Miguel Angel Villasís-Keever

Mexican Institute of Social Security | IMSS · Unidad de Investigación en Análisis y Sïntesis de la Evidencia

Systematic reviews and meta-analyses are proven tools for guiding decision-making in patient care and public policy development. They are deemed the highest level of evidence and have become a cornerstone of clinical practice guidelines in all fields of medicine, with the number of systematic reviews and meta-analyses published increasing yearly in...

The neuroplasticity of adolescents could make them responsive to interventions affecting brain maturation such as yoga and mindfulness. We aimed to determine their efficacy and safety for the management of children and adolescents with obesity. A systematic search using MEDLINE, EMBASE, and PsycInfo was performed up to March 2024. We considered ran...

Acute lymphoblastic leukemia (ALL) is a hematopoietic disorder that mainly affects the child population, and it is characterized by the presence of lymphoid progenitor or precursor cells with different genetic alterations. The origin of this disease is controversial, since some authors assumed that leukemic transformation occurs in a lymphoid proge...

Background Patients with chronic kidney disease (CKD) are at increased risk for cardiovascular disease. Up to 80% of patients with CKD may exhibit inadequate vitamin D (VD) levels, which have been linked to the presence of cardiometabolic factors (CFs) in the adult population. However, research on this association in the pediatric population is lim...

Background: Elevated liver enzyme levels have been associated with metabolic syndrome in both obese and non-obese pediatric populations. This study aims to compare the serum liver enzyme levels in obese adolescents with and without insulin resistance (IR). Methods: A cross-sectional analysis was conducted involving obese adolescents aged 10-18....

Introduction Globally, up to 76.6% of the population may be affected by vitamin D (VD) deficiency, which has been linked to increased morbidity and mortality from COVID-19. This underscores the importance of further research into VD supplementation, particularly for health care workers, who are at higher risk due to indoor work environments and die...

Introduction: a relationship has been observed between elevated levels of liver enzymes and uric acid with the presence of metabolic syndrome (MS) in the pediatric population. Objective: to compare serum liver enzyme and uric acid levels between adolescents with and without MS. Methods: a cross-sectional study was carried out in adolescents wi...

Introduction Vitamin D (VD) deficiency is common in children with chronic kidney disease (CKD) because of multiple factors. During the coronavirus disease 2019 (COVID-19) pandemic, it increased because of medicine shortage and no enough medical service for patients with non-COVID-19 diseases. Objective To analyze the effects of the COVID-19 pandem...

Introduction Multisystem inflammatory syndrome in children associated with coronavirus disease 2019 (MIS-C), a novel hyperinflammatory condition secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, is associated with severe outcomes such as coronary artery aneurysm and death. Methods This multicenter, retrospective,...

Introduction: obesity in the pediatric population is a public health problem. The correlation of uric acid and carotid intima media thickness in adults has been demonstrated. Objective: to identify the correlation of uric acid and carotid intima media thickness in adolescents with obesity. Material and methods: an observational, cross-sectiona...

Objective To determine if the leptin, adiponectin, and leptin/adiponectin ratio (LAR) can predict weight gain at the end of GnRH analogs (GnRHa) treatment in girls with central precocious puberty (CPP). Material and methods Study design: prospective cohort. Serum levels of leptin and adiponectin were determined at diagnosis of CPP. Anthropometry w...

Background Adipokines are associated with cardiovascular disease; in chronic kidney disease (CKD) patients adipokines could be useful prognostic factors. Objectives To explore whether leptin and adiponectin in kidney replacement therapy (KRT) children could have a role on their cardiac function, in the long-term. Design Prospective cohort study w...

Multisystem inflammatory syndrome in children temporally associated with coronavirus disease 2019 (MIS-C), a novel hyperinflammatory condition secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, is associated with severe outcomes such as coronary artery aneurysm and death. This multicenter, retrospective, observatio...

