Does Screening for Depressive Symptoms Help Optimize Duloxetine Use in Knee Osteoarthritis Patients With Moderate Pain? A Cost-Effectiveness Analysis

Objective: Duloxetine is a treatment approved by the US Food and Drug Administration for both osteoarthritis (OA) pain and depression, though uptake of duloxetine in knee OA management varies. We examined the cost-effectiveness of adding duloxetine to knee OA care in the absence or presence of depression screening.

Methods: We used the Osteoarthritis Policy Model, a validated computer microsimulation of knee OA, to examine the value of duloxetine for patients with knee OA who have moderate pain by comparing 3 strategies: 1) usual care, 2) usual care plus duloxetine for patients who screen positive for depression on the Patient Health Questionnaire 9 (PHQ-9), and 3) usual care plus universal duloxetine. Outcome measures included quality-adjusted life years (QALYs), lifetime direct medical costs, and incremental cost-effectiveness ratios (ICERs), discounted at 3% annually. Model inputs, drawn from the published literature and national databases, included annual cost of duloxetine ($721-937); average pain reduction for duloxetine (17.5 points on the Western Ontario and McMaster Universities Osteoarthritis Index pain scale [0-100]), and likelihood of depression remission with duloxetine (27.4%). We considered 2 willingness-to-pay (WTP) thresholds of $50,000/QALY and $100,000/QALY. We varied parameters related to the PHQ-9 and the cost of duloxetine, efficacy, and toxicities to address uncertainty in model inputs.

Results: The screening strategy led to an additional 17 QALYs per 1,000 subjects and increased costs by $289/subject (ICER = $17,000/QALY). Universal duloxetine led to an additional 31 QALYs per 1,000 subjects and $1,205 per subject (ICER = $39,300/QALY). Under the majority of sensitivity analyses, universal duloxetine was cost-effective at the $100,000/QALY threshold.

Conclusion: The addition of duloxetine to usual care for knee OA patients with moderate pain, regardless of depressive symptoms, is cost-effective at frequently used WTP thresholds.