Knee Osteoarthritis

Whether NSAIDs are the most appropriate therapeutic medication for knee osteoarthritis, depends on whether the individual determines that the likely pain relief outweighs the possible side-effects. Decision Aids have been developed to help people understand complex medical information and promote informed preference-based choices. However, Decision Aids still contain a considerable amount of information (e.g. many different side-effects), which can be complicated to understand (e.g. risk information), and be based on unfamiliar outcomes (e.g. ulcers). There are concerns in such complicated decisions, even when using a DA, that cognitive errors lead some individuals to make choices that do not reflect their own preferences and values.

To evaluate the effect of enhancing a decision aid of medications for knee osteorthritis, by individualizing the way information and choices are presented.

We hypothesize that individualizing the way information and choices are presented in a decision aid would improve perceived decision uncertainty and congruence between personal values and choices made.

At a group of pre-selected pharmacies we plan to recruit 150 individuals with physician diagnosed knee OA and seeking pain medication in to a proof-of-concept randomized controlled trial. All participants will receive a decision aid via a computer tablet. After completing the decision aid, the pharmacist and individual will make a decision about treatment that will be recorded. We will randomize each individual to either the experimental or conventional decision aid. There will be a baseline visit where the decision aid is used and a follow-up questionnaire 3 months after a medication has been chosen. Pharmacists and individuals will be blinded to the type of decision aid they receive.

The experimental decision aid (DCIDA) will first comprehensively describe the medication options. Then individuals will be asked the relative importance of characteristics associated with medication options and questions about the type of information they deem to be important to their decision. The responses will dynamically change the way the information on each medication (side-effects, benefits, etc.) is presented and how the choice is framed so that each individual receives the information in a way tailored to their own priorities. The control arm decision aid will follow convention, simply displaying information in a prescribed manner and in the same way for each participant.

We will utilize decision-based outcome measures based on the Ottawa Framework for Shared Decision Making which have been used to evaluate over 80 decision support aids. The primary outcome will be the decision uncertainty subscale of the Decisional Conflict Scale (DCS) which has been used in the primary outcome of previous decision aid studies. Secondary outcomes will include congruence between personal values associated with medication options (relative importance of characteristics such as benefits and harms measured on a 0-100 scale) and choice of medication 3 months after use of the decision aid. Other outcomes will include the other subscales of the DCS, a leaning scale, adherence with medication, and economic costs.

For the primary outcome, the mean score for each measure for each group will be compared using t-tests. We will also use a hierarchical model to account for potential confounders, most importantly to control for clustering at the pharmacy level. A discriminant function analysis will be used to assess congruence between personal values and choices made.

This study is funded by The Arthritis Society. .