One of the aims of E-COMPARED is to examine the value for money of a blended (Internet-based and face-to-face) treatment for depression. Internet-based treatments are offered to patients through secure websites (using a computer, smartphone or tablet), where they can access and complete treatment modules or lessons. Growing evidence demonstrates that Internet-based treatments are effective in reducing depressive symptoms (Andersson & Cuijpers, 2009). One of the advantages of Internet treatments is that they require less time input from therapists per patient in comparison with face-to-face treatments. As a result, more patients can potentially be treated simultaneously at lower costs.

It is not only about the money

Implementation of cost-effective treatments is of crucial importance for healthcare systems. Such treatments can reduce the disease burden while allocating available resources efficiently. In other words, by using scarce resources for those treatments that provide the largest benefits at the lowest costs, recovered resources can be used for other healthcare interventions (e.g. limiting waiting lists by hiring more therapists). The cost-effectiveness of an intervention in comparison with usual care is typically investigated through trial-based or model-based economic evaluations. Both types of analyses will be performed within E-COMPARED.

Trial-based economic evaluations

Trial-based economic evaluations are conducted alongside randomized controlled trials (RCTs). RCTs are deemed the ‘gold standard’ for clinical research and they involve the comparison of an intervention group to a control condition, most frequently a usual care group. In the RCT, information is collected on clinical effects (e.g. depression severity or quality-of-life) and costs (e.g. healthcare utilization, reduced work performance). Subsequently, incremental cost-effectiveness ratios (ICERs) are calculated by dividing the difference in total costs between the intervention and usual care group by the difference in clinical effects. The ICER represents the average incremental cost related to an additional unit of effect (e.g. 5000€/additional recovered patient). The main limitation of this approach is that RCTs are often of limited duration, whereas it is possible that the effects of a treatment may persist or only occur at the longer term. For instance, the RCTs conducted within E-COMPAPRED have a 12-month follow-up, it is, however, possible that the effects of the blended treatment continue after this period.

Model-based economic evaluations

Model-based economic evaluations investigate the long-term cost-effectiveness of an intervention in comparison with usual care. The purpose of model-based studies is to extrapolate beyond the observed data from RCTs and combine data from various sources. For E-COMAPRED, two health-economic models will be used to evaluate the cost-effectiveness of a blended treatment for depression in comparison with usual care over a 5-year time horizon.

One of the models, a discrete event simulation model (DES), can be used to model different patient characteristics representing pragmatically the course of depression. The DES model is very flexible and inherently tracks the individual history of each simulated patient. A preliminary version of DES model is presented in Figure 1 The second model, a cohort Markov model, is less flexible but easier to develop and more transparent for the stakeholders. The main disadvantage of the Markov model is that it is “memoryless” in the sense that it cannot capture the history of a specific individual from the simulated cohort of patients. This may be an important limitation because depression is a recurrent disorder in which the previous history influences the prognosis; for instance the probability of relapse increases with each new depressive episode.

So, what’s new?      

Currently, there is no convincing evidence regarding which of the two modelling techniques (DES model vs. Markov model) is more appropriate to simulate depression. Therefore, another aim of the E-COMPARED project is to perform a head to head comparison of the two types of models to assess whether this will lead to different recommendations regarding the long-term cost-effectiveness of the blended treatment in comparison with usual care for depression.


Figure 1. DES model examining the cost-effectiveness of a blended treatment for depression in comparison with usual care in a 5-year time horizon. Red squares represent the computational framework of the proposed model. Blue circles represent the conceptual framework of the model. The circles show the possible events and the arrows indicate the relationships between these events.


Andersson, G., & Cuijpers, P. (2009). Internet-based and other computerized psychological treatments for adult depression: a meta-analysis. Cogn Behav Ther, 38(4), 196-205. doi:10.1080/16506070903318960


Spyros Kolovos, M.Sc.
VU University Amsterdam, Amsterdam
The Netherlands