INTRODUCTION Evidence about specific carbohydrate diet (SCD) for inflammatory bowel disease (IBD) is limited. We conducted 54 single-subject, double-crossover N-of-1 trials comparing SCD with a modified SCD (MSCD) and comparing each with the participant's baseline, usual diet (UD). METHODS Across 19 sites, we recruited patients aged 7-18 years with IBD and active inflammation. Following a 2-week baseline (UD), patients were randomized to 1 of 2 sequences of 4 alternating 8-week SCD and MSCD periods. Outcomes included fecal calprotectin and patient-reported symptoms. We report posterior probabilities from Bayesian models comparing diets. RESULTS Twenty-one (39%) participants completed the trial, 9 (17%) completed a single crossover, and 24 (44%) withdrew. Withdrawal or early completion occurred commonly (lack of response [n = 11], adverse events [n = 11], and not desiring to continue [n = 6]). SCD and MSCD performed similarly for most individuals. On average, there was <1% probability of a clinically meaningful difference in IBD symptoms between SCD and MSCD. The average treatment difference was -0.3 (95% credible interval -1.2, 0.75). There was no significant difference in the ratio of fecal calprotectin geometric means comparing SCD and MSCD (0.77, 95% credible interval 0.51, 1.10). Some individuals had improvement in symptoms and fecal calprotectin compared with their UD, whereas others did not. DISCUSSION SCD and MSCD did not consistently improve symptoms or inflammation, although some individuals may have benefited. However, there are inherent difficulties in examining dietary changes that complicate study design and ultimately conclusions regarding effectiveness.

中文翻译：

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溃疡性结肠炎和克罗恩病饮食的个性化研究：一系列 N-of-1 饮食试验。

引言 关于特定碳水化合物饮食（SCD）治疗炎症性肠病（IBD）的证据有限。我们进行了 54 项单受试者、双交叉 N-of-1 试验，将 SCD 与改良版 SCD (MSCD) 进行比较，并将每项试验与参与者的基线、常规饮食 (UD) 进行比较。方法 我们在 19 个地点招募了年龄为 7-18 岁的 IBD 和活动性炎症患者。2 周基线 (UD) 后，患者被随机分配至 4 个交替的 8 周 SCD 和 MSCD 周期的 2 个序列中的 1 个。结果包括粪便钙卫蛋白和患者报告的症状。我们报告了比较饮食的贝叶斯模型的后验概率。结果 21 名 (39%) 参与者完成了试验，9 名 (17%) 名参与者完成了一次交叉，24 名 (44%) 名参与者退出。退学或提前完成的情况很常见（缺乏回应 [n = 11]，不良事件 [n = 11]，并且不想继续 [n = 6]）。对于大多数人来说，SCD 和 MSCD 的表现相似。平均而言，SCD 和 MSCD 之间 IBD 症状有临床意义的差异的可能性 <1%。平均治疗差异为-0.3（95%可信区间-1.2，0.75）。与SCD和MSCD相比，粪便钙卫蛋白几何平均值的比率没有显着差异（0.77，95%可信区间0.51，1.10）。与 UD 相比，一些人的症状和粪便钙卫蛋白有所改善，而其他人则没有。讨论 SCD 和 MSCD 并不能始终如一地改善症状或炎症，尽管有些人可能受益。然而，检查饮食变化存在固有的困难，这使得研究设计和最终关于有效性的结论变得复杂。