Over 25% of Americans with Chronic Pain Affected by High Impact Chronic Pain

A proposed concept of High Impact Chronic Pain (HICP) differentiates between people who experience pain duration as well as limitations to daily activities and those with chronic pain without limitations (CPWL).

Using data from the 2011 National Health Interview Survey (NHIS; n = 15,670), investigators found that HICP affected 4.8% of the US adult population, or about 10.6 million individuals. For comparison, study authors cited other sources that estimate the prevalence of chronic pain in US adults from 19% to 43%, or up to 116 million Americans.

“The multidimensional nature of chronic pain is not reflected in commonly used operational definitions based solely on pain duration, resulting in inordinately high prevalence estimates that limit our ability to effectively address chronic pain on a national level,” said Mark Pitcher, PhD, visiting fellow in the Division of Intramural Research at NCCIH and one of the authors of the study, in a statement.

Importantly, the authors describe their method for asking questions of survey participants. The questions about limitations to activities were separated from questions about pain, such that participants were asked about their ability to participate in these activities rather than the extent to which pain interferes with them.

“By not requiring an individual with severe pain to distinguish the increased effort required to carry out important life activities from the actual incapacity to participate in these activities, our findings reflect a more clinically relevant assessment of impact,” wrote study authors. “Moreover, this approach also allows us to directly compare the impact of chronic pain with the impacts of a number of other chronic health conditions, including stroke, kidney failure, cancer and heart disease, to name a few.”

The study reported that chronic pain, defined as pain experienced on most or every day for the previous 3 months, was strongly associated with an increased risk of limitations or disability, even after controlling for other chronic conditions (Odds Ratio [OR] = 4.43, 95% Confidence Interval [CI] = 3.73-5.26). These disabilities included the inability to work for a living, attend school, or engage in social, community, or religious activities. Such limitations were more common among people with chronic pain than those with conditions including stroke, kidney failure, cancer, diabetes, or heart disease.

Additionally, the study reported that many people with High Impact Chronic Pain were not able to work for a living (83.2%, Standard Error [SE] 1.7), reach their educational goals (42.0%, SE 2.1), or participate in leisure or social activities (27.1%, SE 1.9).

In comparing people with High Impact Chronic Pain to those with Chronic Pain Without Limitations, researchers found that those with HICP were more than twice as likely to experience pain intensity in between “a little” and “a lot” (OR 2.19, CI 1.59-3.01), while they were over 4 times as likely to rate their pain intensity as “a lot” (OR 4.72, CI 3.40-6.55).

Study authors stated that there is much more research to be done, but that the data presented is valuable not only to guide such research, but also to provide information to policymakers.

“It is crucial that we fully understand how people’s lives are affected by chronic pain. It will help improve care for individuals living with chronic pain and strategically guide our research programs that aim to reduce the burden of pain at the population level,” said Linda Porter, PhD, director of the Office of Pain Policy at NINDS. “The findings from this study are a strong step toward these goals.”

The study, “Prevalence and profile of High Impact Chronic Pain in the United States,” was published in the Journal of Pain.