Government Hospital, Velayuthampalayam, Karur, Tamil Nadu, India.
Institute of Orthopaedics and Traumatology, Madras Medical College & Rajiv Gandhi Government General Hospital, Chennai, Tamil Nadu, India.
Spine (Phila Pa 1976). 2021 Feb 1;46(3):198-208. doi: 10.1097/BRS.0000000000003645.
Systematic review.
The aim of this study was to assess the robustness of statistically significant outcomes from randomized control trials (RCTs) in spine surgery using Fragility Index (FI) which is a novel metric measuring the number of events upon which statistical significance of the outcome depends.
Many trials in Spine surgery were characterized by fewer outcome events along with small sample size. FI helps us identify the robustness of the results from such studies with statistically significant dichotomous outcomes.
We conducted independent and in duplicate, a systematic review of published RCTs in spine surgery from PubMed Central, Embase, and Cochrane Database. RCTs with 1:1 prospective study design and reporting statistically significant dichotomous primary or secondary outcomes were included. FI was calculated for each RCT and its correlation with various factors was analyzed.
Seventy trials met inclusion criteria with a median sample size of 133 (interquartile range [IQR]: 80-218) and median reported events per trial was 38 (IQR: 13-94). The median FI score was 2 (IQR: 0-5), which means if we switch two patients from nonevent to event, the statistical significance of the outcome is lost. The FI score was less than the number of patients lost to follow-up in 28 of 70 trials. The FI score was found to positively correlated with sample size (r = 0.431, P = 0.001), total number of outcome events (r = 0.305, P = 0.01) while negatively correlated with P value (r = -0.392, P = 0.001). Funding, journal impact-factor, risk of bias domains, and year of publication did not have a significant correlation.
Statistically significant dichotomous outcomes reported in spine surgery RCTs are more often fragile and outcomes of the patients lost to follow-up could have changed the significance of results and hence it needs caution before transcending their results into clinical application. The addition of FI in routine reporting of RCTs would guide readers on the robustness of the statistical significance of outcomes. RCTs with FI ≥5 without any patient lost to follow-up can be considered to have clinically robust results.Level of Evidence: 1.
系统评价。
本研究旨在使用脆弱指数（FI）评估脊柱外科随机对照试验（RCT）中统计学显著结局的稳健性，FI 是一种新的衡量指标，用于衡量依赖于结局统计学显著性的事件数量。
许多脊柱外科试验的特点是结局事件较少，样本量较小。FI 有助于我们识别具有统计学显著二分类结局的此类研究结果的稳健性。
我们从 PubMed Central、Embase 和 Cochrane 数据库中独立且重复地进行了一项脊柱外科已发表 RCT 的系统评价。纳入了 1:1 前瞻性研究设计且报告具有统计学显著二分类主要或次要结局的 RCT。为每个 RCT 计算 FI，并分析其与各种因素的相关性。
70 项试验符合纳入标准，中位样本量为 133（四分位距[IQR]：80-218），中位每个试验报告的事件数为 38（IQR：13-94）。FI 评分中位数为 2（IQR：0-5），这意味着如果我们将两名患者从无事件转换为有事件，那么结局的统计学显著性将会丧失。在 70 项试验中，有 28 项试验的 FI 评分小于失访患者的数量。FI 评分与样本量呈正相关（r=0.431，P=0.001），与总结局事件数呈正相关（r=0.305，P=0.01），与 P 值呈负相关（r=-0.392，P=0.001）。资金来源、期刊影响因子、偏倚风险领域和发表年份与 FI 评分均无显著相关性。
脊柱外科 RCT 报告的统计学显著二分类结局往往较为脆弱，失访患者的结局可能会改变结果的显著性，因此在将其结果转化为临床应用之前需要谨慎。在 RCT 的常规报告中加入 FI 将指导读者了解结局统计学显著性的稳健性。FI≥5 且无任何患者失访的 RCT 可以被认为具有临床稳健的结果。
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