Mario Enrique Rendón-Macías

Birth prevalence of congenital hypothyroidism in Mexico

The Mexican Institute of Social Security (IMSS) provides care for more than 40% of the Mexican population. This report constitutes the first study of the incidence of congenital hypothyroidism (CH) in Mexican children. We performed a prospective study with a population base. CH screening began in 1997 with blood samples from the heel taken 72 h after birth; from 2000, the detection strategy was changed nationwide and blood samples were taken from the umbilical cord in all newborns for determination of thyroid-stimulating hormone (TSH) concentration. We evaluated the annual coverage. TSH concentration was measured by chemoluminescence; TSH values > or =30 microIU/mL in umbilical cord blood and 15 microIU/mL in capillary blood were considered positive cases and were confirmed through hormonal studies. The incidence and 95% confidence intervals [95% CI] were calculated. We found that coverage within the IMSS population was 53% from 1997 to 2000 and had increased to 95% by 2001. A total of 2,777,292 children from 2,975,157 births (93%) were studied between 2000 and 2004. Of these, 4050 had a high TSH concentration leading to suspicion of CH; CH was confirmed in 1286 (32%). The resulting incidence was 4.3/10,000 livebirths [95% CI 3.6, 5.1]. With the results obtained, we conclude that the IMSS strategy of CH screening at birth ensured 95% coverage of children in the system. The birth prevalence of CH reported is among the highest in the world.

Frequency of cancer in children residing in Mexico City and treated in the hospitals of the Instituto Mexicano del Seguro Social (1996–2001)

BackgroundThe objective of this article is to present the frequency of cancer in Mexican children who were treated in the hospitals of the Instituto Mexicano del Seguro Social in Mexico City (IMSS-MC) in the period 1996–2001.MethodsThe Registry of Cancer in Children, started in 1996 in the IMSS-MC, is an on-going, prospective register. The data from 1996 through 2001 were analyzed and the different types of cancer were grouped according to the International Classification for Cancer in Children (ICCC). From this analysis, the general and specific frequencies by age and by sex were obtained for the different groups of neoplasms. Also, the frequency of the stage of the disease that had been diagnosed in cases of children with solid tumors was obtained.ResultsA total of 1,702 new cases of children with cancer were registered, with the male/female ratio at 1.1/1. Leukemias had the highest frequency with 784 cases (46.1%) and, of these, acute lymphoblastic leukemias were the most prevalent with 614 cases (78.3%). Thereafter, in descending order of frequency, were tumors of the central nervous system (CNST) with 197 cases (11.6%), lymphomas with 194 cases (11.4%), germinal cell tumors with 110 cases (6.5%), and bone tumors with 97 cases (5.7%). The highest frequency of cancer was found in the group of one to four year-olds that had 627 cases (36.8%). In all the age groups, leukemias were the most frequent. In the present work, the frequency of Hodgkins disease (~4%) was found to be lower than that (~10%) in previous studies and the frequency of tumors of the sympathetic nervous system was low (2.3%). Of those cases of solid tumors for which the stage of the disease had been determined, 66.9% were diagnosed as being Stage III or IV.ConclusionsThe principal cancers in the children treated in the IMSS-MC were leukemias, CNST, and lymphomas, consistent with those reported by developed countries. A 2.5-fold reduction in the frequency of Hodgkins disease was found. Of the children, the stage of whose disease had been determined, two thirds were diagnosed as having advanced stages of the disease.

Breastfeeding Among Patients with Congenital Malformations

BACKGROUND This study was undertaken in order to 1) determine the frequency of infants with major congenital malformations who are breastfed and 2) identify factors associated with initiating and early weaning of breastfeeding. METHODS We conducted a descriptive cohort study at a tertiary-care pediatric hospital. Subjects included infants <20 days of age with major congenital malformations. According to the feeding pattern, the following three groups were identified: exclusively breastfed (EB); alternating breast and formula (ABF), and exclusively formula (EF).Follow-up interviews were conducted on a monthly basis until the infants were 6 months of age. The feeding pattern was determined during each visit. Reasons for changing the breastfeeding pattern were explored. RESULTS A total of 120 newborns were recruited. At the time of the first interview, 29.2% were EF, 47.5% EB, and 23.3% ABF. By 6 months of age, the feeding patterns were 8.6, 18.1, and 73.3%, respectively. Median length of breastfeeding was 3 months (range: 1-6 months). The maternal prenatal decision to breastfeed (odds ratio [OR] 0.11, 95% confidence interval [95% CI] 0.02-0.52) and attendance at prenatal breastfeeding sessions (OR 0.30, 95% CI 0.17-0.87) were associated with breastfeeding initiation. Conversely, mother-child separation (OR 3.07, 95% CI 1.36-7.01) and low birth weight (OR 2.98, 95% CI 1.36-6.48) were associated with a lack of breastfeeding. The mothers sensation of low milk production was the main reason to change or to stop breastfeeding. CONCLUSIONS In this study, breastfeeding frequency and length among infants with congenital malformations during the first 6 months of life were lower than previously published reports of breastfeeding obtained from healthy infants. Healthcare professionals must encourage breastfeeding in these infants.

