Objective: The purpose of this study was to estimate and compare the disease burden of depression in Germany using preference-based valuations of depressive health states.
Methods: The data came from the European Study of the Epidemiology of Mental Disorders (ESEMeD) in which a representative sample of 3555 non-institutionalised adults aged 18 years or older was interviewed in Germany. Computer assisted personal interviews included EQ-5D, SF-12, time trade-off (TTO) and contingent valuation (willingness-to-pay, WTP). Respondents in whom 12-month prevalence for a depressive disorder according to DSM-IV was identified, were compared to respondents without depressive disorders (controls). Disease burden was measured in terms of loss of quality-adjusted life years (QALYs) and loss of monetary benefit due to depression per year. Valuations of health-related quality of life (HRQL) were derived from EQ-5D (EQ VAS and EQ-5D Index), SF-12 (SF-6D Index) and TTO. Disease burden was estimated by calculating the difference between individual valuation of HRQL/WTP for full health of cases and mean valuation/WTP of controls matched by age and gender. Results were extrapolated to the total population.
Results: Depending on the valuation method, the loss of QALYs per year due to depression in Germany was 144,886 (TTO), 239,152 (EQ-5D Index VAS), 265,085 (EQ-5D Index TTO), 307,139 (EQ VAS) and 403,373 (SF-6D Index). The additional WTP for full health amounted to 4.3 billion Euro.
Conclusions: Depressive disorders caused a substantial disease burden. Subjects affected by depression showed lower preference-based scores compared to subjects without depression. However, calculated QALY losses varied strongly by valuation method.