Pre-gestational versus gestational diabetes: A population based study on clinical and demographic differences

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Abstract

Aims

To assess the clinical and demographic differences in patients with pre-gestational diabetes mellitus (PGDM) compared to those with gestational diabetes (GDM).

Methods

Using the 2001–2007 California Health Discharge Database, we identified 22,331 cases of PGDM and 147,097 cases of GDM via ICD-9-CM codes after excluding cases which were missing race or age data or with extremes of age. Data analyzed included demographics, pre-existing medical conditions, antepartum complications, and intrapartum complications. Logistic regression was used to adjust for potential confounders.

Results

Both PGDM and GDM incidences increased during the study period. Advancing age was associated with increased prevalence of both diseases. Although Asians were found to have the highest prevalence of GDM, they, along with Caucasians, were found have the lowest prevalence of PGDM.

Conditions with increased frequency in PGDM versus GDM included chronic hypertension, renal disease, thyroid dysfunction, fetal CNS malformation, fetal demise, pyelonephritis, and eclampsia. Subjects with PGDM were more likely than those with GDM to have a shoulder dystocia, failed induction of labor, or undergo cesarean delivery.

Conclusions

We have demonstrated clinical morbidities and demographic factors which differ in patients with PGDM compared to patients with GDM. Our findings suggest PGDM to be associated with significantly higher morbidity when compared to GDM. Our findings also suggest that races with the highest tendency for GDM during pregnancy may not necessarily have the highest tendency for PGDM outside of pregnancy.

Introduction

Diabetes complicates approximately 6%–7% of pregnancies in the United States, with California demonstrating a similar prevalence of 7.6% (Lawrence, Contreras, Chen, & Sacks, 2008). Approximately 85% are attributed to gestational diabetes mellitus (GDM), while the remaining are due to pre-gestational diabetes mellitus (PGDM) (Wier, Witt, Burgess, & Elixhauser, 2006).

GDM is currently defined by the American Diabetes Association as “any degree of glucose intolerance with onset or first recognition during pregnancy”(Diagnosis & classification of diabetes mellitus, 2012). The pathogenesis is typically attributed to insulin resistance during pregnancy due to factors such as human placental lactogen and tumor necrosis factor alpha (Metzger et al., 2008, Vambergue et al., 2002). PGDM, on the other hand, includes both type I and type 2 diabetes mellitus (DM) occurring prior to pregnancy.

Previous studies have reported on morbidities of both PGDM and GDM in pregnancy which include fetal macrosomia, neonatal hypoglycemia, perinatal mortality, polyhydramnios, and increased risk of cesarean delivery (American Diabetes Association, (2004), Macintosh et al., 2006, Persson et al., 2009). However, few studies have looked at direct comparisons of morbidity between subjects with PGDM and GDM. Given PGDM’s ability to affect the maternal–fetal dyad at an earlier gestational age, we hypothesize that there will be increased morbidity of PGDM when compared to GDM in all periods of pregnancy (pre-pregnancy, antepartum, and delivery). We also postulate that there will be certain racial predilections towards developing GDM and PGDM. We hypothesize that our results will confirm advancing maternal age to be associated with an increased risk of both conditions. Finally, we believe that incidences of both diseases have increased over time.

The objective of this study was to compare the trends, demographic factors and maternal morbidity between women with GDM versus those with PGDM using a California population cohort.

Section snippets

Patients and methods

This is a retrospective study using health discharge data for all deliveries during 2001–2007 in California. The dataset, provided by the California Office of Statewide Health Planning and Development (OSHPD), is a publicly available dataset comprising cases where a patient is treated in a licensed general acute care hospital in California. Information regarding demographics, diagnoses, specific procedures undergone, and details regarding the patient’s stay, such as source of funding, length of

Results

The prevalence of GDM was 5.34% while PGDM prevalence was 0.82% during the study period. As seen in Fig. 2, both conditions increased over time, even after age adjustment. PGDM increased from 0.69% in 2001 to 0.86% in 2007. GDM increased from 4.40% in 2001 to 6.41% in 2007. The mean maternal age of the entire study population was 31.14 ± 5.71 years standard deviation (SD), with 33.82% of all subjects being of advanced maternal age (age > 35 years).

The baseline characteristics for the 169,428 diabetic

Discussion

Our results demonstrate that both PGDM and GDM differ in several aspects — age distribution, race/ethnicity, and associations with clinical morbidities. Both diseases have increased over time, highlighting the need to investigate possible population-based clinical and demographic interactions.

Our study, to our knowledge, is the first to investigate the increased morbidity of PGDM compared to GDM using a large population. El Mallah et al. described that GDM and PGDM were similar in maternal,

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  • Cited by (0)

    The authors report no conflict of interest.

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