Everyone perceives pain differently. Whether they're in pain from injury or illness, the amount of pain a person experiences is unique to the individual experiencing it. Levels of pain can also be influenced by genetic, cultural, social and psychological factors. This high degree of variability makes measuring pain on a clinical scale a challenge.
That's why clinical trials need to emphasize function as well as pain measurement. The ability to lead a quality and meaningful life where patients are able to engage in their everyday activities is often more important than managing the pain itself, although the two can undoubtedly impact one another. In many clinical trials, pain reduction takes precedence, despite the fact that an objective measurement of pain doesn't exist.
Why focus on function?
By pivoting to focus on function, clinical trials can instead measure physical functioning through patient-reported outcomes — how a patient perceives their pain levels — performance-based activities and other objective measures of activity. This can help researchers understand how effective treatments are at helping patients with acute or chronic pain return to their everyday lives, including at home, in their careers and in the general activities that give them joy and meaning.
It's a much-needed discussion that the Pain Management Best Practices Inter-Agency Task Force, a federal advisory committee established by the Comprehension Addiction and Recovery Act of 2016, pushed for last May. In it, they called for researchers, stakeholders, legislators and other key audiences to strongly consider function when developing effective pain treatment plans.
They determined that a patient-centric approach addressing quality of life improved functionality, and regaining activities of daily living was essential to achieving quality care for acute and chronic pain. The task force suggested this approach can also help strengthen relationships between patients and providers, another crucial factor in healthcare management.
Yet the conversation is not over. There's more that needs to be done as we continue to identify and implement best practices for researching and treating pain. Aside from shifting gears to address function over pain measurement in clinical trials, we must better understand those at the heart of the discussion: the patients themselves who experience, at times, debilitating pain that can go far beyond physical symptoms and the disparities that exist in our studies of pain.
Factors that impact pain measurement
A person's level of function can include work participation, social participation and caregiver burden. These are all essential to consider when developing effective treatments for pain. However, this isn't always the case in clinical trials, which tend to focus less on mental and emotional wellness and more on the physical symptoms of pain itself.
When a patient reports their level of pain, which is generally subjective, their concept of pain will likely be impacted by a number of internal and external factors. For one person, pain can be a level 10. For another, pain may only be a level three. Additionally, the longer that chronic pain is experienced, the more a person's perception of pain can evolve over time. For example, a person who has experienced ongoing pain for years could report more severe levels of pain than someone who's experienced pain lasting several months, simply due to its daily impact.
In examining pain through a biopsychosocial lens, which looks at how biological, psychological and social factors impact health, illness and treatment, one can see the many elements that impact a patient's personal understanding of pain. In a biological sense, recent studies determined that women were more likely to report pain than men (at the time of the findings), and that women non-Hispanic white and non-Hispanic Black women were also more likely to report pain that was "persistent and bothersome."
Women are also at higher risk for common chronic pain conditions, such as low back pain, migraine headaches, fibromyalgia and osteoarthritis. Other researchers have found that minority groups, especially older adults, tend to report higher prevalence of pain.
Disparities in pain assessment and management
Racial disparities in pain assessment and management have been a longstanding issue that can potentially be improved through shifting focus from pain reduction to regaining function. Research has found that 47% of physicians were likely to underestimate the pain of Black patients compared to 35% of physicians when treating non-Black patients. These disparities can result in patients receiving the wrong course of treatment, therefore not relieving their pain.
Then there are social influences on perception of pain. Experiments show that people can exhibit higher pain tolerance when their friend or romantic partner is present, but lower when they are alone. In addition, people under high levels of stress may have lower thresholds for pain. It's another reason why the medical community should collectively aim to prioritize function over pain measurement in clinical trials; solely relying on patients' perceptions may not garner accurate results, which can then impact overall treatment development and research.
As we continue to shape the way we address pain in clinical trials, it's important to keep disparities of trial participants in mind. Developing effective treatment plans that work on a larger scale will ultimately depend on diversity, function measurement, and how well these treatments help patients return to their everyday lives.
A successful treatment is one that not only reduces pain, but allows people to fully engage in their jobs, social lives and other activities that give their lives meaning.