Background: Since the beginning of the pandemic, new knowledge about COVID-19 obtained by research has been disseminated in medical and scientific journals, but the large number of publications that have been generated in such a short time has been impressive. Objective: To perform a bibliometric analysis of the published articles in medical-sci...

Background: leptin and adiponectin are associated with cardiovascular disease in chronic kidney disease (CKD) patients and could be useful prognostic factors. Objectives: to explore the usefulness of the leptin/adiponectin ratio (LAR) to predict the presence or worsening of dyslipidemia during 1 year of follow-up in children receiving kidney rep...

Background The clinical spectrum of COVID-19 is broad, from asymptomatic to severe cases and death. The objective of this study is to analyze the clinical course of patients attended during the first months of the SARS-CoV-2 pandemic in a third-level pediatric hospital.Methods Design: prospective cohort study. Patients with viral respiratory diseas...

Background Some studies suggested that adequate levels of vitamin D (VD) decrease the risk of severe COVID-19. Information about the effectiveness of VD supplementation in children is scarce. Objective To assess the efficacy and safety of VD supplementation compared to the standard of care in hospitalized children with COVID-19. Patients and meth...

Background . Associations between vitamin D (VD) deficiency and the risk of SARS-CoV-2 infection have been documented in cross-sectional population studies. Intervention studies in patients with moderate to severe COVID-19 have failed to consistently document a beneficial effect. Objective . To determine the efficacy and safety of VD-supplementati...

COVID-19 is an infectious disease of variable severity caused by a new coronavirus. Clinical presentation ranges from asymptomatic cases to severe illness. Most cases in newborns appear to be asymptomatic or mild. To conduct a systematic review of the literature on published studies of COVID-19 in newborns with a positive RT–PCR test. The PubMed an...

Background and objective: in chronic kidney disease (CKD) there are several factors that increase the presence of dyslipidemia. The aim of this study was to identify the usefulness of a nutritional intervention, in children with terminal CKD, on dyslipidemia 6 months after intervention start. Materials and methods: a quasi-experiment study (befo...

Background: Knowledge of chronic kidney disease (CKD) with pubertal disorders (PD) in adolescent boys is limited as few studies have explored this disorder. This study aimed to identify the usefulness of assessing hormonal parameters in male adolescents with CKD and their correlation with PD in a 12-month follow-up period. Methods: A prospective...

Background Different interventions have been implemented worldwide for the house-hold monitoring of patients with mild COVID-19 to reduce the burden of healthcare systems and guarantee quality of care. Telephone follow up and treatment kits have not been evaluated in the context of a national-wide primary care program. Aim of the study To compare...

En la elaboración de un protocolo de investigación, los autores deben tomar en cuenta los posibles errores que puedan ocurrir a lo largo del estudio. En la investigación clínica se reconocen dos tipos, los errores aleatorios y errores sistemáticos, estos últimos se denominan sesgos. A le fecha se han descrito decenas de sesgos, por lo que este artí...

Background/objectives: Considering the high number of deaths from coronavirus disease 2019 (COVID-19) in Latin American countries, together with multiple factors that increase the prevalence of vitamin D deficiency, we aimed to determine 25-hydroxyvitamin D (25[OH]D) levels and its association with mortality in patients with critical COVID-19. Su...

Objective: To report the frequency of asymptomatic infection with SARS-CoV-2 in pediatric patients undergoing invasive medical procedures in a tertiary pediatric hospital. Methods: From June to October 2020, a SARS-CoV-2 real-time reverse-transcription polymerase chain reaction (rRT-PCR) test was performed for all pediatric patients scheduled to...

Informar en los estudios sobre el tamaño del efecto de una intervención o del impacto de factor(es) sobre un desenlace, permite tomar mejores decisiones para la aplicación de los resultados a la práctica clínica. En este artículo se presenta la manera de analizar el tamaño del efecto, lo cual puede ser mediante métodos estadísticos directos o indir...

Objective To compare cardiometabolic factors and adipokines between patients with recently diagnosed CPP and controls without CPP, paired by BMI Z scores (BMIz) and classified into girls with adequate nutritional status and girls who are overweight or obese. Methods This cross-sectional study was performed from January 2012 to May 2015 at two tert...

