyme Biosurgery) (43%) and others (57%). Mean age (SD)was 57 (11) years at diagnosis and 71 (18) years at the time of first HA treatment. A high proportion of patients were male (61%), overweight or obese according to standard body mass index cut-points (>80%), had comorbidities [i.e., diabetes (10%); hypertension (66%); and dyslipidemia (13%)], and were predominantly grade 2-3 on radiographic examination (>75%). On average, patients received between 3 and 8 HA treatment cycles. Among all patients, VAS at rest (weight-bearing) significantly improved following treatment (7.2 cm to 4.1 cm, p < 0.05). Mobility (6-minute walk test) also improved post-treatment (321 m to 423 m, p < 0.05). Comparing Hylan G-F 20 with all other HA treatments, post-treatment VAS at rest (weight-bearing) was significantly lower (3.3 cm vs 4.1 cm, p < 0.05) and distance walked (6-minute walk test) was significantly greater (463 m vs 399 m, p < 0.05). Conclusions: Osteoarthritis of the knee is a significant problem in primary care affecting pain and mobility. In this Canadian real-world database, initial analyses indicated that treatment with intra-articular HA may improve pain and mobility. This real-world database may be used as a potential resource for further examination of the effectiveness of HA for reducing pain and improving mobility in knee osteoarthritis.
Petrella, R. J., Gill, D. P., & Wakeford, C. (2014). Prevalence of knee osteoarthritis and impact of hyaluronic acid treatment on pain and mobility in a Canadian real-world population. Osteoarthritis and Cartilage, 22, S222. https://doi.org/10.1016/j.joca.2014.02.428