Chronic Pain Incidence Is High in the U.S.

New cases of chronic pain -- defined as pain experienced on most days or every day over 3 months -- occurred more frequently than new cases of other common chronic conditions, U.S. survey data showed.

Chronic pain incidence was 52.4 cases per 1,000 person-years, reported Richard Nahin, MPH, PhD, of the NIH in Bethesda, Maryland, and co-authors.

This was higher than the incidence of diabetes (7.1 cases/1,000 person-years), depression (15.9 cases), and hypertension (45.3 cases), the researchers said in JAMA Network Open.

Moreover, chronic pain was persistent: nearly two-thirds (61.4%) of adults with chronic pain in 2019 continued to have it in 2020.

The findings come from National Health Interview Survey (NHIS) data and are the first nationwide estimates of chronic pain incidence.

Recent NHIS data showed the prevalence of chronic pain in the U.S. was about 21%, affecting an estimated 51.6 million adults. High-impact chronic pain -- pain severe enough to restrict daily activities -- affected 17.1 million people.

"Understanding incidence, beyond overall prevalence, is critical to understanding how chronic pain manifests and evolves over time," Nahin said in a statement. "These data on pain progression stress the need for increased use of multimodal, multidisciplinary interventions able to change the course of pain and improve outcomes for people."

The NHIS is a cross-sectional poll conducted annually by the National Center for Health Statistics. Nahin and co-authors evaluated 10,415 adults who participated in both the 2019 and 2020 surveys. Participants with chronic pain during both periods were considered to have persistent chronic pain.

The sample included 51.7% women. More than half of the study population -- 54% -- were ages 18 to 49. Most participants (72.6%) were white; 16.5% were Hispanic and 12.2% were Black. Most (70.5%) were not college graduates.

At baseline (2019), 40.3% of participants reported no pain, 38.9% reported non-chronic pain, and 20.8% reported chronic pain.

Of those without pain in 2019, the rate of incident chronic pain was 52.4/1,000 cases (95% CI 44.9-59.9). The rate of incident high-impact chronic pain was 12.0 (95% CI 8.2-15.8). Lower educational attainment and older age were associated with higher rates of chronic pain in 2020, regardless of pain status in 2019.

In 2020, rates of persistent chronic pain and persistent high-impact chronic pain were 462.0 and 361.2 cases per 1,000 person-years, respectively.

Of those reporting non-chronic pain in 2019, 14.9% had progressed to chronic pain at follow-up. Of those reporting chronic pain in 2019, 10.4% had fully recovered (were pain-free) in 2020.

"Although chronic pain is sometimes assumed to persist indefinitely, our finding that 10.4% of adults with chronic pain experienced improvement over time is consistent with previous evidence from studies in Denmark, Norway, Sweden, and the U.K., which revealed rates ranging from 5.4% to 8.7%," the researchers noted.

The study did not include information about the underlying causes of pain and survey data were collected only twice across 2 years of follow-up, Nahin and co-authors acknowledged. It's possible that people experiencing new or persistent chronic pain or high-impact chronic pain were less likely to participate in the 2020 follow-up survey, which may have led to rates being underestimated.

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