Parte del ejercicio de la medicina basada en evidencia incluye el análisis crítico de los estudios de investigación clínica y dentro de este, la interpretación de los resultados presentados. Además de los datos estadísticos, existen estimadores que pueden ayudar a los clínicos a trasladar los hallazgos de las investigaciones a la práctica clínica h...

Los estudios ecológicos son uno de los diseños más frecuentemente empleados para tratar de establecer la asociación de ciertos factores con el desarrollo de enfermedades. Sin embargo, tienen limitaciones principalmente en la forma de realizar las mediciones de las variables, por lo que sus resultados tienen que ser comprobados con estudios de mayor...

Background: Falls are a significant public health problem among older people worldwide. The aim was to perform a new systematic review and meta-analysis to assess whether cataract surgery is effective in reducing the rate of falls in older persons. Methods: The systematic review was performed following the recommendations by the Cochrane Collabo...

Background The prevalence of chronic diseases (CDs) in the pediatric population has increased due to technological advances that decrease mortality and increase survival. Aim of the study To compare the frequency of cardiometabolic factors (CFs) among pediatric patients with CDs with those among children with obesity and overweight without CDs. M...

Background: This study describes 35 years of experience in a tertiary care level hospital that treats cardiac patients with univentricular heart physiology who underwent Glenn surgery. Methods: The study consisted of a retrospective analysis of patients who underwent Glenn surgery, including variables related to pre-operative, intra-operative, a...

Generalmente, las pruebas de diagnóstico son las herramientas necesarias para determinar la presencia o no de enfermedad, pero también pueden ser útiles para la exclusión de otras entidades diferenciales, evaluar la gravedad, establecer tratamientos específicos y estimar posibles resultados pronóstico. Para determinar cuánto puede contribuir una nu...

Background: Few research studies have assessed chronic kidney disease (CKD) with pubertal disorders (PD) in adolescent boys and limited data are available. Thus, this study was planned to identify the usefulness of assessing hormonal parameters in male adolescents with CKD and their relationship with PD with a 1-y follow-up period. Methods: A prosp...

Background: Oropharyngeal mucositis (OM) is one of the main side-effects of oncological therapy. There is no treatment to prevent its occurrence, but some zinc-based therapies have been proven to help in decreasing its intensity. The objective of this study was to determine the effect of zinc in OM in children with acute leukemia in the early stag...

incorporar una nueva prueba de diagnóstico en el ámbito clínico primero es necesario definir su validez a través de sus indicadores de desempeño, sensibilidad y especificidad. Como en cualquier investigación, en este tipo de estudios es posible que los resultados no sean confiables cuando hay sesgos durante su ejecución. En este artículo se discute...

Introduction: It has been described that menstruation is perceived as a natural but cumbersome event, with a negative impact on women's daily life. The objective of this study was to identify the perception of menstruation among female adolescents and the factors that may affect it. Material and methods: Observational, crosssectional, comparativ...

Background In adolescents with chronic kidney disease (CKD), menstrual disorders (MD) are common, which can make the management of CKD difficult and can sometimes delay renal transplantation. This study aimed to identify the usefulness of hormonal measurements in adolescents with CKD and their relationships with MD during a 1-year follow-up. Metho...

Objective: To evaluate the resistin/uric acid index as a prognostic factor associated with body mass index (BMI) z-score change after 1 year of lifestyle interventions for obesity. Study design: In this prospective cohort study, we included 102 adolescents with overweight or obesity (BMI ≥85th percentile). Weight and height were measured at the...

Las revisiones sistemáticas son investigaciones secundarias que compilan los resultados publicados obtenidos a partir de estudios en seres humanos. El término metaanálisis es utilizado para describir el análisis estadístico de la combinación de los resultados de dos o más estudios originales, los cuales debieron ser seleccionados a partir de una re...

