Cost-utility estimates in depression: does the valuation method matter?

Area of Science:

• Health Economics
• Psychiatry
• Clinical Trials

Background:

• Depression significantly burdens society and healthcare systems.
• Cost-utility analyses are crucial for evaluating depression treatments and informing healthcare prioritization.
• Generic preference-based instruments are recommended for measuring utility, but disease-specific methods like depression-free days (DFD) are often used in depression research.

Purpose of the Study:

• To compare utility measurement techniques in a randomized controlled trial for depression.
• To assess the agreement between Quality-Adjusted Life Years (QALYs) measured by the EuroQol (EQ-5D), Short Form 6D (SF-6D), and DFD method.
• To determine if different utility measurement techniques influence conclusions for healthcare decision-makers.

Main Methods:

• Data from the Depression in Elderly with Long-Term Afflictions (DELTA) study, a randomized controlled trial.
• Inclusion of chronically ill patients with co-occurring minor or mild to moderate major depression.
• Assessment of EQ-5D, SF-6D, and Beck Depression Inventory (for DFD estimation) at baseline and at 3, 6, and 12 months.

Main Results:

• Poor agreement was observed between the EQ-5D and DFD methods (Kendall's Tau: 0.33).
• Moderate agreement was found between the EQ-5D and SF-6D (Kendall's Tau: 0.60).
• Despite differing agreement levels, incremental cost-utility ratios led to similar conclusions for decision-makers across all techniques.

Conclusions:

• Utilities derived from the disease-specific DFD method should not be directly compared with those from generic instruments like the EQ-5D.
• Generic instruments are preferred for cost-utility analyses and healthcare prioritization.
• Further research is needed to validate utility weights for the DFD method if it is to be used in the future.