Epidemiological and some clinical characteristics of neuroblastoma in Mexican children (1996–2005)

BackgroundNeuroblastoma (NB) is the principal tumor of the sympathetic nervous system in children under one year of age. The incidence in developed countries is greater than that in developing countries. The aim of this article is to present the epidemiological and some clinical characteristics of Mexican children with NB.MethodsA population-based, prolective study, with data obtained from the Childhood Cancer Registry of the Instituto Mexicano de Seguro Social. Statistical analysis: The simple frequencies of the variables of the study and the annual average incidence (per 1,000,000 children/years) by age and sex were obtained. The trend was evaluated by calculating the annual percentage of change. The curves of Kaplan-Meyer were employed for the survival rate and the log-rank test was used to compare the curves.ResultsOf a total of 2,758 children with cancer registered during the period from 1996–2005, 72 (2.6%) were identified as having Group IV, defined according to the International Classification of Childhood Cancer. The incidence for NB was 3.8 per 1,000,000 children/year; NB was highest in the group of children under one year of age, followed by the group of children between the ages 1–4 years (18.5 and 5.4 per 1,000,000 children/years, respectively). The male/female ratio was 1.1 and there was no trend toward an increase. The time of diagnosis was 26 days (median), but varied according to the stage at diagnosis. Stages III and IV were presented in 88% of the cases. There was no association between the stage, the age at time of diagnosis, or the histological pattern. The overall five-year survival rate was 64%; the patients with stage I, II, III, or IVs did not die; and the five-year survival rate of cases in Stage IV was 40%.ConclusionIt is possible that the low incidence of neuroblastoma in Mexican children is due to the difficulty in diagnosing the cases with the best prognosis, some of which could have had spontaneous regression. There was no trend to an increase; the majority of the cases were diagnosed in the advanced stages; and the overall five-years survival rate was similar to that for developed countries.

Children’s perception on obesity and quality of life: a Mexican survey

BackgroundChild obesity has become a major health problem worldwide. In order to design successful intervention strategies, it is necessary to understand how children perceive obesity and its consequences.MethodsWith the aim to evaluate scholar children perception of obesity as a significant factor on the quality of life, we developed and validated the “Obesity impact on the quality of life perception-questionnaire” (ObI-Q). We surveyed 1335 healthy children aged 6–12 years, randomly selected from elementary schools in Mexico City. The ObI-Q comprises eight multiple-choice items that explore aspects related to the quality of life during adult life; such as health, life span, emotional status, lifestyle, social recognition and economic status. In order to identify perceptional modifier factors, results were analyzed through multivariable logistic regression. Variables included gender, age, and child nutritional status, as well as the child’s perception of parental nutritional status.ResultsObI-Q results showed that most children (64.71%) considered obesity as a negative condition that influences health and social performance. This perception was inversely related to age (OR = 0.64, p = 0.003), as well as to the perception of their mother nutritional status (OR = 0.47, p = 0.01).ConclusionsThis study provides an overview of children’s perception on obesity and its consequences. Because the high proportion of schoolchildren who do not view obesity as an adverse consequence to the quality of life, then the results of this study could be used as part of strategies for the prevention of overweight and obesity.

Epidemiology of cancer in children under one year of age in Mexico City.

In this work, the epidemiology of cancer in children under one year of age in Mexico City is described. A survey (observational, descriptive and prolective study) from 1 January 1996 to 31 December 1999 was conducted at two paediatric hospitals of the Instituto Mexicano de Seguro Social in Mexico City (IMSS-MC). To calculate both the general and the by sex incidence (rates are given per 106) all new cases recorded for children under one year of age (numerator) and Mexico City population served by the IMSS (denominator) were used. When the total of 34 cases that fulfilled the requirements was analysed, an incidence of 194.5 was obtained. Leukaemia occupied first place with a rate of 68.6 and hepatic and germinal cells tumours occupied second place with an incidence of 28.6, whereas peripheral nervous system tumours (neuroblastoma) showed a very low rate (11.4). Overall, the male/female ratio for tumours was 1.4:1, with the ratio varying with different types of tumours. Cancer incidence in this population was shown to be close to that in developed countries, but differed in the distribution of the type of tumour: leukaemia had a very high incidence and that for neuroblastoma was very low.

Incidence of Childhood Hodgkin Lymphoma in Mexico by Histologic Subtypes and Socioeconomic Regions.

