Vol. 17 Num. 68 July-September 2015 ISSN 1665-5796

Vol.

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Evaluation criteria for the interpretation of the oral glucose tolerance test (OGTT) in The National Mother-Child Teaching Hospital San Bartolome

Combined Therapy in Diabetic Macular Edema

History and progress of antiviral drugs: from acyclovir to direct-acting antiviral agents (DAAs) for Hepatitis C

Chikungunya Virus: a general overview

Anaphylaxis: Practical aspects of diagnosis and treatment

Biostatistics advisor:

Eloy Crdenas Estrada Monterrey, Mxico

Antonio Costilla Esquivel Monterrey, Mxico

English translation and style:

Emma Bertha Garca Quintanilla

Juan Pablo Figueroa Delgado

Medicina Universitaria, Volumen 17, nmero 68, julio-septiembre 2015, es una publicacin trimestral de la Revista de Investigacin y Ciencia de la Facultad de Medicina y Hospital Universitario Dr. Jos E. Gonzlez de la U.A.N.L. ISSN 1665-5796.Editada por: Masson Doyma Mxico, S.A. Av. Insurgentes Sur 1388, Piso 8, Col. Actipan Del. Benito Jurez, CP 03230, Mxico, D.F. Tels.: 5524-1069, 5524-4920, Fax: 5524-0468. Reservados todos los derechos. El contenido de la presente publicacin no puede ser reproducido, ni transmitido por ningn procedimiento electrnico o mecnico, incluyendo fotocopia, grabacin magntica, ni registrado por ningn sistema de recuperacin de informacin, en ninguna forma, ni por ningn medio, sin la previa autorizacin por escrito del titular de los derechos de explotacin de la misma. Cualquier forma de reproduccin, distribucin, comunicacin pblica o transformacin de esta obra slo puede ser realizada con la autorizacin de sus titulares, salvo excepcin prevista por la ley. Impresa por Editorial de Impresos y Revistas S. A. de C. V. Emilio Carranza No. 100 Col. Zacahuizco C.P. 03550. Delegacin Benito Jurez, Mxico D.F. Este nmero se termin de imprimir en septiembre de 2014 con un tiraje de 1,200 ejemplares. ndices en los que aparece esta revista: ARTEMISA (Artculos Editados en Mxico sobre informacin en Salud). En Internet, compilada en el ndice Mexicano de Revistas Biomdicas (IMBIOMED) y LATINDEX.

EDITORIAL BOARD

EDITORIAL COMMITTEE

General Director

Editor in Chief

Editor

Editor

Technical Editor

Technical Editor

Technical Editor

Assistant Editor

Santos Guzmn Lpez

Flix Ramn Cedillo Salazar

David Gmez Almaguer

Francisco Javier Bosques Padilla

Carlos Alberto Acosta Olivo

Beatriz Elizabeth De la Fuente Cortez

Alfredo Arias Cruz

Jos Carlos Jaime Prez

Hugo Alberto Barrera Saldaa

Ren Ral Drucker Coln

Rubn Lisker Y.

Ruy Prez Tamayo

Guillermo J. Ruiz Argelles

Ralph Weissleder

Oliverio Welsh Lozano

Monterrey, Mxico

DF, Mxico

DF, Mxico

DF, Mxico

Puebla, Mxico

Boston, EEUU

Monterrey, Mxico

Ariel Ernesto Arias Ramrez

Alejandro Arroliga

Norbert W. Brattig

Mara de los ngeles Castro Corona

Ricardo Cerda Flores

Salvador Cruz Flores

Jos A. Gonzlez Gonzlez

Oscar Gonzlez Llano

Patricia de Gortari

Francisco Forriol Campos

Alejandra Garca Quintanilla

Elvira Garza Gonzlez

Pali Hungin

Jos Luis Iglesias Benavides

Patricia Ileana Joseph Bravo

Susana Kofman Alfaro

David Kershenobich Stalnikowitz

Francisco Lpez Jimnez

Xavier Lpez Karpovitch

Laura E. Martnez de Villarreal

Nahum Mndez Snchez

Claudia Elizalde Molina

Guillermo I. Prez Prez

Mario Henry Rodrguez

Isaas Rodrguez Balderrama

Alejandro Ruiz Argelles

Guillermo J. Ruiz Delgado

Jos Javier Snchez

Josep Mara Segur Vilalta

Gregorio A. Sicard

Rolando Tijerina Menchaca

Lyuba Varticovski

Joseph Varon

Jordi Sierra Gil

Ottawa, Canad

Temple, EEUU

Hamburgo, Alemania

Monterrey, Mxico

Monterrey, NL

St. Louis, EEUU

Monterrey, Mxico

Monterrey, Mxico

DF, Mxico

Madrid, Espaa

Mrida, Mxico

Monterrey, Mxico

Stockton-on-Tees, Reino Unido

Monterrey, Mxico

Cuernavaca, Mxico

DF, Mxico

DF, Mxico

Rochester, EEUU

DF, Mxico

Monterrey, Mxico

DF, Mxico

Monterrey, Mxico

Nueva York, EEUU

Cuernavaca, Mxico

Monterrey, Mxico

Puebla, Mxico

Puebla, Mxico

Madrid, Espaa

Barcelona, Espaa

St. Louis, EEUU

Monterrey, Mxico

Maryland, EEUU

Houston, EEUU

Barcelona, Espaa

Conte

nts

Volume 17Issue 68July-September 2015

EDITORIAL131 Some observations on the publication of articles in Medicine

D. Gmez-Almaguer

ORIGINAL ARTICLES133 Prevalence of sensorineural hearing loss in children and adolescents with diabetes

mellitusJ.L. Trevio-Gonzlez, D.I. Campuzano-Bustamante, O. Flores-Caloca, R. Santos-Lartigue, M.J. Villegas-Gonzlez Jr.

