UT Arlington study finds major gap in pain diagnosis

Millions of Americans experience pain severe enough to interfere with daily life but never receive a medical diagnosis, according to a new study from The University of Texas at Arlington.

Feinuo Sun, assistant professor of kinesiology, led the study that introduced the term “undiagnosed pain,” defined as “self-reported pain without any formal diagnosis of an underlying condition.”

The research team analyzed four years of federal health data and found that at least 21 million U.S. adults reported pain that disrupted their work or household activities despite having no pain-related condition in their medical records. The findings, published in PAIN, the Journal of the International Association for the Study of Pain, point to a significant gap between symptoms patients report and what actually appears in their medical records.

“What this study shows is that a significant number of people experience pain that interferes with their work and daily activities, yet the healthcare system does not capture a reason for that pain,” Dr. Sun said. “That mismatch represents a real problem.”

Pain remains one of the most difficult conditions to diagnose given its subjective nature. The study analyzed data from 2016–2019, a period when pain was classified as a symptom rather than a disease in the healthcare system. In 2022, the World Health Organization updated its International Classification of Diseases to recognize chronic pain as a disease.

That shift is significant because undiagnosed pain can lead to delayed or missed treatment, worsening health conditions, higher long-term healthcare costs and reduced productivity.

“Because pain was not classified as a disease during the years we studied, many people likely had their pain overlooked or inadequately documented, even when it significantly affected their quality of life,” Sun said. 

The study found that from 2016–2019, 30% of adults who reported pain affecting their daily activities—about 68.6 million people—have no formal diagnosis of a common pain condition. Using a broader definition of “diagnosed,” which includes conditions where pain is a secondary symptom, 9.3% of those reporting pain, or about 21.1 million adults, still lack a diagnosis.

“When pain goes undiagnosed, it is very likely to be undertreated or poorly managed,” Sun said. “That can lead to worsening pain over time, reduced quality of life, and negative mental health effects, such as pain catastrophizing.”

Future research will likely examine the impact of the World Health Organization’s reclassification of chronic pain from a symptom to a disease, Sun said.

“First, though, it is critical to understand how much pain the current system has been missing,” she said.