Cost-effectiveness of gestational diabetes screening including prevention of type 2 diabetes: application of the GeDiForCE model in Australia

Abstract

Aims

Gestational diabetes mellitus (GDM) is associated with an increased risk of perinatal complications and of developing type 2 diabetes mellitus (T2DM). A strategy including universal screening following new evidence-based thresholds recommended by the International Association of Diabetes and Pregnancy Study Groups (IADPSG) combined with antenatal care and postpartum lifestyle management could reduce these risks. This new strategy has been endorsed by the Australasian Diabetes in Pregnancy Society (ADIPS) following evidence that showed previous diagnostic thresholds were too high to prevent perinatal adverse events (PAEs) and subsequent T2DM. This study therefore aimed to assess the cost-effectiveness of the new ADIPS GDM strategy in Australia.

Methods

A decision tree model (GeDiForCE) was applied in this study. Our analysis modifies the model and optimizes resource use and cost parameters, to reflect real costs within the Australian context. Data on Australian GDM and T2DM epidemiology, intervention costs and literature were used to estimate model parameters. Costs (in AUD $), averted disability-adjusted life years (DALYs) and net cost per DALY averted during life-time horizon were calculated. Sensitivity analyses were also conducted, by testing the impact of variations in key input variables.

Results

Compared to the previous criteria, the new ADIPS strategy costs AUD $20,671 (USD $15,839) per DALY averted in the base case, however sensitivity analyses reveal it is dominant in over half of cases and has a 86% chance of being dominant and/or cost-effective according to WTP threshold of $151,200 international dollars ($I) or $AUD 217,576 per DALY averted (equal to three times per capita GDP). Compared with no screening or treatment, the new ADIPS strategy saves AUD $25,509 (USD $19,547) per DALY averted.

Conclusions

Using local data and literature estimates, this study shows that use of the new Australian Diabetes In Pregnancy Society gestional diabetes mellitus strategy would lead to cost saving care for pregnant women in Australia when compared to a no screening scenario and is likely to be cost effective when compared to previously used criteria.

Keywords:

• GDM
• cost-effectiveness
• Australia

Disclosure statement

No potential conflict of interest was reported by the author(s).

Box 1 Comparison of current and previous ADIPS recommended criteria

IADPSG criteria (adopted by ADIPS in 2011 in “new ADIPS strategy”) – one step

The diagnosis of GDM at any time during pregnancy* should be based on any one of the following a fasting 75 g OGTT:

1. fasting plasma glucose ≥ 5.1 mmol/;

2. 1-h plasma glucose ≥ 10.0 mmol/L**;

3. 2-h plasma glucose ≥ 8.5–11.0 mmol/L.

*Recommended at first prenatal visit and at 24–28 weeks gestation

**note there are no established criteria for the diagnosis of diabetes mellitus in pregnancy based on the 1-h post-load value

ADIPS 1998 criteria – two step

Recommended morning non-fasting test (GCT) for GDM is performed at 26–28 weeks and positive results are:

1. 1-h post 50 g oral glucose load ≥ 7.8 mmol/L*; or

2. 1-h post 75 g oral glucose load ≥ 8.0 mmol/L.

After a positive screening test, confirmation of diagnosis at 26–30 weeks gestation is based on any one of the following a fasting 75 g OGTT:

1. fasting plasma glucose ≥ 5.5 mmol/L; and/or

2. 2-h plasma glucose ≥ 8.0 mmol/L.