138 Tendencies in medical publicationsH.E. Tamez-Prez, E. Delgadillo-Esteban, S.L. Proskauer-Pea, V. Arenas-Fabbri, A.M. Carranza-Trejo, J.G. Gonzlez-Gonzlez, A.L. Tamez-Pea

143 Effi cacy of antiemetic therapy in patients undergoing laparoscopic cholecystectomyH.A. Llanes-Garza, N.G. Lpez-Cabrera, R. Cacho-De la Vega, D. Palacios-Rios, A.L. Millan-Corrales, M. Pacheco-Jurez, E. Crdenas-Estrada

147 Evaluation of the criteria for the interpretation of the oral glucose tolerance test in the National Mother-Child Teaching Hospital San BartolomeJ.J. Moya-Salazar, L. Pio-Dvila

153 Combined therapy in diabetic macular edemaJ.H. Gonzlez-Corts, J.J. Toledo-Negrete, K. Butrn-Valdez, V. Zapata-Elizondo, B.O. Martnez-Gamero, E.E. Trevio-Cavazos, J.D. Guerra-Leal, J. Mohamed-Hamsho

SCIENTIFIC LETTERS158 Spectrum of hemifacial microsomia in a pre-term newborn. Case presentation and

literature reviewA.Y. Medina-de la Cruz, I. Rodrguez-Balderrama, C.H. Burciaga-Flores, M.E. de la O-Cavazos

162 Prostatic cyst: An unusual cause of hemospermiaF. Hernndez-Galvn, R. Jaime-Dvila, L.S. Gmez-Guerra, A. Gutirrez-Gonzlez, J.F. Lozano-Salinas, J.G. Arrambide-Gutirrez

REVIEW ARTICLES165 History and progress of antiviral drugs: From acyclovir to direct-acting antiviral

agents (DAAs) for Hepatitis CO.L. Bryan-Marrugo, J. Ramos-Jimnez, H. Barrera-Saldaa, A. Rojas-Martnez, R. Vidaltamayo, A.M. Rivas-Estilla

175 Chikungunya virus: A general overviewK.A. Galn-Huerta, A.M. Rivas-Estilla, I. Fernndez-Salas, J.A. Farfan-Ale, J. Ramos-Jimnez

SPECIAL ARTICLE184 Perspective on stroke in Mexico

F. Gngora-Rivera

EXPERTS CORNER: A PERSONAL APPROACH188 Anaphylaxis: Practical aspects of diagnosis and treatment

A. Arias-Cruz

192 Fecal microbiota transplantationJ. Gonzlez-Altamirano, H.J. Maldonado-Garza, E. Garza-Gonzlez, F.J. Bosques-Padilla

Medicina Universitaria. 2015;17(68):131---132

www.elsevier.es/rmuanl

EDITORIAL

Some observations on the publication of articles in

Medicine

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otihaosnttotvi

The University is not only a school for adults, but it playsa major role in the search of new knowledge, in otherwords, research. In addition to assisting patients, teachingcolleagues and students --- undergraduates as well as post-graduates --- it is important to highlight the need and duty ofdoctors to be involved in research.

This does not necessarily require a great set of skillsor special knowledge; it can be as simple as to cooperatein a workgroup that searches for new knowledge of a spe-cific disease, or more complex activities, like designing andimplementing a prospective/comparative study in searchof new evidence and different paths than those previouslyestablished.

In order to broadcast knowledge locally, domesticallyor internationally, it is necessary to publish the conductedresearch. Activity at a convention, like a conference, or aposter displaying the results of research, are far from idealbroadcasting and, in the scientific world, these are con-sidered to be preliminary or simplistic. Final publication isessential in order to transcend and make a difference. Topublish implies finding a magazine interested in the worksubmitted for publication. In this sense quality, originalityand significance are factors which would make its accep-tance and spreading possible, which is part of the finalprocess of quality research, thus the popular saying publishor perish; this stresses, in an exaggerated way, the impor-tance of having a research work finally published.

In this issue of Medicina Universitaria Tamez-Prezet al. analyze the publication trends in a series of high-impact publications. This is measured by the number ofreferences a magazine has versus the number of articlespublished in a specific period of time. These magazinesinclude The New England Journal of Medicine, Lancet andJAMA, among others, hence the high quality of the arti-cles and studies --- comparative, randomized and prospective--- accepted in these publications. This is the base of their

relevance, hence their acceptance and acknowledgement inthe community. In the aforementioned journals, we rarelyfind articles from developing countries, a group to which

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http://dx.doi.org/10.1016/j.rmu.2015.06.0021665-5796/ 2015 Published by Masson Doyma Mxico S.A. on behalf of Uunder the CC BY-NC-ND license (http://creativecommons.org/licenses/b

exico belongs. Studies of major clinical significance require large number of patients, years of follow-up and money forheir elaboration/culmination, and are supported or origi-ate within the pharmaceutical industry or by a society orroup in the US or Western Europe. This occurs and will con-inue to occur until our organization and ability to developtudies with a higher evidence level materializes. Until then,exico will remain in the background in the field of inno-ation, ideas and contributions to the world of science.owever, we must recognize those researchers who strive on

daily basis to show their abilities to innovate despite howomplicated working in a developing country may be. Per-onally, the presence of high-quality articles in high-impactublications, articles which are the product of the resource-ulness, invention and perseverance of invariably optimisticexican doctors, never ceases to amaze.

