AIMS/INTRODUCTION This study aimed to estimate the prevalence of gestational diabetes mellitus (GDM) and use of anti-diabetic medications for patients with GDM in Korea, using data of the period 2007-2011 from the Health Insurance Review and Assessment (HIRA) database, which includes the claims data of 97% of the Korean population.

MATERIALS AND METHODS We used the Healthcare Common Procedure Coding System codes provided by the HIRA to identify women with delivery in the HIRA database between 2009 and 2011. GDM was defined according to ICD-10 codes, and patients with pre-existing diabetes between January 1, 2007 and pregnancy were excluded. A Poisson regression was performed to evaluate the trends in annual prevalence rates.

RESULTS The annual numbers of deliveries in 2009-2011 were 479,160 in 2009, 449,747 in 2010, and 377,374 in 2011. The prevalence of GDM during that period was 7.5% in 2009-2011: 5.7% in 2009, 7.8% in 2010, and 9.5% in 2011. The age-stratified analysis showed that the prevalence of GDM was highest in women aged 40-44 years, at 10.6% in 2009-2011, and that the annual prevalence significantly increased even in young women aged 20-29 years during that period (P < 0.05). More than 95% of the patients with GDM did not take any anti-diabetic medication. Among the anti-diabetic medications prescribed for patients with GDM, insulin was most commonly prescribed (for >98% of the patients with GDM on medication).

CONCLUSIONS The prevalence of GDM in Korean women recently reached 5.7-9.5% in recent years. This represents a public health concern that warrants proper screening and medical care for GDM in women during the childbearing years.