Reporting of loss to follow-up information in randomised controlled trials with time-to-event outcomes: a literature survey

BMC Medical Research Methodology

Thomas Kaiser¹  Ralf Bender²  Guido Skipka¹  Mandy Kromp¹  Elke Vervölgyi¹ 

[1] Institute for Quality and Efficiency in Health Care (IQWiG), Dillenburger Str. 27, 51105 Cologne, Germany;Faculty of Medicine, University of Cologne, Joseph-Stelzmann-Str. 20, 50931 Cologne, Germany

关键词: loss to follow-up;    Kaplan-Meier plot;    survival analysis;    randomised controlled trial;   

Others  :  1139988
DOI  :  10.1186/1471-2288-11-130

 received in 2011-01-04, accepted in 2011-09-21,  发布年份 2011

【 摘 要 】

Background

To assess the reporting of loss to follow-up (LTFU) information in articles on randomised controlled trials (RCTs) with time-to-event outcomes, and to assess whether discrepancies affect the validity of study results.

Methods

Literature survey of all issues of the BMJ, Lancet, JAMA, and New England Journal of Medicine published between 2003 and 2005. Eligible articles were reports of RCTs including at least one Kaplan-Meier plot. Articles were classified as "assessable" if sufficient information was available to assess LTFU. In these articles, LTFU information was derived from Kaplan-Meier plots, extracted from the text, and compared. Articles were then classified as "consistent" or "not consistent". Sensitivity analyses were performed to assess the validity of study results.

Results

319 eligible articles were identified. 187 (59%) were classified as "assessable", as they included sufficient information for evaluation; 140 of 319 (44%) presented consistent LTFU information between the Kaplan-Meier plot and text. 47 of 319 (15%) were classified as "not consistent". These 47 articles were included in sensitivity analyses. When various imputation methods were used, the results of a chi²-test applied to the corresponding 2 × 2 table changed and hence were not robust in about half of the studies.

Conclusions

Less than half of the articles on RCTs using Kaplan-Meier plots provide assessable and consistent LTFU information, thus questioning the validity of the results and conclusions of many studies presenting survival analyses. Authors should improve the presentation of both Kaplan-Meier plots and LTFU information, and reviewers of study publications and journal editors should critically appraise the validity of the information provided.

【 授权许可】

   
2011 Vervölgyi et al; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

Figure 2.

Figure 3.

【 参考文献 】

• [1]Kaplan EL, Meier P: Nonparametric estimation from incomplete observations. Journal of the American Statistical Association 1958, 53:457-481.
• [2]Ryan TP, Woodall WH: The most-cited statistical papers. Journal of Applied Statistics 2005, 32:461-474.
• [3]Bland JM, Altman DG: Survival probabilities (the Kaplan-Meier method). BMJ 1998, 317(7172):1572.
• [4]Altman DG, Bland JM: Time to event (survival) data. BMJ 1998, 317(7156):468-469.
• [5]Pocock SJ, Clayton TC, Altman DG: Survival plots of time-to-event outcomes in clinical trials: good practice and pitfalls. Lancet 2002., 359(1686-1689)
• [6]Altman DG: Practical Statistics for Medical Research. Chapman & Hall/CRC; 1999.
• [7]Altman DG, De Stavola BL, Love SB, Stepniewska KA: Review of survival analyses published in cancer journals. British Journal of Cancer 1995., 72(511-518)
• [8]Mathoulin-Pelissier S, Gourgou-Bourgade S, Bonnetain F, Kramar A: Survival end point reporting in randomized cancer clinical trials: A review of major journals. Journal of Clinical Oncology 2008., 26(3721-3726)
• [9]Schemper M, & Smith TL: A note on quantifying follow-up studies of failure time. Controlled Clinical Trials 1996., 17(343-346)
• [10]Nutzenbewertung der Statine unter besonderer Berücksichtigung von Atorvastatin: Arbeitspapier [http:/ / www.iqwig.de/ download/ Arbeitspapier_Nutzenbewertung_der_S tatine_unter_besonderer_Beruecksich tigung_von_Atorvastatin_.pdf] webcite
• [11]Clopidogrel versus Acetylsalicylsäure in der Sekundärprophylaxe vaskulärer Erkrankungen: Abschlussbericht; Auftrag A04-01A [http:/ / www.iqwig.de/ download/ A04-01A_Abschlussbericht_Clopidogre l_versus_ASS_in_der_Sekundaerprophy laxe.pdf] webcite
• [12]Toerien M, Brookes ST, Metcalfe C, de Salis I, Tomlin Z, Peters TJ, Sterne J, Donovan JL: A review of reporting of participant recruitment and retention in RCTs in six major journals. Trials 2009., 10(52)
• [13]Glossary. Cochrane Handbook for Systematic Reviews of Interventions 4.2.5 [updated May 2005] [http://www.cochrane.org/resources/handbook/] webcite
• [14]Andersen PK, Borgan O, Gill RD, Keiding N: Statistical Models Based on Counting Processes. 2nd edition. New York: Springer; 1997.
• [15]Pintilie M: Competing Risks: A Practical Perspective. 1st edition. Chichester, England: John Wiley & Sons, Ltd; 2006.
• [16]Guyatt GH, Sackett DL, Cook DJ: Users' guide to the medical literature. 2. How to use an article about therapy or prevention. A. Are the results of the study valid? Journal of the American Medical Association 1993, 270:2598-2601.
• [17]Royston P, Parmar MK, Altman DG: Visualizing length of survival in time-to-event studies: a complement to Kaplan-Meier plots. J Natl Cancer Inst 2008, 100:92-97.
• [18]Clark TG, Altman DG, De Stavola BL: Quantification of the completeness of follow-up. Lancet 2002, 359:1309-1310.
• [19]Montori VM, Guyatt GH: Intention-to-treat principle. Can Med Ass J 2001, 165:1339-1341.
• [20]Shih WJ: Problems in dealing with missing data and informative censoring in clinical trials. Current Controlled Trials in Cardiovascular Medicine 2002, 3(1):4. BioMed Central Full Text
• [21]Moher D, Hopewell S, Schulz KF, Montori V, Gotzsche PC, Devereaux PJ, Elbourne D, Egger M, Altman DG: CONSORT 2010 explanation and elaboration: updated guidelines for reporting parallel group randomised trials. BMJ 2010, 340:c869.
• [22]Altman DG: Endorsement of the CONSORT statement by high impact medical journals: survey of instructions for authors. BMJ 2005, 330(7499):1056-1057.
• [23]Akl EA, Briel M, You JJ, Lamontagne F, Gangji A, Cukierman-Yaffe T, Alshurafa M, Sun X, Nerenberg KA, Johnston BC, et al.: Lost to follow-up Information in Trials (LOST-IT): a protocol on the potential impact. Trials 2009., 10(40)