Relationship between change in pain intensity and functional outcomes in patients with chronic pain receiving twice daily extended-release hydrocodone bitartrate

Abstract

Objective: Evaluate levels of pain relief achieved in patients with chronic pain treated with hydrocodone-extended release (HC-ER) up to 48 weeks and show that these levels were associated with secondary functional and global outcomes.

Design: Post hoc analyses were based on a previously reported study that started with an open-label conversion/titration phase for ≤ 6 weeks followed by an openlabel 48-week treatment phase.

Setting: Private practice and institutional pain centers.

Participants: Three hundred ninety-one opioid-experienced subjects with moderate to severe pain for ≥ 3 months.

Interventions: Individualized doses (20-300 mg) of extended-release hydrocodone every 12 hours.

Main outcome: Almost 60 percent (232/391) of subjects achieved moderate or substantial levels of pain relief (≥ 30 percent reduction in pain score) during the study.

Results: Subjects who achieved moderate or substantial pain relief demonstrated significant (p <0.001) improvements in Oswestry Disability Inventory (ODI), all pain interference outcomes, and Subject Global Assessment of Medication. Subjects with substantial pain relief had decreases in ODI, Hospital Anxiety and Depression Scale (HADS) anxiety, and HADS depression scores of -13.4 ± 14.92, -1.9 ± 3.37, and -1.7 ± 3.26, respectively. The five most commonly reported treatment-emergent adverse events were constipation (12.5 percent), back pain (11.1 percent), nausea (9.9 percent), vomiting (9.7 percent), and arthralgia (7.8 percent) and are consistent with opioid therapy.

Conclusions: Moderate or substantial levels of pain relief were associated with the greatest functional improvements in patients treated with HC-ER. These results may help define success of opioid therapy and determine if it should be continued or an alternative treatment should be tried.

Trial registration: ClinicalTrials.gov NCT11115569.