Prevalence of gad antibodies in gestational diabetes mellitus and its correlation with postpartum diabetes mellitus

Malihe Mohammadi,1,* Farnoosh farzam,2

1. Department of biology, Faculty of basic science, University of Sistan and Baluchestan
2. Department of biology, Faculty of basic science, University of Sistan and Baluchestan

Abstract

Introduction

Gestational diabetes mellitus (gdm) refers to any degree of glucose intolerance that is first diagnosed during pregnancy. the prevalence of gdm have been reported between 1 to 14% among pregnant women, due to factors including the population studied, diagnostic criteria, the ethnic and racial characteristics. gestational diabetes is associated with adverse maternal and neonatal outcomes and some women with gdm develop diabetes in the future. although gdm shares many features with type 2 diabetes, some studies have shown that a variable percentage of women with gdm develop specific autoantibodies towards pancreatic β-cell. among various autoantibodies, glutamic acid decarboxylase autoantibody (gada) was the most common reported single autoantibody in women with gdm. presence of mentioned antibodies in gdm has a high positive predictive value for type 1 diabetes after delivery. various studies have shown gada positive women more frequently require insulin to treat their diabetes during pregnancy. however, there have been no studies carried out regarding the prevalence of gad antibodies during gdm and relation between the possession of it and the frequency of develop diabetes after pregnancy in iran. therefore, the aim of this study was to assess the prevalence of gad autoantibody during pregnancy and to estimate the later development of diabetes after delivery.

Methods

147 female patients diagnosed with gdm and 147 control healthy pregnant women were selected and gada assessment was used for diagnosis autoimmune patients. gad antibodies were determined in all women with gestational diabetes using isletest gad diagnostic kit (diametra co., italy). also the need for insulin therapy during and after gdm was recorded. in post pregnancy follow-up, the prevalence of diabetes in these groups was determined. the classification of diabetes was done according to the guidelines of the american diabetes association. this study is carried out in a teaching hospital and primary health centers in torbat–e heydarieh city (razavi khorasan province, iran). all statistical analyses were performed with statistical package for social science (spss) 16.0 and p < 0.05 was considered as statistically significant level.

Results

Of 147 women with gdm, 9 ones (6.1%) were gada positive. during pregnancy 14.3% (21 of 147) of the women with gdm were treated with insulin. of these, 5 women were autoantibody positive and 16 ones were gada negative. therefore gada positive women with gdm required more frequent insulin therapy than gada negative women (55.6% vs 11.6%). 33.3% of gdm that treated with insulin (7 of 21) developed diabetes after pregnancy. of all women with gdm one woman (0.7%) developed type 1 diabetes and 7 subjects (4.8%) developed type 2 diabetes in follow-up. none of the gada negative women developed type 1 diabetes after pregnancy but 2.9% (4 of 138) of them developed type 2 diabetes, while in autoantibody positive group, 33.3% (3 of 9) developed type 2 diabetes and 11.1% (1 of 9) developed type 1 diabetes after delivery.

Conclusion

In different studies has been reported that the frequency of gad autoantibodies in gdm ranges between 0 to 38%. in this study prevalence of gada in gdm was 6.1% that is conformably to other studies of world. our data showed that the presence of gad antibodies in gdm is related with need for insulin therapy during pregnancy and can increases the risk of developing diabetes in the future. therefore, in order to faster and better treatment of patients, screening of autoantibodies in women with gdm and post-pregnancy follow-up can be useful for early diagnosis of diabetes.

Keywords

Gestational diabetes mellitus, diabetes mellitus, glutamic acid decarboxylase antibodies, prevalence