Intention-to-treat Concept: A Review

Overview

Journal Perspect Clin Res

Specialty General Medicine

Date 2011 Sep 8

PMID 21897887

Citations 667

Authors

Sandeep K Gupta

Affiliations

Soon will be listed here.

Abstract

Randomized controlled trials often suffer from two major complications, i.e., noncompliance and missing outcomes. One potential solution to this problem is a statistical concept called intention-to-treat (ITT) analysis. ITT analysis includes every subject who is randomized according to randomized treatment assignment. It ignores noncompliance, protocol deviations, withdrawal, and anything that happens after randomization. ITT analysis maintains prognostic balance generated from the original random treatment allocation. In ITT analysis, estimate of treatment effect is generally conservative. A better application of the ITT approach is possible if complete outcome data are available for all randomized subjects. Per-protocol population is defined as a subset of the ITT population who completed the study without any major protocol violations.

Citing Articles

TaiChi-MSS protocol: enhancing cognitive and brain function in MCI patients through Tai Chi exercise combined with multisensory stimulation.

Zhou C, Yang G, Wang Y, Zhu R, Zhu D Front Aging Neurosci. 2025; 17:1514127.

PMID: 40071122 PMC: 11893585. DOI: 10.3389/fnagi.2025.1514127.

Effects of Accentuated Eccentric and Maximal Strength High-Resistance Training Programs with or Without a Curcumin-Based Formulation Supplement on Body Composition, Blood Pressure, and Metabolic Parameters in Older Adults.

Juesas A, Saez-Berlanga A, Babiloni-Lopez C, Martin E, Garrigues-Pelufo L, Ferri-Caruana A Diseases. 2025; 13(2).

PMID: 39997069 PMC: 11854016. DOI: 10.3390/diseases13020062.

Assessing the effectiveness of continuous glucose monitoring compared with conventional monitoring in enhancing surgical outcomes for patients with diabetes: protocol for a multicentre, parallel-arm, randomised, pragmatic trial in China.

Duan Y, Ding L, Gao Z, Wang Y, Cao H, Zhang H BMJ Open. 2025; 15(2):e090664.

PMID: 39965943 PMC: 11836829. DOI: 10.1136/bmjopen-2024-090664.

The "SES NXT" digital intervention for children of relationship dissolution: Study protocol for a randomized controlled trial study.

Overup C, Johnsen D, Skriver M, Sander S, Lange T, Hald G Internet Interv. 2025; 39():100797.

PMID: 39807447 PMC: 11728899. DOI: 10.1016/j.invent.2024.100797.

Efficacy of home based computerized adaptive cognitive training in patients with post stroke cognitive impairment: a randomized controlled trial.

Soni A, Kumar M, Kothari S Sci Rep. 2025; 15(1):1072.

PMID: 39774282 PMC: 11707344. DOI: 10.1038/s41598-025-85511-3.

References

Sheiner L . Is intent-to-treat analysis always (ever) enough?. Br J Clin Pharmacol. 2002; 54(2):203-11. PMC: 1874399. DOI: 10.1046/j.1365-2125.2002.01628.x. View

Lewis J, Machin D . Intention to treat--who should use ITT?. Br J Cancer. 1993; 68(4):647-50. PMC: 1968589. DOI: 10.1038/bjc.1993.402. View

Heritier S, Gebski V, Keech A . Inclusion of patients in clinical trial analysis: the intention-to-treat principle. Med J Aust. 2003; 179(8):438-40. DOI: 10.5694/j.1326-5377.2003.tb05627.x. View

Sainani K . Making sense of intention-to-treat. PM R. 2010; 2(3):209-13. DOI: 10.1016/j.pmrj.2010.01.004. View

Montori V, Guyatt G . Intention-to-treat principle. CMAJ. 2002; 165(10):1339-41. PMC: 81628. View

Streiner D, Geddes J . Intention to treat analysis in clinical trials when there are missing data. Evid Based Ment Health. 2002; 4(3):70-1. DOI: 10.1136/ebmh.4.3.70. View

DAgostino Sr R, Massaro J, Sullivan L . Non-inferiority trials: design concepts and issues - the encounters of academic consultants in statistics. Stat Med. 2003; 22(2):169-86. DOI: 10.1002/sim.1425. View

Soares I, Vaz Carneiro A . Intention-to-treat analysis in clinical trials: principles and practical importance. Rev Port Cardiol. 2003; 21(10):1191-8. View

Sabin C, Lepri A, Phillips A . A practical guide to applying the intention-to-treat principle to clinical trials in HIV infection. HIV Clin Trials. 2001; 1(2):31-8. DOI: 10.1310/e9yd-7caa-p7a0-g1j7. View

10.

Bubbar V, Kreder H . The intention-to-treat principle: a primer for the orthopaedic surgeon. J Bone Joint Surg Am. 2006; 88(9):2097-9. DOI: 10.2106/JBJS.F.00240.top. View

11.

Wiens B, Zhao W . The role of intention to treat in analysis of noninferiority studies. Clin Trials. 2007; 4(3):286-91. DOI: 10.1177/1740774507079443. View

12.

Dasgupta A, Lawson K, Wilson J . Evaluating equivalence and noninferiority trials. Am J Health Syst Pharm. 2010; 67(16):1337-43. DOI: 10.2146/ajhp090507. View

13.

Zee B . Planned equivalence or noninferiority trials versus unplanned noninferiority claims: are they equal?. J Clin Oncol. 2006; 24(7):1026-8. DOI: 10.1200/JCO.2005.04.9684. View

14.

Have T, Normand S, Marcus S, Brown C, Lavori P, Duan N . Intent-to-Treat vs. Non-Intent-to-Treat Analyses under Treatment Non-Adherence in Mental Health Randomized Trials. Psychiatr Ann. 2011; 38(12):772-783. PMC: 2921714. DOI: 10.3928/00485713-20081201-10. View

15.

Moher D, Schulz K, Altman D . The CONSORT statement: revised recommendations for improving the quality of reports of parallel-group randomized trials. Ann Intern Med. 2001; 134(8):657-62. DOI: 10.7326/0003-4819-134-8-200104170-00011. View

16.

Feinman R . Intention-to-treat. What is the question?. Nutr Metab (Lond). 2009; 6:1. PMC: 2631586. DOI: 10.1186/1743-7075-6-1. View

17.

Kruse R, Alper B, Reust C, Stevermer J, Shannon S, Williams R . Intention-to-treat analysis: who is in? Who is out?. J Fam Pract. 2002; 51(11):969-71. View

18.

Hollis S, Campbell F . What is meant by intention to treat analysis? Survey of published randomised controlled trials. BMJ. 1999; 319(7211):670-4. PMC: 28218. DOI: 10.1136/bmj.319.7211.670. View

19.

Piaggio G, Elbourne D, Altman D, Pocock S, Evans S . Reporting of noninferiority and equivalence randomized trials: an extension of the CONSORT statement. JAMA. 2006; 295(10):1152-60. DOI: 10.1001/jama.295.10.1152. View

20.

Abraha I, Montedori A . Modified intention to treat reporting in randomised controlled trials: systematic review. BMJ. 2010; 340:c2697. PMC: 2885592. DOI: 10.1136/bmj.c2697. View