When it comes to pain, function matters

For decades, hospital patients across the United States have been asked the same question: “On a scale of zero to 10, what is your pain?" But this commonly used numeric rating scale (NRS) for assessing a patient’s pain can be subjective and can result in gaps in care, said Aksharananda (Akshar) Rambachan, M.D., assistant professor of medicine at the School of Medicine, University of California, San Francisco.

“What we have found in our research is that nurses use the numeric rating scale inequitably across different patient groups, and there are a lot of weaknesses with the numeric rating scale in certain situations,” Rambachan said in an interview.

For example, for patients with chronic pain conditions such as sickle cell disease or long-term opioid use, the numbers might not provide clinicians with a clear way to treat those patients.

Rambachan argues that provider assessment of pain also needs to consider how pain impacts the various aspects of the patient’s life, whether that’s mood, activity, sleep, the ability to take care of themselves, or carrying out their usual activities, he said. “There is a more multidimensional way of assessing pain to help target treatment.”

Structured functional assessment that is used along with the numeric pain score can provide a more complete picture of how pain impacts a patient on a daily basis. In a recent paper published in JAMA Internal Medicine, Rambachan and his colleagues at the University of California, San Francisco, discuss two such function assessment tools: the Functional Pain Scale (FPS) and the Defense and Veterans Pain Rating Scale (DVPRS).

Both of these are validated tools, and they tie numeric scores to specific levels of functional impairment rather than pure intensity. The DVPRS, developed for and deployed across the entire Veterans Affairs health system, incorporates supplemental questions about how pain is interfering with mood, sleep, and activity.

Rambachan said used together, the numeric pain score and the function scores give clinicians a far more complete clinical picture. The concept of functional impairment, he noted, tends to resonate intuitively.

“It’s important to get your down from an eight to a four, but I also think it’s important to make sure that patients can get out of bed or are able to play with their grandkids or are able to cook for themselves," he said.

The VA’s tool, Rambachan said, offers a proof of concept. As the largest integrated healthcare system in the United States, the VA has demonstrated that implementing functional pain assessment at scale is logistically feasible. For civilian hospitals, Rambachan said clinician education and updates to electronic health record systems would likely be needed.

The use of the functional scores also aligns with CMS’s Age-Friendly Hospital Measure, which went into effect in 2025 and requires hospitals to screen for mobility and frailty.