Outcomes
Only clinical outcomes were used as endpoints in the analysis, as shown
in Figure 1. The reasons why certain secondary outcomes were not
explicitly included in the decision tree are shown in Appendix S2. While
these outcomes were not assigned individual nodes, the use of NHS
guidelines (Appendix S3) allowed for the cost of these outcomes to be
grouped and used in the cost of treatment complications included in the
decision tree.
The data on outcomes was collected in two ways in the ANODE trial.
Firstly, the number of people with one of the primary outcomes of
suspected maternal infection was recorded 6 weeks after delivery through
telephone interviews and hospital records. The secondary outcomes were
collected based on a questionnaire also completed at the same time and
included their Mean EQ-5D-5L values1.
The EQ-5D-5L score ranges from 0 to 1, with a higher score indicating
greater quality of life. The ANODE trial reported a mean EQ-5D-5L score
of 0.935 and 0.927 for the co-amoxiclav and placebo groups
respectively1. However, within these groups there was
variation that needed to be considered such as those patients that
experienced sepsis or no infection at all. To account for this, an
EQ-5D-5L score for sepsis of 0.848 was acquired from the
literature16. All other endpoints of the decision tree
involved forms of localised infection or systemic infection not
resulting in sepsis and were accordingly attributed the mean EQ-5D-5L
value reported in the ANODE trial1. Due to the short
6-week time horizon, no discounting of benefit data was
required17.