Patients with advanced knee OA are often faced with the decision about TKA. This decision can be difficult, particularly if patients do not clearly understand the benefits and risks of each option (undergoing surgery or continuing medical management alone). It is important to ensure patients are effectively informed and decisions are not guided by misperceptions and false beliefs. The decision process itself involves multiple health care providers and discussions regarding pros and cons of surgery and patient preferences.29
In this study, we examined the effect of a decision aid supplemented by an adaptive conjoint analysis program on decisional conflict regarding treatment options in individuals with knee OA. We used three different tools: (i) an educational booklet developed by the NIH, (ii) a videobooklet decision aid developed by the Foundation for Informed Decision Making and (iii) a computer-based adaptive conjoint analysis values clarification exercise with the videobooklet decision aid. Decisional conflict decreased among all patient groups receiving information about treatment options for OA. This finding was expected and supports theory in which information provided to patients about risks and benefits of treatment options decreases decisional conflict. Previous studies measuring change in the decisional conflict after decision aids range from −2.5 to −17.1.14
The magnitude of reduced decisional conflict in our cohort varied between groups. Those who received the control brochure had the smallest reduction in decisional conflict, while those who viewed the videobooklet had the greatest reduction in decisional conflict. Furthermore, those in the control group continued to have scores greater than 25, indicating the potential for high decisional conflict and uncertainty while those in the videobooklet and videobooklet+ACA group had scores below 25 indicating readiness to implement a decision. Both groups receiving the videobooklet intervention had increased improvement with respect to individuals receiving the booklet alone. The videobooklet decision aid not only described OA and the potential treatments like the control group, but also included outcomes of the options, communicated risks, benefits and uncertainties using audiovisual and graphical methods and suggested the patients take their own values into account when deciding about TKA. In addition, the videobooklet integrated testimonials of patients that had chosen surgical and non-surgical treatment options and emphasized communication with the patient's physician which may have added to its overall effectiveness when compared to the booklet.30-32
The various components of the decision aid provide a possible explanation to the greater magnitude in reduced decisional conflict found in our study compared to previous studies. Weng et al. utilized the same videobooklet produced by FIMDM to determine the effect of the decision aid on knowledge, expectations and decisional conflict. They found the video to be effective in creating realistic expectations. In addition, viewers of the video felt more confident in their knowledge of the efficacy of TKA treatment. In their cohort, the post-intervention decisional conflict score was 25.8 which is similar to our cohorts' final score of 25.33
Previous randomized control trials have compared patient decision aids to usual care and simple to complex decision aids. Few, to our knowledge, have been utilized in the area of decision-making for OA treatment, utilizing TKA as a treatment option. As summarized by O'Connor and colleagues in the 2009 Cochrane Review, 10 studies compared decision aids to usual care for a variety of decisions and evaluated decisional conflict.14
Decisional conflict decreased in all of the included studies when comparing the decision aid versus usual care. In the meta-analysis, O'Connor and colleagues also included a comparison of the impact of simple versus complex decision aids on decisional conflict. Their results indicated only one of seven studies demonstrated significant reductions in decisional conflict with detailed versus simple decision aids. This is comparable to our results in that we did not see a further decrease in decisional conflict among the videobooklet+ACA group when compared to the group that received the videobooklet only.14,34
Potential respondent fatigue could be one explanation to our findings: participants in the videobooklet group took approximately one hour to view the video and complete the questionnaires, while those in the videobooklet+ACA took on average two hours. To further investigate the potential effect of respondent fatigue on decisional conflict we evaluated scale reliability of the total decisional conflict post scores among the three groups, using Cronbach's alpha and mean to variance ratios, to determine if for those engaged in the videobooklet+ACA intervention variability increase (and reliability decreased) in their responses. The internal consistency was excellent and consistent between groups (0.96, 0.94 and 0.94 for control, videobooklet and videobooklet+ACA groups, respectively). Mean to variance ratios were 9.71, 7.76 and 9.60 for control, videobooklet and videobooklet+ACA groups, respectively. No statistically significant differences were observed in the mean to variance ratio between groups. This suggests that respondent fatigue did not have an impact on the reliability of the outcome measure.
Another potential explanation for the greater reduction in decisional conflict among the videobooklet only group is that the ACA exercise in addition to the information provided by the videobooklet was cognitively rigorous, and in fact reduced clarity about the decision, increasing uncertainty. It has been suggested that complex decisions do not always benefit from intense cognitive evaluation, and that in these circumstances ‘gist’ driven decisions may be more satisfying.35
We only assessed ACA in addition to the videobooklet decision aid. Previous studies in which patient preferences were elicited utilizing conjoint analysis alone demonstrate patients are able to evaluate multiple risks, benefits and uncertainties regarding specific treatment options.19
Fraenkel et al. utilized ACA to elicit preferences regarding treatment options for OA including non-steroidal anti-inflammatory drugs, cyclooxygenase-2 inhibitors, glucosamine and/or chondroitin, opioids or capsaicin. They found patients preferred topical capsaicin most likely due to due to low probability of adverse effects. Patients in this study however did not receive additional information about the decision from another decision aid. Fraenkel also did not include TKA as a potential treatment option. In addition, decisional conflict was not evaluated.
Although the content of the decision aids utilized in this study were comprehensive, additional specific content areas were not included. The aids utilized in this study did not include content regarding costs of the treatments. This may be an area of concern for many with OA considering the cost of TKA can be over U$S 100,000 for a person at end-stage OA and multiple comorbidities.36
It is important to note, also, the control group used in this study did not receive ‘standard of care.’ Rather, the control group received publically available educational materials about OA and treatment options, offering a reasonable comparison with the two decision aid groups.
Our participants were over the age of 55 years old, mostly female, and with high prevalence of obesity, characteristics that are representative of patients with knee OA at large.37
However, they were mostly White and educated and may not be representative of OA patients from ethnically diverse backgrounds, or low literacy levels, considering treatment options. Our recruitment methods may have generated volunteer bias. Less than 20% of the participants were recruited from the previous study and over 65% of our participants were recruited from newspaper ads. Recruitment from the waiting room of a physician visit may have generated a different population; however we feel our recruitment methods generated a more representative group of all patients with knee OA, not only those who were receiving current care for their OA.
Participants described experiences of friends or family members who had already undergone TKA. The experiences of others may influenced the decision-making process and affect toward surgical options, however we did not formally evaluate these influences. Future evaluations of treatment decision-making should incorporate experiences and heuristics.
The ACA program may have in fact increased decisional conflict after the delivery of the videobooklet. This however may not be a negative effect of the ACA program. It is important to consider the variation within our participant group in stage of decision regarding TKA. Although decisional conflict is generally assessed as a negative attribute of a decision, it is useful to think that decisional conflict may be expected for many in this population and they work through the decision. Those that viewed the videobooklet and participated in the ACA program were able to view the risks and the benefits of TKA specifically and may have delayed their decision or become uncertain regarding their preferences. This does not necessarily indicate they will not make a quality decision, or be satisfied with the decision; instead it suggests additional thought into the decision.
Our findings suggest that a comprehensive videobooklet including a decision aid significantly improved decisional conflict in patients with knee OA when considering multiple treatment options. Participating in the ACA exercise, however, did not contribute to additional reductions in decisional conflict. In addition, certainty about treatment decisions can vary after exposure to information, suggesting that early patient education about treatment options for OA during the discussion with the primary care physician or rheumatologist is needed. Long-term effectiveness of these tools on the quality of the decision, overall satisfaction with the decision, and final impact on preferences about TKA is yet to be determined.