Opioids in Non-Cancer Pain: Improvements in Disability with Fentanyl Transdermal System Treatment for Chronic Low Back Pain: Results from an Observational Trial

Chronic low back pain (CLBP) burdens patients with numerous challenges, including functional limitations and disability. Restoration of function - including physical, social, and mental functioning - is essential for a successful treatment plan. Although pain relief is an important outcome, the subjective report of pain relief is a problematic measure. Given the complexity of CLBP and its assessment, functional and health-related quality of life measures are extremely valuable. The objective was to determine the impact of treatment with transdermal fentanyl (TDF) on functional disability in CLBP patients. An observational, naturalistic trial at 17 clinical centers in the US; CLBP patients were eligible if their physicians were transitioning them from short-acting opioids to TDF. Patients completed the Oswestry Disability Index (ODI), an instrument consisting of 10 questions designed to assess disability in patients with back pain. A 10-point numeric rating scale (NRS) of pain intensity was also used. Both measurements were taken at baseline and following a minimum of 9 weeks of treatment. 122 patients completed the baseline and follow-up visits; 36% male; mean age 46.1±10.6 years; mean CLBP duration 106.4±98.2 months). At baseline, mean total ODI score was 53.6±13.1, suggesting relatively high disability; mean NRS was 7.5±1.5. At follow-up, mean ODI score improved 6.5±13.1 points (p<0.001), corresponding to a moderate effect size (0.50). The NRS score improved 1.4±2.0 points (p<0.001). The change in ODI exceeds the accepted minimal clinically important difference, indicating that patients experienced a clinically significant improvement in functioning. Significant improvements on the ODI and NRS were observed for both genders. In this preliminary analysis in a usual-care setting, TDF treatment for at least 9 weeks significantly reduced disability and pain intensity in patients with CLBP.