Los ensayos clínicos toman gran relevancia en el desarrollo de nuevos fármacos al evaluar la farmacocinética, farmacodinamia, eficacia, seguridad y sus posibles efectos adversos. Para que un nuevo fármaco esté disponible para su uso cotidiano en pacientes, desde hace más de cuatro décadas se propuso un modelo que consiste en la realización de estud...

Introduction: Background: there are multiple factors that increase the presence of dyslipidemia in chronic kidney disease (CKD). Objective: to determine if the android/gynecoid ratio (A/GR) has utility as a cardiometabolic factor for dyslipidemia in pediatric patients with chronic renal failure. Materials and methods: cohort study. Patients with t...

Introduction: Objective: to identify the factors related to the presence of hospital malnutrition (HM) in patients under five years of age hospitalized in a third level care unit. Material and methods: cohort study. Patients under five years of age hospitalized were included. The record identified age, sex, pathological history, reason for admissi...

La investigación en seres humanos no puede llevarse a cabo sin cumplir con los principios éticos de autonomía, beneficencia y justicia. Los antecedentes históricos que destacaron la necesidad de contar con documentos para guiar la conducta de los investigadores señalan hechos lamentables para la humanidad. Aun cuando desde hace más de 50 años se pu...

Background: People with febrile neutropaenia are usually treated in a hospital setting. Recently, treatment with oral antibiotics has been proven to be as effective as intravenous therapy. However, the efficacy and safety of outpatient treatment have not been fully evaluated. Objectives: To compare the efficacy (treatment failure and mortality)...

Background: Oropharyngeal mucositis (OM) is one of the primary complications arising during oncological treatment, which significantly reduces the patient's quality of life (QoL). The aim of this study was to translate, culturally adapt, and validate the use of a new Spanish version of the Oropharyngeal Mucositis-Specific Quality-of-Life instrumen...

Objective: In neonates on total parenteral nutrition (TPN), amino acids may be a risk factor for developing total parenteral nutrition-associated cholestasis (TPNAC). We aimed, first, to compare methionine, cysteine, and taurine plasma levels between neonates on TPN who were receiving an intravenous amino acid solution based on a breast milk amino...

Background: Pediatric sepsis is considered the main cause of hospital death around the world. Many groups have tried to create tools that facilitate its early identification, as the shock index (SI), defined as the ratio between cardiac frequency and systolic blood pressure. The objective of this study was to determine the utility of SI to predict...

Background: Biliary atresia (BA) is a condition that obstructs biliary flow. If it is not corrected surgically, it can cause cirrhosis and death before 2 years of age. In Mexico, since 2013, the stool color card (SCC) was incorporated into the National Health Card (NHC) for the screening of BA. This study aimed to evaluate the impact of SCC for the...

Introduction: Most cases of toxic epidermal necrolysis and Stevens-Johnson syndrome have presentations with mucosal and skin involvement, derived from the reaction to certain drugs, which clinically constitute the same disease spectrum, although with a different degree of epidermolysis. Case presentation: Male patient of 11 years of age, admitted t...

Background: Ambulatory therapy in low-risk patients with cancer, fever, and neutropenia seems to be a secure and effective alternative. This study aimed to compare the effectiveness and safety of the antimicrobial treatment in early discharge vs. in-hospital treatment in children with cancer and febrile neutropenia (FN) with low risk of invasive b...

The concept of validity in research refers to what is true or what is close to the truth. It is considered that the results of an investigation will be valid when the study is free of errors. The errors or biases appear in the development of research, are due to methodological problems and, in general, can be grouped into three: selection bias, mea...

Systematic reviews and meta-analyses are proven tools for decision-making in health care, both for patients and public policy. For example, nowadays they constitute a substantial part of evidence-based clinical practice guidelines. However, the number of systematic reviews developed so far, and their use to improve the health of older adults has be...

Introducción: La enfermedad renal crónica (ERC) se asocia con alteraciones menstruales, y el manejo del sangrado uterino suele ser complejo por las condiciones de este grupo de pacientes. El objetivo de este trabajo fue describir la respuesta clínica al tratamiento hormonal de las alteraciones menstruales de adolescentes con ERC. Métodos: Se prese...

