“Introduction
Epidemiological research on chronic pain (pain lasting ≥3 months) and high-impact chronic pain (HICP) (chronic pain associated with substantial restrictions in life activities, including work, social, and self-care activities) in the US has increased substantially since the release of the Institute of Medicine (currently the National Academy of Medicine) report on pain in 2011 and the Department of Health and Human Services National Pain Strategy (NPS) in 2016.
[..] we used data from the 2019-2020 National Health Interview Survey (NHIS) Longitudinal Cohort (NHIS-LC) to determine the IRs [incidence rates] of chronic pain across demographic groups to refine our understanding of populations with an increased risk of chronic pain, a goal consistent with the US Centers for Disease Control and Prevention Healthy People 2030 pain objectives. [..]
Methods
For the NHIS years 2019 to 2020, adults in the sample were asked 2 questions about pain suggested by the NPS as a validated measure of pain status and modified by the NCHS: (1) “In the past 3 months, how often did you have pain? Would you say never, some days, most days, or every day?” and (2) “Over the past 3 months, how often did pain limit your life or work activities? Would you say never, some days, most days, or every day?” Chronic pain was defined as pain on most days or every day during the past 3 months, as recommended by the NCHS. High-impact chronic pain was defined as chronic pain that limited life or work activities on most days or every day during the past 3 months. [..]
Results
Among 10 415 individuals included in the analytic sample, 51.7% (95% CI, 50.3%-53.1%) were female, 48.3% (95% CI, 46.9%-49.7%) were male, 54.0% (95% CI, 52.4%-55.5%) were aged 18 to 49 years, 46.0% (95% CI, 44.5%-47.6%) were 50 years or older, 70.5% (95% CI, 69.1%-71.9%) were not college graduates, and 28.8% (95% CI, 27.4%-30.2%) were college graduates. Participants were followed up for a mean (SD) of 1.3 (0.3) years. [..]
At baseline, 40.3% (95% CI, 38.8%-41.8%) of participants reported no pain, 38.9% (95% CI, 37.5%-40.2%) reported nonchronic pain, and 20.8% (95% CI, 19.6%-21.9%) reported chronic pain. Most participants reported the same pain status at both their 2019 baseline report and their 2020 follow-up; for example, 62.3% (95% CI, 60.0%-64.4%) of those pain free at baseline remained pain free at follow-up, 54.0% (95% CI, 51.9%-56.2%) of those with nonchronic pain in 2019 continued to report nonchronic pain in 2020, and 61.4% (95% CI, 58.6%-64.1%) of those with chronic pain at baseline also reported chronic pain at follow-up. Among those pain free in 2019, the 1-year cumulative incidence for chronic pain in 2020 was 6.3% (95% CI, 5.3%-7.3%), while the 1-year cumulative incidence for HICP was 1.4% (95% CI, 0.9%-1.9%). We also observed evidence for both pain progression and pain recovery. Of those reporting nonchronic pain in 2019, 14.9% (95% CI, 13.5%-16.3%) had progressed to chronic pain at follow-up; of those reporting chronic pain in 2019, 10.4% (95% CI, 8.4%-12.3%) had fully recovered (ie, were pain free) in 2020. [..]
Regardless of baseline pain status, older participants had higher rates of chronic pain than younger participants, and those without a college degree had higher rates of chronic pain than those with a college degree. Asian participants with nonchronic or chronic pain at baseline had lower rates of chronic pain compared with White participants. Regardless of baseline pain status, no differences in the rates of chronic pain were seen between male and female participants. Non-Hispanic participants with nonchronic pain at baseline had higher rates of chronic pain in 2020 than Mexican participants. [..]
Discussion
In this cohort study, nearly two-thirds (61.4%) of adults with chronic pain in 2019 continued to have chronic pain in 2020. While 14.9% of those with nonchronic pain reported chronic pain 1 year later, only 6.3% of those pain free in 2019 developed incident chronic pain and only 1.4% exhibited an onset of HICP. Lower educational attainment and older age were associated with higher rates of chronic pain in 2020 regardless of pain status in 2019. Of note, the incidence of chronic pain (52.4 cases per 1000 PY [person-years]) was high compared with other chronic diseases and conditions for which the incidence in the US adult population is known, including diabetes (7.1 cases per 1000 PY), depression (15.9 cases per 1000 PY), and hypertension (45.3 cases per 1000 PY).
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 UK, which revealed rates ranging from 5.4% to 8.7%. Also similar across our study and these 4 studies were the rates of 1-year cumulative incidence for chronic pain at baseline, which ranged from 1.8% to 8.3%. The observed differences likely reflect variability in study methods, including how chronic pain was defined, the populations studied, and the length of follow-up. The rates for persistent chronic pain varied from 47.9% in the youngest cohort (aged ≥16 years at entry) to 93.5% in the oldest cohort (aged ≥65 years at entry). These rates suggest an age effect consistent with our finding that participants 50 years or older had a 29% higher adjusted RR of persistent pain than younger participants.”
Full article, RL Nahn, T Feinberg, FP Kapos, et al., JAMA Network Open, 2023.5.16