ABSTRACT
We have evaluated the pitfalls in reporting sample size calculation in randomized controlled trials (RCTs) published in the 10 highest impact factor anaesthesia journals.Superiority RCTs published in 2013 were identified and checked for the basic components required for sample size calculation and replication. The difference between the reported and replicated sample size was estimated. The sources used for estimating the expected effect size (Δ) were identified, and the difference between the expected and observed effect sizes (Δ gap) was estimated.We enrolled 194 RCTs. Sample size calculation was reported in 91.7% of studies. Replication of sample size calculation was possible in 80.3% of studies. The original and replicated sample sizes were identical in 67.8% of studies. The difference between the replicated and reported sample sizes exceeded 10% in 28.7% of studies. The expected and observed effect sizes were comparable in RCTs with positive outcomes (P=0.1). Studies with negative outcome tended to overestimate the effect size (Δ gap 42%, 95% confidence interval 32-51%), P<0.001. Post hoc power of negative studies was 20.2% (95% confidence interval 13.4-27.1%). Studies using data derived from pilot studies for sample size calculation were associated with the smallest Δ gaps (P=0.008).Sample size calculation is frequently reported in anaesthesia journals, but the details of basic elements for calculation are not consistently provided. In almost one-third of RCTs, the reported and replicated sample sizes were not identical and the assumptions for the expected effect size and variance were not supported by relevant literature or pilot studies.
Subject(s)
Anesthesiology/standards , Periodicals as Topic/standards , Randomized Controlled Trials as Topic/standards , Sample Size , Humans , Publishing/standards , Research DesignABSTRACT
INTRODUCTION: Data on the prevalence and pattern of infection after living-donor liver transplantation (LDLT) are scarce in Egypt. We therefore conducted this study to quantify the incidence, risk factors, and pattern of bacterial resistance post-LDLT in 3 hospitals in Egypt. PATIENTS AND METHODS: We conducted a retrospective, multicenter study of the medical records of 246 patients who underwent LDLT between January 2006 and April 2011 at 3 transplant centers in Egypt. RESULTS: Of 246 patients enrolled in this study, 127 (52%) developed infectious complications after LDLT, with 416 episodes of infection occurring within 3 months of transplantation. Biliary tract infection was the most common, occurring in 169 (40.6%) patients. The rate of infection with Gram-negative bacteria was higher than that of infection with Gram-positive bacteria (310 [74%] vs 87 [21%]; P < .001). Overall, 75% of Gram-negative isolates were multidrug resistant. Significant independent risk factors for infection were portal vein thrombosis (odds ratio, 2.4; P = .037) and biliary complications (odds ratio, 5.4; P < .001). CONCLUSIONS: Our data showed a high-resistance pattern of bacterial infection after LDLT in Egypt. Early biliary complications were an independent risk factor for bacterial infection.
