Ehlers Cooper B, Curley Andrew J, Fackler Nathan P, Minhas Arjun, Rodriguez Ariel N, Pasko Kory, Chang Edward S
Georgetown University School of Medicine, El Segundo, California, USA.
MedStar Georgetown University Hospital, Washington, DC, USA.
Orthop J Sports Med. 2021 Dec 20;9(12):23259671211064626. doi: 10.1177/23259671211064626. eCollection 2021 Dec.
The statistical significance of a given study outcome can be liable to small changes in findings. values are common, but imperfect statistical methods to convey significance, and inclusion of the fragility index (FI) and fragility quotient (FQ) may provide a clearer perception of statistical strength.
PURPOSE/HYPOTHESIS: The purpose was to examine the statistical stability of studies comparing primary single-bundle to double-bundle anterior cruciate ligament reconstruction (ACLR) utilizing autograft and independent tunnel drilling. It was hypothesized that the study findings would be vulnerable to a small number of outcome event reversals, often less than the number of patients lost to follow-up.
Systematic review; Level of evidence, 2.
Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the authors searched PubMed for comparative studies and randomized controlled trials (RCTs) published in select journals, based on impact factor, between 2005 and 2020. Risk-of-bias assessment and methodology scoring were conducted for the included studies. A total of 48 dichotomous outcome measures were examined for possible event reversals. The FI for each outcome was determined by the number of event reversals necessary to alter significance. The FQ was calculated by dividing the FI by the respective sample size.
Of the 1794 studies screened, 15 comparative studies were included for analysis; 13 studies were RCTs. Overall, the mean FI and FQ were 3.14 (IQR, 2-4) and 0.050 (IQR, 0.032-0.062), respectively. For 72.9% of outcomes, the FI was less than the number of patients lost to follow-up.
Studies comparing single-bundle versus double-bundle ACLR may not be as statistically stable as previously thought. Comparative studies and RCTs are at substantial risk for statistical fragility, with few event reversals required to alter significance. The reversal of fewer than 4 outcome events in a treatment group can alter the statistical significance of a given result; this is commonly less than the number of patients lost to follow-up. Future comparative study analyses might consider including FI and FQ with values in their statistical analysis.
给定研究结果的统计学显著性可能容易受到研究结果微小变化的影响。P值很常见，但用于传达显著性的统计方法并不完美，纳入脆弱性指数（FI）和脆弱性商数（FQ）可能会更清楚地了解统计强度。
目的/假设：目的是研究比较采用自体移植物和独立隧道钻孔的单束与双束前交叉韧带重建（ACLR）的研究的统计稳定性。假设研究结果容易受到少数结局事件逆转的影响，通常少于失访患者的数量。
系统评价；证据等级，2级。
按照系统评价和Meta分析的首选报告项目（PRISMA）指南，作者在PubMed中搜索2005年至2020年间在选定期刊（基于影响因子）上发表的比较研究和随机对照试验（RCT）。对纳入的研究进行偏倚风险评估和方法学评分。共检查了48个二分结局指标是否可能发生事件逆转。每个结局的FI由改变显著性所需的事件逆转数确定。FQ通过将FI除以各自的样本量来计算。
在筛选的1794项研究中，纳入15项比较研究进行分析；13项研究为RCT。总体而言，平均FI和FQ分别为3.14（IQR，2 - 4）和0.050（IQR，0.032 - 0.062）。对于72.9%的结局，FI小于失访患者的数量。
比较单束与双束ACLR的研究在统计学上可能不如先前认为的稳定。比较研究和RCT存在显著的统计脆弱性风险，改变显著性所需的事件逆转很少。治疗组中少于4个结局事件的逆转就可以改变给定结果的统计学显著性；这通常少于失访患者的数量。未来的比较研究分析可能会考虑在统计分析中纳入FI和FQ以及P值。
