Three numbers get used interchangeably in this field and they mean different things. Getting them straight is not pedantry; it changes what an intervention should look like.
What is prevalence?
How many people have the condition now. For chronic pain: an estimated 20.4% of US adults, about 50.0 million people, with 8.0% — 19.6 million — having high-impact chronic pain that frequently limits life or work activities. That is 2016 National Health Interview Survey data.
Prevalence tells you how big a service needs to be. It does not tell you whether the problem is growing.
What is incidence in simple terms?
How many new cases arise per unit of time. For chronic pain among previously pain-free US adults: 52.4 per 1,000 person-years, with high-impact chronic pain at 12.0 per 1,000 person-years. That is higher than the published incidence of high blood pressure (45.3), depression (15.9) and diabetes (7.1).
Incidence tells you the trajectory. A service sized to current prevalence, with an incidence like that, falls behind every year.
How long does chronic pain last?
Whether people stay in the condition. Among adults with chronic pain in 2019, 61.4% still had it a year later, and 10.4% were pain free. Both halves matter: this is mostly not a passing state, and it is not always permanent either.
What mistakes make a prevalence figure misleading?
Quoting a confidence interval bound as the estimate. Our own earlier material said chronic pain incidence was “60 in 1,000” — that is the upper bound of the 95% confidence interval around 52.4, not the estimate. It is an easy error and it inflates a figure by about 15%.
The other one: quoting a rate without naming the population it was measured in. “52.4 per 1,000” is meaningless without “among adults who were pain free at baseline.” The same study reports 116.2 per 1,000 for adults who had non-chronic pain at baseline and 462.0 for those who already had chronic pain. Same study, same year, three very different numbers.
More: the scale of chronic pain.
Frequently asked questions
What is the difference between prevalence and incidence?
Prevalence counts how many people have a condition right now. Incidence counts how many new cases appear over a set period of time. For chronic pain, prevalence is an estimated 20.4% of US adults, about 50.0 million people. Incidence is 52.4 new cases per 1,000 person-years among adults who were pain free at the start. Prevalence sizes a service; incidence shows where it is heading.
What are examples of prevalence?
Chronic pain is a clear example. The 2016 National Health Interview Survey estimated that 20.4% of US adults, about 50.0 million people, had chronic pain. Another 8.0%, or 19.6 million people, had high-impact chronic pain that frequently limits life or work activities. Those figures tell you how many people need care today, not whether the problem is growing.
What is an example of incidence?
Among US adults who were pain free at the start, new chronic pain appeared at 52.4 per 1,000 person-years, and high-impact chronic pain at 12.0 per 1,000 person-years. That is higher than the published incidence of high blood pressure (45.3), depression (15.9) and diabetes (7.1). A rate like that means a service sized only to today’s numbers falls behind every year.
Sources
Every figure on this page is traceable to the source listed here.
- Dahlhamer J, Lucas J, Zelaya C, Nahin R, Mackey S, DeBar L, Kerns R, Von Korff M, Porter L, Helmick C. Prevalence of chronic pain and high-impact chronic pain among adults — United States, 2016. MMWR Morb Mortal Wkly Rep. 2018;67(36):1001–1006. PMID 30212442. View source.
- Nahin RL, Feinberg T, Kapos FP, Terman GW. Estimated rates of incident and persistent chronic pain among US adults, 2019–2020. JAMA Netw Open. 2023;6(5):e2313563. PMID 37191961. View source.