Benjamin Djulbegovic

and 13 more

Rationale, aims and objectives 39 Evidence-based medicine (EBM) holds that estimates of effects of health interventions based on 40 high-certainty evidence (CoE) are expected to change less frequently than the effects generated 41 in low CoE studies. However, this foundational principle of EBM has never been empirically 42 tested. 43 Methods 44 We reviewed all systematic reviews and meta-analyses in Cochrane Database of Systematic 45 Reviews from January 2016 through May 2021 (n=3,323). We identified 414(207x2) and 384 46 (192x2) pairs of original and updated Cochrane reviews that assessed CoE and pooled 47 treatment effect estimates. We appraised CoE using the Grading of Recommendations 48 Assessment, Development and Evaluation (GRADE) method. We assessed the difference in 49 effect sizes between the original versus updated reviews as a function of change in CoE, which 50 we report as a ratio of odds ratio (ROR). We compared ROR generated in the studies that 51 changed CoE from very low/low (VL/L) to moderate/high (M/H) vs. MH/H VL/L. We also 52 assessed the heterogeneity and inconsistency (using the tau and I2 statistic), the change in 53 precision of effect estimates (by calculating the ratio of standard errors) (seR), and the absolute 54 deviation in estimates of treatment effects (aROR). 55 Results 56 57 We found that CoE originally appraised as VL/L had 2.1 (95%CI: 1.19 to 4.12; p=0.0091) times 58 higher odds to be changed in the future studies than M/H CoE. However, the effect size was not 59 different when CoE changed from VL/L M/H vs. M/H VL/L [ROR=1.02 (95%CI: 0.74 to 1.39) 60 vs. 1.02 (95%CI: 0.44 to 2.37); p=1 for the between subgroup differences]. aROR was similar 61 between the subgroups [median (IQR):1.12 (1.07 to 1.57) vs 1.21 (1.12 to 2.43)]. We observed 62 large inconsistency (I 2=99%) and imprecision in treatment effects (seR=1.09). 63 Conclusions 64 We provide the first empirical support for a foundational principle of EBM showing that low65 quality evidence changes more often than high CoE. However, the effect size was not different 66 between studies with low vs high CoE. The finding that the effect size did not differ between low 67 and high CoE indicate urgent need to refine current EBM critical appraisal methods
Objective: To find out the preferred and actual mode of delivery of obstetricians’ own children. Design: Cross-sectional survey. Setting: Three Congresses of Gynecology and Obstetrics and four large maternity hospitals in Rio de Janeiro, Brazil. Population: Physicians who held a specialty degree in gynecology & obstetrics or were trainees in this specialty and worked in the state of Rio de Janeiro. Methods: Prevalence and 95% confidence interval. Main Outcome Measures: Preferred and actual mode of delivery for own children. Results: A total of 465 participants answered the questionnaire in the three Congresses and four maternity hospitals. Seventy six percent (95% CI 71 - 81) of the 262 participants who delivered at least one child had Caesarean for the first child. Seventy two percent (95% CI 68 - 76) claimed they would prefer a vaginal birth for their own children, but only a third of those (34%) delivered vaginally. Conclusions: In a group of well informed, socially privileged and empowered women (especially regarding childbirth decisions), the most common mode of delivery was Caesarean, not the natural vaginal birth. Thus, even for those who want to try and reduce the number of Caesareans, it appears that their success will demand broader strategies, than simply to focus on physicians perversely forcing (or talking into) powerless misinformed women to deliver through C-section; this narrative seems to be wrong, at least in the sample of women in our study. Tweetable Among obstetricians in Rio de Janeiro 76% had a Caesarean for their own children