Obeziteli Çocuklarda Glikoz Metabolizma Bozukluklarının Erken Tespitinde HbA1c ve 1. Saat OGTT Plazma Glukoz Düzeyi OGTT'nin Yerini Alabilir mi?

Abstract

Amaç: Bu çalışmanın amacı, obeziteli çocuk ve ergenlerde glukoz metabolizma bozuklğunu (prediyabet veya diyabet) belirlemede HbA1c ve 1. Saat OGTT glukoz düzeylerinin tanısal performansını değerlendirmek ve karşılaştırmaktır. Gereç ve Yöntemler: Çalışmaya, Nisan 2021 ile Eylül 2025 tarihleri arasında OGTT yapılmış olan 6-18 yaş arası obeziteli çocuklar çalışmaya dahil edilmiş olup, çalışma grubu toplam 98 olgudan oluşmaktadır. Katılımcılar Amerikan Diyabet Birliği (ADA) kriterlerine göre Normal glukoz metabolizması grubu (NGM, n=55) ve prediyabet (n=36) ile diyabetes mellitusu (n=7) içeren Glukoz metabolizma bozukluğu grubu (GMB, n=43) olarak iki gruba ayrılmıştır. Antropometrik ve biyokimyasal parametreler gruplar arasında uygun parametrik veya nonparametrik testler kullanılarak karşılaştırılmıştır. HbA1c ve 1. Saat OGTT plazma glukozunun (≥155 mg/dL) GMB'yi saptamadaki tanısal performansı, alıcı işletim karakteristiği (ROC) eğrisi analizi, duyarlılık, özgüllük ve OGTT'ye dayalı tanı ile uyum Cohen’s kappa testi kullanılarak değerlendirilmiştir. Bulgular: BMI SDS, GMB grubunda NGM grubuna kıyasla anlamlı derecede daha yüksekti (2,6 ± 1,5'ye karşı 2,1 ± 1,4, p = 0,012). 1. Saat OGTT plazma glukoz düzeyi, GMB'yi belirlemede mükemmel ayırt edici yetenek göstermiş (AUC = 0,835, p < 0,001), ≥155 mg/dL eşik değerinde %65,1 duyarlılık ve %87,3 özgüllük sağlamıştır. Buna karşılık, HbA1c GMB için zayıf bir ayırt edici yetenek göstermiştir (AUC = 0,598, p = 0,080). 1. saat OGTT plazma glukozu ile OGTT'ye dayalı tanı arasındaki uyum orta düzeydeyken (κ = 0,47, p < 0,001), HbA1c için istatistiksel olarak anlamlı bir uyum saptanmamıştır (κ = 0,136, p = 0,146). Sonuç: Obez çocuklarda, 1. saat OGTT plazma glukoz düzeyi, HbA1c'ye kıyasla glukoz metabolizma bozukluklarını belirlemede daha duyarlı ve doğru bir belirteçtir. Yüksek riskli pediatrik popülasyonların değerlendirmesinde 1. saat glukoz ölçümünün dahil edilmesi, disgliseminin daha erken saptanmasını kolaylaştırabilir.

Keywords

• HbA1c
• 1 saatlik OGTT glukozu
• OGTT
• Prediyabet
• Çocukluk çağı obezitesi
• ROC analizi

Supporting Institution

Bu araştırma kamu, ticari veya kâr amacı gütmeyen sektörlerdeki herhangi bir fon kuruluşundan özel bir hibe almamıştır.

Ethical Statement

Bu çalışma Zonguldak Bülent Ecevit Üniversitesi Klinik Araştırmalar Etik Kurulu tarafından onaylanmış olup Helsinki Deklarasyonu etik standartlarına uyulmuştur (onay tarihi: 1 Ekim 2025; onay numarası: 2025/17).

Thanks

Çalışmaya katılan çocuklar ve ailelerine teşekkür ederiz. Rutin klinik ve laboratuvar süreçlerde görev alan ilgili birimlere katkılarından dolayı teşekkür ederiz.

Can HbA1c and 1-Hour Glucose Replace OGTT in Obese Children in Early Detection of Glucose Metabolism Disorders?

Abstract

Aim: This study aims to evaluate and compare the diagnostic performance of HbA1c and 1-hour plasma OGTT glucose levels for identifying glucose metabolism disorders (prediabetes or diabetes) in obese children and adolescents. Material and Methods: Children aged 6–18 years with obesity who underwent OGTT between April 2021 and September 2025 were included, yielding a total of 98 cases in the study cohort. Participants were primarily categorized according to American Diabetes Association (ADA) criteria into two main groups: Normal glucose metabolism (NGM, n=55) and Glucose metabolism disorder (GMD, n=43), which included both prediabetes (n=36) and diabetes mellitus (n=7). Anthropometric and biochemical parameters were compared between groups using appropriate parametric or nonparametric tests. The diagnostic performance of HbA1c and 1-hour OGTT-PG (≥155 mg/dL) for detecting GMD was evaluated using receiver operating characteristic (ROC) curve analysis, sensitivity, specificity, and agreement (Cohen’s kappa) with the OGTT-based diagnosis.. Results: BMI SDS was significantly higher in the GMD group compared to the NGM group (2.6 ± 1.5 vs. 2.1 ± 1.4, p = 0.012). The 1-hour OGTT-PG level showed excellent discriminative ability for identifying GMD (AUC = 0.835, p < 0.001), with a sensitivity of 65.1% and specificity of 87.3% at the ≥155 mg/dL cut-off. In contrast, HbA1c demonstrated weak discriminative ability for GMD (AUC= 0.598, p = 0.080). Agreement between 1-hour OGTT-PG and OGTT-based diagnosis was moderate (κ = 0.47, p < 0.001), whereas HbA1c alone did not show statistically significant concordance (κ = 0.136, p = 0.146). Conclusion: In children with obesity, the 1-hour OGTT-PG level is a more sensitive and accurate marker for identifying glucose metabolism disorders than HbA1c. Incorporating the 1-hour OGTT-PG measurement into the assessment of high-risk pediatric populations may facilitate the earlier detection of dysglycemia.

Keywords

• HbA1c
• 1-hour OGTT-PG
• OGTT
• Prediabetes
• Pediatric obesity
• ROC analysis

Supporting Institution

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Ethical Statement

This study was approved by the Zonguldak Bulent Ecevit University Clinic Research Ethics Committee and adhered to the ethical standards of the Declaration of Helsinki (approval date: October 1, 2025; approval number: 2025/17).

Thanks

We thank the children and their families for their participation. We also acknowledge the assistance of departments responsible for routine laboratory and clinical evaluations.

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