Background: Incidence rates of the histologic subtypes of Hodgkin lymphoma (HL) differed with socioeconomic conditions. Materials and Methods: HL cases from the Register of Childhood Cancer (below 15 y of age) for 2 socioeconomic regions were analyzed. Central region has a high socioeconomic index; and the southern region a low index. The incidence rates (cases per million children/year) were estimated according to histologic subtypes, age groups, sex, clinical stages, time to diagnosis, and overall survival by regions. Results: The overall incidence was greater in the south (6.8 vs. 4.6), principally due to higher incidence of mixed cellularity subtype (3.8 vs. 1.0). In the south, the highest incidence was found in the 5- to 9-year-old group (9.2), whereas in the central region it was found in the 10- to 14-year-old group (7.4). There was a delay of ∼3 weeks in the time to diagnosis (P=0.36) in the south, but no difference in the percentage of advanced stages, adjusted by histologic subtype (61%, III and IV). The overall survival was 71%, differences were identified only for mixed cellularity cases (center=89.2 vs. south=61.5%, P=0.03). Conclusions: Incidences of HL subtypes differed in relation to socioeconomic conditions in Mexico. In the south, the incidence of mixed cellularity was higher and there was an earlier peak of presentation.

Quality of care for children with upper respiratory infections at Mexican family medicine clinics

BACKGROUND Upper respiratory infections are the principal cause of morbidity in children <5 years of age. The objectives of this study were (i) to develop quality-of-care indicators for evaluation of care for children with upper respiratory infections (URI) at the primary care level using data from the electronic health records and (ii) to evaluate the quality of URI care offered to children <5 years of age at family medicine clinics (FMCs). METHODS Development of indicators following the RAND-UCLA method was used. A cross-sectional analysis of quality of care provided for children with URI in four FMCs in Mexico City where 10,677 children <5 years of age with URI participated. The source of information was data from 2009 electronic health records. Quality of care was evaluated using six indicators developed in the first stage of this study. RESULTS The quality of care evaluation identified that only 15% of children had registries of intentional search of respiratory distress signs and 27% received information on warning signs. More than 61% of children diagnosed with uncomplicated and nonstreptococcal URI received antibiotic prescription during the first visit. In the case of children diagnosed with streptococcal pharyngitis or tonsillitis, 57.5% received the appropriate antibiotic. On average, the percentage of recommended care received was 47.2%. CONCLUSIONS It is reasonable to promote the use of electronic health records to routinely evaluate the quality of URI care. It is necessary to consider quality flaws that were found in order to endorse strategies aimed at strengthening the technical capacity of health personnel to exercise evidence-based clinical practice.

Systematic Review and Meta-Analysis

Systematic reviews and meta-analyses are proven tools for decision-making in health care, both for patients and for 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 and application to improve the health of elderly has been somehow slow. This chapter describes in detail each of the steps necessary to conceptualize and conduct systematic reviews and meta-analysis. It begins with a description of the different uses these types of tools have today. Subsequently the differences they have with narrative reviews are given. With regard to the methodology to assemble them, it starts in the form of how the research question is formulated, which is the essence for the construction of each of systematic reviews. Then we continue with the selection of studies, first by searching in different electronic databases (e.g., Medline). Once studies are located, each of them should be reviewed thoroughly to determine if they comply strictly with the selection criteria. Finally, with the selected studies the next step is data extraction from each one, which eventually constitutes the results section of the systematic review. Noteworthy, in each of the steps we pointed out each of the aspects necessary to make the reviews with the highest quality. The last part of the chapter focuses on the different alternatives of meta-analyses and how they need to be carried out.

Decisión clínica para la realización de tomografía axial computarizada de cráneo en niños con traumatismo craneoencefálico no severo

BACKGROUND The main goal of this article was to evaluate if the decision to perform cranial computed tomography (CT) in children with minor head injury is determined by the presence or absence of the physician during assessment in the emergency room. METHODS Clinical files of 92 patients from 8 months to 4 years of age were selected. Those children were evaluated at the emergency department of the Spanish Hospital of Mexico due to non-severe traumatic brain injury. Glasgow Coma Scale (GCS) score was determined in all patients. Groups of patients were compared: 1) patients having CT, 2) patients with a physician who attended the initial assessment, 3) patients whose attending physician did not arrive to assess the patient and 4) patients assessed by the emergency room staff. RESULTS 38% of patients with non-severe brain injury underwent CT, 8.6% had a brain injury visible on the CT. Moderate intensity impacts were greater in patients with CT. Regarding the ECG, it was found that most children scored 15 points (p=0.03). In patients without a physician, a greater trend was demonstrated for performing CT. CONCLUSIONS Patients with minor head injury but without neurological signs should undergo a detailed clinical evaluation in order to avoid unwarranted CT.