Correlation Between Glycated Hemoglobin and Homa Indices in Type 2 Diabetes Mellitus: Prediction of Beta-Cell Function from Glycated Hemoglobin

Summary Background: The present study aimed to determine the most efficient insulin resistance function related to gly - cemic control expressed as glycated hemoglobin (HbA1c) in type 2 diabetes mellitus patients (T2DM). The other aim is to derive equations for the prediction of beta cell functions containing HbA1c as a parameter in addition to fasting glucose and insulin. Methods: T2DM Patients were grouped according to the following: (1) degree of control (good, fair, and poor control) and (2) insulin resistance as observed in obtained data and significant differences revealed by the homeostasis model assessment (HOMA) of related parameters (insulin resistance = HOMA2IR, beta-cell function = HOMA%B, and in sulin sensitivity = HOMA%S) among groups. Corre - lations and forecasting regression analysis were calculated. Results: HbA1c was found to be correlated with insulin resistance parameters in T2DM subgroups. This correlation was also significantly correlated with HOMA%B and the quantitative insulin sensitivity check index (QUICKI) in fair and poor control groups. Regression analysis was used to predict the forecasting equations for HOMA%B. The best applicable equations were derived for healthy control (HOMA2%B=-1.76*FBG+5.00*Insulin+4.69*HbA1c+189.84) and poor control groups (HOMA2%B=0.001* FBG+0.5*Insulin-8.67*HbA1c+101.96). These equations could be used to predict b-cell function (HOMA%B) after FBG, insulin and HbA1c values were obtained for healthy and poor control groups. In the good and fair control groups, the applicability of the HOMA model fails to yield appropriate results. Conclusions: Beta-cell function is correlated with QUICKI and HbA1c and could be predicted properly from HbA1c, insulin, and glucose in the healthy and poor control groups. New regression equations were established that involve HbA1c. Kratok sadržaj Uvod: Cilj ove studije bio je da se odredi najefikasnija funk- cija insulinske rezistencije u odnosu na glikemijsku kontrolu izraženu kroz glikolizirani hemoglobin (HbA1c) kod obolelih od dijabetes melitusa tipa 2 (T2DM). Drugi cilj bio je da se izvedu jednačine za predviđanje funkcije beta ćelija koje, po- red glukoze natašte i insulina, kao parametar sadrže HbA1c. Metode: Pacijenti sa T2DM grupisani su prema sledećim obeležjima: (1) stepenu kontrole (dobra, zadovoljavajuća i slaba kontrola) i (2) insulinskoj rezistenciji utvrđenoj na osno- vu dobijenih podataka i značajnih razlika između grupa otkri- venih pomoću procene modela homeostaze (HOMA) srod- nih parametara (insulinske rezistencije - HOMA2IR, funkcije beta ćelija - HOMA%B i osetljivosti na insulin - HOMA%S). Korelacije i predikciona regresiona analiza su izračunate. Rezultati: Utvrđeno je da je HbA1c bio u korelaciji sa para- metrima insulinske rezistencije u podgrupama sa T2DM. Ova korelacija takođe je značajno korelisana sa HOMA%B i indeksom QUICKI (kvantitativni indeks insulinske osetljivosti) u grupama sa zadovoljavajućom i slabom kontrolom. Re- gresiona analiza je upotrebljena za predviđanje predikcionih jednačina za HOMA%B. Najprimenljivije jednačine izve- dene su za grupu zdravih kontrolnih subjekata (HOMA2%B =-1,76*FBG+5,00*insulin+4,69*HbA1c+189,84) i grupu sa slabom kontrolom (HC>MA2%B=0,001*FBG+0,5*in- sulin-8,67*HbA1c+101,96). Ove jednačine mogle su se upotrebiti za predviđanje funkcije beta ćelija (HOMA%B) pošto su dobijene vrednosti FBG, insulina i HbA1c za zdravu grupu i grupu sa slabom kontrolom. U grupama sa dobrom i zadovoljavajućom kontrolom pokušaj primene modela HOMA nije dao odgovarajuće rezultate. Zaključak: Funkcija beta ćelija koreliše sa QUICKI i HbA1c i može se pravilno odrediti na osnovu HbA1c, insulina i glukoze u zdravoj grupi i grupi sa slabom kontrolom. Usta- novljene su nove regresione jednačine koje uključuju HbA1c.