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Follow-on rifaximin for the prevention of recurrence following standard treatment of infection with Clostridium difficile: a competing risks analysis provides a full picture of possible treatment effects
  1. Maja Katharina von Cube,
  2. Martin Schumacher,
  3. Martin Wolkewitz
  4. on behalf of COMBACTE-MAGNET Consortium
  1. Faculty of Medicine and Medical Center, Institute for Medical Biometry and Statistics, University of Freiburg, Freiburg, Germany
  1. Correspondence to Maja Katharina von Cube, Faculty of Medicine and Medical Center, Institute for Medical Biometry and Statistics, University of Freiburg, Freiburg D-79104, Germany; cube{at}

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With interest we read the article by Major et al 1 on the effect of rifaximin ‘follow-on’ treatment to prevent recurrent Clostridium difficile infection (rCDI).

Major et al point out the advantage of their study sample being composed of elderly patients who represent the frailties and comorbidities of the target population. The frailty of the sample is reflected by the, compared with other trials on new agents, higher mortality rate, which is considered to increase the generalisability of the results to daily clinical practice.

A main statistical challenge when studying a frail patient population using a non-fatal endpoint is dealing with mortality.2

Patients who died without rCDI are no longer at risk of a recurrent infection. Thus, death is a competing risk of rCDI.

In their analysis, Major et al first exclude patients who have died or have withdrawn from the study before end of follow-up by using generalised estimating equations to estimate the risk difference (RD) of rCDI. Second, they treat them equally as randomly censored by using a Kaplan-Meier estimator (K-M) to estimate the …

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  • Contributors MKvC performed the simulation study and wrote the letter. MS critically revised the letter and provided major comments. MS and MW formulated the main problem. MW supervised the writing process and provided major comments. All authors read and approved the final manuscript.

  • Funding MKvC has received support from the Innovative Medicines Initiative Joint Undertaking under grant agreement no. 115737-2 (Combatting bacterial resistance in Europe - molecules against Gram negative infections [COMBACTE-MAGNET]). MW has been funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, grant No WO 1746/1-1).

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Patient consent for publication Not required.

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