Radiography as primary outcome in rheumatoid arthritis:: acceptable sample sizes for trials with 3 months' follow up
Radiography as primary outcome in rheumatoid arthritis:: acceptable sample sizes for trials with 3 months' follow up
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DOI：
10.1136/ard.2003.014043
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发表时间：
2004-11-01
影响因子：
27.4
通讯作者：
van der Heijde, D
中科院分区：
文献类型：
--
作者：
Bruynesteyn, K;Landewé, R;van der Heijde, D
目的：探讨X线平片是否可以显示3个月内类风湿性关节炎（RA）引起的关节损伤的变化。方法：对188对间隔3个月拍摄的胶片进行评估。根据 Sharp/van der Heijde 方法，在（按时间顺序）和不（配对）了解电影序列的情况下对他们进行评分。对不同患者亚群的关节损伤变化进行了群体和个体水平的分析。根据进展大于最小可检测变化 (SDC) 的患者百分比来估计检测统计和临床显着差异所需的样本量。结果：通过时间顺序和配对评分方法都可以看到关节损伤的变化。如果基于时间变化评分，则关节损伤进展大于相应 SDC（1.7 和 2.4）的患者百分比在子集中从 18% 变化到 64%，如果使用成对变化评分，则从 9% 变化到 36%。在几个子集中可以看到可接受的样本量估计值，具体取决于（a）所研究的药物如何降低关节损伤进展的个体风险（通过绝对或相对风险降低模型）； (b) 损害如何评分（按时间顺序或配对）； (c) 基线风险； (d) 是否使用两侧或一侧测试。 结论： RA 引起的关节损伤变化可以在 3 个月内可靠地检测到。这一发现可用于计划以放射学进展作为主要结果的短期随机对照试验。
Objectives: To investigate whether plain radiographs can show changes in joint damage due to rheumatoid arthritis (RA) within 3 months.Methods: 188 film pairs taken with a 3 month interval were evaluated. They were scored with (chronological) and without (paired) knowledge of the sequence of the films according to the Sharp/van der Heijde method. Changes in joint damage were analysed on a group and an individual level for different subsets of patients. Sample sizes required to detect statistically and clinically significant differences were estimated based on the percentages of patients with progression larger than the smallest detectable change (SDC).Results: Changes in joint damage were seen by both the chronological and the paired scoring method. The percentage of patients with progression of joint damage larger than the corresponding SDCs (1.7 and 2.4) varied in the subsets from 18% to 64% if based on the chronological change-scores and from 9% to 36% using paired change-scores. Acceptable sample size estimates were seen in several subsets, depending on (a) how the investigated drug would reduce the individual risk of progression of joint damage (by an absolute or a relative risk reduction model); (b) how damage was scored (chronological or paired); (c) the baseline risk; and (d) whether a two sided or one sided test would be used.Conclusions: Changes in joint damage due to RA can be detected reliably already within 3 months. This finding can be used to plan short term, randomised controlled trials with radiographic progression as primary outcome.