By Mark Sullivan, MD & Jane Ballantyne, MD

The 0-to-10 pain intensity scale that has become a familiar feature of clinical care had its origin in experimental psychophysics studies that investigated the relationship between noxious stimulus intensity and pain experience. In acute postoperative care, this scale may have improved pain control in the days immediately following surgery.

In palliative care and cancer pain care, the scale was combined with the “titrate to effect” opioid dosing principle to aggressively target pain levels in seriously ill patients with poor prognoses. It began to seriously distort clinical pain care only when it was extended to the outpatient care of patients with chronic non-cancer pain.

Cancer pain treatment in the 1980s was simpler due to its clear origin in progressive tissue destruction and short time frame of treatment at the end of life. We have discussed above how this 0-to-10 pain intensity metric neglects important aspects of pain (e.g., meaning, extent, constancy), isolates pain and its treatment from their effect on the patient’s life, and selects high-risk patients for the riskiest opioid regimens.

Although these scores have been repeatedly shown not to improve chronic pain care as was hoped, they continue to be used in most health care systems. They also may be implicated in the over-prescription of opioids. We believe these scores should be phased out in favor of more personalized and qualitative measures, applied only when pain is the focus of clinical care.

Use of a simple quantitative pain metric, such as the pain intensity score, makes clinical pain assessment simple and allows averaging across populations of patients. It makes certain clinical epidemiology and quality improvement projects possible. But it also distorts these projects because it implies that zero pain is the goal. Or the scale is combined with policy that sets another arbitrary threshold for pain requiring clinical attention (such as 4/10 that the Veterans Administration used in the past). All these score-focused strategies err by isolating the goals of chronic pain care from the patient’s life.

One of the briefest alternatives to the 0-to-10 pain intensity score is the 3-item PEG scale, adapted from the longer Brief Pain Inventory (BPI) used in many clinical pain research studies. It has been shown to capture almost all the information of the longer BPI when used in a primary care setting. This scale adds two more 0-to-10 scales to a 0-to-10 “Pain severity” scale. One asks how much the pain interferes with “Enjoyment of life,” the other with “General activities.” The total PEG score thus provides a fuller picture of the effect of pain on the patient’s life by adding assessments of role function and emotional function. It begins to refocus care away from the sensation of pain and onto the patient with pain. While the PEG is an important improvement on the pain intensity scale, hopefully we will see more feasible comprehensive personalized pain measures developed.

More broadly, we must ask if it makes sense, or advances the goal of pain relief, to measure pain when the clinical context is not one where pain is expected. This has become common as part of the effort to increase the “visibility” of pain in clinical settings. But does it make sense to ask the patient presenting for a routine eye exam or flu shot, “Do you have any pain?” This assumes that all pain is a medical problem with a medical solution. During most routine visits, there is not time to delve into the context of the patient’s pain or even treat the pain appropriately—at best, a note to the patient’s primary care provider, if there is one, or perhaps a referral to a pain clinic, if there is one.

If pain treatment is not mandated by a pain intensity score, what should indicate the need for pain treatment, especially opioid treatment? The Joint Commission, which accredits hospitals and other health care institutions, has begun to grapple with this issue. In 2001, the Joint Commission infamously recommended the use of quantitative pain scales to monitor patients’ pain in hospitals. Their recommendation contributed to the widespread use of the 0-to-10 pain intensity scale in hospitals and clinics. The new standards proposed in 2018 specifically recommend pain assessment and treatment standards tied to functional outcomes. In the hospital, patients’ pain should be controlled not to zero or some other arbitrarily defined minimum, but to promote relevant functions such as breathing, coughing, weight bearing, and walking. These criteria help determine when patients can be discharged from the hospital to home, so they are the appropriate criteria for pain management in the hospital.

The medical necessity of pain treatment outside the hospital is more complicated because life outside the hospital is more complicated. At a minimum, we must distinguish between common chronic pain and high-impact chronic pain, which only includes pain with daily functional limitations. While chronic pain itself has a prevalence of 20 percent in the United States, high-impact chronic pain has a prevalence of 8 percent. This high-impact group with significant functional limitations has more need for medical treatment than those with chronic pain alone.

The medical necessity of pain treatment needs to be determined by the effects of the pain, not by its intensity or its causes. This conflicts with the usual way we demarcate medical problems from non-medical problems in our society. Classically, medical problems consist of diseases or injuries causing symptoms. But a causal disease often cannot be identified for chronic pain. So we can’t understand the medical necessity of pain treatment if we stay locked into the disease-versus-symptom thinking typical of the biomedical model. Chronic pain is neither a disease nor just the symptom of another disease. That is what makes it complicated. One of the principal benefits of pain treatment is reducing or eliminating the functional deficits caused by pain. It is these deficits that determine the medical necessity of pain treatment as balanced against the deficits induced by the pain treatment itself.

Mark Sullivan is a psychiatrist. Jane Ballantyne is an anesthesiologist. They are authors of The Right to Pain Relief and Other Deep Roots of the Opioid Epidemic.