In the medical world we have the advantage of beingble to search for valuable information in different typesf studies, from an outstanding clinical case, to retrospec-ive observational studies and case-control, among others.verything is of value.

On the other hand, in this day and age, the publicationf articles in these high-profile journals is not necessarilyhat important. The spreading of knowledge through thenternet nowadays is such that information democracyas reached science, it just takes the touch of a button toccess information of any publication indexed in Pubmedr any other entries. This allows for studies and papers ofupposedly less significance, published in low-impact jour-als, to be easily seen, eventually referenced and obviouslyranscending and having an impact in the scientific world,hus in the benefit of patients and their surroundings. Thene must is language: English, whether we like it or not, ishe language of modern science, therefore Medicina Uni-ersitaria has decided to take this step forward towardsnternationalization. We are on the right track, the speed

an be improved and we will continue trying, eventuallyetting us closer to the major journals in the scientificorld.

niversidad Autnoma de Nuevo Len. This is an open access articley-nc-nd/4.0/).

dx.doi.org/10.1016/j.rmu.2015.06.002http://www.elsevier.es/rmuanlhttp://crossmark.crossref.org/dialog/?doi=10.1016/j.rmu.2015.06.002&domain=pdfdx.doi.org/10.1016/j.rmu.2015.06.002http://creativecommons.org/licenses/by-nc-nd/4.0/

1

UANL, Av. Madero y Gonzalitos s/n, Colonia Mitras CentroMonterrey, C.P. 64460, Monterrey, N.L., Mexico.

32

D. Gmez-Almaguer

Hematology Service at the Dr. Jos E. Gonzlez

University Hospital of the UANL, Monterrey, N.L., Mexico

Corresponding author at: Servicio de Hematologa,Hospital Universitario Dr. Jos Eleuterio Gonzlez de la

EDITORIAL

Tel.: +52 81 83488510.E-mail address: dgomezalmaguer@gmail.com

mailto:dgomezalmaguer@gmail.com

Medicina Universitaria. 2015;17(68):133---137

www.elsevier.es/rmuanl

ORIGINAL ARTICLE

Prevalence of sensorineural hearing loss in childrenand adolescents with diabetes mellitus

J.L. Trevino-Gonzleza,, D.I. Campuzano-Bustamantea, O. Flores-Calocab,R. Santos-Lartiguea, M.J. Villegas-Gonzlez Jr.a

a Department of Otolaryngology and Head and Neck Surgery of the Dr. Jos Eleuterio Gonzlez University Hospital of theAutonomous University of Nuevo Len, Mexicob Department of Endocrino-Pediatrics of the Dr. Jos Eleuterio Gonzlez University Hospital of the Autonomous University ofNuevo Len, Mexico

Received 23 June 2015; accepted 23 June 2015Available online 17 August 2015

KEYWORDSDiabetes mellitustype I;Insulin-dependentdiabetes;Sensorineural hearingloss;Deafness;Children

AbstractObjective: To establish the prevalence of sensorineural hearing loss (SNHL), as well as thepredisposing risk factors, in children and adolescents with type 1 diabetes mellitus (T1DM)attending the Service of Endocrino-Pediatrics and Otolaryngology Department of the Dr. JosEleuterio Gonzlez University Hospital and the Materno-Infantil Hospital, from January 2011to December 2012.Material and methods: A total of 84 children with T1DM, with ages between 6 and 18 years old,were studied. Values of glycated hemoglobin (HbA1c) were assessed and Tonal audiometry andSpeech audiometry tests were performed.Results: A total of 84 patients with a diagnosis of T1DM were studied, out of which 12 (14.3%)presented SNHL. Fifty percent of patients with hearing loss were in the age range of 10---13years old. Regarding time of evolution with the disease (T1DM), 33% of patients with more than5 years with T1DM presented SNHL, and nearly 88.9% of the patients with less than 5 yearswith T1DM presented normal hearing (p = 0.011). Moreover, 65.47% of the patients presentedcomplications due to poor glycemic control at some point in the evolution of their disease. All

(100%) diabetic patients with SNHL and 91% of the patients without SNHL had HbA1c valuesgreater than 6%. In patients with hearing impairments, 83.3% suffered mild and 16.4% sufferedmoderate hearing loss. Most presented bilateral hearing loss, with the right ear dominating.Acute frequencies, mainly 8000 kHz, were the most affected.

Corresponding author at: Servicio de Otorrinolaringologa del Hospital Universitario Dr. Jos Eleuterio Gonzlez de la UniversidadAutnoma de Nuevo Len, Ave. Madero y Gonzalitos s/n Colonia Mitras Centro, C.P. 64460, Monterrey, N.L., Mexico. Tel.: +52 81 83 334299;fax: +52 81 83 3329 17.

