Psychosocial Correlates of Objective, Performance-Based, and Patient-Reported Physical Function Among Patients with Heterogeneous Chronic Pain.

BACKGROUND

Improving all aspects of physical function is an important goal of chronic pain management. Few studies follow recent guidelines to comprehensively assess physical function via patient-reported, performance-based, and objective/ambulatory measures.

PURPOSE: To test 1) the interrelation between the 3 types of physical function measurement and 2) the association between psychosocial factors and each type of physical function measurement.

METHODS

Patients with chronic pain (N=79) completed measures of: 1) physical function (patient-reported disability; performance-based 6-minute walk-test; objective accelerometer step count); 2) pain and non-adaptive coping (pain during rest and activity, pain-catastrophizing, kinesiophobia); 3) adaptive coping (mindfulness, general coping, pain-resilience); and 4) social-emotional dysfunction (anxiety, depression, social isolation and emotional support). First, we tested the interrelation among the 3 aspects of physical function. Second, we used structural equation modeling to test associations between psychosocial factors (pain and non-adaptive coping, adaptive coping, and social-emotional dysfunction) and each measurement of physical function.

RESULTS

Performance-based and objective physical function were significantly interrelated (r=0.48, p<0.001) but did not correlate with patient-reported disability. Pain and non-adaptive coping (β=0.68, p<0.001), adaptive coping (β=-0.65, p<0.001) and social-emotional dysfunction (β=0.65, p<0.001) were associated with patient-reported disability but not to performance-based or objective physical function (ps>0.1).

CONCLUSION

Results suggest that patient-reported physical function may provide limited information about patients' physical capacity or ambulatory activity. While pain and non-adaptive reactions to it, adaptive coping, and social-emotional dysfunction may potentially improve patient-reported physical function, additional targets may be needed to improve functional capacity and ambulatory activity.

TRIAL REGISTRATION: ClinicalTrials.gov NCT03412916.