Intention-to-treat analysis may be more conservative than per protocol analysis in antibiotic non-inferiority trials: a systematic review

Autor: Anthony D. Bai, Adam S. Komorowski, Carson K. L. Lo, Pranav Tandon, Xena X. Li, Vaibhav Mokashi, Anna Cvetkovic, Aidan Findlater, Laurel Liang, George Tomlinson, Mark Loeb, Dominik Mertz, for the McMaster Infectious Diseases Fellow Research Group
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: BMC Medical Research Methodology, Vol 21, Iss 1, Pp 1-10 (2021)
Druh dokumentu: article
ISSN: 1471-2288
DOI: 10.1186/s12874-021-01260-7
Popis: Abstract Background In non-inferiority trials, there is a concern that intention-to-treat (ITT) analysis, by including participants who did not receive the planned interventions, may bias towards making the treatment and control arms look similar and lead to mistaken claims of non-inferiority. In contrast, per protocol (PP) analysis is viewed as less likely to make this mistake and therefore preferable in non-inferiority trials. In a systematic review of antibiotic non-inferiority trials, we compared ITT and PP analyses to determine which analysis was more conservative. Methods In a secondary analysis of a systematic review, we included non-inferiority trials that compared different antibiotic regimens, used absolute risk reduction (ARR) as the main outcome and reported both ITT and PP analyses. All estimates and confidence intervals (CIs) were oriented so that a negative ARR favored the control arm, and a positive ARR favored the treatment arm. We compared ITT to PP analyses results. The more conservative analysis between ITT and PP analyses was defined as the one having a more negative lower CI limit. Results The analysis included 164 comparisons from 154 studies. In terms of the ARR, ITT analysis yielded the more conservative point estimate and lower CI limit in 83 (50.6%) and 92 (56.1%) comparisons respectively. The lower CI limits in ITT analysis favored the control arm more than in PP analysis (median of − 7.5% vs. -6.9%, p = 0.0402). CIs were slightly wider in ITT analyses than in PP analyses (median of 13.3% vs. 12.4%, p
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