Research Examines Chronic Pain Relationships in Patient-Reported Outcomes

A recent study exploring chronic pain and patient-reported outcomes (PROs) examined the interrelationship between 3 types of physical function measurement (patient-reported disability; performance-based 6-minute walk-test; and objective accelerometer step count) as well as the association between psychosocial factors and each type of physical function measurement.

Such information is necessary because understanding and targeting all factors involved in chronic pain can improve the success of treatments. “Few studies follow recent guidelines to comprehensively assess physical function via patient-reported, performance-based, and objective/ambulatory measures,” wrote the authors, in explaining why they undertook this work.

An estimated 50 million Americans have chronic pain, which may affect not only physical function but psychosocial functioning as well. Left untreated, chronic pain contributes to an estimated $560 billion in direct medical costs, lost productivity, and disability programs annually, the CDC has reported.

Most physical function research in chronic pain has targeted PROs; however, physical function involves more than an individual’s perception of functioning.

In addition, previous studies evaluating the relationship between the different aspects of physical function in chronic pain have generally found conflicting results on the association between PROs and accelerometer-measured physical function.

Psychosocial factors include pain and non-adaptive coping, adaptive pain coping and social-emotional dysfunction; non-adaptive coping could include pain during rest and activity, pain catastrophizing, and kinesiophobia. Adaptive coping includes mindfulness, general coping, and pain resilience.

In this study, 79 patients with chronic pain completed measures of physical function; pain and non-adaptive coping; adaptive coping; and social-emotional dysfunction, such as anxiety, depression, social isolation, and emotional support.

The researchers tested the interrelationship among the 3 physical function measures, and also used a conceptual model to test associations between the 3 psychosocial factors and each measurement of physical function.

They first examined data from 2 mind-body trials and recruited participants who completed PROs assessing physical function, pain and non-adaptive coping, and social-emotional dysfunction as well as the 6-minute walk test (6MWT36). Patients received a wGT3X-BT ActiGraph accelerometer to wear it over their right hip. They also had to maintain their regular levels of activity, and to fill out a daily device-wear and activity log.

Results showed that performance-based and objective physical function were significantly interrelated (r = 0.48, P < .001) but did not correlate with patient-reported disability.

Pain and non-adaptive coping (β = 0.68, P < .001), adaptive coping (β = 0.65, P < .001) and social-emotional dysfunction (β = 0.65, P< .001) were linked with patient-reported disability but not to performance-based or objective physical function (ps> 0.1).

“Findings confirm that patient-reported, performance-based, and objective assess different aspects of function,” the researchers wrote. PROs about physical function may illustrate little when it comes to physical capacity or ambulatory activity. While including factors such as adaptive coping, social-emotional dysfunction, and non-adaptive pain reactions may add some improvement, additional targets may be needed to improve functional capacity and ambulatory activity.

Reference

Greenberg J, Mace RA, Popok PJ, et al. Psychosocial correlates of objective, performance-based, and patient-reported physical function among patients with heterogeneous chronic pain.J Pain Res. 2020;13:2255-2265. doi: 10.2147/JPR.S266455