E-mail address: josel-2011@live.com.mx (J.L. Trevino-Gonzlez).

http://dx.doi.org/10.1016/j.rmu.2015.06.0041665-5796/ 2015 Universidad Autnoma de Nuevo Len. Published by Masson Doyma Mxico S.A. This is an open access article under theCC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

dx.doi.org/10.1016/j.rmu.2015.06.004http://www.elsevier.es/rmuanlhttp://crossmark.crossref.org/dialog/?doi=10.1016/j.rmu.2015.06.004&domain=pdfmailto:josel-2011@live.com.mxdx.doi.org/10.1016/j.rmu.2015.06.004http://creativecommons.org/licenses/by-nc-nd/4.0/

134 J.L. Trevino-Gonzlez et al.

:Conclusion: SNHL prevalence among our diabetic population was 14.3%, which indicates that asixth of our diabetic type 1 population will develop SNHL. According to the results obtained,SNHL is more frequent among patients who have had T1DM for more than 5 years. Nevertheless,more studies are required to confirm that there is a relation between time spent with the diseaseand SNHL. 2015 Universidad Autnoma de Nuevo Len. Published by Masson Doyma Mxico S.A. This isan open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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Oeta84 patients were divided into 3 groups based on age: 6---9,10---13, and 14---18 years old. We observed that 72 patientswith a T1DM diagnosis showed normal hearing while 12 T1DMpatients showed sensorineural hearing loss (Fig. 1).

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ntroduction

he World Health Organization (WHO) defines diabetesellitus (DM) as a multiple-etiology metabolic disorder,

haracterized by chronic hyperglycemia and other metabolicbnormalities, which result in absolute or relative insulineficiency. It is the most frequent endocrine-metabolic dis-rder in children and adolescents, and has remained theain type of diabetes in children.1---4

Type 1 diabetes mellitus (T1DM) is a disease with an eti-logy of intervening environmental factors which interactith a genetic-predisposition component; it is considered ahronic autoimmune disease which causes the destructionf the pancreatic cells which produce insulin.5

The average age of the onset of the disease is between 7nd 15 years of age; however, it may occur at any age.6

alues of the HbA1c > 6% higher than the normal range5---6%) have been considered a risk of developing micro- andacroangiopatic complications. The affection of the blood

essels which supply the inner ear and the vascular stria haveeen reported by different authors as a physiopathologicalause of SNHL in T1DM patients.3,7 Treatment with insulin,aintaining on average HbA1c of 7.2%, reduces the onset

nd progression of microangiopatic complications, atrophy,nd demyelination of the spiral ganglion by up to 76%.8,9,13

Sensorineural hearing loss (SNHL) is a loss of hearing atny frequency more than 25 dB, with conductive and sen-orineural gaps lower that 20 dB, and affecting the patientsbility to communicate, his or her education, job prospectsnd social relationships, and also causes stigmatization.11,12

The reported prevalence of SNHL is up to 33% in childrenith T1DM versus 0.3---0.5% in healthy children. In Mexico

here is a lack of sufficient epidemiologic information whichefines the hearing condition prevailing in our population.12

aterials and methods

prospective longitudinal, analytic, comparative study wasonducted on a total of 87 patients of both sexes, ages---18, with a T1DM diagnosis, from the Service of Endocrino-ediatrics and Otolaryngology Department of the Dr. Josleuterio Gonzlez University Hospital and the Materno-nfantil Hospital, from January 2011 to December 2012.

We included patients who agreed to participate in the

rotocol through a signed informed consent, signed by theirarents and/or guardians and/or the patient. We excludedatients with noise exposure, a family history of deafness,se of ototoxic medications, otitis media, a history of

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revious ear surgery (except ventilation tube insertion) andM type 2.

All subjects in this study were given a questionnaire,hich included family, prenatal, natal and personal patho-

ogical and non-pathological history. Patients underwentasic otorhinolaryngological exploration, tone audiometrynd oral audiometry using an audiometer AUDIOTEST 259b,anufactured for Interacustics, Type 2 Tone Audiometer,

ype B-E-T speech audiometer in a soundproof cabin Acous-ics Systems, Model RE-142, Serial #21413a, made in USA.he study was approved by the Ethics and Research Commit-ee of the School of Medicine of the Universidad Autnomae Nuevo Len (UANL by its Spanish acronym) with the reg-stration key OT12-002.

The information obtained was gathered in a databasesing Excel, performing statistical analysis using SPSS 20.0.e obtained the traditional statistics in the quantitative

nd qualitative variables, looking to establish differencesetween both groups through hypothesis tests for means androportions, to establish the absence or presence of associa-ion and correlation using chi square, Pearson or Spearman,ith a confidence and reliability of 95%.

esults

ut of the 87 recruited patients with a T1DM diagnosis, wexcluded a patient with a history of chronic otitis media ofhe right ear, one with otitis media with bilateral effusionnd a patient with a final diagnosis of T2DM. The remaining

igure 1 Average of patients with type 1 diabetes with normalearing and sensorineural hearing loss.

http://creativecommons.org/licenses/by-nc-nd/4.0/http://creativecommons.org/licenses/by-nc-nd/4.0/

Prevalence of sensorineural hearing loss 135

8.30%

50.00%

41.20%

26.40%

36.00%

37.50%

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6 to 9 years

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T1DM = siabetes sellitus type 1; SNH = sensorineural hearing loss

Figure 2 Comparison of both groups by age range.

