1287:
157:
variation of this is the participants who receive the treatment from the group they were not allocated to, who should be kept in their original group for the analysis. This issue causes no problems provided that the systematic reviewer can extract the appropriate data from the trial reports. The rationale for this approach is that, in the first instance, the goal is to estimate the effects of allocating an intervention in practice, not the effects in the subgroup of the participants who adhere to it.
1275:
55:
status for units assigned to different treatments or incorporation of compliance into the analysis. Although ITT analysis is widely employed in published clinical trials, it can be incorrectly described and there are some issues with its application. Furthermore, there is no consensus on how to carry
156:
ITT analysis requires participants to be included even if they did not fully adhere to the protocol. Participants who strayed from the protocol (for instance, by not adhering to the prescribed intervention, or by being withdrawn from active treatment) should still be kept in the analysis. An extreme
90:
In an ITT population, none of the patients are excluded and the patients are analyzed according to the randomization scheme. In other words, for the purposes of ITT analysis, everyone who is randomized in the trial is considered to be part of the trial regardless of whether he or she is dosed or
94:
For example, if people who have a more refractory or serious problem tend to drop out of a study at a higher rate, even a completely ineffective treatment may appear to be providing benefits if one merely compares the condition before and after the treatment for only those who finish the study
457:
Chêne, Geneviève; Morlat, Philippe; Leport, Catherine; Hafner, Richard; Dequae, Laurence; Charreau, Isabelle; Aboulker, Jean-Pierre; Luft, Benjamin; Aubertin, Jean; Vildé, Jean-Louis; Salamon, Roger (June 1998). "Intention-to-Treat vs. On-Treatment
Analyses of Clinical Trial Data".
143:
which selects the subset of the patients who received the treatment of interest—regardless of initial randomization—and who have not dropped out for any reason. This approach can introduce biases to the statistical analysis. It can also inflate the chance of
136:(for instance, by withdrawal due to adverse effects of the intervention) and no response is obtainable for these patients. However, full application of ITT analysis can only be performed where there is complete outcome data for all randomized subjects.
679:
Alshurafa, Mohamad; Briel, Matthias; Akl, Elie A.; Haines, Ted; Moayyedi, Paul; Gentles, Stephen J.; Rios, Lorena; Tran, Chau; Bhatnagar, Neera; Lamontagne, Francois; Walter, Stephen D.; Guyatt, Gordon H. (15 November 2012).
257:
Alshurafa, Mohamad; Briel, Matthias; Akl, Elie A.; Haines, Ted; Moayyedi, Paul; Gentles, Stephen J.; Rios, Lorena; Tran, Chau; Bhatnagar, Neera; Lamontagne, Francois; Walter, Stephen D.; Guyatt, Gordon H. (2012).
46:
is based on the initial treatment assignment and not on the treatment eventually received. ITT analysis is intended to avoid various misleading artifacts that can arise in intervention research such as non-random
139:
In order to include such participants in an analysis, outcome data could be imputed which involves making assumptions about the outcomes in the lost participants. Another approach would be
79:
to the treatment groups in a study. ITT analysis provides information about the potential effects of treatment policy rather than on the potential effects of specific treatment.
344:"Modified versus standard intention-to-treat reporting: are there differences in methodological quality, sponsorship, and findings in randomized trials? A cross-sectional study"
754:
67:
analyzed by the intention-to-treat (ITT) approach provide unbiased comparisons among the treatment groups. Intention to treat analyses are done to avoid the effects of
103:
Medical investigators often have difficulties in completing ITT analysis because of clinical trial issues like missing data or poor treatment protocol adherence.
106:
To address some of these issues, many clinical trials have excluded participants after the random assignment in their analysis, which is often referred to as
642:
Heritier, Stephane R; Gebski, Val J; Keech, Anthony C (October 2003). "Inclusion of patients in clinical trial analysis: the intention-to-treat principle".
