Cited by 715Statistical Methods in Clinical TrialsAdvanced Causal Inference TechniquesMeta-analysis and systematic reviews

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Intention-to-Treat Analysis: Implications for Quantitative and Qualitative Research

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NEWELL, DAVID J·1992·International Journal of Epidemiology

DOI 10.1093/ije/21.5.837

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Abstract

Newell D J (Department of Medical Statistics, University of Newcastle upon Tyne, UK). Intention-to-treat analysis: implications for quantitative and qualitative research. International Journal of Epidemiology 1992, 21: 837–841 Intention-to-treat analysis is an important aspect of randomized controlled trials of health care interventions. The concept is now widely accepted in theory, but not always implemented in practice. Failure to analyse by intention-to-treat can give misleading and indeed life-threatening interpretations. In some studies, a case is put for estimating the effect that would have been observed if all patients had received the allocated treatment. Situations where this is valid are rare, but an example is given of such an exceptional study. The relevance of the intention-to-treat concept is not always taken into account in qualitative research. Interviews with new mothers who delivered their babies at home in a hypothetical controlled trial of home versus hospital confinement would provide fascinating accounts of the pleasures of successful delivery at home. But by definition the interviews would exclude the hazard and drama of necessary transfers to hospital due to complications in late pregnancy and early labour. The intention-to-treat approach would avoid this bias.

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Schwartz D, Flamant R, LeUouch i. Clinical Trials. London: Academic Press, 1980.