The 6---9 group included 20 patients (9 girls and 11 boys)with diabetes with an evolution time of less than 5 years; 10(50%) subjects presented a history of previous complicationslike ketoacidosis, hyperglycemia or hypoglycemia, 2 (10%)patients had HbA1c < 6 and 18 HbA1c > 6, and 1 (5%) sub-ject presented mild SNHL for 8000 kHz thresholds. The 10---13group included a total of 30 patients (13 girls and 17 boys);29 (34.5%) had had diabetes mellitus for less than 5 years and1 (1.21%) for over 5 years, 18 (21.4%) patients presented ahistory of ketoacidosis, hypo- or hyperglycemia, 29 (34.52%)presented HbA1c > 6 and 1 (1.19%) HbA1c < 6; mild SNHL wasdisplayed in 3 (3.57%) subjects and 1 (1.19%) patient dis-played moderate SNHL, and all 4 patients were in hearingthresholds of 8000 kHz. The 14---18 group consisted of 34patients (40.47%) (20 girls and 14 boys), 22 (64.70%) withan evolution time of less than 5 years and 12 (35.29%) formore than 5 years; complications like ketoacidosis, hypo-or hyperglycemia were reported by 27 of them; 3 (8.82%)subjects showed an HbA1c < 6 and 31 (91.17%) an HbA1c > 6;SNHL occurred within this group in 7 individuals (mild in 6and moderate in 1). In all patients, SNHL was observed inthresholds of 8000 kHz (See Table 1).

In our study, we were able to observe a percentage preva-lence of SNHL of 14.3% (12 out of 84 patients). Also, 64patients (76.19%) with T1DM were older than 10 years ofage, as opposed to a small group of 20 patients (23.80%)between the ages of 6 and 9 (Fig. 2). There were no differ-ences in gender, each representing 50%. In regard to time of

evolution of T1DM, 15.47% (13 patients) with over 5 yearswith T1DM presented SNHL, and 84.52% (71 patients) withless than 5 years with T1DM presented normal hearing, thisbeing a statistically significant value (p = 0.011) (Fig. 3).

66.70%

88.90%

33.30%

11.10%

0.00% 20.00% 40.00% 60.00% 80.00% 100.00 %

T1DM + SNH

T1DM + normal hearing

T1DM = diabetes mellitus type 1; SNH = sensorineural hearing loss

More than 5 years with T1DM 5 years or less with T1DM

Figure 3 Comparison of both groups by T1DM evolution time.

Tabl

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35%

65%

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10%

20%

30%

40%

50%

60%

70%

Previous complications (ketoacidosis, hyper/hypo glycemia)

N = 84 patients; h ypoglyce mia: glyce mia < 60 mg/dL; hyperglycemia : glyce mia 126-250mg/dL; ketoacidosis: glyce mia > 250 mg/dL + ketonemia and ketonuria.

No 29/84 Yes 55/84

Figure 4 Previous complications from uncontrolled blood glu-cose in both groups.

83.30%

16.70%

0%

0%

0.00% 20 .00% 40 .00% 60 .00% 80 .00% 100 .00%

Light 20 to 40 DB

Moderate 41 to 60 DB

Severe 61 to 80 DB

Profound more than 80 DB

T1DM = diabetes melli tus type 1 ; SN H = sensorineural hearing loss T1DM + SNH

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Figure 5 Degrees of sensorineural hearing loss.

Out of the 84 patients, 55 (64.47%) presentedomplications at some point during the evolution of theirisease due to glycemic irregularities; the most frequentomplication was ketoacidosis and the least prevalent wasypoglycemia (Fig. 4).

In the present study, 100% of diabetic patients with SNHL12 patients) and 91% of patients with normal hearing pre-ented HbA1c values greater than 6%, showing an averagealue of 7.5% in the general population studied. Accord-ng to age groups, the group consisting of children between

and 12 years presented, on average, an HbA1c value of.24%, while the group consisting of children between 13nd 19 years of age presented, on average, an HbA1c valuef 7.67%.

Of all the SNHL patients, 83.30% (10 patients) presentedild hearing loss and 16.70% (2 patients) moderate hear-

ng loss (Fig. 5). Most patients presented bilateral hearingoss, predominately on the right ear. The 8000 kHz thresholdsere the most affected. (Table 1)

iscussion

n SNHL prevalence of up to 33% in children with T1DMas been considered, versus 0.3---0.5% in healthy children.n Mexico, there is a lack of epidemiologic information that

an define the hearing condition which prevails among ouropulation.12

The observed prevalence in our studied group was 14.3%,ontrary to the rate reported in different publications.

adi

J.L. Trevino-Gonzlez et al.

owever, we must keep in mind that most of the studiedopulation is American or European. It is important to stresshe fact that there are still many T1DM cases that haveot been diagnosed, but with the obtained results at thisoint, we are able to infer that up to a sixth of the diabeticopulation in our society will develop SNHL.

Regarding age, the obtained information matches the oneound in the bibliography. Most children are in the mentionedeak ranges, especially above 10 years of age, beginningith hormone changes that are a normal part of puberty anddolescence. Nevertheless, based on the obtained resultse are able to see that the patients age does not represent

risk factor for the presence of SNHL.According to the American Diabetes Association (ADA)

nd the Diabetes medical attention standards of 2014, theoal for HbA1c in type 1 diabetic patients varies depend-ng on age. Concerning values

1

1

1

Prevalence of sensorineural hearing loss

in these patients is similar to the one that patients withpresbycusis would present, but at an earlier age comparedto the population without T1DM.

This research provided valuable data to lead the wayfor new researches in these types of patients, and estab-lish a timely and protocol-led assessment for their glycemiccontrol as well as their hearing, thus avoiding hearingcomplications which patients with a T1DM of long durationpresent, like SNHL and sudden hearing loss. Also, later stud-ies are recommended where a long-term follow-up is givento these patients in order to determine the causation degreeof the studied risk factors on the base pathology.

Conflicts of interest

The authors have no conflicts of interest to declare.

Funding

No financial support was provided.

