ORIGINAL CONTRIBUTION Optimising trial outcomes and patient retention for the MACRO trial for chronic rhinosinusitis* Abstract Background: This study aimed to evaluate current subjective and objective outcome assessments for the MACRO (defning best Management for Adults with Chronic RhinOsinusitis) Trial which compares antibiotics, placebo and sinus surgery. This was to iden- tify any redundant assessments and to include patient perspectives to determine acceptability for confrmation in the trial. Methods : Adults CRS patients meeting the provisional eligibility criteria for the MACRO trial were recruited to this mixed-method study at 2 sites. Correlations between the objective outcome measures and SNOT-22 scores were evaluated. Selected participants took part in a semi-structured telephone interview to explore their experiences and views of undergoing outcome measures. Results: Seventy patients (37% male) were recruited, 36 had CRS without nasal polyps, 34 had CRS with nasal polyps. There was a weak inverse correlation between the SNOT-22 “Blockage” ratings and Peak Nasal Inspiratory Flow readings, a moderate inverse correlation between the SNOT-22 “Smell” ratings and Snifn’ Sticks scores, but no signifcant correlation between the SNOT-22 and Saccharin test results. The participants’ experience of the trial visit was positive with an acceptable duration of trial visit. Most proposed outcome measures were valued by participants with the exception of the Saccharin test. Discussion: The Sniffin’ Sticks test and PNIF correlate with their respective component SNOT-22 scores but are considered important by patients; PNIF is simple, cheap test to perform. The Saccharin test will be removed as participants did not value it and was not highly rated in parallel work on a core outcome set for CRS. Key words: outcome assessment, chronic rhinosinusitis, endoscopic sinus surgery, randomised controlled trial, patient selection- reported outcome measures Ngan Hong Ta 1 , Claire Hopkins 2 , Jane Vennik 3 , Carl Philpott 1,4 1 Norwich Medical School, University of East Anglia, Norwich, UK 2 ENT Department, Guy’s and St Thomas’ NHS Foundation Trust, London, UK 3 University of Southampton, Southampton, UK 4 ENT Department, James Paget University Hospital NHS Foundation Trust, Great Yarmouth, UK Rhinology 57: 0, 000 - 000, 2019 https://doi.org/10.4193/Rhin19.142 *Received for publication: April 5, 2019 Accepted: June 17, 2019 1 Introduction Chronic Rhinosinusitis (CRS) is a common sinonasal syndrome but current guidance on treatments is limited by a paucity or low quality of evidence on which it is based. A series of Cochra- ne reviews evaluating the efectiveness of medical treatments in CRS confrmed the lack of high quality RCTs but also the lack of consistent outcome measures for this condition (1-3) . The Eu- ropean Position Paper on Rhinosinusitis and Nasal Polyps (EPOS 2012) (4) emphasised that one of the research needs is to address this gap in the evidence base. In 2016, the UK National Institute of Health Research (NIHR) funded the MACRO Programme (De- fning best Management of Adults with Chronic RhinOsinusitis) for £3.2 million to include a 3-arm multi-centre randomised con- trolled trial (RCT) to compare longer-term antibiotics, placebo and endoscopic sinus surgery simultaneously (5) . The selection of appropriate outcome measures is crucial in designing any multicentre RCTs. The chosen outcome measures should satisfy both requirements of being able to measure the efect of diferent interventions and to measure outcomes consi- dered to be important to patients (6) . With the proposed MACRO trial in mind, the research team were keen to ensure that any objective outcome measures provided meaningful information Corrected Proof