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Frändin, K., Borell, L., Grönstedt, H. K., Bergland, A., Helbostad, J. L., Puggaard, L., Andresen, M., Granbo, R., & Hellström, K. (2009) · Aging Clinical and Experimental Research · doi:10.1007/bf03324921 · Cited by 19
Vaccine Trials
Farrington, P., & Miller, E. (2001) · Molecular Biotechnology · doi:10.1385/mb:17:1:43 · Cited by 19
Mobile phone-based interventions for improving contraception use
Perinpanathan, T., Maiya, S., van Velthoven, M. H., Nguyen, A. T., Free, C., & Smith, C. E. (2023) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd011159.pub3 · Cited by 24
Does the Method of Component Fixation Influence Clinical Outcomes After Total Knee Replacement? A Systematic Literature Review
Arnold, J. B., Walters, J. L., Solomon, L. B., & Thewlis, D. (2013) · The Journal of Arthroplasty · doi:10.1016/j.arth.2012.09.021 · Cited by 19
“Only one study [17] reported that intention-to-treat (ITT) analysis [29] was undertaken.”
Background
Carbon dioxide insufflation for endoscopic retrograde cholangiopancreatography: A meta-analysis and systematic review
Cheng, Y. (2012) · World Journal of Gastroenterology · doi:10.3748/wjg.v18.i39.5622 · Cited by 19
Antiviral prophylactic intervention for chronic hepatitis C virus in patients undergoing liver transplantation
Gurusamy, K. S., Tsochatzis, E. A., Davidson, B. R., & Burroughs, A. K. (2010) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd006573.pub2 · Cited by 19
Abdominal lift for laparoscopic cholecystectomy
Gurusamy, K. S., Koti, R. S., Samraj, K., & Davidson, B. R. (2012) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd006574.pub3 · Cited by 19
Liver resection versus other treatments for neuroendocrine tumours in patients with resectable liver metastases
Gurusamy, K. S., Ramamoorthy, R., Sharma, D., & Davidson, B. R. (2008) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd007060 · Cited by 19
Evaluation of clinical outcomes of radiofrequency ablation and surgical resection for hepatocellular carcinoma conforming to the Milan criteria: A systematic review and meta‐analysis of recent randomized controlled trials
Jia, Z., Zhang, H., & Li, N. (2021) · Journal of Gastroenterology and Hepatology · doi:10.1111/jgh.15440 · Cited by 18
Empowering pharmacists in asthma management through interactive SMS (EmPhAsIS): study protocol for a randomized controlled trial
Vera, M. A. D., Sadatsafavi, M., Tsao, N., Lynd, L. D., Lester, R. T., Gastonguay, L., Galo, J. S., FitzGerald, J. M., Brasher, P. M. A., & Marra, C. A. (2014) · Trials · doi:10.1186/1745-6215-15-488 · Cited by 19
“The analysis of the association of the intervention with the outcome will generally be based on regression analysis, and will be performed according to the intention-to-treat principle [59].”
Method
Management of people with intermediate-stage hepatocellular carcinoma
Roccarina, D., Majumdar, A., Thorburn, D., Davidson, B. R., Tsochatzis, E. A., & Gurusamy, K. S. (2017) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd011649.pub2 · Cited by 18
Quality of Reporting Randomized Controlled Trials in Cancer Nursing Research
Guo, J.-W., Sward, K., Beck, S., & Staggers, N. (2014) · Nursing Research · doi:10.1097/nnr.0000000000000007 · Cited by 11
“…analysis, whereby all participants randomly assigned to a treatment are used in analysis of effects regardless of whether they were complete or noncompliant to the study protocol, helps to avoid overestimation of intervention effectiveness (Gupta, 2011; Montori & Guyatt, 2001; Newell, 1992).”
Method
A Multicenter Cluster Randomized Controlled Trial of Strategies to Improve Thyroid Function Testing
Daucourt, V., Saillour-Glenisson, F., Michel, P., Jutand, M.-A., & Abouelfath, A. (2003) · Medical Care · doi:10.1097/01.mlr.0000053216.33277.a4 · Cited by 20
Analgesic effectiveness of subcutaneous carbon-dioxide insufflations as an adjunct treatment in patients with non-specific neck or low back pain
T., Dillner, A., Franke, A., & Resch, K. (2001) · Complementary Therapies in Medicine · doi:10.1054/ctim.2001.0434 · Cited by 18
Cervicogenic Headache: Locus of Control and Success of Treatment
Stanton, W. R., & Jull, G. A. (2003) · Headache The Journal of Head and Face Pain · doi:10.1046/j.1526-4610.2003.03187.x · Cited by 18
Outpatient versus inpatient treatment for acute pulmonary embolism
Yoo, H. H. B., Nogueira, V. D. S. N., Bôas, P. J. F. V., & Broderick, C. A. (2019) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd010019.pub3 · Cited by 18
“Newell 1992 Newell DJ. Intention-to-treat analysis: implications for quantitative and qualitative research.”
Longitudinal Patterns of Engagement and Clinical Outcomes: Results From a Therapist-Supported Digital Mental Health Intervention
Aschbacher, K., Rivera, L. M., Hornstein, S., Nelson, B. W., Forman‐Hoffman, V. L., & Peiper, N. C. (2023) · Psychosomatic Medicine · doi:10.1097/psy.0000000000001230 · Cited by 19
“than performing listwise deletion and conducting completer-only analyses, which can introduce selectivity biases and yield biased effects (55).”
Background
Pancreatogastrostomy versus pancreatojejunostomy for RECOnstruction after partial PANCreatoduodenectomy (RECOPANC): study protocol of a randomized controlled trial UTN U1111-1117-9588
Wellner, U. F., Brett, S. I., Bruckner, T. M., Limprecht, R., Rossion, I., Seiler, C. M., Sick, O., Wegener, I., Hopt, U. T., Keck, T., et al. (2012) · Trials · doi:10.1186/1745-6215-13-45 · Cited by 17
“The analysis will be performed according to the standard (non-modified) intention to treat principle [26,27].”
Method
Costs and health outcomes associated with primary vs secondary care after an asthma-related hospitalization: a population-based study.
Sadatsafavi, M., Fitzgerald, M., Marra, C., & Lynd, L. (2013) · Chest · doi:10.1378/chest.12-2773 · Cited by 16
Early versus delayed laparoscopic cholecystectomy for biliary colic
Gurusamy, K. S., Samraj, K., & Davidson, B. R. (2008) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd007196 · Cited by 17
Palliative cytoreductive surgery versus other palliative treatments in patients with unresectable liver metastases from gastro-entero-pancreatic neuroendocrine tumours
Gurusamy, K. S., Sharma, D., & Davidson, B. R. (2008) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd007118 · Cited by 17
Antiviral therapy for recurrent liver graft infection with hepatitis C virus
Gurusamy, K. S., Osmani, B., Xirouchakis, E., Burroughs, A. K., & Davidson, B. R. (2009) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd006803.pub2 · Cited by 17
Early versus delayed post-operative bathing or showering to prevent wound complications
Toon, C. D., Sinha, S., Davidson, B. R., & Gurusamy, K. S. (2013) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd010075.pub2 · Cited by 17
Pharmacological interventions for prevention or treatment of postoperative pain in people undergoing laparoscopic cholecystectomy
Gurusamy, K. S., Vaughan, J., Toon, C. D., & Davidson, B. R. (2014) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd008261.pub2 · Cited by 51
The Role of Hydraulic Silicate Cements on Long-Term Properties and Biocompatibility of Partial Pulpotomy in Permanent Teeth
Kang, C., Seong, S., Song, J. S., & Shin, Y. (2021) · Materials · doi:10.3390/ma14020305 · Cited by 16
“This helped to avoid overoptimistic estimates of efficacy of the intervention by ignoring non-compliance, protocol deviations, withdrawal, and/or any unfavorable event occurring after randomization in clinical practice [38].”
Research methodology used in studies of child disaster mental health interventions for posttraumatic stress
Pfefferbaum, B. J., Newman, E., Nelson, S. D., Liles, B. D., Tett, R. P., Varma, V., & Nitiéma, P. (2013) · Comprehensive Psychiatry · doi:10.1016/j.comppsych.2013.08.014 · Cited by 16
“Studies were coded according to whether the authors performed an intent-to-treat analysis (whether all participants assigned to a treatment arm, including those who did not complete the trial, were included in the analysis) [16,17].”
BackgroundMethod
The influence of psychosocial difficulties on women's attrition in an HIV/STD prevention program
Beadnell, B. A., Baker, S. A., Knox, K., Stielstra, S., Morrison, D. M., Degooyer, E., Wickizer, L., Doyle, A., & Oxford, M. L. (2003) · AIDS Care · doi:10.1080/09540120310001618658 · Cited by 16
A prospective randomized controlled study of auricular point acupressure to manage chronic low back pain in older adults: study protocol
Yeh, C. H., Li, C., Glick, R. M., Schlenk, E. A., Albers, K. M., Suen, L. K. P., Lukkahatai, N., Salen, N., Pandiri, S., Ma, W., et al. (2020) · Trials · doi:10.1186/s13063-019-4016-x · Cited by 13
Does Exercise Improve Cognitive Performance? A Conservative Message from Lord's Paradox
Liu, S., Lebeau, J.-C., & Tenenbaum, G. (2016) · Frontiers in Psychology · doi:10.3389/fpsyg.2016.01092 · Cited by 14
Alberta Diabetes and Physical Activity Trial (ADAPT): A randomized theory-based efficacy trial for adults with type 2 diabetes - rationale, design, recruitment, evaluation, and dissemination
Plotnikoff, R. C., Courneya, K. S., Sigal, R. J., Johnson, J. A., Birkett, N., Lau, D., Raine, K. D., Johnson, S. T., & Karunamuni, N. D. (2010) · Trials · doi:10.1186/1745-6215-11-4 · Cited by 15
“Physical activity data, clinical data, and HRQL measures will be analyzed using Linear-mixed model (LMM) analyses employing intention-to-treat principles [40] using the Statistical Program for Social Sciences (SPSS) 16.”
Method
Evaluation of the Effectiveness and Implementation of an Adapted Evidence-Based Mammography Intervention for African American Women
Highfield, L. D., Hartman, M. A., Bartholomew, L. K., Balihe, P., & Ausborn, V. A. (2015) · BioMed Research International · doi:10.1155/2015/240240 · Cited by 15
“Study results will test the hypothesis in which the effectiveness of the original EBI will be retained after adaptation and provide lessons learned for future intervention implementation in the real-world setting of mammography screening.”
Background
Reviewing the reviewers: the quality of reporting in three secondary journals.
Devereaux, P. J., Manns, B., Ghali, W. A., Quan, H., & Guyatt, G. H. (2001) · Europe PMC (PubMed Central) · Cited by 15

