Breakthrough pain in community-dwelling patients with cancer pain and noncancer pain, part 2: impact on function, mood, and quality of life

Background: Prior studies of breakthrough pain (BTP) largely focus on patients with advanced cancer or those receiving inpatient care. Very few studies have evaluated BTP in populations with chronic noncancer pain. Data that illuminate the impact of BTP may not generalize to other, less selected patient populations.Aim: The aim of this study was to evaluate the impact of BTP in opioid-treated ambulatory patients with chronic cancer pain or noncancer pain treated in community practices.Methods: Eligible patients—those with any diagnosis who reported chronic pain for at least 3 months, who were receiving long-term opioid therapy, and who met criteria for controlled baseline pain—were recruited for a cross-sectional observational study by primary care physicians or community-based oncologists at 17 sites in the United States. The patients responded to a structured interview for breakthrough pain and also completed the Brief Pain Inventory-Modified Short Form (BPI-SF) and the Brief Battery for Health Improvement 2 (BBHI 2).Results: Of 355 patients screened, 191 were eligible and 177 (93 percent) provided data for analysis. Twenty-six of the 78 with cancer pain (33 percent) and 48 of the 99 with noncancer pain (48 percent) had BTP. Compared with those without BTP, both patients with cancer (p = 0.004) and patients without cancer (p = 0.019) with BTP had increased pain interference in function, as measured by the BPI-SF, and patients without cancer were more impaired than patients with cancer. On the BBHI 2, BTP was associated with increased somatic complaints (p = 0.036 cancer and p = 0.024 noncancer) and pain complaints (p = 0.037 cancer and p = 0.037 noncancer); among patients without cancer, BTP was also associated with increased difficulties with functioning (p = 0.023), depression (p = 0.039), and decreased quality of life (p = 0.003).Conclusions: These data extend published observations about the association between BTP and adverse effects on mood and function to populations undergoing routine treatment in the community setting and provide evidence that these associations are greater in those with noncancer pain. They suggest the need for additional studies to clarify causality and determine whether undertreatment of BTP is a factor contributing to adverse pain-related outcomes.