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The statistical analysis plan for the clinical outcomes of the AZTEC trial is described.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Methods and design<\/jats:title>\n                <jats:p>A double-blind, randomised, placebo-controlled trial of a 10-day course of intravenous azithromycin (20\u00a0mg\/kg for 3\u00a0days; 10\u00a0mg\/kg for 7\u00a0days) administered to preterm infants born at\u2009&lt;\u200930\u00a0weeks\u2019 gestational age across UK tertiary neonatal units. Following parental consent, infants are randomly allocated to azithromycin or placebo, with allocated treatment starting within 72\u00a0h of birth. The primary outcome is survival without moderate\/severe CLD at 36\u00a0weeks\u2019 postmenstrual age (PMA). Serial respiratory fluid and stool samples are being collected up to 21\u00a0days of life. The target sample size is 796 infants, which is based on detecting a 12% absolute difference in survival without moderate\/severe CLD at 36\u00a0weeks\u2019 PMA (90% power, two-sided alpha of 0.05) and includes 10% loss to follow-up.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Results<\/jats:title>\n                <jats:p>Baseline demographic and clinical characteristics will be summarised by treatment arm and in total. Categorical data will be summarised by numbers and percentages. Continuous data will be summarised by mean, standard deviation, if data are normal, or median, interquartile range, if data are skewed. Tests of statistical significance will not be undertaken for baseline characteristics. The primary analysis, on the intention to treat (ITT) population, will be analysed using multilevel logistic regression, within a multiple imputation framework. Adjusted odds ratios, 95% confidence intervals, and <jats:italic>p<\/jats:italic>-values will be presented. For all other analyses, the analysis population will be based on the complete case population, which is a modified ITT population. All analyses will be adjusted for gestational age and treatment arm and account for any clustering by centre and\/or multiple births as a random effect.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Conclusion<\/jats:title>\n                <jats:p>We describe the statistical analysis plan for the AZTEC trial, including the analysis principles, definitions of the key clinical outcomes, methods for primary analysis, pre-specified subgroup analysis, sensitivity analysis, and secondary analysis. The plan has been finalised prior to the completion of recruitment.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Trial registration<\/jats:title>\n                <jats:p>ISRCTN registry ISRCTN11650227. Registered on 31 July 2018.<\/jats:p>\n              <\/jats:sec>","DOI":"10.1186\/s13063-022-06604-2","type":"journal-article","created":{"date-parts":[[2022,8,23]],"date-time":"2022-08-23T07:04:55Z","timestamp":1661238295000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["AZTEC\u2014azithromycin therapy for prevention of chronic lung disease of prematurity: a statistical analysis plan for clinical outcomes"],"prefix":"10.1186","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5894-570X","authenticated-orcid":false,"given":"Tin Man Mandy","family":"Lau","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John","family":"Lowe","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Timothy","family":"Pickles","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kerenza","family":"Hood","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sailesh","family":"Kotecha","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Gillespie","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2022,8,23]]},"reference":[{"issue":"10","key":"6604_CR1","doi-asserted-by":"publisher","first-page":"e041528","DOI":"10.1136\/bmjopen-2020-041528","volume":"10","author":"J Lowe","year":"2020","unstructured":"Lowe J, Gillespie D, Hubbard M, Zhang L, Kirby N, Pickles T, et al. 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Ethics permission has granted by the Wales Research Ethics Committee 2 (Ref 18\/WA\/0199) and regulatory permission by the Medicines and Healthcare Products Regulatory Agency (CTA reference 21323\/0050\/001\u20130001). NHS permission has been granted by the Health Research Authority and capacity and capability confirmed by each individual NHS organisation. The study is registered on EudraCT (2018\u2013001109-99), ISRCTN (ISRCTN11650227), and on the National Institute for Health Research portfolio (CPMS 39385). Cardiff University is the Sponsor.Oversight of the study is being performed by an independent Data Monitoring Committee and an independent Trial Steering Committee. Appointments to these committees were made with approval of the NIHR HTA.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval and consent to participate"}},{"value":"Parental input was obtained during the grant application on the design and conduct of the study. Parent representatives also reviewed public-facing information (e.g., information sheets and consent forms) and are members of the Trial Management Group.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent for publication"}},{"value":"The authors declare that they have no competing interests.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"704"}}