If You Want Patients with Knee Osteoarthritis (OA) to Exercise: Tell them about NSAIDS

Abstract

PURPOSE: Exercise is an important adjunctive treatment for knee OA; however it is underutilized, in part because of the known difficulties related to initiating and adhering to exercise programs. Although there are ample data documenting the latter, patient preferences for exercise in comparison to other options have not been examined. METHODS: Participants were recruited as part of an intervention trial to improve decision-making in knee OA. Patients with knee pain on most days of the preceding month completed an Adaptive Conjoint Analysis interactive computer survey designed to elicit patient preferences for a cream (capsaicin), oral medications, [acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs)], intra-articular (IA) injections (up to four times per year) and exercise (low impact aerobic exercise and/or strength training three times per week). Preferences were determined based on individual respondent's trade-offs between: route of administration, probability of having less pain, probability of improved strength and endurance, risk of dyspepsia, and risk of ulcer. Preferences were calculated as "shares" which sum to 100. RESULTS: 90 subjects completed the computer tool; mean age ± SD = 68 ± 9 (range = 53-87). Patients preferred exercise over other treatment options whether IA injections and NSAIDs were described as being 20% or 50% more effective at decreasing symptoms compared to other options. The relative importance assigned to treatment benefits and risks were 29% and 41% respectively. Patient demographic characteristics were not related to preferences; however, patients with more self reported knee pain were less likely to prefer exercise compared to their counterparts (r = -0.3, p=0.004). CONCLUSIONS: In this study, patients preferred exercise over pharmacologic options for treatment of knee OA. Preferences were driven by patients' unwillingness to accept the risk of adverse effects. Our findings also suggest that subjects with greater knee pain may be more reluctant to exercise compared to their counterparts. Presentation of exercise in the context of other available therapies might increase patient willingness to try exercising by making the trade-offs between exercise and medications more apparent.

Figure 1

Screening Choice Task

Figure 2

Example of an ACA Paired-Comparison Question.