About 39 million people in the U.S., or 19%, have persistent pain, and the incidence varies according to age and gender, according to a recent study.
For the study, researchers at the Washington State University College of Nursing in Spokane defined persistent pain as frequent or constant pain lasting longer than three months. Their research goals were to:
Identify groups at higher risk for persistent pain.
Identify body sites, chronic conditions and disabilities associated with persistent pain.
Assess the relationship between persistent pain and anxiety, depression and fatigue.
Describe the individual experience of persistent pain.
Researchers used data from the 2010 Quality of Life Supplement of the National Health Interview Survey to calculate the prevalence of persistent pain. They also calculated persistent pain based on risk group, chronic condition and disability status.
Findings were published in the October issue of The Journal of Pain, the peer-reviewed publication of the American Pain Society.
Results of the analysis showed about 19% of U.S. adults reported persistent pain in 2010, and older adults were more likely to experience persistent pain than younger adults. The age group at highest risk of persistent pain was adults ages 60-69, findings showed. Women also had a slightly higher risk of persistent pain than men.
Persistent pain was more common in adults who were overweight (18.2%) or obese (25.3%), compared with those at a healthy weight (14.6%). Those who had been hospitalized one or more times in the previous year also were at higher risk for persistent pain (35.5%) than those who had not been hospitalized during that time (17.3%), the study found.
Persistent pain also correlated with other indices of health-related quality of life, such as anxiety, depression and fatigue, the researchers found. Their analysis found 45.3% of adults who reported daily feelings of anxiety also reported persistent pain, as did 56.8% of those with depression and 63.7% of those with fatigue.
The study also found persistent pain was closely linked to disability, with adults who could not work because of disability at the highest risk of reporting persistent pain (60.6%). About half of the adults who were limited in type or amount of work reported persistent pain, findings showed.
In 2011, the Institute of Medicine reported about 100 million Americans have chronic pain. Study authors said the disparity between the estimated pain incidence in their study and what the IOM reported is attributable almost entirely to differences in definitions of persistent pain.
In the 2010 NHIS, about 60% of adults reported lower back pain in the past three months, and all of them would have been described in the IOM report as having chronic pain. However, only 42% of the NHIS study respondents with back pain described their pain as frequent or daily and lasting more than three months.
From a public health perspective, the difference is significant, researchers wrote in the study. Those with persistent pain have high rates of work disability, fatigue, anxiety and depression. They also are at higher risk for long-term exposure to and dependency on pain medications.
From a public health planning perspective, persistent pain can be thought of as an indicator of unmet need for pain management in the general population, as well as an obvious risk factor for disability, depression and dependency, the authors wrote.