References

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www.elsevier.es/rmuanl

RIGINAL ARTICLE

endencies in medical publications

.E. Tamez-Prez, E. Delgadillo-Esteban , S.L. Proskauer-Pena, V. Arenas-Fabbri,

.M. Carranza-Trejo, J.G. Gonzlez-Gonzlez, A.L. Tamez-Pena

ffice of Research, School of Medicine of the Autonomous, University of Nuevo Len, Mexico

eceived 10 June 2014; accepted 14 April 2015vailable online 19 August 2015

KEYWORDSEvidence-basedmedicine;Randomized clinicaltrials;Review, Systematic;Cohort studies;Meta-analysis

AbstractObjectives: To describe the trends of research design in publications from high-impact medicaljournals.Methods: A cross-sectional, descriptive study was conducted by searching the 2011 electronicpublications of the journals: New England Journal of Medicine, Journal of the American MedicalAssociation, The Lancet, British Medical Journal, and Annals of Internal Medicine. Studies wereclassified as primary and secondary. The journal impact factor was taken from the JournalCitation Report website. Descriptive statistics were used to analyze and interpret the data.Results: We analyzed 1130 publications: 804 primary and 326 secondary studies, which rep-resented 71.2% and 28.8% of the total publications, respectively. Among the primary studies,randomized clinical trials (30.4%) were the most prevalent, followed by cohort studies (21.9%)and case reports (9.0%).Conclusions: These findings can have implications in Evidence-Based Medicine programs. Liter-ature review should focus on reviewing secondary articles first, then experimental studies andfinally, observational studies.

2015 Published by Masson Doyma Mxico S.A. on behalf of Universidad Autnoma de NuevoLen. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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Corresponding author at: Subdireccin de Investigacin, Facul-ad de Medicina, Universidad Autnoma de Nuevo Len, Edificio dea Biblioteca Central de la Facultad de Medicina, planta baja, Av.

rancisco I, Madero Pte. s/n y Dr. Eduardo Aguirre Pequeno, Col.itras Centro, C.P. 64460, Monterrey, N.L., Mexico.

E-mail address: enrique.delgadilloest@uanl.edu.mxE. Delgadillo-Esteban).

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ttp://dx.doi.org/10.1016/j.rmu.2015.04.002665-5796/ 2015 Published by Masson Doyma Mxico S.A. on behalf of Under the CC BY-NC-ND license (http://creativecommons.org/licenses/b

ntroduction

n the area of continuous medical education, in order tochieve the gold standard in medical attention, growth andurrent information, frequent review of medical literature

s necessary. In modern medicine, healthcare excellence isombined with scientific rigor in the practice of evidence-ased medicine (EBM). This new paradigm in medicalducation integrates the use of the best clinical evidence

niversidad Autnoma de Nuevo Len. This is an open access articley-nc-nd/4.0/).

dx.doi.org/10.1016/j.rmu.2015.04.002http://www.elsevier.es/rmuanlhttp://crossmark.crossref.org/dialog/?doi=10.1016/j.rmu.2015.04.002&domain=pdfhttp://creativecommons.org/licenses/by-nc-nd/4.0/http://creativecommons.org/licenses/by-nc-nd/4.0/mailto:enrique.delgadilloest@uanl.edu.mxdx.doi.org/10.1016/j.rmu.2015.04.002http://creativecommons.org/licenses/by-nc-nd/4.0/

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Tendencies in medical publications

and experience in the diagnostic and therapeutic decision-making process. Proposed in 1992,1 its implementationhas been replacing the authoritarian management and thepurely heuristic in medicine. Using competences such assearch strategies, critical reading and the application of evi-dence to the context of the patient2,3 to create and base anintervention. Some of its objectives are: to promote criti-cal thinking, to promote continuous learning, to reduce theimpact of medical error and improve the patients progno-sis. Nevertheless, despite having acceptance among somemedical circles; critics point out the difficulty of integratingEBM into clinical practice.4---6 They question its epistemo-logical value7,8 and comment regarding the resistance of itsimplementation in some health centers and universities.9

Regarding medical education, the integration of adynamic learning model must deliver results and content. Anadequate curriculum should categorize content according toits level of complexity and difficulty. In the evidence-basedmedicine scenario, the competences must prepare doctorsto evaluate and integrate the best evidence in order to gen-erate an answer to a clinical problem. But, taking this intoconsideration, what does it take to answer a clinical ques-tion? In the process of critical reading, a study can applyto clinical context if it complies with internal and exter-nal validity. Therefore, the search of studies with a highlevel of evidence is the first step. This represents a factin medical journals with a high impact factor. First, in thereview-by-pairs process, reviewers included in the editorialcommittee publish in high impact journals.10 Concerning theresearchers participation, they recruit a higher number ofpatients, evaluate major results and analyze subgroups.11

With the selection of publications, the method sectionis evaluated on the integrity of the statistical analysis,12

while in results, the inclusion of a confidence interval13

and clinical significance range is common.14 Despite all ofthe above, research design may offer a replicable exampleof information with high clinical value. Thus, the objectiveof the present study is to examine the publication tenden-cies in the different research designs in high-impact medicaljournals.

Materials and methods

A transversal descriptive study was conducted. We eval-uated issues of the following journals published during2011: The New England Journal of Medicine, Journalof the American Medical Association, Annals of InternalMedicine, The Lancet and BMJ. The impact factor wasobtained from the Journals Citation Report.15 These pub-lications were then classified as primary (originals) andsecondary (revisions) studies according to their focus. Themain studies section was sub-divided according to thetype of study and experimental (randomized clinical tri-als) and observational designs (prevalence, control caseand cohort). The secondary studies section included: nar-rative review and systematic review, with and without

meta-analysis, excluding genomic studies of this cate-gory.

