Chabok A, Påhlman L, Hjern F, Haapaniemi S, Smedh K; AVOD Study Group.
Br J Surg. 2012 Apr;99(4):532-9
An open label multicenter RCT from Sweden comparing usual antibiotic treatment versus no antibiotics (IV fluids only) in the treatment of acute uncomplicated diverticulitis showed that there was no statistical difference in rate of complications while in hospital or in a 12 month follow-up period (1.0% vs. 1.9% complication rate in Abx vs no Abx group P=0.302). Due to study limitations such as the lack of blinding, possible selection bias for milder cases and lack of power, JC attendees were not convinced to yet change our current practice.
By: Dr. Lisa Harman
(Presented January 2013)
Open label trials may be promoted as pragmatic trials but a lack of blinding to treatment allocation is a fundamental threat to internal validity. Blinding reduces ascertainment bias (the likelihood of differential assessment of outcome). It is not always possible to undertake blinding in a RCT. But a critical reader will ask whether it was possible to blind outcome assessors. If the answer is yes, then this leads to concern about the validity of RCT results.
By: Dr. Lisa Calder