Predictors of Increased Fragility Index Scores in Surgical Randomized Controlled Trials: An Umbrella Review

Area of Science:

• Medical research methodology
• Surgical clinical trials
• Evidence-based medicine

Background:

• The fragility index (FI) quantifies the robustness of statistical significance in randomized control trials (RCTs).
• FI is increasingly used to assess the quality of RCTs, particularly in surgery.
• This review systematically evaluated the use of FI in published systematic reviews of surgical RCTs.

Purpose of the Study:

• To identify and describe systematic reviews that utilized the fragility index (FI) to assess surgical RCTs.
• To determine common factors associated with higher FI values in surgical RCTs.
• To evaluate the robustness of findings in surgical RCTs based on published systematic reviews.

Main Methods:

• A comprehensive search of three databases (PubMed, MEDLINE, Embase) was conducted.
• Systematic screening of titles, abstracts, and full texts identified 50 relevant reviews of surgical RCTs.
• Data extraction included study characteristics, median FI, and associations with variables like sample size and p-value.

Main Results:

• The pooled median FI across 1007 RCTs in 50 reviews was 3 (IQR: 1-7), with most reviews focusing on orthopaedic surgery.
• Moderate correlation found between FI and p-value (r=-0.413), and mild correlations with sample size (r=0.188) and event number (r=0.129).
• The median FI values reported were generally low, ranging from 2-5.

Conclusions:

• Surgical RCTs, based on a sample of systematic reviews, exhibit low fragility index values, suggesting limited robustness.
• There is a need to improve the study design of future surgical RCTs to enhance the reliability of statistically significant findings.
• Enhancing the robustness of surgical research is essential for advancing evidence-based practice.