[Glycosylated hemoglobin A1c as a diagnostic test for diabetes mellitus in adolescents with overweight and obesity]

Rev Med Inst Mex Seguro Soc. 2015;53 Suppl 3:S294-9.
[Article in Spanish]

Abstract

Background: In 2009 it was introduced a new diagnostic criteria based on hemoglobin A1c (HbA1c) greater than or equal to 6.5 % in the adult population; some studies suggest that the cutoff may be smaller in pediatric population. The objective was to determine the utility of HbA1c greater than or equal to 6.5 % as a diagnostic test for DM in Mexican adolescents with overweight or obesity.

Methods: Full somatometry was performed. Also, Tanner stage, blood pressure, blood glucose, glucose tolerance curve (GTC) and HbA1c were analyzed. Specificity, sensitivity, positive and negative predictive values and ROC curve were calculated for the diagnosis of DM with HbA1c.

Results: 109 adolescents between 10 and 16 years referred for obesity or overweight plus comorbidities were studied; 58 % were females, the age was of 13 ± 1.74 years, the BMI percentile 95.3, and the HbA1c 5.73 ± 0.9 %. It was made a diagnosis of DM in 9 cases (8.3 %), prediabetes in 8 (7.3 %) and normal glucose tolerance in 92 (84.4 %). The HbA1c mean was 5.6 ± 0.04, 5.7 ± 0.4, and 5.6 ± 0.73 %, respectively. HbA1c greater than or equal to 6.5 % had a sensitivity of 12.5 %, a specificity of 89.8 %, a PPV of 10.65 and a NPV of 14.28. The best cutoff point for diagnosing DM through ROC curve was 5.45 %, with a sensitivity of 62.5 %, a specificity of 57.1 %, PPV 2.53 and NPV 33.3.

Conclusions: The level of HbA1c greater than or equal to 6.5 % had low sensitivity and specificity for the diagnosis of DM. A lower cutoff point is insufficient to use HbA1c as a diagnostic criterion. These results are consistent with the ones of other journals.

Introducción: en 2009 se introdujo un criterio diagnóstico para la diabetes mellitus 2 (DM2) en población adulta, basado en los niveles de hemoglobina glucosilada (HbA1c) mayor o igual a 6.5 %; el punto de corte en población pediátrica podría ser menor. Se buscó determinar la utilidad de este criterio en adolescentes mexicanos con sobrepeso u obesidad. Métodos: se hizo somatometría completa, revisión del estadio de Tanner y presión arterial, glucemia, curva de tolerancia a la glucosa (CTOG) y HbA1c. Se calculó especificidad, sensibilidad, valores predictivos positivos y negativos y curva ROC para el diagnóstico de DM con HbA1c. Resultados: se estudiaron 109 pacientes entre 10 y 16 años referidos por obesidad o sobrepeso más comorbilidades, 58 % mujeres, edad 13 ± 1.74 años, IMC percentil 95.3 y HbA1c 5.73 ± 0.9 %. Se estableció el diagnóstico de DM en 9 casos (8.3 %), prediabetes en 8 (7.3 %) y tolerancia normal a la glucosa en 92 (84.4 %), el promedio de HbA1c fue de 5.6 ± 0.04, 5.7 ± 0.4 y 5.6 ± 0.73 %, respectivamente. La HbA1c mayor o igual a 6.5 % tuvo una sensibilidad de 12.5 %, especificidad de 89.8 %, VPP 10.65 y VPN 14.28. El mejor punto de corte para diagnosticar DM por curva ROC de HbA1c fue de 5.45 %, con sensibilidad de 62.5 % y especificidad de 57.1 %, VPP 2.53 y VPN 33.3. Conclusiones: el nivel de HbA1c mayor o igual a 6.5% tuvo baja sensibilidad y especificidad para diagnosticar DM. Un punto de corte menor es insuficiente para utilizar la HbA1c como criterio diagnóstico.

Keywords: Adolescent; Child; Glycosylated hemoglobin A.

Publication types

  • Clinical Trial

MeSH terms

  • Adolescent
  • Biomarkers / blood
  • Child
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / diagnosis*
  • Diabetes Mellitus, Type 2 / etiology
  • Female
  • Glycated Hemoglobin A / metabolism*
  • Humans
  • Male
  • Mexico
  • Overweight / complications
  • Pediatric Obesity / complications*
  • ROC Curve
  • Sensitivity and Specificity

Substances

  • Biomarkers
  • Glycated Hemoglobin A
  • hemoglobin A1c protein, human