Footnotes

• Contributors LZ and ERS: data acquisition and analysis, writing and editing of manuscript. AR: data acquisition and patient recruitment. NAK: ethics and patient recruitment. LF: data acquisition and supervision. MM: study design, obtained funding, critical review of manuscript. MMW, NJT and GH: study concept and design, obtained funding, critical review of manuscript.

• Funding We would like to acknowledge the project support of the Princess Alexandra Hospital (PA) Research Foundation and the NHMRC (APP1084544).

• Competing interests None declared.

• Ethics approval Metro South Health Human Research Ethics Committee; The University of Queensland Medical Research Ethics Committee. Written consent was obtained from all participants.

• Provenance and peer review Not commissioned; internally peer reviewed.