Objective: To compare serum resistin concentrations between prepubertal girls with a BMI > 85th percentile and girls with precocious puberty (CPP) who have and have not undergone GnRH analog treatment. Patients and methods: This is a cross-sectional study in girls with a BMI > 85th percentile and a median age of 8 years. We included 31 girls wit...

Introducción: La sepsis en pediatría es la principal causa de muerte hospitalaria. Se han intentado crear herramientas que faciliten su identificación, como el índice de choque (IC), definido como el cociente entre frecuencia cardíaca y tensión arterial sistólica. El objetivo de este trabajo fue identificar el mejor momento del IC para predecir la...

Objective: To provide meta-analytic estimates of self-harm from all community-based studies of adolescents from 1990 through 2015, estimates of suicidal risk, and characteristics including age profile, frequency, types, seeking help, and reasons. Method: Databases, bibliographies, and the internet were searched for cross-sectional and cohort stu...

Los estudios experimentales se utilizan para evaluar la eficacia y efectividad de una intervención terapéutica (farmacológica o quirúrgica), preventiva (como la vacunación o los cambios estilo de vida) o educativa (por ejemplo, taller para mejorar la calidad y la atención a la salud). Existen diferentes estudios experimentales, pero en la actualida...

Background: Bile duct atresia (BVA) is a condition that causes obstruction to biliary flow, not corrected surgically, causes cirrhosis and death before 2 years of age. In Mexico from 2013 the visual colorimetric card (VVC) was incorporated for the timely detection of BVA to the National Health Card (NHC). The aim of this study was to evaluate the...

Introduction: In congenital adrenal hyperplasia (CAH), obesity, hyperinsulinemia and leptin levels are increased. Objective: To identify the frequency of cardiometabolic risk factors (CRF) in children and adolescents with CAH and to explore the relationship with leptin levels. Method: Cross-sectional study of 40 patients who underwent anthropo...

Los reportes de casos clínicos corresponden a artículos que tienen la más baja evidencia entre los diferentes estudios de investigación. Sin embargo, no solo son comunes y significativos en el ámbito médico, sino que en muchas ocasiones han sido la base para la generación de investigación. El propósito de la publicación puede ser científico o educa...

Experimental studies are used to assess the efficacy and effectiveness of therapeutic (pharmacological or surgical), preventive (such as vaccination or lifestyle changes) or educational interventions (e.g., workshops to improve quality and healthcare). There are different experimental studies but, currently, randomized controlled trial (RCT) is rec...

Clinical case reports correspond to articles that have the lowest level of evidence within different research trials. However, not only are they common and significant in the medical field, but they have often been the basis the generation of research. The purpose of their publication can be scientific or educational. In general terms, the discover...

Background The nurseries program (NP) was created to support parents with 1 to 3-year-old children living in poverty situation in Mexico, and includes education and child daycare for 8 hours five days per week. The objective of this study was to evaluate the association between length of stay in the NP and the level of development in children. Met...

El análisis estadístico se divide en 2 grandes componentes: el análisis descriptivo y el análisis inferencial. Una inferencia es la elaboración de conclusiones a partir de las pruebas que se realizan con los datos obtenidos de una muestra. Las pruebas estadísticas se emplean con la finalidad de establecer la probabilidad de que una conclusión que s...

Background Type 1 diabetes (T1D) usually occurs in the pediatric age and affects the growth of children. The aim of this work was to describe growth and growth failure associated factors in a population of children with T1D in a tertiary level pediatric hospital. Methods A case-control nested in a cohort study was conducted. We included patients w...

Background: Although pulmonary involvement is common in patients with cancer, its frequency and nature is seldom reported in the medical literature. Objective: To determine the frequency and type of lung pathological conditions revealed by autopsy in children with cancer. Methods: All reports from autopsies performed in children with cancer fr...