The Fragility and Reliability of Conclusions of Anesthesia and Critical Care Randomized Trials With Statistically Significant Findings: A Systematic Review.

OBJECTIVES: The Fragility Index, which represents the number of patients responsible for a statistically significant finding, has been suggested as an aid for interpreting the robustness of results from clinical trials. A small Fragility Index indicates that the statistical significance of a trial depends on only a few events. Our objectives were to calculate the Fragility Index of statistically significant results from randomized controlled trials of anesthesia and critical care interventions and to determine the frequency of distorted presentation of results or "spin". DATA SOURCES: We systematically searched MEDLINE from January 01, 2007, to February 22, 2017, to identify randomized controlled trials exploring the effect of critical care medicine or anesthesia interventions. STUDY SELECTION: Studies were included if they randomized patients 1:1 into two parallel arms and reported at least one statistically significant (p < 0.05) binary outcome (primary or secondary). DATA EXTRACTION: Two reviewers independently assessed eligibility and extracted data. The Fragility Index was determined for the chosen outcome. We assessed the level of spin in negative trials and the presence of recommendations for clinical practice in positive trials. DATA SYNTHESIS: We identified 166 eligible randomized controlled trials with a median sample size of 207 patients (interquartile range, 109-497). The median Fragility Index was 3 (interquartile range, 1-7), which means that adding three events to one of the trials treatment arms eliminated its statistical significance. High spin was identified in 42% (n = 30) of negative randomized controlled trials, whereas 21% (n = 20) of positive randomized controlled trials provided recommendations. Lower levels of spin and recommendations were associated with publication in journals with high impact factors (p < 0.001 for both). CONCLUSIONS: Statistically significant results in anesthesia and critical care randomized controlled trials are often fragile, and study conclusions are frequently affected by spin. Routine calculation of the Fragility Index in medical literature may allow for better understanding of trials and therefore enhance the quality of reporting.

Predictors of a negative labour and birth experience based on a national survey of Canadian women.

BACKGROUND: A negative birth experience has been shown to have a significant impact on the well-being and future choices of mothers. The objective of this study was to assess the prevalence of, and identify the risk factors associated with a negative birth experience for women in Canada. METHODS: The study was based on secondary data analysis of the Maternity Experiences Survey (MES), a Canadian population database administered to 6,421 Canadian women in 2006. The examined outcome - negative birth experience - was derived from mothers' self-report of overall labour and birth experience. Independent variables were maternal demographics, health characteristics, pregnancy-related characteristics, and birth characteristics. Multivariable logistic regression analysis was performed to determine the significant predictors of negative birth experience. Adjusted Odds Ratios (AOR) and 95 % Confidence Intervals (CI) are reported. RESULTS: Negative birth experience was reported among 9.3 % of women. The main significant predictors of a negative birth experience included older age (AOR 2.29, 95 % CI, 1.03-5.07), violence experienced in the past two years (AOR, 1.62, 95 % CI, 1.21-2.18), poor self-perceived health (adjusted OR, 1.95, 95 % CI, 1.36-2.80), prenatal classes attended (adjusted OR, 1.36, 95 % CI, 1.06-1.76), unintended pregnancy (adjusted OR, 1.30, 95 % CI, 1.03-1.63), caesarean birth (AOR, 1.65, 95 % CI, 1.32-2.06), and neonate admission to intensive care (AOR, 1.40, 95 % CI, 1.08-1.82). CONCLUSION: Significant predictors of a negative labour and birth experience were identified through this study, a first in the Canadian context. These findings suggest future research directions and provide a basis for the design and evaluation of maternal health policy and prevention programs.