<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0120-5552</journal-id>
<journal-title><![CDATA[Revista Salud Uninorte]]></journal-title>
<abbrev-journal-title><![CDATA[Salud, Barranquilla]]></abbrev-journal-title>
<issn>0120-5552</issn>
<publisher>
<publisher-name><![CDATA[Fundación Universidad del Norte, División de Ciencias de la]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0120-55522019000100057</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Causas de pérdidas de pacientes durante los ensayos clínicos con asignación aleatoria: estudio metaepidemiológico]]></article-title>
<article-title xml:lang="en"><![CDATA[Causes of patient loss during clinical trials: a meta-epidemiological study]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[HINCAPIÉ TABARES]]></surname>
<given-names><![CDATA[DANIELA]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[PÉREZ CARRILLO]]></surname>
<given-names><![CDATA[VANESSA]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[DONADO GÓMEZ]]></surname>
<given-names><![CDATA[JORGE HERNANDO]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Universidad Pontificia Bolivariana  ]]></institution>
<addr-line><![CDATA[Medellín ]]></addr-line>
<country>Colombia</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad Pontificia Bolivariana  ]]></institution>
<addr-line><![CDATA[Medellín ]]></addr-line>
<country>Colombia</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Universidad Pontificia Bolivariana  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Colombia</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>04</month>
<year>2019</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>04</month>
<year>2019</year>
</pub-date>
<volume>35</volume>
<numero>1</numero>
<fpage>57</fpage>
<lpage>71</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_arttext&amp;pid=S0120-55522019000100057&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_abstract&amp;pid=S0120-55522019000100057&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_pdf&amp;pid=S0120-55522019000100057&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[RESUMEN  Objetivo: Los ensayos clínicos controlados aleatorizados representan el estudio de elección para evaluar la seguridad y la eficacia de intervenciones contra problemas de salud. La validez interna de estos se puede ver afectada por las frecuentes pérdidas de pacientes que se presentan. El objetivo de este estudio es describir cuáles son las principales causas de pérdidas de pacientes durante los ensayos clínicos en el área de medicina, si hay diferencias según el grupo al que pertenezcan y si se realizó análisis por intención a tratar.  Metodología: Estudio observacional descriptivo. Se escogió una muestra por conveniencia de 100 ensayos clínicos controlados relacionados con el área de medicina, publicados en los últimos cinco años (2011- 2016), de cuatro revistas de alto impacto científico, y se identificaron las principales causas de pérdidas de pacientes.  Resultados: Se revisó un total de 100 artículos de medicina. Se identificaron 15 causas de pérdidas de pacientes durante los ensayos clínicos; las tres más prevalentes según el número de pacientes fueron pérdida del seguimiento (61.42%), descontinuación de la intervención (25.28%), y muerte (2.34%). Las tres más frecuentes según el número de ensayos clínicos fueron pérdida del seguimiento (73%), retiro (34%), y muerte (31%). En el 36% de los ensayos clínicos analizados se empleó un análisis por intención de tratar.  Conclusión: En el total de ensayos clínicos revisados se observó que la causa más prevalente de pérdida de pacientes fue la pérdida en el seguimiento. Asimismo, el análisis por intención de tratar se empleó en aproximadamente un tercio de los artículos revisados.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[ABSTRACT  Objective: Randomized controlled clinical trials represent the study of choice to evaluate the safety and effectiveness of interventions against any health problems. The internal validity of these can be affected by the frequent losses of patients. The main objective of the study is to describe what are the main causes of loss of patients during clinical trials in the area of medicine in four major medical journals of high impact factor, if there are differences according to the group that they belong and if the authors performed the intention to treat analysis.  Methods: Descriptive observational study. A convenience sample of 100 controlled clinical trials, related to the area of medicine was selected, the articles were published in the last five years (2011- 2016), of four journals of high scientific impact, in which the main causes of loss of patients were identified.  Outcomes: A total of 100 articles of internal medicine were reviewed. We identified 15 causes of patient losses during clinical trials; the three most prevalent according to the number of patients were loss of follow-up (61.42%), discontinuation of the intervention (25.28%), and death (2.34%). The three most frequent according to the number of clinical trials were loss of follow-up (73%), retirement (34%) and death (31%). An analysis by intention to treat was used in 36% of the clinical trials analyzed.  Conclusion: In the total of reviewed clinical trials, the most frequent cause of loss of patients was loss of follow-up. Furthermore, the intention to treat analysis was used in about one third of the articles reviewed.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[análisis estadístico]]></kwd>
<kwd lng="es"><![CDATA[análisis de intención de tratar]]></kwd>
<kwd lng="es"><![CDATA[ensayo clínico controlado aleatorio]]></kwd>
<kwd lng="es"><![CDATA[medicina interna]]></kwd>
<kwd lng="es"><![CDATA[metodología]]></kwd>
<kwd lng="en"><![CDATA[statistical analysis]]></kwd>
<kwd lng="en"><![CDATA[intention to treat analysis]]></kwd>
<kwd lng="en"><![CDATA[randomized controlled trial]]></kwd>
<kwd lng="en"><![CDATA[internal medicine]]></kwd>
<kwd lng="en"><![CDATA[methodology]]></kwd>
</kwd-group>
</article-meta>
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