Authors: NEWELL, D. J.
Affiliations: Newcastle University (GB)
Corresponding author: NEWELL, DAVID J
ORCID: NEWELL, DAVID J
Venue: International Journal of Epidemiology
Publisher: Oxford University Press (OUP)
Published: 1992
Volume: 21
Issue: 5
Pages: 837-841
ISSN: 0300-5771 (ISSN-L)
1464-3685
DOI: 10.1093/ije/21.5.837
OpenAlex: W2106051200
Cited by: 715
References: 6
Citations by year: 2026: 4 · 2025: 15 · 2024: 24 · 2023: 22 · 2022: 21 · 2021: 16 · 2020: 16 · 2019: 16 · 2018: 25 · 2017: 36 · 2016: 31 · 2015: 35 · 2014: 51 · 2013: 62 · 2012: 34
FWCI: 5.99
Type: journal article
Language: en
Open access: bronze
doi.org
Locations: International Journal of Epidemiology (publishedVersion)
PubMed (publishedVersion)
Topics: Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Clinical Trials
Physical Sciences › Mathematics › Statistics and Probability › Advanced Causal Inference Techniques
Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
Keywords: intention-to-treat analysis, randomized controlled trials, health interventions, qualitative research, home birth, hospital confinement, allocation bias, treatment effect estimation
MeSH terms: Data Interpretation, Statistical, Evaluation Studies as Topic, Humans, Patient Compliance, Random Allocation, Research Design, Therapeutics, Cohort Studies, Randomized Controlled Trials as Topic

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Intention-to-Treat Analysis: Implications for Quantitative and Qualitative Research

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