Methods: Participants were 63% (196) female, mean age was 56.28 years (SD = 11.49). Average pain in past 24 hours from the Brief Pain Inventory (BPI) composite was 5.81 (SD = 2.40) on a 0-10 scale. The components of Medication Management, Pain Advocacy, and Living with Pain were tailored to African Americans, individualized to the patient, and delivered over 5 weeks. Components were measured by existing and investigator-developed instruments. Perceived control over pain, measured by cognitive, pharmacologic, and emotional control, and feelings of control, was a mediator of the outcomes of pain, pain-related distress, and functional status. The primary outcomes of pain, pain-related distress, and functional status were measured weekly. Intermediate outcomes of perceived control over pain and measure of the intervention components were measured at baseline, week 7 (evaluation of intervention), and week 12 (durability).
Results: There were no baseline differences in gender, marital status, education, metastasis, perceived control over pain, pain, pain-related distress, and functional status. As typical with behavioral intervention trials, a monotone pattern of missing data was observed due to death (5%), illness (10%), and lost to follow-up (9%). The total complete case sample was 236 (24% incomplete cases). Including baseline characteristics in the models did not make any difference in the estimation of treatment effects. Linear mixed model analyses of the primary outcomes of pain, pain-related distress, and functional status, showed significant linear decreases in each of the outcome measures over the 7 week over the 7 weeks between baseline and intervention evaluation (p <.01). Intervention effects were tested by comparing linear trends across groups. Intent-to-treat (ITT) and complete-case analyses gave similar results for pain-related distress and functional status; in both, differences in linear trend were significant as predicted (p < .01). The difference in linear trend for pain was not significant in the ITT (p = .065) but significant in complete case analysis (p = .041).
This study demonstrated improving perceived control over pain decreases pain-related distress and improves functional status in African Americans with cancer-related pain. Results from a previous study supported the need for nurses to incorporate perceived control over pain as part of the assessment process and to intervene using the potential methods for increasing perception of control over pain as discussed8. Potential nursing interventions for increasing control over pain include: educating patients about pain management modalities; individualizing therapy to meet patient’s needs including acceptable modifications of pharmacological regimen; providing options for patients to manage episodes of breakthrough pain; teaching patients how to use nonpharmacological modalities; and educating patients about when to call the clinician if pain is not controlled5,9. The stronger effects observed for pain-related distress and functional status were anticipated because the POP-C intervention was expected to reduce distress and increase functional status irrespective of pain. Perceived control over pain was strongly associated with pain-related distress and is more amenable to the development of nursing interventions that can improve functional status. These results support the POP-C intervention and, validate the effects of the POP-C intervention for African Americans with cancer pain. Transforming these findings into practice, use of the components of the POP-C intervention when caring for African American patients with cancer pain will allow nurses to increase patient’s perceived control over pain, leading to improved functional status.