An observed statistically significant difference between two interventions does not necessarily imply that this difference is clinically important for patients and clinicians. We aimed to assess if treatment effects of randomized controlled trials (RCTs) for low back pain (LBP) are statistically significant and clinically relevant, and if RCTs were powered to achieve clinically relevant differences on continuous outcomes. We searched for all RCTs included in Cochrane Systematic Reviews focusing on the efficacy of rehabilitation interventions for LBP and published until April 2017. RCTs having sample size calculation and a planned minimal important difference were considered. In the primary analysis, we calculated the proportion of RCTs classified as “statistically significant and clinically relevant”, “statistically significant but not clinically relevant”, “not statistically significant but clinically relevant”, and “not statistically significant and not clinically relevant”. Then, we investigated how many times the mismatch between statistical significance and clinical relevance was due to inadequate power. From 20 eligible SRs including 101 RCTs, we identified 42 RCTs encompassing 81 intervention comparisons. Overall, 60% (25 RCTs) were statistically significant while only 36% (15 RCTs) were both statistically and clinically significant. Most trials (38%) did not discuss the clinical relevance of treatment effects when results did not reached statistical significance. Among trials with non-statistically significant findings, 60% did not reach the planned sample size, therefore being at risk to not detect an effect that is actually there (type II error). Only a minority of positive RCT findings was both statistically significant and clinically relevant. Scarce diligence or frank omissions of important tactic elements of RCTs, such as clinical relevance, and power, decrease the reliability of study findings to current practice.

中文翻译：

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下背部疼痛的随机对照试验中的康复干预：统计学意义的证据通常不相关

在两种干预措施之间观察到的统计学显着差异不一定意味着该差异对患者和临床医生具有重要的临床意义。我们旨在评估针对腰背痛（LBP）的随机对照试验（RCT）的治疗效果是否具有统计学意义和临床相关性，以及RCT是否有能力在持续预后方面取得临床相关差异。我们搜索了《 Cochrane系统评价》中包括的所有RCT，重点关注LBP康复干预措施的有效性，并于2017年4月发布。考虑了具有样本量计算和计划的最小重要差异的RCT。在初步分析中，我们计算了被分类为“具有统计学意义和临床相关性”的RCT的比例，“具有统计学意义但无临床意义”，“无统计学意义但有临床意义”和“无统计学意义且无临床意义”。然后，我们调查了统计学上的显着性和临床相关性之间的不匹配是由于能力不足引起的多少次。从包括101个RCT在内的20个合格SR中，我们确定了42个RCT，包括81个干预措施的比较。总体而言，有60％（25个RCT）具有统计学意义，而只有36％（15个RCT）具有统计学和临床​​意义。当结果未达到统计学意义时，大多数试验（38％）没有讨论治疗效果的临床相关性。在具有非统计意义的发现的试验中，有60％未达到计划的样本量，因此有可能无法检测到实际存在的影响（II型错误）。仅少数RCT阳性阳性结果具有统计学意义和临床意义。RCT的重要战术要素（如临床相关性和能力）的勤勉尽责或坦率的遗漏降低了研究结果对当前实践的可靠性。