Low impact of randomized controlled trials published in Latin American journals indexed in MEDLINE over a 6-year periodLow impact of randomized controlled trials published in Latin American journals indexed in MEDLINE over a 6-year period

Objective The prevalence of inclusion of randomised controlled trials (RCTs) published in Latin American journals has not been evaluated yet. This study aims to assess the extent to which RCTs published in Latin American medical journals are cited and used in systematic reviews. Study design and setting We did a descriptive observational study on RCTs published in MEDLINE-indexed Latin American journals from 2010 to 2015. The primary outcome was the inclusion of these trials in systematic reviews. The secondary outcome was the total number of citations that each RCT received as reported by Google Scholar. Results Twenty-nine journals were selected. After searching these journals, we found 135 RCTs that fulfilled the inclusion criteria. These RCTs accounted for 2% of all research articles published in these journals. Of these, 55 (41%) were included by 202 systematic reviews. Of the nine most-cited RCTs by systematic reviews and meta-analyses, only two were published in Spanish. Nine RCTs received zero citations by any article type. Most RCTs had small sample sizes. Conclusions The overall impact of RCTs published in Latin American journals is low. Efforts are needed to improve the methodological quality, pertinence and dissemination of trials, particularly if published in Spanish.目的 目前尚未有研究评估拉丁美洲期刊发表的随机对照试验（randomised controlled trials, RCTs）的被收录情况。本研究旨在评估拉丁美洲医学期刊发表的随机对照试验在系统综述中的被引用与应用程度。 研究设计与研究场景 本研究为描述性观察性研究，研究对象为2010年至2015年间收录于医学文献分析与检索系统（MEDLINE）的拉丁美洲期刊中发表的随机对照试验。本研究的主要结局指标为上述试验在系统综述中的被收录情况，次要结局指标为谷歌学术（Google Scholar）报告的每一项随机对照试验的总被引次数。 结果 本研究共纳入29种期刊。经检索上述期刊后，共筛选出符合纳入标准的135项随机对照试验，占这些期刊所发表全部研究论文的2%。其中，55项（41%）被202篇系统综述所收录。在被系统综述与荟萃分析（meta-analyses）引用频次最高的9项随机对照试验中，仅2项以西班牙语发表。另有9项随机对照试验未被任何类型的文献引用。绝大多数随机对照试验的样本量较小。 结论 拉丁美洲期刊发表的随机对照试验整体影响力较低。亟需采取措施提升试验的方法学质量、研究针对性与传播推广效果，针对以西班牙语发表的试验而言尤为如此。