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.

Breakthrough pain in community-dwelling patients with cancer pain and noncancer pain, part 1: prevalence and characteristics.

BACKGROUND: Most breakthrough pain (BTP) studies assess patients with advanced cancer or those receiving inpatient care. Studies in noncancer populations are limited to surveys of pain clinics and patients with other advanced diseases. To better understand BTP, data are needed from less selected populations. AIM: The aim of this study was to evaluate BTP in opioid-treated ambulatory patients with chronic cancer or noncancer pain treated in community practices. METHODS: Primary care physicians or community-based oncologists recruited a convenience sample for a cross-sectional study of BTP at 17 sites in the United States. Physicians could not be pain specialists. Patients were eligible if they had any type of pain for > or = 3 months and were receiving an opioid drug on a regular basis that controlled the pain. The patients responded to a structured interview comprising items that assessed the baseline pain and items that assessed BTP, if present. RESULTS: In total, 355 patients were screened, 191 were eligible and 177 (93 percent) provided data for analysis. Seventy-eight patients had cancer pain and 99 had noncancer pain. Patients with cancer were older (mean +/- SD age 61.3 +/- 11.2 years vs 51.4 +/- 13.6 years, p < 0.001), and patients without cancer had more neuropathic pain (21 vs 12 percent, p < 0.05) and a longer pain duration (median 3.5 vs 1 years, p < 0.001). BTP occurred in 33 percent with cancer and 48 percent with noncancer pain (p = 0.042). BTP did not vary by diagnosis, but neuropathic pain was more common in those with BTP (27 vs 10 percent, p < 0.001). In patients with and without cancer, the median daily number of episodes was 1, the median time to maximum pain was 1-2 minutes, and the median duration was 45-60 minutes. There were fewer BTP precipitants in the patients with cancer (46 vs 80 percent of pains, p < 0.05), and they had less predictable pain (p < 0.05). CONCLUSIONS: The prevalence of BTP among community-dwelling patients is lower than that found in prior studies of more selected populations. BTP is more prevalent among patients with noncancer pain than patients with cancer pain, and although there are many similarities, some differences may be relevant to treatment strategies.