Duloxetine use in chronic painful conditions – individual patient data responder analysis
Article first published online: 3 JUN 2013
© 2013 The Authors. European Journal of Pain published by John Wiley & Sons Ltd on behalf of European Pain Federation - EFIC®.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
European Journal of Pain
Volume 18, Issue 1, pages 67–75, January 2014
How to Cite
Moore, R.A., Cai, N., Skljarevski, V. and Tölle, T. R. (2014), Duloxetine use in chronic painful conditions – individual patient data responder analysis. European Journal of Pain, 18: 67–75. doi: 10.1002/j.1532-2149.2013.00341.x
There was no direct funding source. Institutional support came from the Oxford Pain Relief Trust.
Conflicts of interest
RAM reports board membership, consultancy, or lecture fees from Reckitt Benkiser, Pfizer, MSD, Eli Lilly, Menarini and Astellas. TRT reports board membership, consultancy or lecture fees from Astellas, Grünenthal, Eli Lilly, UCB, Pfizer, Mundipharma, Janssen-Cilag. VS and NC are employees of Eli Lilly and Company and may be minor shareholders.
- Issue published online: 9 DEC 2013
- Article first published online: 3 JUN 2013
- Manuscript Accepted: 3 MAY 2013
Duloxetine has been studied in four distinct chronic pain conditions – osteoarthritis (OA), fibromyalgia, chronic low back pain (CLBP) and diabetic peripheral neuropathic pain (DPNP). These trials have involved large numbers of patients with at least moderate pain, and have used similar methods for recording pain intensity, over about 12 weeks.
Data from the trials were pooled according to painful condition, and reanalysed at the level of the individual patient and using increasing levels of pain intensity reduction (<15%, 15–29%, 30–49%, ≥50%), with different imputation methods on withdrawal.
The proportion of patients recording at least 50% pain intensity reduction plateaued after 2–6 weeks in fibromyalgia, and 8–12 weeks in other conditions. The duloxetine-specific benefit [number needed to treat (NNT) for at least 50% pain intensity reduction] was fairly constant after about 2 weeks for DPNP and fibromyalgia and after about 4 or 5 weeks for OA and CLBP. In all conditions, responses were bimodal, with patients generally experiencing either very good or very poor pain relief. Last-observation-carried-forward imputation produced numerically and occasionally statistically better (lower) NNTs than use of baseline-observation-carried-forward (true response).
Baseline-observation-carried-forward (true response), which combines the success of high levels of pain relief with the failure to experience pain relief on withdrawal of the drug is conservative and probably reflective of clinical practice experience. The distribution of effect was not normal; few patients had the average response and averages are not an appropriate descriptor for these data.