[Predictive models of gestational diabetes, a new prediction mode]. / Modelos predictivos de diabetes gestacional, un nuevo modelo de predicción.

OBJECTIVES: Recognized the value of gestational diabetes (GD) as a health problem, our aim in this work has been to analyze the diagnostic performance of the different today's existing criteria (GEDE, O'Sullivan and Carpenter) after the overload of 100 g of glucose and revise how to increase its efficiency. MATERIALS AND METHODS: We carried out a description of all the variables. In the analytical phase of the work, we used Pearson's Chi square to see if there were differences in the percentage of cases collected in each health center and the proportions contrast test to study the differences between the experimental prevalence. We completed binary logistic regression models using as result variable having or not having gestational diabetes (yes/no) and as predictors the four measurements of the curve with 100 g of glucose overload. To decide which model was better, the stepwise backward-forward analysis and the surface of the ROC curve generated by each of them were considered. RESULTS: We obtained a sample of 170 pregnant women from six different Primary Care Area of Seville health centers who had shown a positive O'Sullivan test with a median age of 35 years. There were significant differences in the prevalence proportions according to the criteria used: GEDE/O'Sullivan p < 0.001; GEDE/Carpenter p < 0.001. Logistic models with three and four predictor variables were equal in discriminatory diagnostic capacity when the GEDE criteria were used (area under the ROC curve = 0.96, 95% CI: 0.93-0.98). The back-forward stepwise analysis stayed with the three-variable model as the most parsimonious. The same did not occur when applying the other two criteria. CONCLUSIONS: Regarding an observational design, we state that there are significant differences in the prevalence proportions observed according to the criteria applied (p < 0.001) and we can also support that using the GEDE criteria, the taking of the third hour could be dispensed with, based on Bayesian criteria and the application of the ROC curve analysis.

Comparación de biomarcadores de primer trimestre en gestantes normotensas según su grado de obesidad en el tercer trimestre / Comparison of first trimester biomarkers in normotensive pregnancies according to their level of obesity in the third trimester

INTRODUCCIÓN: Nuestro trabajo tiene como objetivo aumentar la eficiencia del cribado de aneuploidías del primer trimestre de la gestación mediante la creación de modelos predictivos que sirvan para identificar gestantes en riesgo de desarrollar sobrepeso u obesidad en el tercer trimestre e instaurar medidas preventivas de obesidad a partir de ellos. MÉTODOS: Estudio observacional de tipo ambispectivo realizado en atención primaria, en el que se han recogido un total de 380 registros correspondientes a otros tantos embarazos. Se han muestreado 6 centros de salud con las variables siguientes: edad en la gestación, proteína A placentaria asociada al embarazo (PAPP-A) (mU/ml), gonadotropina coriónica humana (b-HCG) (ng/ml), semana de recogida de la muestra para el cribado de primer trimestre, índice de masa corporal (IMC) a las 12 y a las 28 semanas de gestación, TSH a las 12 semanas de gestación, presión arterial sistólica (PAS), presión arterial diastólica (PAD) y presión arterial media (PAM) a las 12 y a las 28 semanas de gestación. Se recodificó la variable IMC a las 28 semanas, clasificando a las embarazadas en peso normal (IMC<25), sobrepeso (IMC 25-29,99) y obesas (IMC≥30). El IMC a las 28 semanas recodificada fue la variable resultado del modelo de regresión logística ordinal. Utilizamos el estudio ANOVA de varios factores para discernir diferencias entre las presiones arteriales. Se aceptó un error alfa del 5%. RESULTADOS: Las medianas de la PAPP-A y de b-HCG medidas en el primer trimestre son menores de manera progresiva en los grupos de gestantes con normopeso, sobrepeso y obesidad observadas en el tercer trimestre. Estos valores son predictores del peso en el tercer trimestre (regresión logística ordinal) (PAPP-A: p = 0,022; b-HCG: p = 0,002). Ninguna gestante desarrolló preeclampsia. Las PAS, PAD y PAM en el tercer trimestre fueron significativamente diferentes (ANOVA de varios factores; p < 0,05). DISCUSIÓN: La regresión logística ordinal demuestra que la disminución de los valores observada de PAPP-A y de b-HCG en el primer trimestre es predictora del grado de obesidad de forma significativa y gradual en una muestra de gestantes normotensas. No hemos querido confeccionar un modelo de regresión ordinal incluyendo el IMC de las 12 semanas por la colinealidad interna que aportaría al estar basada la variable resultado en él. El efecto predictor de la b-HCG es más homogéneo que el de la PAPP-A para el estado de sobrepeso y obesidad

INTRODUCTION: This study aims to improve the efficiency of aneuploidy screening in the first trimester of pregnancy by creating predictive models that serve to identify pregnant women at risk of becoming overweight or obese in the third trimester and to using them to implement preventive measures of obesity. METHODS: An ambispective, observational, primary care study was conducted in which a total of 380 records corresponding to as many pregnancies were collected. Samples were collected from patients of 6 health centres, in order to determine the following variables: age at gestation, pregnancy-associated plasma protein A (PAPP-A) (mU/ml), human chorionic gonadotropin (b-HCG) (ng/ml), sample collection week for first trimester screening, body mass index at 12 and 28 weeks gestation (BMI), TSH at 12 weeks gestation, and systolic, diastolic, and mean arterial blood pressure (SBP, DBP, and MBP, respectively) at 12 and 28 weeks gestation. The BMI variable was recoded at 28 weeks, classifying pregnant women as normal weight (BMI<25), overweight (BMI 25-29.99), or obese (BMI≥30). The recoded BMI at 28 weeks was the variable resulting from the ordinal logistic regression model. An ANOVA study of several factors was used to discern differences between arterial pressures. A 5% alpha error was accepted. RESULTS: The PAPP-A and b-HCG medians measured in the first trimester are progressively lower in the groups of pregnant women with normal weight, overweight, and obesity observed in the third trimester. These values are predictors of the weight in the third trimester (ordinal logistic regression) (PAPP-A: P=.022; b-HCG: P=.002). No pregnant woman developed pre-eclampsia. The SBP, DBP, and MBP in the third trimester were significantly different (ANOVA in several factors; P<.05). DISCUSSION: The ordinal logistic regression demonstrates that the decrease in the observed values of PAPP-A and b-HCG in the first trimester is a predictor of the level of significant and gradual obesity in a sample of normotensive pregnant women. An ordinal regression model including the 12-week BMI was not made due to the internal collinearity that it would provide if the result variable was based on it. The predictive effect of b-HCG is more homogeneous than that of PAPP-A for the level of overweight and obesity