The potential impact of pain on health outcomes among patients with chronic obstructive pulmonary disease

Background Pain among COPD patients is under-recognized and has not received in depth exploration. Our objective was to examine the relationship between patient-reported levels of pain with other characteristics to examine the associations with psychological distress, functional performance, and health care utilization. Methods This was a cross sectional analysis of baseline data from a randomized trial of physical activity selfmanagement. Pain was assessed using the Bodily Pain domain of the SF-12. Psychological distress was assessed with the SF-12 Mental composite score (MCS). Both SF-12 Scores range from 0 to 100; lower scores are suggestive of greater pain and greater psychological distress. Functional performance was assessed by 6 minute walk distance (6MW), Chronic Respiratory Questionnaire Dyspnea (CRQ). Healthcare utilization was based on self-reports for the 6 months prior to enrollment. Other patient characteristics included socio-demographics, body mass index (BMI) and spirometry. The distribution of pain was assessed and categorized into quartiles, we assessed for trends across pain quartiles using the Cochran-Armitage trend test for categorical variables and linear contrasts for continuous variables. Results Among the 325 patients with baseline data, we observed that the highest pain quartile was associated with younger age (P-trend=0.0003), higher BMI (P-trend=0.002), greater psychological distress (P-trend<0.0001), and less severe spirometric impairment (P-trend=0.0004). In addition to this, we observed a large and clinically significant negative impact on CRQ dyspnea, 6MW distance, and health care utilization (P-trend <0.01). Those who reported being in the high pain quartile more often reported hospitalizations and use of urgent care for lung and non-lung disease in the previous 6 months, as well as utilization of home health services. Conclusions Our findings suggest that pain has a large, clinically significant impact on psychological distress, functional performance and health care utilization. In order to improve the health outcomes of COPD patients reporting pain, effective interventions which enhance the recognition and management of pain are needed.