Efficacy of the Sustained-Release Hydromorphone in Neuropathic Pain Management: Pooled Analysis of Three Open-Label Studies

This pooled analysis was designed to determine whether the analgesic response to treatment with OROS hydromorphone, as measured by the "pain on average" scale of the Brief Pain Inventory (BPI), was different in patients with neuropathic pain compared to those with nociceptive pain, after adjusting for differences in baseline characteristics. Three open-label studies on patients with neuropathic and nociceptive malignant and nonmalignant chronic pain were analyzed. A mixed model for repeated measures linear regression analysis was used to compare the effect of OROS hydromorphone on patients with neuropathic and nociceptive pain, adjusting for potentially confounding factors. Data from patients with pure neuropathic pain and mixed pain were also compared. Safety and tolerability was assessed by recording the number of adverse events. The primary outcome was "pain on average" (BPI item 5) over time. Secondary outcomes were the effect of OROS hydromorphone on other BPI items including "pain relief" and "interference with sleep." Patients with neuropathic pain showed a similar response to treatment with OROS hydromorphone to those patients with nociceptive pain. There was no statistically significant difference between the pain groups (difference between groups -0.552 at visit 7; P = .060 for overall difference between groups). For some outcome variables, treatment was more effective for patients with neuropathic pain. The treatment was generally well tolerated. This pooled analysis shows that treatment with OROS hydromorphone had similar efficacy for neuropathic and nociceptive pain.