A recent study published in JAMA Network Open estimated the rates of chronic pain among adults in the United States (US).
Study: Estimated Rates of Incident and Persistent Chronic Pain Among US Adults, 2019-2020. Image Credit: ESBProfessional/Shutterstock.com
Research on chronic pain has increased in the US in the past decade, and several studies have described the prevalence of high-impact chronic pain (HICP) and chronic pain. Only a few studies have reported chronic pain incidence rates (IRs).
The National Center for Health Statistics (NCHS) of the US Centers for Disease Control and Prevention (CDC) conducts the annual National Health Interview Survey (NHIS) of non-institutionalized civilians from 50 US states and the District of Columbia.
About the study
In the present study, researchers estimated IRs of chronic pain using data from the 2019-20 NHIS- longitudinal cohort (LC). The NCHS randomly selected 21,161 participants from NHIS for inclusion in NHIS-LC in 2019. Of these, 10,415 individuals who participated in 2020 were included for analysis. The study outcomes were IRs of HICP and chronic pain.
During the 2019-20 NHIS, participants were asked how often they had experienced pain in the past three months and how often it limited their daily life and work activities.
The researchers defined chronic pain as experiencing pain every day or on most days in the past three months, whereas HICP was the chronic pain that limited their work or daily life activities every day or on most days in the past three months.
Baseline characteristics were compared between NHIS-LC participants and NHIS subjects from 2019 excluded in the LC. The proportions of subjects with non-chronic or chronic pain and without pain in 2020 were calculated and stratified by baseline pain status.
Further, age-standardized and crude rates of chronic pain and HICP were estimated per 1000 person-years. Additionally, rates were calculated by demographic features.
The analytic sample comprised 51.7% females and 48.3% males; 54% of the cohort were aged 18-49, and the remaining were aged 50 or older. Only 28.8% of the cohort were college graduates.
Subjects were followed up for an average of 1.3 years. Most subjects were White (72.6%), followed by Black participants (12.2%).
Baseline demographic features were well-balanced between NHIS and NHIS-LC participants, except that NHIS subjects not part of the LC were likelier to report an unknown pain status.
Over 40% of participants at baseline reported no pain, whereas nearly 39% reported non-chronic pain. Chronic pain was reported by approximately 21% of participants in 2019.
Moreover, a majority of individuals had the same pain status in 2020. That is, 62%, 54%, and 61% of subjects with no pain, non-chronic pain, and chronic pain in 2019 reported the same pain status in 2020, respectively.
The one-year cumulative incidence of chronic pain and HICP among pain-free subjects in 2019 was 6.3% and 1.4%, respectively.
Notably, around 15% of those with non-chronic pain at baseline progressed to chronic pain in 2020. Moreover, 10.4% of subjects with chronic pain at baseline recovered by 2020.
The IRs of chronic pain and HICP in 2020 were 52.4 and 12 cases per person-years, respectively, among those without pain at baseline.
Chronic pain IRs were substantially higher among those with baseline non-chronic (116 cases/1,000 person-years) or chronic pain (462 cases/1,000 person-years). High HICP IRs were observed for subjects with baseline chronic pain (190 cases/1,000 person-years) or HICP (361 cases/1,000 person-years). Older subjects had increased rates than younger individuals, irrespective of age.
Participants without a college education reported higher rates of chronic pain than those with a college education. Asians with baseline chronic or non-chronic pain showed lower rates of chronic pain than White participants.
There were no differences by the sex of participants, regardless of pain status at baseline. Further, adjusted regression analyses reproduced these differences in rates.
In sum, the team observed that 61.4% of adults with baseline chronic pain continued to experience it in 2020. Around 15% of adults with baseline non-chronic pain reported chronic pain after one year.
The incidence of chronic pain among pain-free participants at baseline was 6.3%. Older age and lower educational status were associated with elevated rates of chronic pain during the follow-up.
The incidence of chronic pain was much higher than for other chronic conditions, such as diabetes, hypertension, and depression, among US adults. Over 10% of adults with baseline chronic pain were fully recovered by the next year, consistent with prior evidence.
The findings highlight the high disease burden of chronic pain and the need for prevention and early management of pain.