Duloxetine 120 mg produced more quality-adjusted life-years compared with amitriptyline in adult patients with moderate to severe fibromyalgia in a decision analytical model.
Investigators used a Markov cohort state transition model to estimate lifetime costs and quality-adjusted life-years (QALY) associated with amitriptyline and three US Food and Drug Administration–approved fibromyalgia treatments: pregabalin, duloxetine, and milnacipran. The simulated cohort reflected patients aged 18 years or older with moderate to severe fibromyalgia and consisted predominantly of women (94.4%) with a mean age of 48.4 years.
The model incorporated treatment-specific transition probabilities from a Bayesian network meta-analysis of 36 randomized clinical trials, along with utility values and direct and indirect costs derived from published sources. The patients transitioned annually between mild, moderate, and severe pain states or mortality over a lifetime horizon.
From the US health care payer perspective, which included indirect costs such as productivity losses, duloxetine 120 mg generated more QALYs compared with amitriptyline (10.40 vs 9.99) at slightly higher lifetime cost ($115,770 vs $115,145), yielding an incremental cost-effectiveness ratio of $1,536 per QALY. At a willingness-to-pay threshold of $100,000 per QALY, duloxetine 120 mg produced an incremental net monetary benefit of $40,075 vs amitriptyline.
Several strategies were economically dominated, meaning they resulted in higher costs with fewer QALYs than competing options. These included pregabalin 150 mg, 300 mg, and 600 mg; duloxetine 60 mg; and both milnacipran regimens. Pregabalin 450 mg also generated fewer QALYs compared with duloxetine 120 mg despite higher lifetime cost ($117,434).
When indirect costs such as productivity losses were included, duloxetine 120 mg produced the highest QALYs (10.40) and the lowest lifetime cost ($712,910), making it cost-saving relative to amitriptyline. Pregabalin 450 mg also generated more QALYs compared with amitriptyline (10.23 vs 9.99) at lower cost ($725,782 vs $741,972), although it remained economically dominated by duloxetine 120 mg.
Sensitivity analyses showed that duloxetine 120 mg had the highest probability of being cost-effective across most willingness-to-pay thresholds, although the probability didn't exceed 55%, reflecting uncertainty in model parameters.
The investigators noted that the model didn't fully capture real-world treatment patterns such as dose adjustments or combination therapy and relied on published cost estimates that may vary across practice settings.
“These findings suggest that duloxetine 120 mg offers the greatest economic value for this patient population while highlighting the importance of accounting for societal costs in fibromyalgia treatment decisions,” wrote lead study author Sarah S. Downen, PharmD, MS, of the Department of Pharmaceutical Outcomes and Policy at the College of Pharmacy at the University of Florida, and colleagues.
The authors reported no conflicts of interest.
Source: JAMA Network Open