Descriptive statistics were utilized for better data mana-gement and interpretation.

mta(

139

esults

ut of the 1130 publications analyzed in 2011, the jour-als published an average of 3 main studies and 1 secondarytudy per issue (results shown in Table 1). 337 randomizedlinical trials (30.4%) were published in the main studies cat-gory. On the other hand, observational studies 243 (21.9%),ncluded 102 cohorts (9.02%), 59 case reports (5.2%) and2 (4.6). Regarding the secondary studies, 226 publicationsere classified as narrative reviews (20%), 67 as systemic

eviews (5.9%) and 33 as systemic reviews with meta-analysis2.9%).

The New England Journal of Medicine published 241 arti-les, divided as follows: 0 (0%) meta-analysis, 1 (0.5%)ystematic review, 33 (15.55%) narrative reviews, 11051.4%) clinical essays, 17 (7.9%) cohorts, 6 (2.8%) controlases, 5 (2.3%) prevalence and 42 (19.6%) case reports.

The Lancet published 337 articles, divided as follows: (1.8%) meta-analysis, 3 (0.9%) systematic reviews, 12035.6%) narrative reviews, 110 (29.7%) randomized clinicalrials, 46 (13.6%) cohorts, 4 (1.2%) control cases, 5 (1.2%)revalence and 53 (15.7%) case reports.

The Journal of the American Medical Association, for itsart, published 202 studies, divided as follows: 18 (8.9%)eta-analysis, 2 (1%) systematic reviews, 14 (6.9%) narrative

eviews, 42 (20.8%) randomized clinical trials, 81 (40.1%)ohorts, 32 (15.8%) control cases, 10 (5%) prevalence and 31.5%) case reports.

BMJ included 270 publications, divided as follows: 10.4%) meta-analysis, 43 (15.9%) systematic reviews, 5319.6%) narrative reviews, 72 (26.7%) randomized clinicalrials, 69 (25.6%) cohorts, 15 (5.6%) control cases, 17 (6.3%)revalence and 0 (0%) case reports.

Last but not least, Annals of Internal Medicine published07 studies, divided as follows: 8 (7.5%) meta-analysis, 1816.8%) systematic reviews, 6 (5.6%) narrative reviews, 2018.7%) randomized clinical trials, 34 (31.8%) cohorts, 21.9%) control cases, 15 (14%) prevalence and 4 (3.7%) caseeports.

Regarding original studies, NEJM published 180 (84.1%),he Lancet 208 (61.7%), JAMA 168 (83.2%), BMJ 173 (64.1%)nd Annals of Internal Medicine 75 (70.1%). The tendenciesor secondary studies were NEJM 34 (15.9%), The Lancet29 (38.3%), JAMA 34 (16.8%), BMJ 97 (35.9%) and Annalsf Internal Medicine 32 (39.9%).

iscussion

n our frequency distribution analysis, publication distribu-ion was linked to evidence levels. Randomized clinical trialsere the most represented studies, followed by cohorts.ur results suggest that medical journals with a high-impact

actor publish studies with a high evidence level (Fig. 1).A relevant finding significantly documented in The New

ngland Journal of Medicine and The Lancet was the highrequency with which case reports were published, repre-enting up to 15% of the total of their publications. Another

ajor finding is the tendencies the journals have according

o their geographic location. European journals (The Lancetnd BMJ) published secondary studies to a greater extentFig. 2). These findings raise a question: What implications

140 H.E. Tamez-Prez et al.

Tabl

e

1

Dis

trib

utio

n

of

publ

icat

ions

acco

rdin

g

to

stud

y

type

in

2011

.

CR

PR

CC

Co

CCT

NR

SR

Me

Or

Sc

Ob

Ex

n

FI

JAM

A

3

(1.5

)

10

(5)

32

(15.

8)

81

(40.

1)

42

(20.

8)

14

(6.9

)

2

(1)

18

(8.9

)

168

(83.

2)

34

(16.

8)

126

(62.

4)

42

(20.

8)

202

30.0

2An

nals

4

(3.7

)

15

(14)

2

(1.9

)

34

(31.

8)

20

(18.

7)

6

(5.6

)

18

(16.

8)

8

(7.5

)

75

(70.

1)

32

(29.

9)

55

(51.

4)

20

(18.

7)

107

16.7

3La

ncet

53

(15.

7)

5

(1.5

)

4

(1.2

)

46

(13.

6)

100

(29.

7)

120

(35.

6)

3

(0.9

)

6

(1.8

)

208

(61.

7)

129

(38.

3)

108

(32)

100

(29.

7)

337

38N

EJM

42

(19.

6)

5

(2.3

)

6

(2.8

)

17

(7.9

)

110

(51.

4)

33

(15.

4)

1

(0.5

)

0

(0)

180

(84.

1)

34

(15.

9)

70

(32.

7)

110

(51.

4)

214

53.2

9BM

J

0

(0)

17

(6.3

)

15

(5.6

)

69

(25.

6)

72

(26.

7)

53

(19.

6)

43

(15.

9)

1

(0.4

)

173

(64.

1)

97

(35.

9)

101

(37.

4)

72

(26.

7)

270

14.0

910

2

(9)

52

(4.6

)

59

(5.2

)

247

(21.

