PEER simplified decision aid: osteoarthritis treatment options in primary care

We would like to thank Dr Roger Suss for his letter regarding our Osteoarthritis Decision Aid1 that accompanies the Systematic Review2 and are pleased he finds it a valuable summary.

Dr Suss states we did not define meaningfully improved pain but in the third sentence of the article we state meaningful reductions in pain are “generally defined as a 30% or more reduction in pain, but specific definitions of clinically meaningful vary widely across studies.” The decision aid itself does include this estimate (~30%) in the title to assist clinicians when discussing treatment options with their patients.

Dr Suss raises some other specific concerns and states a number of times he had to read the whole article to understand the tools. While PEER is always seeking to simplify evidence and make it as accessible as possible, we feel that a quick review of the instructions for any tool or resource is not unreasonable. The article is 368 words (100 more than the letter) before the graphics. That is significantly more abbreviated than the majority of available guidelines and evidence synopses.

With regards to specific concerns raised:

1) The exercise benefit is implausible: Yes, it likely is. How to apply the meta-analyses results of response rate is much debated. Pulling numbers directly from the meta-graph is easiest, uses the raw absolute numbers and offers a good approximation in most cases. However, many evidence experts believe we should apply the relative risk (or rate ratio) to standardized numbers (drawn from a population). In decision aids, this allows the relative benefits of interventions to be more easily compared but still presents absolute numbers. For our standardized control (placebo) event rate, we used the average of control rates across all studies. It is not without other limitations however. The foremost is that interventions with good relative benefit but a comparatively low control rates (like exercise) will appear more effective. On other hand, topical NSAIDs studies had a higher placebo response rate so conversion in those cases leads to a slight reduction of the absolute effect.

While we recognize the effect of activity on osteoarthritis is likely inflated by this methodology, we felt that the downside is more people may consider an attempt at increased activity. If the overestimation encouraged even a few more people to increase their activity, the net gains would only be positive across multiple other health outcomes. Additionally, we want to apply the methodology equally across all interventions and selectively applying the results would add further bias.

2) Opioids are potentially harmful: From the sensitivity analysis of our systematic review, trials less than 4 weeks found benefit in opioid therapy. There was no benefit at 4-12 weeks or beyond 12 weeks. When all the data is pooled, the short-term trials drove the results to a (marginally) positive benefit. As the evidence team, we felt it was not appropriate to select only certain results for some therapies and not for others. However, we wanted to provide clinicians and their patients with information to recognize that while opioids may have some small benefit in the short term, they likely don’t have benefit as a long-term pain medicine but do have potential for harm with long term use.

3) Glucosamine, chondroitin, and viscosupplementation appear twice: As above, we felt would be important for users of the tool to understand the challenges in interpreting the results of studies of these interventions. Many readers will know the evidence is, at best, conflicting. By showing clinicians the lack of effect in public funded trials, we gave them and their patients an opportunity to reflect on what that might mean for them. Some will not care and choose to value the results of all trials while some will place more value the results of public funded studies. We wanted to give clinicians and patients the options to see both and determine for themselves.

We are presently completing a series of large systematic reviews of common chronic pain conditions in primary care (osteoarthritis, back pain and neuropathic pain). Once these are done, we will progress to a simplified guideline on chronic pain management in primary care. After that committee is formed, we hope to be able to provide more clarity. As the evidence team, we try to minimize the influence of our potential biases by avoiding over interpretation of the systematic review results, preferring instead to simply present the results found with the caveats identified. We will select a guideline committee who (like us) do not have financial conflicts of interest. They will be encouraged to make recommendations considering the complexities of all the evidence – particularly regarding opioids, chondroitin, glucosamine, and viscosupplementation. PEER prefers that a guideline committee of family physicians and other clinicians assist in the final application of the evidence. For now, we provide the best available evidence and try to minimize our potential influence or bias on interpretations. In many ways, we are asking clinicians (and patients) to be their own guideline committee with all the available evidence to make good choices.

Even when we start with pooled RCTs, there is no perfect solution to take data and translate it to easy to understand numbers, particularly when we try to present all the information and minimize any biases (those in the studies and those we may possess). Many other society and groups prefer instead to provide no actual numbers or comparisons, instead using vague terms, advocating some therapies over others, or just listing options. In these cases, with limited or non-existent information, we cannot come close to an informed choice. The approach we used is a compromise, derived from the best available research on how to present numbers and data to patients,3 allowing them to make the best available decisions.

G. Michael Allan MD CCFP, James McCormack PharmD, Michael R. Kolber MD CCFP MSc Joey Ton PharmD, Adrienne J. Lindblad ACPR PharmD, Christina S. Korownyk MD CCFP.

References

1. Lindblad AJ, McCormack J, Korownyk CS, Kolber MR, Ton J, Perry D, Thomas B, Moe S, Garrison S, Dugré N, Chan K, Allan GM. PEER simplified decision aid: osteoarthritis treatment options in primary care. Can Fam Physician. 2020;66:191-193.
2. Ton J, Perry D, Thomas B, Allan GM, Lindblad AJ, McCormack J, et al. PEER umbrella systematic review of systematic reviews: Management of osteoarthritis in primary care. Can Fam Physician. 2020;66:e89-e98.
3. Zipkin DA, Umscheid CA, Keating NL, Allen E, Aung K, Beyth R, et al. Evidence-based risk communication: a systematic review. Ann Intern Med. 2014;161:270-280

The systematic review comparing various osteoarthritis treatment options is a valuable summary of the evidence and I thank the authors for their work.

Unfortunately the page of 100 face diagrams is misleading and does not accurately and clearly summarize the evidence collected. "Meaningfully improved pain" is not defined in the article so it is not clear exactly what is being measured in the diagrams. It looks as though 94% of the patients to whom I prescribe exercise will have improvement (54% of them due to the exercise and 40% related to natural variation in disease severity). This leaves only 6% who will get worse or stay the same. One has to read the text in detail to discover the statistical compromises that resulted in this implausible result.

The accompanying table lists opioids as being likely harmful, but the the 100 faces diagram makes them look modestly beneficial. Only the text makes it clear that this is because the diagram represents short term outcomes and the table focuses on long term outcomes (which is appropriate for a chronic disease).

Glucosamine, chondroitin, and viscosupplementation appear twice on the page of 100 face diagrams, but only the text makes it clear that the benefits are unclear because industry funded trials with positive results could not be replicated.

I am glad that I read the whole article and it will help me with quantifying benefits in sharing decision making with my patients, but I will definitely not be using the 100 face diagram as a communication aid. It is not a good summary of the evidence so carefully collected in the systematic review.