Background PPAR alpha agonists, or fibrates, are used for the treatment of dyslipidemia. Fibrates are also capable to reduce pain, local and systemic inflammation, and change subchondral bone morphology. Pleiotropic properties of fibrates make them a potential drug class for the use in osteoarthritis. No study to date has evaluated fibrate effects on knee symptoms in persons with knee pain and/or knee OA.
Objectives To assess the effects of fibrates on longitudinal changes in knee pain, function and stiffness measures in persons with knee pain having established OA or being at risk for OA development.
Methods For the current study we used longitudinal data obtained from both Incidence and Progression Subcohorts of the Osteoarthritis Initiative (OAI), which is publically available at http://oai.epi-ucsf.org.). The outcome variables studied were Western Ontario McMaster Osteoarthritis Index (WOMAC) pain, function, and stiffness subcategories. We selected patients who had WOMAC pain score >0 at baseline. The use of fibrates was defined as at least one recorded use during first three years of the study, excluding baseline use. To minimize selection bias, participants were matched into fibrate users/non-users pairs using genetic matching based on demographic characteristics, body mass index, prior knee surgery, baseline outcome measures, and Physical Activity Scale for the Elderly. The outcomes were assessed at baseline and annually until year 3. Generalized estimating equations (GEE) were used to model the relationship between outcomes and fibrate use by time interaction.
Results Thirty five incident fibrate users were matched with 35 participants not receiving PPAR alpha agonists. After matching, all standardized differences of means were less than 0.05 indicating that covariates were well balanced between groups. Fibrate use by time interaction was associated with statistically significant improvement of WOMAC function and WOMAC total scores. There was also a trend towards decrease in WOMAC pain score (table).
Conclusions In OA and non-OA persons with knee pain PPAR alpha agonists are associated with longitudinal improvement of knee function and trend towards decrease in knee pain. These observational findings substantiate experimental studies investigating therapeutic potential of fibrates in both early stage and advanced knee OA.
Disclosure of Interest None declared