9)

344

(30.

4)

226

(20)

67

(5.9

)

33

(2.9

)

804

(71.

2)

326

(28.

8)

460

(40.

7)

344

(30.

4)

1130

Dat

a

are

show

n

as

n

(%);

CR,

case

repo

rt;

PR,

prev

alen

ce

repo

rt;

CC,

case

---co

ntro

l;

Co,

coho

rt;

CCT,

cont

rolle

d

clin

ical

tria

l;

NR,

narr

ativ

e

revi

sion

;

RS,

syst

emat

ic

revi

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;

Me,

met

a-an

alys

is;

Or,

orig

inal

publ

icat

ion;

Sc,

seco

ndar

y

publ

icat

ion;

IF,

impa

ct

fact

or;

Ob,

obse

rvat

iona

l stu

dy;

Ex,

expe

rim

enta

l stu

dy.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

JAMA Ann als Lancet NEJM

Observat ional Studies Experimental Studies Secondary Studies

Fi

cl

dcpecBttRiustmopli

igure 1 Distribution of observational and experimental stud-es.

an this have? In order to answer this question correctly, theimitations and advantages of each design were evaluated.

Experimental studies represent a high degree of evi-ence since they allow a direct determination of theausal connection of two phenomena. Another significantoint is its ability to reduce the amount of systematicrrors.16 With randomization, an equilibrium between theharacteristics of the compared groups is established.linding, concealment and intention-to-treat analysis allowhe reduction of skewing in any type of randomized clinicalrial. Unfortunately, one of the biggest disadvantages ofCT is in the context of clinical practice. Paradoxically,

nternal factors such as the strict inclusion criteria, eval-ation of efficiency and short-term follow-up17 limit thetudys ability to establish a general conclusion. The facthat significant results are obtained does not necessarilyean that they can be applied in a real life scenario. In

ther words, the results at that moment only apply to the

opulation being studied. Also external factors of the studyike high costs, ethical considerations18 and low financingn the case of rare diseases are also an important issue.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

JAMA Ann als Lancet NEJM BMJOriginal Studies Secondary Studies

Figure 2 Distribution of original and secondary studies.

niw

C

T

F

N

R

1

1

1

1

1

15. Sobral DT, Vidigal KS, Farias e Silva K. Digestive symptoms inyoung individuals: survey among medical students. Arq Gas-troenterol. 1991;28:27---32.

16. Panacek EA, Thomoson CB. Basics of research (part 3): research

Tendencies in medical publications

Consequently, the difficulty in clinical trials relies moreimportantly on external validation.

Observational studies represent the lowest level in theevidence hierarchy. They are useful in clinical scenarios likein evaluating disparity and load and determining risk factorswhich contribute to the development of a disease.19 In medi-cal history, cohorts play an important role in documentingassociations, like in the Framingham study, or the conclusivedata of the effectiveness of insulin analogs for the treatmentof patients with type 1 or 2 diabetes.20 Additionally, cohortstudies help determine safety profiles of medications. Forexample, the SCOUT study assessed the effectiveness ofsibutramine in 10,744 patients with obesity and high cardio-vascular risk for a period of 6 years. Compared to placebos,the sibutramine group showed a noticeable increase in mor-tality rates and cardiovascular events despite the significantweight loss.21 This influenced its recall by the FDA in 2009.

In contrast with experimental studies, studies with-out intervention represent a clearer, uncontrolled andunadjusted model of the disease. Nevertheless, internalvalidation is an important issue. The highest difficulty inobservational studies lies in interpretation, since there aresome factors like bias in selection, confusion factors or recallbias and thus the results may lead to different conclusions.

According to the information obtained, it is possibleto conclude that there are different problems in researchwithin primary studies. European and American magazineshave different criteria concerning their publications guide-lines; in other words, there is no standard in the level ofevidence regarding article revision. Perhaps a major implica-tion in relation to the impact factor lies more in the contextof transnational medicine. That is to say, The New EnglandJournal of Medicine published mostly randomized clinicaltrials, studies frequently cited and with a higher impact inmedical practice. Hence, a dichotomy is formed betweenthe management of concepts: validity versus generalization.Observational studies are not as valid; however they includeconcepts which are more applicable in populations. On thecontrary, experimental studies have a great epistemologicalvalue, but only represent the set of the population beingstudied.

Secondary studies represent the highest level of evi-dence. They offer a summary of the investigation question.In the context of evidence-based medicine, both validity andgeneralization are important. The findings in these studieshave a greater approximation to the Bradford---Hill criteria;nevertheless, the limitation in secondary studies lies in thepresence of publication bias.

One of the strengths of this study was the analysis of arepresentative sample of the publications in different jour-nals in the yearly period. A similar trend was reported ina study conducted in 2003, but with different objectives22

and a much smaller sample. A limitation of the study wasthe classification of evidence according to the study design,without evaluating the existence of discrepancies in themethodology, like the presence of bias or the weight ofconfusion factors.

In conclusion, the tendency of publications or journals

with a high impact factor is oriented to a greater extent tothe publication of primary and observational studies; how-ever, European journals such as The Lancet and BMJ publisha good amount of secondary studies. Future studies are

1

141

ecessary to determine not only the validity, but also thempact of an article. The amount of quotations correlatedith the publication of studies with a high level of evidence.

onflict of interest

he authors have no conflicts of interest to declare.

unding

o financial support was provided.

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where are we 20 years later? Part 1. Can J Neurol Sci.2013;40:465---74.

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