Authors’ contributions
JCT, ELT, EW, RMM and SMN contributed to the design, implementation and analysis of this methodological study. JLD, DEN, FCH, SMN, ELT and RMM were responsible for obtaining funding and for the design and implementation of the CAP trial on which the study is based. EW managed the data used in the study. All authors reviewed the manuscript. The author(s) read and approved the final manuscript.