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of participants from the study or crossover. ITT is also simpler than other forms of study design and analysis, because it does not require observation of
1046:
1042:
1092:
1050:
1038:
747:
1213:
1129:
317:
48:
740:
682:"Inconsistent Definitions for Intention-To-Treat in Relation to Missing Outcome Data: Systematic Review of the Methods Literature"
260:"Inconsistent Definitions for Intention-To-Treat in Relation to Missing Outcome Data: Systematic Review of the Methods Literature"
1251:
82:
Since it started in the 1960s, the principle of ITT has become widely accepted for the analysis of controlled clinical trials.
132:
An important problem is the occurrence of missing data for participants in a clinical trial. This can happen when patients are
1096:
818:
929:
1244:
1265:
1223:
164:, only patients who complete the entire clinical trial according to the protocol are counted towards the final results.
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Montedori A; Bonacini MI; Casazza G; Luchetta ML; Duca P; Cozzolino F; Abraha I. (February 2011).
1291:
1134:
1084:
899:
828:
786:
667:
566:"What is meant by intention to treat analysis? Survey of published randomised controlled trials"
210:"What is meant by intention to treat analysis? Survey of published randomised controlled trials"
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321:
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95:(ignoring those who were enrolled originally, but have since been excluded or dropped out).
17:
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1000:
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68:
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370:
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259:
183:
72:
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471:
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393:
Lachin JM (June 2000). "Statistical
Considerations in the Intent-to-Treat Principle".
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499:"Understanding the Intention-to-treat Principle in Randomized Controlled Trials"
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out an ITT analysis in the presence of missing outcome data.
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1196:
1158:
1107:
1057:
1031:
993:
963:
954:
880:
827:
774:
110:or mITT. Trials employing mITT have been linked to
607:Montori, V. M.; Guyatt, G. H. (13 November 2001).
208:Hollis, Sally; Campbell, Fiona (September 1999).
148:; this effect is greater the larger the trial.
564:Hollis, S.; Campbell, F. (11 September 1999).
748:
8:
960:
755:
741:
733:
715:
705:
624:
589:
522:
406:
369:
359:
293:
283:
233:
1047:Preventable fraction among the unexposed
1043:Attributable fraction for the population
1270:
1051:Preventable fraction for the population
1039:Attributable fraction among the exposed
200:
503:Western Journal of Emergency Medicine
7:
1214:Correlation does not imply causation
1130:Animal testing on non-human primates
613:Canadian Medical Association Journal
108:modified intention-to-treat analysis
27:Form of analysis for clinical trials
541:"Intention-to-treat analysis (ITT)"
656:10.5694/j.1326-5377.2003.tb05627.x
25:
318:"Further issues in meta-analysis"
1285:
1273:
497:McCoy, Eric (18 October 2017).
1097:Pre- and post-test probability
819:Patient and public involvement
609:"Intention-to-treat principle"
1:
472:10.1016/s0197-2456(97)00145-1
417:10.1016/S0197-2456(00)00046-5
1224:Sex as a biological variable
707:10.1371/journal.pone.0049163
644:Medical Journal of Australia
515:10.5811/westjem.2017.8.35985
285:10.1371/journal.pone.0049163
1188:Intention-to-treat analysis
1160:Analysis of clinical trials
1089:Specificity and sensitivity
843:Randomized controlled trial
558:Intention-to-Treat Analysis
189:Randomized controlled trial
179:Protocol (natural sciences)
174:Analysis of clinical trials
44:randomized controlled trial
18:Intention to treat analysis
1339:
460:Controlled Clinical Trials
395:Controlled Clinical Trials
125:
65:Randomized clinical trials
1232:
1197:Interpretation of results
930:Nested case–control study
799:Academic clinical trials
582:10.1136/bmj.319.7211.670
446:Nature Clinical Practice
226:10.1136/bmj.319.7211.670
141:efficacy subset analysis
1017:Relative risk reduction
865:Adaptive clinical trial
809:Evidence-based medicine
792:Adaptive clinical trial
361:10.1186/1745-6215-12-58
1005:Number needed to treat
91:completes the trial.
