Gestational diabetes screening with the new IADPSG guidelines: a cost-effectiveness analysis

Abstract

Objective: This study investigates the cost effectiveness of gestational diabetes mellitus screening using the new International Association of Diabetes in Pregnancy Study Group (IADPSG) guidelines.

Study design: A decision analytic model was built comparing routine screening with the 2-hour (2h) oral glucose tolerance test (OGTT) vs the 1-hour glucose challenge test. All probabilities, costs, and benefits were derived from the literature. Base case, sensitivity analyses, and a Monte Carlo simulation were performed.

Results: Screening with the 2h OGTT was more expensive, more effective, and cost effective at $61,503/quality-adjusted life year. In a 1-way sensitivity analysis, the more inclusive IADPSG diagnostic approach remained cost effective as long as an additional 2.0% or more of patients were diagnosed and treated for gestational diabetes mellitus.

Conclusion: Screening at 24-28 weeks' gestational age under the new IADPSG guidelines with the 2h OGTT is expensive but cost effective in improving maternal and neonatal outcomes. How the health care system will provide expanded care to this group of women will need to be examined.

Figure 1

The decision analytic model comparing universal screening with the 2h OGTT vs. the 1h GCT. Not all branches are shown to facilitate display. Lines that do not terminate in a triangle indicate they are collapsed to facilitate display and are the same as branches that are already open.

Figure 2

Univariate Sensitivity Analyses a. One-way sensitivity analysis of the percentage of additional GDM diagnoses with the 2h OGTT. Screening with the 2h OGTT was cost-effective (below the cost-effectiveness threshold of $100,000/QALY) as long as an additional 2.04% of patients would be diagnosed with GDM under the new IADPSG guidelines. b. One-way sensitivity analysis of the cost of 2h OGTT. Screening with the 2h OGTT was cost-effective as long as the cost of the 2h OGTT was less than $175.74. c. One-way sensitivity analysis of the cost of GDM treatment. Screening with the 2h OGTT was cost-effective as long as the cost of GDM treatment was less than $1971. d. One-way sensitivity analysis of the efficacy of treatment. Screening with the 2h OGTT was cost-effective as long as treatment met more than 74.9% of its reported treatment efficacy.

Figure 3

Two-Way Sensitivity Analyses a. Two-way senstitivity analysis on the cost of the 1h GCT vs. the cost of the 2h OGTT. The blue-hatch region represents where screening with the 2-h OGTT is cost effective (below the cost-effectiveness threshold of $100,000/QALY). The model remained cost-effective at an incremental cost for the 2h OGTT over the 1h GTT of less than $92.56 b. Two-way senstitivity analysis on the percent efficacy of treatment vs. the cost of GDM treatment. The blue-hatch region represents where screening with the 2h OGTT is cost effective. At the baseline GDM treatment cost of $1971, 2h OGTT screening was cost effective with treatment efficacy as low as 74.9%. At 100% efficacy, the cost of GDM treatment can be as high as $2630 and still be cost-effective. c. Two-way senstitivity analysis on the probability of preeclampsia in Group 2 with vs. without treatment. Screening with the 2h OGTT was cost-effecive as long as the incremental reduction in preeclamsia was greater than 0.55% in Group 2 as a result of GDM diagnosis and treatment d. Two-way senstitivity analysis on the probability of cesarean section in Group 2 with vs. without treatment. Screening with the 2h OGTT was cost-effective as long as the incremental reduction in cesarean section was greater than 2.7% as a result of GDM diagnosis and treatment.

Figure 4

Monte Carlo simulation of 10,000 random women showing there is a 75.7% probability that treatment is cost-effective at a threshold of $100,000/quality-adjusted life year.