Cost-effectiveness of lifestyle counselling as primary prevention of gestational diabetes mellitus: findings from a cluster-randomised trial.

AIMS: The aim was to evaluate the cost-effectiveness of primary prevention of gestational diabetes mellitus (GDM) through intensified counselling on physical activity, diet, and appropriate weight gain among the risk group. MATERIALS AND METHODS: The cost-effectiveness analysis was based on data from a cluster-randomised controlled GDM prevention trial carried out in primary health-care maternity clinics in Finland. Women (n = 399) with at least one risk factor for GDM were included. The incremental cost-effectiveness ratio (ICER) was calculated in terms of birth weight, 15D, and perceived health as measured with a visual analogue scale (VAS). A bootstrap technique for cluster-randomised samples was used to estimate uncertainty around a cost-effectiveness acceptability curve. RESULTS: The mean total cost in the intervention group was €7,763 (standard deviation (SD): €4,511) and in the usual-care group was €6,994 (SD: €4,326, p = 0.14). The mean intervention cost was €141. The difference for costs in the birth-weight group was €753 (95% CI: -250 to 1,818) and in effects for birth weight was 115 g (95% CI: 15 to 222). The ICER for birth weight was almost €7, with 86.7% of bootstrap pairs located in the north-east quadrant, indicating that the intervention was more effective and more expensive in birth weight terms than the usual care was. The data show an 86.7% probability that each gram of birth weight avoided requires an additional cost of €7. CONCLUSIONS: Intervention was effective for birth weight but was not cost-effective for birth weight, 15D, or VAS when compared to the usual care. TRIAL REGISTRATION: ISRCTN 33885819