tantial costs to the healthcare system.? The first randomized clinical trial comparing on-demand versus a planned-relaparotomy strategy in patients with severe peritonitis (RELAP trial) indicated no clear differences in primary clinical outcomes.? To assess the economic impact of differences in resource use, we performed a full economic evaluation from a societal sellckchem perspective alongside this trial.? Mean total costs per patient were 20% lower in the on-demand group as compared with the planned group.? The substantial difference in costs renders the on-demand strategy a far more efficient relaparotomy strategy in patients with severe peritonitis.

AbbreviationsAPACHE: Acute Physiology and Chronic Health Evaluation; CRF: clinical report form; CEA: cost-effectiveness analysis; CMA: cost-minimization analysis; CT: computed tomography; FFP: fresh frozen plasma; HR-QoL: health-related quality of life; ICU: intensive care unit; OD: on demand relaparotomy; PCD: percutaneous drainage; PR: planned relaparotomy; RELAP trial: randomized controlled trial comparing relaparotomy on demand with planned relaparotomy; US: ultrasound; US$: United States dollar; 95% CI: 95% confidence interval.Competing interestsThe authors declare that they have no competing interests.Authors’ contributionsMAB, DJG, HO, JBR, and CAJMB designed the clinical study. BCO, CAJMB, and MAB designed the economic evaluation alongside the clinical trial. OR and CWM were responsible for the coordination of the study, including contacting patients and collecting and entering data.

KRB and OR were responsible for assessment and processing of follow-up data. BCO, KRB, OR, JBR, and MAB were responsible for the cost analyses. HGG, PWG, BL, MFG, and EPS were responsible for including more than 10% of the randomized patients in their participating hospital. BCO analyzed data and prepared initial versions of the manuscript. BCO, KRB, OR, JBR, and MAB were responsible for the final manuscript. BCO, KRB, OR, JBR, and MAB interpreted and discussed all data. All authors read, reviewed, and approved the final manuscript.Supplementary MaterialAdditional file 1:Table reporting units of resource use, unit costs (�), valuation method and volume source used for the cost analyses.Click here for file(84K, DOC)NotesSee related commentary by Ghaferi, http://ccforum.

com/content/14/3/168AcknowledgementsDutch Peritonitis Study GroupRELAP trial clinical centers and investigators of the Dutch Peritonitis Study Group All investigators are from Departments of Surgery unless specified: (E) Clinical Epidemiology and Biostatistics, (I) Intensive Care, or (MP) Medical Psychology.O van Ruler MD; KR Boer MSc (E); JB Reitsma MD, PhD (E); CW Mahler MD; EA Reuland MSc; JWO van Till MD; BC Opmeer PhD (E); PMM Bossuyt PhD (E); MJ Schultz MD, PhD (I); MA Sprangers MD, PhD (MP); DJ Gouma MD, PhD; AV-951 H Obertop MD, PhD; CAJM de Borgie MD, PhD (E); MA Boermeester MD, PhD, Academic Medical Center, Amsterdam; EPh Steller MD, PhD; P. Tanis MD, Ph