OBJECTIVES: Appropriate recognition of treatment sequencing is crucial to many policy decisions and related economic evaluations. The decision problem can become complex when accounting for extensive treatment sequences and pertinent factors relating to the disease. A methodological review was conducted to identify the breadth of decision analytic modelling approaches used for evaluating treatment sequences.

METHODS: A comprehensive literature review of MEDLINE, Embase and Cochrane library. Studies were categorised according to modelling approach and decision problem. Treatment sequencing assumptions were analysed.

RESULTS: CONCLUSIONS: Modelling treatment sequences may require a complex model, which can be time consuming to develop and implement. Using simplistic assumptions, regarding sequencing effects, results in significant uncertainty around the effectiveness and cost-effectiveness estimates, the extent of which is generally unknown. This needs to be recognised in decision making, and further evaluated.