75:, which may break the
1009:Number needed to harm
896:Cross-sectional study
848:Scientific experiment
804:Clinical study design
438:Per-protocol analysis
162:per-protocol analysis
152:Adherence to protocol
116:conflicts of interest
975:Cumulative incidence
160:In comparison, in a
112:industry sponsorship
42:of the results of a
882:Observational study
814:Real world evidence
768:experimental design
698:2012PLoSO...749163A
276:2012PLoSO...749163A
1168:Risk–benefit ratio
1135:First-in-man study
1085:Case fatality rate
926:Case–control study
900:Longitudinal study
552:Intention to Treat
32:intention-to-treat
1323:Clinical research
1261:
1260:
1209:Survivorship bias
1173:Systematic review
1140:Multicenter trial
1103:
1102:
1093:Likelihood-ratios
1065:Clinical endpoint
1033:Population impact
987:Period prevalence
764:Clinical research
619:(10): 1339–1341.
576:(7211): 670–674.
220:(7211): 670–674.
134:lost to follow-up
77:random assignment
16:(Redirected from
1330:
1290:
1289:
1278:
1277:
1276:
1269:
1108:Trial/test types
983:Point prevalence
961:
904:Ecological study
887:EBM II-2 to II-3
858:Open-label trial
853:Blind experiment
829:Controlled study
757:
750:
743:
734:
729:
719:
709:
675:
638:
628:
603:
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509:(6): 1075–1078.
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320:. Archived from
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146:a false positive
118:by the authors.
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1313:Clinical trials
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1001:Risk difference
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787:Trial protocols
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408:10.1.1.463.2948
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30:In medicine an
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1252:List of topics
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1125:Animal testing
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1077:Mortality rate
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870:Platform trial
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782:Clinical trial
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692:(11): e49163.
676:
650:(8): 438–440.
639:
604:
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491:External links
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466:(3): 233–248.
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184:Clinical trial
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126:Main article:
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1183:Meta-analysis
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1150:Vaccine trial
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1145:Seeding trial
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914:Retrospective
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834:EBM I to II-1
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324:on 2013-11-10
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1025:Hazard ratio
909:Cohort study
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326:. Retrieved
322:the original
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128:Missing data
122:Missing data
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31:
29:
1318:Experiments
1292:Mathematics
1219:Null result
1178:Replication
1073:Infectivity
995:Association
946:Case report
936:Case series
919:Prospective
554:– Tufts.edu
1302:Categories
1021:Odds ratio
1013:Risk ratio
979:Prevalence
965:Occurrence
941:Case study
328:2012-11-02
195:References
53:compliance
1081:Morbidity
1069:Virulence
971:Incidence
545:Bandolier
403:CiteSeerX
354:(1): 58.
69:crossover
60:Rationale
49:attrition
1280:Medicine
1245:Glossary
1238:Category
1115:In vitro
956:Measures
775:Overview
726:23166608
686:PLOS ONE
672:20646182
664:14558871
635:11760981
600:10480822
560:– Bu.edu
533:29085540
442:Glossary
425:10822117
380:21356072
304:23166608
264:PLOS ONE
244:10480822
168:See also
40:analysis
1266:Portals
1120:In vivo
717:3499557
694:Bibcode
524:5654877
480:9620807
444:of the
371:3055831
295:3499557
272:Bibcode
86:Example
73:dropout
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348:Trials
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99:Issues
1059:Other
668:S2CID
626:81628
591:28218
235:28218
898:vs.
766:and
722:PMID
660:PMID
631:PMID
596:PMID
529:PMID
476:PMID
421:PMID
376:PMID
300:PMID
240:PMID
114:and
71:and
712:PMC
702:doi
652:doi
648:179
621:PMC
617:165
586:PMC
578:doi
574:319
570:BMJ
519:PMC
511:doi
468:doi
413:doi
366:PMC
356:doi
290:PMC
280:doi
230:PMC
222:doi
218:319
214:BMJ
36:ITT
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34:(
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