P-087 - (Poster #87) Does topically applied menthol provide effective pain relief for runners during sporting events? A real-world evidence feasibility study

Topically applied menthol is an effective analgesic that can be used to provide temporary relief from aches and pains of muscles associated with strains and sprains. Multiple studies have investigated the analgesic effect of topically-applied menthol, but to-date these studies have been conducted in small samples and, in some cases, not conducted using optimal trial designs – introducing potential biases and limiting the interpretation of the results. Major sporting events, such as marathons, where large numbers of runners with different demographic characteristics experience varying degrees of pain, provide an opportunity to evaluate the analgesic effectiveness of topically applied menthol in a real-world setting.

The Chicago Marathon, which attracts more than 50,000 runners each year, serves as an ideal setting to collect real-world data to potentially shed light on how effective topically applied menthol is at providing pain relief. By conducting a feasibility study at this marathon event, we can build a strong evidence base to better understand the factors that impact runners’ pain experience and assess whether topically applied menthol provides effective pain relief.


Purpose/Objectives:

The aim of this real-world evidence feasibility study is to explore trial design options and outcome measures to inform the experimental design of a future large-scale real world evidence study. The overarching goal is to establish the infrastructure needed to collect high-quality data in real-world settings and to investigate whether topically applied menthol provides effective pain relief. Specific aims of this feasibility study include: (i) understanding the demographic characteristics of the study population; (ii) identifying streamlined data collection opportunities; (iv) informing the design of a real-world evidence study; and (iv) obtaining estimates of outcome variance related to verbal pain reports to facilitate sample size calculations for a large-scale effectiveness trial to test the analgesic impact of topically applied menthol.



Methods:

A team of research scientists attended the Chicago Marathon post-race event (Grant Park – “27^th Mile Post-Race Party”) where runners gathered after completing the Chicago Marathon race. An anonymous survey (created using Qualtrics) was distributed to post-race marathon runners. Survey questions requested information about participant’s (i) demographic characteristics; (ii) use of analgesics before and during the race; and (iii) verbal pain reports before and after (within 10 seconds) the post-race application of topical menthol (Biofreeze Menthol Pain Relieving Aerosol Spray; Menthol 10.5%), in a body location requested by the runner. A 0-10 visual analogue scale (VAS) pain score was used, where 0 is no pain and 10 is the worst pain imaginable. In addition, to address for potential bias in pain reporting, the impact of positive and negative treatment expectation was assessed using a modified version of the Stanford Expectations of Treatment Scale (SETS). Ethical approval to conduct the study was provided by University of Michigan Medical School Institutional Review Board (IRBMED, Ame00153539 for HUM00261089).



Results:

Anonymised survey data were collected from 192 runners (69% male, 31% female), which represented 100% of participants approached and asked to complete the survey. Most runners reported pain located in either the upper (44%) or lower (43%) legs. Participants age ranged from 16 to over 75 years old, and post-race pain increased with age. Runners who completed the marathon had an average pain score of 6.0 (SD 1.81), which reduced to 4.0 (SD 1.85) within 10 seconds of menthol being applied to the skin (Biofreeze Menthol Pain Relieving Aerosol Spray; Menthol 10.5%; n=160), in body areas identified as being painful by the runners. This 2.0 point reduction in pain score represented a clinically meaningful pain reduction (defined as >2-point reduction in pain on the VAS pain scale). The observed reduction in pain was consistent across sex and age, with no notable differences across groups. Overall, the post-race marathon runnersreported a reduction in pain within 10 seconds of the topical menthol being applied to the skin. In addition, 7/10 runners experienced at least a 2-point reduction in pain post treatment. We assessed the impact of positive/negative treatment expectation and demonstrated that neither a positive nor a negative expectation of pain relief efficacy had an impact on the magnitude of the reported pain relief. Overall, 89% of runners reported that the application of menthol to the skin aided their recovery.


Conclusions/Implications for future research and/or clinical care:

We confirmed the feasibility of conducting a large real-world evidence study to assess the analgesic effectiveness of applying topical menthol to the skin after exercise, in post-race marathon runners. We (i) established the demographics of the study population, (ii) created a study protocol to collect data using a streamlined approach, (iii) successfully used a novel method to address positive/negative treatment expectations, and (iii) obtained estimates of outcome variance in our verbal pain report measures to facilitate sample size calculations for a large-scale effectiveness trial to test the analgesic impact of topically applied menthol. In conclusion, our feasibility study suggested that we can conduct and adequately power a large-scale real-world study investigating the efficacy of topically applied menthol.