Illustrating risk difference and number needed to treat from a randomized controlled trial of spinal manipulation for cervicogenic headache.
Illustrating risk difference and number needed to treat from a randomized controlled trial of spinal manipulation for cervicogenic headache.
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DOI：
10.1186/1746-1340-18-9
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发表时间：
2010-05-24
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影响因子：
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通讯作者：
Vavrek, Darcy
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文献类型：
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作者：
Haas, Mitchell;Schneider, Michael;Vavrek, Darcy
背景技术背景：一名参与者获益所需治疗的数量（NNT）被认为是报告随机试验二元结局的有用且有临床意义的方法。从我们的随机对照试验的连续数据分析表明，以前的一个显着的和临床上重要的差异，有利于脊柱操作在一个轻massage control.METHODS：80名参与者被随机接受脊柱操作或轻按摩控制（n = 40/组）。前四周颈源性头痛（主要结局）、残疾和数量的改善被分为两个阈值的二元结局：30%代表最小的临床重要变化，50%代表临床成功。在12周和24周随访时，使用二项式回归（广义线性模型）对各组进行比较，以计算校正后的组间风险差异（RD）和校正组间基线差异后需要治疗的人数（NNT）。结果：对于头痛，脊柱操作更可能使临床上重要的改善（30%或50%）：调整后的RD = 17%至27%，NNT = 3.8至5.8（p = 0.005至0.028）。一些统计学上显着的结果有利于操作被发现头痛残疾和number.CONCLUSION：脊柱操作证明了一个临床上重要的改善颈源性头痛方面的好处。建议使用调整后的NNT;然而，调整后的RD可能比NNT更容易解释。该研究证明了结果如何取决于将变量二分为二进制结果的阈值。ClinicalTrials.gov
BACKGROUND: The number needed to treat (NNT) for one participant to benefit is considered a useful, clinically meaningful way of reporting binary outcomes from randomized trials. Analysis of continuous data from our randomized controlled trial has previously demonstrated a significant and clinically important difference favoring spinal manipulation over a light massage control.METHODS: Eighty participants were randomized to receive spinal manipulation or a light massage control (n = 40/group). Improvements in cervicogenic headache pain (primary outcome), disability, and number in prior four weeks were dichotomized into binary outcomes at two thresholds: 30% representing minimal clinically important change and 50% representing clinical success. Groups were compared at 12 and 24-week follow-up using binomial regression (generalized linear models) to compute the adjusted risk difference (RD) between groups and number needed to treat (NNT) after adjusting for baseline differences between groups. Results were compared to logistic regression results.RESULTS: For headache pain, clinically important improvement (30% or 50%) was more likely for spinal manipulation: adjusted RD = 17% to 27% and NNT = 3.8 to 5.8 (p = .005 to .028). Some statistically significant results favoring manipulation were found for headache disability and number.CONCLUSION: Spinal manipulation demonstrated a benefit in terms of a clinically important improvement of cervicogenic headache pain. The use of adjusted NNT is recommended; however, adjusted RD may be easier to interpret than NNT. The study demonstrated how results may depend on the threshold for dichotomizing variables into binary outcomes.TRIAL REGISTRATION: ClinicalTrials.gov NLM identifier NCT00246350.