Aims: Report weight change baseline up to 12–15 months in duloxetine-treated patients during clinical trials of chronic painful conditions of diabetic peripheral neuropathic pain (DPNP), fibromyalgia, chronic low back pain (CLBP) and chronic knee pain as a result of osteoarthritis.
Methods: Weight change data from 16 duloxetine studies in chronic painful conditions were pooled by pain condition and duration, creating 10 datasets. Datasets included placebo-controlled, open-label and routine-care-controlled designs. Assessments included mean weight change from baseline, baseline body mass index category, potentially clinically significant (PCS) weight change and weight-related treatment-emergent adverse events.
Results: Total number of patients was 5111 with mean baseline weight ranging from 70 to 97 kg. All duloxetine groups had significant mean weight loss compared with placebo at acute phase completion (p ≤ 0.001). In studies > 3 months, patients from fibromyalgia and CLBP studies had overall mean weight increase (up to 1.1 kg), whereas patients in DPNP studies had overall mean weight loss (−0.33 to −1.7 kg) at end-point. Overall, the percentage of patients with PCS weight gain was 0.4–16% and PCS weight loss was 2.5–9.9%.
Discussion: Weight change data in clinical trials of patients with fibromyalgia or CLBP treated with duloxetine for up to 15 months were consistent with data reported in 10 clinical trials of patients with major depressive disorder (MDD) using duloxetine up to 52 weeks. Patients with DPNP had weight loss at end-point.
Conclusion: Mean weight changes and percentages of patients with PCS weight loss and weight gain observed in DPNP, fibromyalgia and CLBP with long-term duloxetine treatment were consistent with those reported previously for MDD studies.