questions on randomised trials by dionigi and coworkers

LETTER TO THE EDITOR

Questions on randomised trials by Dionigi and coworkers

Stefan Sauerland & Christian T. R. Gross

Received: 18 July 2012 /Accepted: 30 September 2012# Springer-Verlag Berlin Heidelberg 2013

To the EditorThe randomised study by Dionigi et al. [1] is a valuablecontribution to the literature on thyroidectomy. The studycompared two popular dissection devices “head-to-head”.Such direct comparisons are certainly more interesting thana comparison of one dissection device versus conventionaldissection using scalpel and electrocautery. However, sev-eral reporting problems make it difficult to accept the studyas fully valid:

1. The study had more than one primary endpoint,which brings up the problem of multiple statisticalsignificance testing. Ideally, a clinical trial shoulddefine just one primary endpoint, and this endpointshould be made publicly available in a study regis-try, such as ClinicalTrials.gov or the German Clin-ical Trials Register.

2. The trial flow chart shows that obviously not 182but rather 187 patients were randomised, of whomfive were lost to follow-up. Therefore, the state-ment that “182 consecutive patients” were rando-mised is not tenable. The quality of the trial is not

necessarily compromised by the fact that fivepatients were lost to follow-up. However, if all fivepatients came from the same group and failed toattend follow-up visits because of complications,this information would be critical for the trial.Therefore, it is essential to report the group assign-ments for these patients and the reasons underlyingloss to follow-up.

3. Possibly most problematic is the case which is listedin the flow chart only as “instrument break” withoutany further explanation. Due to the double meaningsof the word “break” two questions arise: Did one ofthe instruments break apart during thyroidectomy?Or was the instrument “having a break” (i.e. tem-porarily unavailable)?

4. Shortly after the publication of the article, anotherarticle was published by the same group of authors[2]. The other article describes the same study as inthe present article, except for the difference, thatnow 199 (Fig. 1) rather than 182 patients wereincluded. Neither of the two articles cites the otherone, so that readers will not notice this case ofduplicate or salami publication. The authors shouldalso be asked to explain why they published interimresults without labelling them as such.

5. On comparison of the two articles, some data areconflicting. In the first publication [1], for example,the average body mass index (BMI) was reportedas 26 kg/m2 for the 92 patients in the FOCUSgroup. In the second publication [2], the average

Electronic supplementary material The online version of this article(doi:10.1007/s00423-012-1013-x) contains supplementary material,which is available to authorized users.

S. Sauerland (*) :C. T. R. GrossInstitute for Quality and Efficiency in Healthcare (IQWiG),Cologne, Germanye-mail: stefan.sauerland@iqwig.de

Langenbecks Arch SurgDOI 10.1007/s00423-012-1013-x

BMI in this group with now 96 patients was only24 kg/m2, which is mathematically impossible. Fur-thermore, the number of patients with iPTH meas-urements <20 pg/mL requiring calcium substitutionwas lower in the second than in the first article inspite of the larger sample size in the second article.This suggests that key outcomes lacked a cleardefinition.

Generally, it is quintessential to adopt good reportingpractices, especially when dealing with randomised clin-ical trials. The Consolidated Standards of ReportingTrials criteria should be closely followed [3]. Sincemany decades, it is academic standard that each scien-tific article should contain substance, which has beenneither published nor submitted elsewhere [4].

Conflicts of interest None.

References

1. Dionigi G, Boni L, Rausei S, Frattini F, Ferrari CC, ManganoA, Leotta A, Franchin M (2012) The safety of energy-baseddevices in open thyroidectomy: a prospective, randomisedstudy comparing the LigaSure™ (LF1212) and the Harmonic®FOCUS. Langenbecks Arch Surg 397(5):817–823

2. Dionigi G, Van Slycke S, Rausei S, Boni L, Dionigi R (2012)Parathyroid function after open thyroidectomy: a prospective ran-domized study for LigaSure Precise versus Harmonic FOCUS.Head Neck. doi:10.1002/hed.23005

3. Schulz KF, Altman DG, Moher D, Group CONSORT (2010) CON-SORT 2010 Statement: updated guidelines for reporting parallelgroup randomised trials. Trials 11:32

4. Anonymous (1969) Definition of “sole contribution”. N Engl J Med281(12):676–677Fig. 1 Study design from Dionigi et al. [2]

Langenbecks Arch Surg